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1. 7272272 53 5 5 2 5 ANN 53727225422 53 5 5 YNY YYY SSSAAA AAN A 2 2 01 ev NAIINSSSISAZLZISSSISSSNSSSSSSSIEINZZINSS BNISNVETN SISSSISNSSNAZZULINSSSILNSNuvSNISNSSSvedcS AISNSINVINAVINANA4ISBSINZINZISSNESSSSNSNSSSSSZLZA ZINZBSSINNSSNSN INN NAN ININ ZAIN ANN NAINA NINN VAVAVAVAVAVAVAVAVAVAVAVA VAIN AVA VA VAVAVA IS ISS ISIS ANNNYN YNNYNY Y YANNYY Y YY NSN AA AAAY NNNYNY VINNY AVN VANE VAY VAY NNAINE AVIVA YN 535 55727272 597272 53 53 53 53 522 YAAN NNN YNY ANY YANAN YNY SY NN A VISNSSINSSINZLZPZINSNSSSALZINSSSL LINSSSNdNxevecebSSS IN NA LINAZVINZISNSSNVNINSNSVINZISBSSNCINZSSSNAZSSSNASNSSINS ENNN PSSSISSSSSSSSSSAZISSSSSSABSSSZISSSENSSSSSUAN EEE KEK EEE VAVAVAVAVAVAVAVAVAVAVAVAVAVA Figure 34 The downstream part of TIN file in detail 70 Figure 35 The TIN file with pit cells flat triangles and flow direction in Watershed SB10 11 Soil type and land use data are featured GIS data They can be created by drawing a few polygons an
2. 5000 H H H H H H H 0 10 20 30 40 50 60 70 90 80 Figure 56 The travel time and contributing area diagram for Down_Stream7 7 5 2 ISO UH derivation After the isochrone diagram is obtained the outflow of the sub watershed can be obtained by routing the isochrone diagram through a linear reservoir Clark 1945 Singh 1988 whose storage constant is the time of concentration of the sub watershed T can be estimated by multiplying the largest travel time of the sub watershed by 0 75 Suppose the average inflow of the sub watershed is 7 at time interval the outflow at the beginning ant the end of time interval is O and O then the average outflow of at 0040 time interval t is The outflow of at the end of time interval t can be calculated using Equation 7 4 D C D 7 4 where Cy and can be calculated by Equation 7 5 and Equation 7 6 At 7 5 T 0 5 At 9 C 1 7 6 where 7 time of concentration At time interval of the unit hydrograph Equation 7 4 Equation 7 5 and Equation 7 6 can also be derived from Equation 2 18 Equation 2 18 and Equation 2 18 by assigning X 0 in cubic foot per second is calculated by J 1 inch x contributing area of time t ff 12 inch ft 600 104 sec t 0 be assumed to be 0 With this information we
3. 143 4 146 151 6 ADD 154 LEVELPOOLL E sissssssssiasssissccsosssncousnasnsascunsseseosanncateanseiceeuaessasennssesassannisionvsonse 159 KINEMATIC WAVE FE D Kn ap SD DER 164 APPENDIX B USER S MANUAL 168 169 B 1 WATERSHED tasas tn sensn sensns 170 B 2 55 171 DIMENSIONLESS UNIT HYDROGRAPH DUH GENERATION 172 SUB WATERSHED HYDROGRAPH 172 BS MUSKINGUM 173 B 6 HYDROGRAPH ADDITION eere rentes tn sensa sensn sensn 174 7 RESERVOIR ROUTINCG IK NER 175 B S KINEMATIC ROUTING 176 MASTER 177 B10 HWM EXECUTION 177 BIBLIOGRAPHY
4. 40 39 JOB CONTROL SETTING 41 310 DISPLAY OUTPUT sccsscssscssavsissssasessonesonsscsessusssvisesisanssonssnsssessuarsacenssensensisessens 42 311 EVALUATION OF PARAMETER INFLUENTCE eerte 42 4 0 1 99 ENVIRONMENTAL RESEARCH OVERVIEW 44 41 PROJECT INTRODUCTION weno nian 44 42 PROJECT COMPONENTS 46 4 2 1 Task A Evaluation of erosion and sediment controls 46 4 2 2 Task Hydrologic monitoring and modeling 47 4 2 3 Task C Monitoring and assessment of wetland hydro biological iili 51 4 2 4 Task Evaluation of stream restoration rehabilitation and iugi 52 5 0 DIFFICULTIES IN MODEL BUILDING eeeeee eee enne 53 5 1 DIFFICULTIES STATEMENT 53 52 WATERSHED DELINEATION FOR A LARGE NATURAL WATERSHED A O 55 5 2 1 Importing DEM 55 5 2 2 Computing flow direction cu nnsnnii ati Rp EM MD UHR PIB IEEE PIN REM MM M 56 5 2 3 Determining the outlet point and stream feature arcs
5. 179 LIST OF TABLES Table 1 Classification of antecedent moisture condition 11 Table 2 The relationship between important model parameters and model results 42 Table 3 Runoff Rainfall Ratio for Each Storm Event in Watershed Two 85 Table 4 Watershed parameters for Watershed Two Oct 07 2005 86 Table 5 Routing Parameters for Watershed Two Oct 07 2005 86 Table 6 CN for each land use for Watershed Two Oct 07 2005 86 Table 7 Curve Number for Watershed Two Oct 25 2005 87 Table 8 CN for each land use for Watershed Two Oct 25 2005 87 Table 9 The comparison of the three criteria in two events for Watershed Two 90 Table 10 Coefficients of velocity ft s versus slope 96 relationship for estimating travel VELOCES P NUR SR 99 Table 11 The travel time and contributing area for Right Highway 101 Table 12 Important parameters used in specific storm 114 Table 13 The comparison of the three criteria for Watershed 120 Table 14 Up Stream sub watershed and AMC for eight events in WMS 1
6. 16 25 LUMPED CHANNEL 17 2 6 TOPOGRAPHICALLY BASED BASE FLOW MODELING 19 27 SIMPLER LUMPED BASED FLOW 1 23 28 GIS BASED WATERSHED 24 3 0 GIS BASED HYDROLOGICAL MODEL WMS APPROACH 29 31 WMS INTRODUCTION 29 32 COORDINATE SYSTEM SETTING AND CONVERSION 29 33 SOURCE DATA IMPORTING AND CREATING cerent 30 34 WATERSHED 31 35 DRAINAGE COMPONENT 33 3 6 IMPORTING AND CREATING OF LAND USE AND SOIL DATA 34 37 WATERSHED INFORMATION AND CALCULATION METHOD 37 3 7 1 Basin Gata 37 3 7 2 iq 38 3 7 3 Loss 39 3 7 4 Unit hydrosraph method 40 38 CHANNEL AND RESERVOIR
7. G Revised proposal work plan and costs I 99 Environmental Research RFQ Number 03 02 C07 Unpublished project proposal 2004 Quinn P F The roll of digital terrain analysis in hydrological modeling Unpublished Ph D dissertation Lancaster University U K 1991 182 Quinn and Beven J Spatial and temporal prediction of soil moisture dynamics runoff variable source areas and evapotranspiration for Plynlimon mid Wales Hydrol Process Vol 7 pp 425 448 1993 Rawls W J D L Brakensiek and N Miller Green Ampt infiltration parameters from soils data J Hydraul Div Am Soc Civ Eng Vol 109 No 1 pp 62 70 1983 Shamsi U M GIS Applications for Water Wastewater and Stormwater Systems CRC Press 2005 Shamsi U M GIS Tools for Water Wastewater and Stormwater Systems ASCE Press Reston VA 2002 Sherman L K Streamflow from rainfall by the unit hydrograph method Eng News Record 108 501 505 1932 Singh V P Hydrologic Systems Rainfall runoff Modelling Vol I Prentice Hall Englewood Cliffs NJ 1988 Soil Conservation Service National Engineering Handbook section 4 Hydrology U S Dept of Agriculture Washington D C 1972 Soil Conservation Service Urban hydrology for small watersheds tech rel no 55 U S Dept of Agriculture Washington D C 1975 Swensson M T Refinements on a GIS based spatially distributed rainfall runoff
8. 20 21 51 Q1 are the initial storage and outflow of the reservoir INITIAL is the initial elevation of the reservoir INTERV is 5 min 2 300 sec REAL INTERV INITIAL S1 Q1 Y 1 100 INDEX and J are indices RESNUM is the reservoir number SBWSNUM is the sub watershed number FLAG is an indicator RESINTERVAL is the reservoir s character s interval numbers INTEGER INDEX J SBWSNUM RESNUM FLAG RESINTERVAL CHARACTER 20 X 1 100 20 BEFORE AFTER DISCHARGE STORAGE ELEVATION RELATIONSHIP The following characters are file name representatives OPEN 31 FILE PARAMETER TXT STATUS OLD DO 20 J 1 100 READ 31 END 21 X J Y J CONTINUE LINE J 1 CLOSE 31 STATUS KEEP SBWSNUM Y 69 RESNUM Y 70 INITIAL Y 71 INTERV 300 Select the file to read IF SBWSNUM EQ 1 THEN BEFORE HYDRO_1 TXT AFTER RHYDRO 1 TXT ENDIF IF SBWSNUM EQ 2 THEN BEFORE HYDRO 2 TXT AFTER RHYDRO 2 TXT ENDIF IF SBWSNUM EQ 3 THEN BEFORE HYDRO 3 TXT AFTER RHYDRO 3 TXT ENDIF IF SBWSNUM EQ 4 THEN BEFORE HYDRO 4 TXT AFTER RHYDRO 4 TXT ENDIF IF SBWSNUM EQ 5 THEN BEFORE HYDRO 5 TXT AFTER RHYDRO 5 TXT ENDIF IF SBWSNUM EQ 6 THEN BEFORE HYDRO 6 TXT AFTER RHYDRO 6 TXT ENDIF IF SBWSNUM EQ 7 THEN BEFORE HYDRO 7 TXT AFTER RHYDRO_7 TXT ENDIF IF SBWSNUM EQ 8 THEN BEFORE HYDRO 8 TXT AFTER RHYDRO 8 TXT 160 ENDIF IF SBWSNUM EQ 9 THEN BEFORE HYDRO 9 TXT AFTER RHYDRO 9 TXT ENDIF IF SBWSNUM EQ
9. Up Left Right Right Right Right Down Stream Highway Highwayl Highway2 Highway3 Highway4 Stream n 11 52 6 4 7 68 7 04 5 76 3 84 3 84 acre Hos 658 804 75 7 78 7 78 3 812 65 Basin 785 44 843 19 84434 932 45 744 28 575 51 663 68 length ft Overland 9 993 0 02 0 01 0 01 0 01 0 01 0 02 slope There are five outlet channel flow routings Their parameters are listed in Table 5 Table 5 Routing Parameters for Watershed Two Oct 07 2005 Event WV ft s NSTPS AMSKK hr X hr Up_ Stream N A because diversion pipe is used Left 0 0016 80 6 577 0 2 Rightl 0 0016 73 6 029 0 2 Right2 0 0016 121 9 979 0 2 Right3 0 0016 145 12 028 0 2 Right4 0 0016 111 9 167 0 2 Final N A because no routing at the final outlet where WV The water velocity in the channel NSTPS The number of integer steps for the Muskingum routing AMSKK Muskingum coefficient in hours for the reach Channel Length WV X Muskingum X coefficient for the reach The curve numbers for each land use type are listed in Table 6 Table 6 CN for each land use for Watershed Two Oct 07 2005 Event Index Land use name CN value for Soil Type D 0 Up Stream 65 1 Highway 90 2 Down Stream 65 3 Highway Sides 70 86 6 5 2 Parameters for Watershed Two Oct 25 2005 Event Like in Oct 07 2005 Event rainfall distribution and
10. a Figure 41 Half hour incremental rainfall for eight storm events a From Oct 07 to Oct 10 2005 Total rainfall depth 2 90 inch 79 Half hr rainfall inch Half hr rainfall inch 0 07 0 06 0 05 0 04 0 03 0 02 0 01 0 0 35 0 3 0 25 0 2 0 1 0 05 Oct 25 2005 Half Hour Incremental Rainfall 0 12 24 36 48 60 72 84 96 108 120 Time Hr since 00 00 Oct 25 2005 Figure 41 b Half hour incremental rainfall from Oct 25 to Oct 29 2005 Total rainfall depth 0 64 inch Nov 27 2005 Half Hour Incremental Rainfall o 12 24 36 48 60 72 84 Time Hr since 00 00 Nov 27 2005 Figure 41 c Half hour incremental rainfall from Nov 27 to Dec 02 2005 Total rainfall depth 2 80 inch 80 Half hr rainfall inch Half hr rainfall inch 0 25 0 2 0 15 0 1 0 05 0 45 0 12 24 36 48 60 72 84 96 108 120 132 14 0 4 0 35 0 3 0 25 0 2 0 15 0 1 0 05 0 Jan 17 2006 Half Hour Incremental Rainfall 0 24 48 72 o6 120 144 Time Hr since 00 00 Jan 17 2006 Figure 41 d Half hour incremental rainfall from Jan 17 to Jan 22 2006 Total rainfall depth 1 70 inch Mar 11 2006 Half Hour Incremental Rainfall 4 Time Hr since 00 00 Mar 11 2006 Figure 41 Half hour incremental rainfall from Mar 11 to Mar 16 2006
11. 58 5 2 4 Defining the watershed boundary eeeee eee eren eerte enne 59 5 2 5 Creating Sub watersheds sscccsscocssssssssssssssscsssssesssssesssssssssssesssasesses 60 53 1 99 DEM DATA 61 54 WATERSHED DELINEATION IN I 99 BASED ON DEM DATA 65 55 TOPOGRAPHICAL ANALYSIS BASED ON TIN 69 6 0 I 99 ENVIRONMENTAL RESEARCH CASE 72 6 1 MODEL ASSEMBLY FOR WATERSHED ONE eerte 73 62 MODEL ASSEMBLY FOR WATERSHED 76 vi 63 MODELED RAINFALL 79 64 PARAMETER SELECTION AND MODEL CALIBRATION 83 65 PARAMETERS FOR WATERSHED 85 6 5 1 Parameters for Watershed Two Oct 07 2005 Event 85 6 5 2 Parameters for Watershed Two Oct 25 2005 Event 87 6 6 WMS RESULTS FOR WATERSHED TWO eeeeeeee reete tn nen tnnn 87 6 6 1 Watershed Two Event of Oct 07 2005 88 6 6 2 Watershed Two Event of Oct 25 2005 89 67 ANALYSIS OF WMS RESULTSS reete eee eee eese teens seasons tasse tasas enono 89 7 0 HIGHWAY WATERSHED MODEL HWM D
12. Down_Stream A 0 01 mi 2 Right_Highway1 Soil type data file A 0 01 mi 2 A 0 01 mi 2 Up_Stream 002 mi 2 Land use data file Figure 38 Schematic layout for Watershed Two 77 Right Highwayl respectively Their characteristics are obtained from pond designer and are displayed in Figure 39 and Figure 40 The last sub watershed Down Stream is located at the bottom of the whole watershed Water from this part is clean water and flows directly to the final outlet Each sub watershed has an outlet The outlet names of the sub watershed are UpStrm Left Rightl Right2 Right3 Right4 and Final respectively Because water from Up Stream flows directly to the Final outlet a water diversion and return is used in UpStrm routing Rightl to Right4 and Left outlets use regular channel routing The Final outlet has no routing since it is at the end of the whole watershed As stated in Section 6 1 the watershed s land use layer 18 divided into five parts and four categories The four categories are Up Stream Highway Down Stream and Highway Sides The curve number calculation is the same as in Watershed One The soil type layer of the watershed is set to unique type D loam due to its small area The two detention ponds are modeled as reservoirs The reservoirs are accompanied with outlets Rightl and Left Since there is no heavy rainfall in previous days before each modeled rainfall event an initial co
13. 0000000 zh 20 23 21 22 98 99 Although the theoretical range of is O Infinity the practical range is 0 42 0 98 Code output Files UHPROTOTYPE TXT UHTp and UHK are the only two parameters used in this program 1 100 and X 1 100 are arrays storing parameters that are read from PARAMETER TXT tis the pseudo time its range is 0 5 REAL UHTp UHK Y 1 100 t UH 0 5000 UHArea ratio INTEGER I CHARACTER 20 X 1 100 Read all parameters from a file OPEN 30 FILE PARAMETER TXT STATUS OLD DO 20 1 100 READ 30 END 23 CONTINUE CLOSE 30 STATUS KEEP UHTp Y 87 UHK Y 88 UHArea UHTp 2 UHK ratio 1 33595 UHArea DO 21 I 0 5000 t 0 1 l IF UHTp EQ 0 THEN IF I EQ 0 THEN ratio 1 ELSE UH I ratio EXP t UHTp UHK ENDIF ELSE IF I LE UHTp 10 THEN UH I ratio t UHTp ELSE UH I ratio EXP t UHTp UHK ENDIF ENDIF CONTINUE Write to UHPROTOTYPE TXT OPEN 10 FILEZ UHPROTOTYPE TXT STATUSZ UNKNOWN DO 22 1 0 5000 WRITE 10 UH I CONTINUE CLOSE 10 STATUS KEEP PRINT 98 FORMAT New UH is generated Please close the window PRINT 99 FORMAT and check the output files STOP END 142 EXCESSRAINFALL F program Highway Watershed Model HWM is organized as followings 1 SCS curve numb
14. The second point is at the left boundary it has the coordinate of 1440 ft 1235 ft The third point is at the up ridge of the watershed it has the coordinate of 285 ft 1190 ft The origin is selected to be the center of a north arrow in the map Figure 38 shows the schematic layout for Watershed Two The whole watershed is divided into seven sub watersheds Up Stream Right Highwayl Right Highway2 Right Highway3 Right Highway4 Left Highway Down Stream From the whole watershed s view the water flows from south east to north west Up Stream is located in the upper part of the watershed Water collected from this part is clean water The clean water flows through a lateral channel and then goes to the most downstream outlet by an underground pipe directly The underground pipe is modeled as water diversion in WMS Right Highwayl to Right Highway2 is the right part of the highway Left Highway 18 the left part of the highway These five sub watersheds collect dirty water from the highway On the highway every 450 ft interval distance there are two catch basins used to collect dirty water The catch basins conduct water from the highway to the detention ponds through an underground pipe The two detention ponds 5810 and SB11 are at the bottom of sub watershed Left Highway and 76 Right_Highway4 22 Shallow Eco tone Right Highway3 0 01 mi 2 N Ri Hi 2 Well Logger
15. of antecedent moisture conditions for each class is shown in Table 1 Table 1 Classification of antecedent moisture condition AMC for the SCS method of rainfall abstractions SCS 1972 Total 5 day antecedent rainfall inch AMC Group Dormant season Growing season I Less than 0 5 Less than 1 4 II 0 5 to 1 1 1 4 to 2 1 1 1 2 1 11 In this research SCS abstraction method is employed to obtain excess rainfall which is used to generate hydrograph in later procedures As we can see from above discussion several parameters are needed in Horton model such as minimum or ultimate infiltration maximum or initial infiltration rate f and decay coefficient k More parameters are needed in Green Ampt equation These parameters are not available In contrast the only parameter in SCS CN method is the curve number which can be found in National Engineering Handbook SCS 1972 based on soil type and land use The land use and soil type are relatively easy to determine The environmental research is performed according to PennDOT s need PennDOT requires a pragmatic model which they can operate transfer to other projects or make revision after the model has been built Thus SCS CN method is selected according to project s practical situation Evaporation is considered as a loss of the top That is evaporation is subtracted from rainfall depths prior to calculating infiltrat
16. 1 5EXCESSRAINFALL exe 1 6EXCESSRAINFALL exe 1 7EXCESSRAINFALL exe 2 1HYDRO exe 2 2HYDRO exe 2 3HYDRO exe 2 4HYDRO exe 2 5HYDRO exe 2 6HYDRO exe 2 7HYDRO exe A_MUSKINGUM exe B ADD exe C MUSKINGUM exe D ADD exe E MUSKINGUM exe F ADD exe G MUSKINGUM exe del HYDRO 4 TXT ren RHYDRO 4 TXT HYDRO 4 TXT HH LEVELPOOL exe MUSKINGUM exe J WAVE exe del HYDRO 6 TXT ren RHYDRO 6 TXT HYDRO 6 TXT KK LEVELPOOL exe L ADD exe rem Finished 140 QOOOO000000000000000000000 A A 2 LINEAR EXP UH F The program Highway Watershed Model is organized as followings 1 SCS curve number method is used to generate excess rainfall EXCESSRAINFALL F Parameters needed to input CN Curve number for each sub watershed AMC Antecedent moisture conditions 2 SCS Unit hydrograph is used to generate hydrograph at the outlet HYDRO F Parameters needed to input Tc Time of concentration of the sub watershed Area Area of the sub watershed 3 Muskingum method is used to route hydrograph in channel MUSKINGUM F Parameters needed to input K Muskingum coefficient X Muskingum coefficient 4 Linear reservoir or Level pool method is used to route hydrograph in reservoir LINEARRESERVOIR F 1 time of travel Parameters needed to input K Travel time of the reservoir LEVELPOOL F Parameters needed to input Initial Initial condi
17. 2 24 T tan The mean watershed storage deficit S is obtained by integrating Equation 2 24 over the entire area of the watershed zol ra 5 A m In 225 a gt where A the fractional area of the topographic index class i 20 Assuming that the water table recharge and the soil transmissivity are spatially constant then and n are eliminated from Equation 2 25 and 5 is expressed as 5 8 1 zi 2 26 tan f where is the areal average of the topographic index gt l tan f At each topographic index class 4 unsaturated and saturated zone fluxes are modeled A 2L 2 27 0 Figure 6 shows the schematic diagram of the representation of the local storage deficit S for different topographic indices Un saturated aquifer Sathrated aquifer Saturated aquifer Aquifuge Aquifuge n satujated aquifer Figure 6 The schematic diagram of the representation of the local storage deficit for different topographic indices Campling 2002 Modified The vertical drainage 4 from the unsaturated store at any point 7 is controlled by the local saturated zone deficit D which depends on the depth of the local water table Beven and Wood 1983 q 2 28 21 where S the storage in the unsaturated zone time delay constant that introduces longer residence times to cater for deep wa
18. Figure 35 Figure 36 Figure 37 Figure 38 Figure 39 Figure 40 Figure 41 Figure 42 Figure 43 Figure 44 Figure 45 Figure 46 Figure 47 Figure 48 Figure 49 Figure 50 Figure 51 Figure 52 The GRID file view in ArcGIS and WMS sse 64 The DEM file for I 99 Environmental Research sees 66 The DEM file with the flow direction the stream networks and stream feature TCS t eee 66 The automatically generated watershed boundary 67 The original DEM file for Watershed SB10 11 sees 68 The DEM file with the flow direction the stream networks and stream feature arcs for Watershed SB10 11 68 The automatically generated watershed boundary flats and pit cells for Watershed 69 The TIN file for Watershed 5 10 1 70 The downstream part of TIN file in detail sse 70 The TIN file with pit cells flat triangles and flow direction in Watershed auda UR ORAE SER ELE NEM 71 Schematic layout for Watershed sieben 13 Elevation storage outflow relationship 1 75 Schematic layout for Watershed Two sse TI Elevation storage outflow relationship o
19. Initial condition of the reservoir elevation ADD F No parameters Only input hydrographs are needed If X 0 the Muskingum routing method becomes linear reservoir routing method LINEARRESERVOIR F program is similar to MUSKINGUM F Because a hydrograph may be routed many times through channel and reservoir it is very complicated to use different names at every routing Thus we use name HYDRO_ TXT at the outlet of a sub watershed and routing We use name RHYDRO_ TXT after each routing A hydrograph may be routed many times Each time before routing the hydrograph from RHYDRO_ TXT must be changed to YDRO_ TXT if needed kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk Version KNEMATIC_WAVE F Created by Weizhe An April 1 1 06 Input HYDRO 4 Geometry characteristics of pipe Output 4 This section is for input data K is the storage constant X is the wedge parameter INTERV is rainfall interval 5 min used in RUNOFF program C1 C2 are coefficient of Muskingum routing 1 is the Muskingum input Q is the Muskingum output They are expressed as C1 C2 C3 in the book Applied Hydrology Ven Te Chow ISBN 0 07 10810 2 P258 REAL K X Q 0 2880 1 0 2880 Y 1 100 C VELOCITY is the result kinematic celerity TOTALTIME inflow time travel time 164 SLP is
20. Simultaneously these processes also greatly change the hydrological conditions and have negative influences on storm water quantity and quality For water quantity urbanization increases the percentage of impervious area in a watershed thus the surface runoff in a post development area becomes greater than in that in pre development area Consequently the base flow and interflow in post development area is significantly reduced Furthermore the discharge flow time pattern changes i e the peak discharge increases and peak time become shorter Besides quantity water quality is affected by a combination of natural and human factors Natural factors affecting water quality include precipitation intensity and amount geology soil types topography and vegetation cover etc Meybeck et al 1989 provided a detailed review of this topic Most of these factors can be and have been affected by humans for example changes in river discharge due to construction abstraction urbanisation or impounding discharges from industry agriculture or sewerage etc Meybeck M et al 1989 To protect communities from adverse environmental disturbance the evaluation of the influence of urbanization or construction is urgently needed for the corresponding watershed areas 12 PROBLEMS STATEMENT The Pennsylvania Department of Transportation PENNDOT is constructing the U S Route 220 1 99 State Route S R 6220 project that is a part of a large ef
21. The travel time and contributing area diagram for Left Highway6 103 The travel time and contributing area diagram for Down Stream7 104 Pipe cross Sector sica vasa nnda EM bd bod pef 107 Development of the storage outflow function for level pool routing on the basis of storage elevation and elevation outflow 110 Measured and HWM modeled hydrograph for Oct 07 2005 Event 115 Measured and HWM modeled hydrograph for Oct 25 2005 Event 116 Measured HWM modeled hydrograph for Nov 27 2005 Event 116 Measured and HWM modeled hydrograph for Jan 17 2006 Event 117 Measured and HWM modeled hydrograph for Mar 11 2006 Event I Measured and HWM modeled hydrograph for May 11 2006 Event 118 Measured and HWM modeled hydrograph for June 26 2006 Event 118 Measured and HWM modeled hydrograph for Sept 01 2006 Event 119 Scatter plot for measured and modeled runoff volume 121 Scatter plot for measured and modeled peak discharge 122 Scatter plot for measured and modeled peak 122 Up Stream sub watershed CN and AMC for eight events in WMS 126 Up Stream sub watershed CN and AMC for eight events in HWM 129 Measured and WMS modeled hydrogra
22. determines the area and detail represented in the image Images in WMS are used to derive data such as pipes streams confluences land use and soil type files etc It also provides a background map to the watershed In order to use the image to represent proper length area and orientation the user must geo reference the image Geo referencing an image defines x and y coordinates so that distances areas and orientations computed from the image are correct To geo reference the image correctly users need to know the coordinates of two or three points on the image The coordinates can be the Universal Transverse Mercator UTM system the geographic system state plane or the local system Once the coordinate of two or three points are determined all other points in the map can be determined according to the relative position of these points Different coordinate systems can be converted to each other if necessary Geo referencing is extremely important if multiple function layers are imported to represent the same region In this situation correct geo referencing guarantees the coincidence of the same points lines and polygons in the different layers 3 3 SOURCE DATA IMPORTING AND CREATING Digital Elevation Models DEM is a commonly used digital elevation source and an important part of using WMS for watershed characterization Many agencies provide DEM data These include the Meteorological Resource Center http www webgis com U
23. it can be seen that four day APD may be a better indicator of AMC The R square value is defined in Equation 8 1 5 55 ge 55 55 55 R 8 1 where SS y is the total sum of square SS y y is the explained sum of square 55 gt y is the residual sum of square and y actual value of statistic variables y average value of statistic variables A y modeled expected value of statistic variable 124 Table 14 Up Stream sub watershed CN and for eight events in WMS PD amp CN 2 Day 4 Day 7 Day APD APD APD CN Oct 07 2005 0 0 0 65 8 Oct 25 2005 0 29 1 14 1 18 98 27 2005 0 0 08 0 08 80 1 17 2006 0 0 63 0 91 75 1 11 2006 0 01 0 02 0 03 80 1 11 2006 0 0 0 75 1 June 26 2006 0 62 1 28 1 96 Sept 01 2006 0 0 75 221 90 APD Antecedent Precipitation Depth CN Upstream Sub watershed Curve Number Two day CN AMC Relationship for Watershed SB10 11 110 Curve Number 70 W Upstream CN Linear Upstream CN 60 50 0 0 1 0 2 0 3 0 4 0 5 0 6 0 7 2 days precipitation inch a Two day APD and CN 125 110 Curve Number Curve Number Four day CN AMC Relationship for Watershed SB10 11 Upstream CN Linear Upstream CN 100 a 70 60 50 4 0 0 2 0 4 0 6 0 8
24. regions where precipitation data series are available but runoff data are scarce a deterministic rainfall runoff model is a good tool Kavvas et al 2004 presented a new model Watershed Environmental Hydrology Model WEHY to the modeling of hydrologic processes in order to account for the effect of heterogeneity within natural watersheds The parameters of the WEHY are related to the physical properties of the watershed and they can be estimated from readily available information on topography soils and vegetation land cover conditions Chen et al 2004a The parameters can be obtained from GIS database of a watershed without resorting to a fitting exercise The model was applied to the Shinbara Dam watershed and has produced promising runoff prediction results Chen et al 2004b Liang 2003 presented two improvements on the three layer variable infiltration capacity VIC 3L model which is also originally developed by Liang The VIC model is a macro scale hydrologic model that solves full water and energy balances It can be applied to various watershed sizes ranging from small watersheds to continental and global scale One improvement of the research is to include the infiltration excess runoff generation mechanism in the VIC model by considering effects of spatial sub grid soil heterogeneities on surface runoff and soil moisture simulations The other is to consider the effects of surface and groundwater interaction on soil moisture
25. routing and adding procedures are fixed in the model If a different watershed is studied the structure of the model will change The fixed structure model is easy to use but less flexible All parameters are input by a text file To execute the model the user only needs to run the master program of the model Another version of the same model is flexible but difficult to use The user needs to run the routing and adding program individually and interactively but the order of routing and adding can be changed anytime The user needs more hydrological knowledge and familiarity with the watershed to run the flexible model 111 7 10 ROUTING AND ADDING ORDER Based on Figure 46 the modeling order for Watershed Two is executed as follow 1 10 11 12 Hydrograph from sub watershed 1 H1 is routed to sub watershed 2 outlet The routed hydrograph is RH1 is added to hydrograph at sub watershed 2 H2 The added hydrograph is 2 AH2 is routed to sub watershed 3 outlet to become RAH2 is added to hydrograph at sub watershed 3 The added hydrograph is AH3 AH3 18 routed to sub watershed 4 outlet to become RAH3 is added to hydrograph at sub watershed 4 H4 The added hydrograph is AH4 AH4 is routed to Pond SB 10 to become RAH4 is routed to sub watershed 7 outlet through Pond SB 10 to become RRAH4 Hydrograph from sub watershed 5 H5 is routed to sub watershed 7 outlet The route
26. used For comparing with an observed hydrograph Excel format is often used 311 EVALUATION OF PARAMETER INFLUENCE No model is perfect In order to evaluate if the model is satisfactory several important modeling characteristics should be compared with the observed hydrograph They are the total volume of the runoff the number of peaks each peak time and each peak discharge value Different modeling parameters influence the modeling results in different ways Table 2 lists the relationship between some important model parameters and model results Table 2 The relationship between important model parameters and model results Increase Parameters Decrease Opposite Influences Parameter Basin Watershed Decrease Later Decrease Length Water Increase Early Increase Routing Velocit No of Steps Initial Increase Early or No Increase Reservoir Elevation Change 42 It is strange that the number of peaks of the discharge seldom changes with the above parameters Actually the number of peaks of the discharge is mostly controlled by precipitation pattern i e the number of peaks and distribution of the precipitation After surface flow and channel routing the number of peaks of the discharge will be fewer than the number of peaks of the precipitation However large peaks in precipitation separated by long time intervals will be reflected in the peaks of the discharge The above table indicates the parameters and mo
27. which is used in building the rain gage coverage polygons Gagel to Gage 10 are storm total stations and they compose a Thiessen network The temporal distribution of Gagel to Gage10 is determined by nearest recording station 38 Gage10 Figure 14 A mix use of storm total and temporal distribution recording station 3 7 3 Loss method WMS provides several options in loss method modeling The uniform loss method is the simplest method It uses an initial value and a uniform value to define infiltration losses The Horton loss method uses the starting value of the loss coefficient and the exponential factor as the main parameters The Green Ampt method employs initial effective saturation effective porosity hydraulic conductivity and wetting front soil suction head to compute infiltration rate and accumulative infiltration SCS curve number loss method is used in this research These methods are described in detail in Chapter Two 39 37 4 Unit hydrograph method Several unit hydrograph methods such as Snyder unit hydrograph Clark unit hydrograph and SCS dimensionless unit hydrograph are available in WMS model The SCS unit hydrograph is used in this research The most important parameter in SCS is the lag time Several different equations have been published to determine the lag time of a basin User also can define the lag time equation himself Many of them use some of the geometric attributes computed automatically Eq 3 1 is
28. 10 THEN BEFORE HYDRO 10 TXT AFTER RHYDRO 10 TXT ENDIF C IF RESNUM EQ 1 THEN DISCHARGE DISCHARGE 1 STORAGE STORAGE 1 TXT RELATIONSHIP RELATIONSHIP 1 TXT ELEVATION ELEVATION 1 TXT ENDIF IF RESNUM EQ 2 THEN DISCHARGE DISCHARGE 2 STORAGE STORAGE 2 TXT RELATIONSHIP RELATIONSHIP 2 TXT ELEVATION ELEVATION 2 TXT ENDIF IF RESNUM EQ 10 THEN DISCHARGE DISCHARGE 10 STORAGE STORAGE 10 TXT RELATIONSHIP RELATIONSHIP 10 TXT ELEVATION ELEVATION 10 TXT ENDIF IF RESNUM EQ 11 THEN DISCHARGE DISCHARGE 11 TXT STORAGE STORAGE 11 TXT RELATIONSHIP RELATIONSHIP 11 TXT ELEVATION ELEVATION 11 ENDIF FLAG 1 INDEX 1 OPEN 30 STATUS OLD FILE ELEVATION OPEN 40 STATUS OLD FILE DISCHARGE OPEN 50 STATUS OLD FILE STORAGE OPEN 60 STATUS OLD FILE RELATIONSHIP DO WHILE FLAG EQ 1 READ 30 END 101 ELE INDEX INDEX INDEX 1 END DO 101 INDEX 1 DO WHILE FLAG EQ 1 READ 40 END 102 DIS INDEX INDEX INDEX 1 END DO 102 INDEX 1 DO WHILE FLAG EQ 1 161 READ 50 END 103 STO INDEX INDEX INDEX 1 END DO 103 INDEX 1 DO WHILE FLAG EQ 1 READ 60 END 104 REL INDEX INDEX INDEX 1 END DO 104 PRINT Calculation is in progress please wait Check if the initial condition is correct 100 IF INITIAL LT ELE 1 0 05 OR INITIAL GT ELE INDEX 1 0 05 THEN PRINT initial elevation is out of reservoir range P
29. 18 98 Nov 27 2005 0 0 08 0 08 68 Jan 17 2006 0 0 63 0 91 80 Mar 11 2006 0 01 0 02 0 03 66 May 11 2006 0 0 0 65 June 26 2006 0 62 1 28 1 7 96 Sept 01 2006 0 0 75 2 27 85 APD Antecedent Precipitation Depth CN Upstream Sub watershed Curve Number 127 Curve Number Curve Number Two day CN AMC Relationship for Watershed SB10 11 W Upstream CN 0 5928 Linear Upstream CN n 60 50 0 0 1 0 2 0 3 0 4 0 5 0 6 0 7 2 days precipitation inch a Two day APD and CN Four day CN AMC Relationship for Watershed SB10 11 110 4 W Upstream CN Li Upsti CN 3554 inear Upstream CN R 0 9858 B B 90 80 m 70 60 50 0 0 2 0 4 0 6 0 8 1 1 2 1 4 4 days precipitation inch b Four day APD and CN 128 Seven day Relationship for Watershed SB10 11 110 4 Upstream CN 0 6829 Linear Upstream CN 100 4 90 80 Curve Number 70 60 5 0 0 5 1 1 5 2 2 5 7 days precipitation inch c Seven day APD and CN Figure 71 Up Stream sub watershed CN and AMC for eight events in HWM Although Figure 70 b is the best fitting among WMS models for CN and AMC its R square value is only 0 7191 The relationship of CN and AMC is not very well defined The goodness of fit needs to be improved In contrast Figure 71 b which is the best
30. 5 The author found this shape of DUH gave much larger peak discharge early peak time and quick recession This behavior suggests the idea of increasing the relative peak time 7 and decreasing the recess constant K in DUH In order to depict the DUH in a systematic and easily modified manner the author represents the first part of DUH as a linear rise and the second part of DUH as an exponential recession Thus the LE DUH method uses two parameters T relative peak time and relative recessing constant to describe the watershed unit hydrograph response Small 7 indicates quick rising while large indicates slow rising Small absolute value of indicates quick recession while large absolute value of indicates slow recession Different value of 7 and are able to change the DUH in a great extent and to describe different watershed shape Figure 47 illustrates four different combinations of T and One problem arises when applying different values of 7 and K The area under the DUH is not a constant As we can see from Figure 47 the area under the fourth DUH is much larger than the first one it is also larger than the other two DUHs This induces non equal of runoff for the same rainfall which is obviously incorrect One solution to this problem is to normalize all DUH areas equal to the area under the SCS DUH which is about 1 33595 and is proved to be correct in water budget This is accomplished by shrinking or
31. OPEN 80 FILE EXCESS 10 TXT STATUS UNKNOWN DO WHILE PN GT 0 READ 70 PRECIPITATION CALL EXCESS EXCESSACCUM PRECIPITATION RET WRITE 75 EXCESSACCUM PN PN 1 END DO CLOSE 75 STATUS KEEP CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC C C 98 99 Read from EXCESSACCUM TXT file and write to EXCESS EXCESSACCUM TXT can be used in many watersheds EXCESS is particular to each watersheds OPEN 75 FILEZ EXCESSACCUM TXT STATUS OLD PNZPDUR 2 PREVIOUS 0 DO WHILE PN GT 0 READ 75 TEMPPREC IF PN EQ PDUR 2 THEN EXCESSPREC TEMPPREC ELSE EXCESSPREC TEMPPREC PREVIOUS END IF PREVIOUS TEMPPREC IF EXCESSPREC LT 0 0001 EXCESSPREC 0 WRITE 80 EXCESSPREC PN PN 1 END DO CLOSE 70 STATUS KEEP CLOSE 75 STATUS KEEP CLOSE 80 STATUSZ KEEP PRINT 98 FORMAT Calculation finished Please close the window PRINT 99 FORMAT and check the output files STOP END Subroutine of calculating the rainfall excess Applied Hydrology Ven Te Chow ISBN 0 07 010810 2 P148 SUBROUTINE EXCESS A C B REAL A B C C is the precipitation B is the potential max retention IF C LT 0 2 B THEN A 0 0 ELSEIF C GE 0 2 B THEN A C 0 2 B 2 C 0 8 B ENDIF RETURN END 145 OOOO000000000000000000000 A 4 HYDRO F program Highway Watershed Model HWM is organized as followings 1 SCS curve number method is used to generate excess rain
32. Research the design schematic of the model is especially suitable for the project HWM module structures are documented in this chapter 7 2 WATERSHED DELINEATION First the modeled watershed is divided into several sub watersheds according to topographical characteristics Mountain ridges are normally used as sub watersheds divider Deep valleys are normally used as watershed channel The sub watershed and channel schematic map can be drawn before modeling This part of work is done manually and is the pre processing part of the hydrological model component Figure 45 is the schematic of Watershed One Figure 46 is the schematic of Watershed Two 93 Up Side2 Highway3 Down Side4 Up Streaml Pipe Routing Manning 0 025 Length 300 ft Slope 0 1667 Diameter 18 inch Down Stream5 Figure 45 Schematic diagram of Watershed One Right Highwayl Up Stream5 Left Highway6 Right Highway2 Pipe Routing Manning 0 025 Length 260 ft Slope 0 2981 Diameter 30 inch Right Highway3 Right Highway4 Figure 46 Schematic diagram of Watershed Two 94 7 3 EXCESS RAINFALL GENERATION Not all the rainfall is converted to runoff Part of rainfall 18 lost due to infiltration evaporation evapotranspiration etc For short term rainfall runoff modeling the evaporation and evapotranspiration can be assumed to be negligible compared to infiltration The excess rainfall can be generated from tota
33. applied to find the direct runoff and streamflow hydrograph For calculation convenience the time interval used in 15 defining the excess rainfall hyetograph ordinates should be the same as that for which the unit hydrograph was specified The discrete convolution equation n lt M Q es P eu 2 14 m i can be used to yield the direct overland runoff hydrograph where P The excess rainfall U The unit hydrograph n The nth time interval recording runoff and unit hydrograph m The mth time interval recording rainfall M The total number of time interval recording runoff 2 4 DISTRIBUTED CHANNEL ROUTING Similar to surface water distributed model the distributed channel flow model is based on partial differential equations the Saint Venant equations for one dimensional flow that allow the flow rate and water level to be computed as functions of space and time They describe the passage of a flood wave down a section of reach both in space and time On the contrary the lumped model does not use the Saint Venant equations and only considers time factor for solutions The Saint Venant equations include the continuity equation and momentum equation In complete form the Saint Venant equations are Chow et al 1988 Continuity equation ces 0 2 15a Ox 100 1 0 0 Momentum equation 20 2 15b j 200 ex 6 51 eon Local Convective Pressure Gravity Friction accelerat
34. channel and reservoir routing parameters estimation and job control setting are irrelevant to the topographic GIS data Although land use and soil type data are also categorized as GIS data they can be created manually easily The reason is land use and soil type data are featured polygon or polyline GIS data while topographic GIS data are grid data Creating featured GIS data can be accomplished by drawing a few polygons and assign them certain properties Creating topographic GIS data needs to assign thousands of 54 pixels different values This cannot accomplished manually The main difficulty in the model is the availability and accuracy of topographic GIS data 52 WATERSHED DELINEATION FOR A LARGE NATURAL WATERSHED To illustrate the procedure of delineating a large natural watershed Little Pine Creek Watershed LPCW is employed here LPCW covers about 15 02 km 5 8 mile and is located mostly with Shaler and O Hara Townships in north central Allegheny County Pittsburgh Pennsylvania LPCW was selected because it contains no significant detention pond or other storage Little Pine Creek is a tributary of Pine Creek which flows into the Allegheny River at the town of Etna The DEM data files were obtained from Pennsylvania Spatial Data Access PASDA website 5 2 1 Importing DEM data DEM data should be imported into WMS The imported DEM data is shown in Figure 18 55 RS ij 1 POSER ONS
35. data 3 The watershed has ponds and flat areas As stated in Chapter Three pits or flat elements can be a problem because the water flows into the pit and never flows out The model cannot determine the flow direction if a flat area is encountered WMS has tools to remove a small amount of error elements by changing their values through interpolation However these tools are useless if huge amount of pits flat points congregate together to form a big pond Even if they are removed the model can not reflect the real watershed characteristics 4 In the highway construction an infiltration gallery under the roadway is constructed to catch the infiltration water from the construction area Runoff from new impervious surfaces resulting from construction would be collected and routed to storm water management ponds An underground pipe is also installed to conduct water from upstream clean area directly to downstream outlet without passing the ponds Underground filtration gallery detention pond and underground pipe are much different from regular stream and must be modeled using a suitable model component As stated in Chapter Three after obtaining the topographic GIS data watershed delineation is the next procedure in building the hydrological model The above problems mainly influence the watershed delineation After watershed is properly delineated the following procedures such as drainage component editing basin parameters estimation
36. fitting among HWM models for CN and AMC shows very good fit with R square value 0 9858 The better fit of CN AMC relationship in HWM indicates that the CN can be determined accurately by using the fitting curve in future event modeling This is another strength of HWM over WMS 129 85 COMPARISON WITH WMS 8 5 1 Three indicators comparison Chapter Six and Chapter Eight display results from WMS and HWM From the direct observation of Figure 43 and Figure 44 with Figure 59 and Figure 60 we can see that the modeled hydrographs from HWM are better than those from WMS This section further compares the performance of WMS with HWM Three indicators are used total runoff volume peak discharge and peak time From Table 9 and Table 13 it is found that all total runoff volumes from WMS and HWM are satisfactory The average absolute deviation AAD of total runoff volume of HWM is 3 43 96 which is a little larger than that of WMS A large difference can be observed for peak discharge One of two modeled peak discharges in WMS 18 not satisfactory while all the modeled peak discharges are satisfactory in HWM The AAD of peak discharge in HWM is only 3 26 96 which is much smaller than that of WMS A large difference can also be seen for peak time One of two modeled peak times in WMS is not satisfactory while all the modeled peak times are satisfactory in HWM The AAD of peak time in HWM is 15 min which is much smaller than that of WMS Altho
37. for later use in the following Section B 4 The input and output file parameters are shown in Table 18 Table 18 Input and output of LINEAR EXP UH F File Input Output data Definition PARAMETERS TXT Tr Kr User defined input UHPROTOTYPE TXT DUH abscissas and coordinates Program defined output B 4 SUB WATERSHED HYDROGRAPH GENERATION Program used HYDRO F This program is used to convert the unit hydrograph to the appropriate sub watershed hydrograph by the event The input and output file parameters are shown in Table 19 In order to determine the actual runoff hydrograph at the outlet of each watershed the unit hydrographs must be scaled for the appropriate amount of rainfall Since the Excess Rainfall Hyetograph ERH has already been determined for each of the sub watersheds this process is simple First the program ensures that the time coordinates of the two graphs are same so that they are compatible Based on the discrete convolution equation Equation 2 14 the values of excess rainfall are multiplied with the corresponding values from the derived unit hydrograph Each instance of excess rainfall amounts is modeled with its own UH thus the final hydrograph is sum of each of these products lagged by the appropriate time based on when the excess rainfall occurred 172 Once completed this portion of the model will generate text files containing the coordinates of the direct runoff hydrograph
38. function of time as _ Ip I fo e 2 1 where 7 infiltration capacity into soil mm hr f minimum or ultimate value of f at 0 mm hr f maximum or initial value of f at 0 mm hr t time from beginning of storm Ar decay coefficient hr This equation describes the exponential decay of infiltration capacity evident during heavy storms Required parameters are and k The actual values of f and k depend on the soil vegetation and initial moisture content These parameters can be estimated using results from field infiltration meter tests for a number of sites of the watershed and for a number of antecedent wetness conditions If it is not possible to use field data to find estimates of f f and k the guidelines given by the U S Environmental Protection Agency can be used Huber et al 1988 The Green Ampt equation Green et al 1911 for infiltration rate is f t 2 2 F t is the cumulated infiltration and can be expressed P FO Q 3 where A0 1 5 0 s initial effective saturation dimensionless 0 lt s lt 1 0 effective porosity dimensionless 0 lt s lt 1 hydraulic conductivity m hr t infiltration time hr Y wetting front soil suction head The cumulated infiltration can be calculated by successive substitution using Equation 2 3 The infiltration parameters are given by Rawls et al 19
39. geographic information system GIS for everyone 3rd Edition Redlands 1999 Fontaine T A Rainfall Runoff Model Accuracy for an Extreme Flood Journal of Hydraulic Engineering Vol 121 No 4 pp 365 374 1995 Fread D L Technique for implicit dynamic routing in rivers with major tributaries Water Resour Res Vol 9 No 4 pp 918 926 1973 Garrote L and Becchi I Objective Oriented Software for Distributed Rainfall Runoff Models Journal of Computing in Civil Engineering Vol 11 No 3 pp 190 194 1997 Green H A Ampt Studies soil physics part I the flow of air and water through soils J Agric Sci Vol 4 No 1 pp 1 24 1911 180 Gunaratnam D J and Perkins E Numerical Solution of Unsteady Flows in Open Channels Massachusetts Institute of Technology Department of Civil Engieering Hydrodynamics Laboratory Report No 127 p216 1970 Gupta V K Rodriguez Iturbe I and Wood E F Scale Problems in Hydrology D Reidel Dordrecht Holland 1986 Gupta V K Waymire E and Wang C T A representation of an instantaneous unit hydrograph from geomorphology Water Resour Res Vol 16 No 5 pp 855 862 1980 Henderson F M Open channel Flow New York McMillan p364 1966 Huber W C and Dickinson R E Storm Water Management Model Version 4 User s Manual Environmental Research Laboratory Office of Research and Development U S Environmenta
40. hydraulic parameters for Watershed Environmental Hydrology WEHY Model Journal of Hydrologic Engineering Vol 9 No 6 pp 465 479 2004a Chow T Maidment D R and Mays L W Applied hydrology 1988 McGraw Hill Book Company New York 179 Clark Storage and the unit hydrograph Trans Am Soc Civil Engrs 110 1419 1446 1945 Cristina C M and Sansolone J J Kinematic Wave Model of Urban Pavement Rainfall Runoff Subject to Traffic Loadings Journal of Environmental Engineering Vol 129 No 7 pp 629 636 2003 Dooge J L A general theory of the unit hydrograph Journal of Geophysical Research Vol 64 No 2 pp 241 256 1959 Eastman J R Idrisi32 Tutorial Clark Labs Clark University Worcester MA 1999 Emerick J Improving upon a geographical information system based spatially distributed rainfall runoff model Unpublished master s thesis University of Pittsburgh PA 2001 Environmental Modeling Research Laboratory Brigham Young University Watershed Modeling System 6 1 Tutorial 1999 Environmental Modeling Research Laboratory Brigham Young University Watershed Modeling System 7 1 Tutorial 2004 Environmental Systems Research Institute ArcGIS 9 Using ArcMap Redlands 2004 Environmental Systems Research Institute Edited by Michael Zeiler ArcGIS 9 Exploring ArcObjects Redlands 2002 Environmental Systems Research Institute Getting to know ArcView GIS the
41. is the difference of try and error result and actual discharge min is the minimum difference value real input diff min temp1 temp2 celerity temp3 radius is the pipe radius manning is the manning coeff slope is the pipe slope coeff and temp is the temp variable theta is the angle used in calculation result is the temporary result const is the manning constant real radius manning const slope coeff theta temp result This section is to calculate the coefficients radius 1 25 manning 0 025 const 1 49 slope 1432 5 1355 0 260 0 coeff const slope 0 5 manning radius 0 6667 min input solve the equation by try and error DO 10 try 0 6 28 0 01 temp 0 5 radius 2 try SIN try result coeff temp 1 6667 try 0 6667 diff ABS input result diff L T min THEN min diff theta try ENDIF CONTINUE after solved the theta we can calculate the celerity area 0 5 radius 2 theta SIN theta temp1 1 6667 area theta 0 6667 temp3 0 6667 area theta 1 6667 temp2 temp3 0 5 radius 2 1 COS theta celerity coeff temp1 temp2 IF input LE 0 001 THEN celerity 0 ENDIF END 167 APPENDIX USER S MANUAL OF HWM 168 PREFACE The Appendix B explains the following issues 1 Functions of each module in HWM 2 The required input and output files of each module in HWM 3 The executing procedure of HWM Users should be advised that the order placed h
42. its properties distribution and effects on the earth s surface soil and atmosphere McCuen 1997 Water circulation in the air land surface and underground constitutes hydrologic cycle The cycle has no beginning or end Hydrology researchers are often faced with problems of runoff prediction contaminant concentrations water stages etc Due to the great spatial and temporal variability of watershed characteristics precipitation patterns contaminant transport rules and the number of variables involved in the physical processes rainfall runoff relationship is one of the most complex hydrologic phenomena Prediction of hydrological process is extremely important to water resources engineering Figure 1 illustrates the main hydrological processes at a local scale Precipitation evaporation evaporation ae oem Land Water transpiration LI surface body stemflow Vegetation through rainfall capillary rise flood infiltration Y interflow Stream Soil channel t baseflow percolation capillary rise Groundwater aquifer recharge watershed discharge Figure 1 Main hydrological processes at a local scale Ward 1975 Modified In recent years in many places of the world the processes of rapid population growth highway construction urbanization and industrialization have increased the demand for clean water
43. model for a small watershed unpublished master s thesis University of Pittsburgh PA 2003 U S Army Corps of Engineers Hydrologic Engineering Center Hydrologic Modelling System HEC HMS Technical Reference Manual Davis California 2000 S Army Corps of Engineers Hydrologic Engineering Center Geospatial Hydrologic Modeling Extension HEC GeoHMS User s Manual Version 1 1 Dec 2003 U S Army Corps of Engineers Hydrologic Engineering Center Hydrologic Modeling System HEC HMS User s Manual Version 2 1 Jan 2001 Ward R C Principle of Hydrology McGraw Hill Book Company UK Limited London 1975 Web source http www pasda psu edu Whigham P A and Crapper P F Modeling rainfall runoff using genetic programming Mathematical and Computer Modeling Vol 33 pp 707 721 2001 183 Yue S and Hashino M Unit Hydrograph to model quick and slow runoff components of stream flow Journal of Hydrology Vol 227 pp 195 206 2000 Zoch R T On the relation between rainfall and stream flow Monthly Weather Rev 62 315 322 1934 64 105 121 1936 65 135 147 1937 184
44. more pixels while a small object is represented using fewer pixels Digital Elevation Models DEM are regular grid data structures that contain two dimensional arrays of elevations where the spacing between elevations is constant in the x and y directions In this manner it is like a grid file The resolutions of DEM are normally 30 x 30 square meters or 90x 90 square meters Triangulated Irregular Networks TIN is another type of digital elevation map A TIN is built from a series of irregularly spaced points with elevations that describe the surface at that point In contrast to DEM the elevation points are irregularly distributed From these points a network of linked triangles is constructed Adjacent triangles sharing two nodes and an edge connect each other to form a surface A height can be calculated for any point on the surface by interpolating a value from the nodes of nearby triangles In addition each triangle face has a specific slope and aspect TIN can be used for visualization as background elevation maps for generating new TIN or DEM or perform basin delineation and drainage analysis A TIN file is flexible in representing different variation terrain If a watershed elevation varies too much in a small area more points are needed for accuracy purpose However if a watershed elevation is very flat in a large area fewer points can be used to save storage space On the contrary DEM always represents a watershed usin
45. the same as explained above Figure 51 to Figure 56 show the travel time and contributing area in diagram format Right Highway2 Time Area Diagram Contributing Area Square feet 40 Travel Time mins Figure 51 The travel time and contributing area diagram for Right Highway2 102 Right_Highway3 Time Area Diagram 60000 5 8 Contributing Area Square feet 8 10000 10 20 30 21 50 60 70 Travel Time mins Figure 52 The travel time and contributing area diagram for Right Highway3 Right Highway4 Time Area Diagram 180000 160000 140000 8 8 8 8 80000 B m o o 20 30 40 50 60 1 Contributing Area Square feet 8 Travel Time mins Figure 53 The travel time and contributing area diagram for Right Highway4 Up 8 5 Time Area Diagram 300000 250000 200000 150000 100000 o 10 20 30 40 50 60 Travel Time mins tributing Area Square feet Figure 54 The travel time and contributing area diagram for Up Stream5 Left_Highway Time Area Diagram 10 20 30 40 580 60 70 90 10 10 10 130 140 150 Travel Time mins Figure 55 The travel time and contributing area diagram for Left Highway6 103 Down_Stream Time Area Diagram 40000
46. the same method as the SCS UH A simplified model of a triangular unit hydrograph is shown in Figure 3 b where the time is in hours and the discharge in m s cm or cfs in Soil Conservation Service 1972 The parameters used in remaining part of LEUH are also the same as in the SCS UH The time of recession is approximated as 1 677 Because the area under the unit hydrograph should be equal to a direct runoff of 1 cm or 1 inch it can be derived that que 7 1 where C 2 08 in international unit system 483 4 in English unit system A the drainage area in square kilometers square miles The basin lag time t 0 67 where T the time of concentration of the watershed As illustrated in Figure 3 b time of rise T can be expressed in terms of lag time t and the duration of effective rainfall t S OMS 7 2 The use of LEUH is similar to that of SCS UH except Figure 48 is employed instead of Figure 3 a Due to different values of 7 and K the valid length of abscissa in Figure 48 will be much larger than that of Figure 3 a which is a constant 5 For example when 7 10 and 10 the abscissa can be as large as 35 Time of concentration 7 is approximately the longest travel time within the basin In general the longest travel time corresponds to the longest drainage path To determine Te the flow path is broken into segments with the flow in each segment being represented 98 by some t
47. time of the reservoir LEVELPOOL F Parameters needed to input Initial Initial condition of the reservoir elevation ADD F No parameters Only input hydrographs are needed If X 0 the Muskingum routing method becomes linear reservoir routing method LINEARRESERVOIR F program is similar to MUSKINGUM F Because a hydrograph may be routed many times through channel and reservoir it is very complicated to use different names at every routing Thus we use name HYDRO_ TXT at the outlet of a sub watershed and routing We use name RHYDRO_ TXT after each routing A hydrograph may be routed many times Each time before routing the hydrograph from RHYDRO_ TXT must be changed to YDRO_ TXT if needed kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk Version LEVELPOOL F Created by Weizhe An April 16 06 Input HYDRO_ TXT Output RHYDRO_ TXT This section is for input data INTERV is rainfall interval 5 min 300 sec used in RUNOFF program 1 is the Level pool input Q is the Level pool output ADDINPUT is a middle variable array it stores two adjacent inflow it is column 4 of Table 8 2 3 in Chow s text book REAL Q 1 2880 I 1 2880 ADDINPUT 1 2880 VARAIBLE1 AND VARIABLE2 are column 5 and 6 of Table 8 2 3 in Chow s text book REAL VARIABLE 1 1 2880 VARIABLE2 1 2880 ELE DIS STO REL are temporary arrays to store the reservoir characters REAL ELE 1 30 DIS 1 30 STO 1 30 REL 1 30 159
48. travel Parameters needed to input K Travel time of the reservoir LEVELPOOL F Parameters needed to input Initial Initial condition of the reservoir elevation ADD F No parameters Only input hydrographs are needed If X 0 the Muskingum routing method becomes linear reservoir routing method LINEARRESERVOIR F program is similar to MUSKINGUM F Because a hydrograph may be routed many times through channel and reservoir it is very complicated to use different names at every routing Thus we use name HYDRO_ TXT at the outlet of a sub watershed and routing we use name RHYDRO_ TXT after each routing A hydrograph may be routed many times Each time before routing the hydrograph from RHYDRO_ TXT must be changed to YDRO_ TXT if needed kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk Version MUSKINGUM F Created by Weizhe An April 11 06 Input HYDRO_ TXT K X Output RHYDRO_ TXT This section is for input data K is the storage constant X is the wedge parameter INTERV is rainfall interval 5 min used in RUNOFF program C1 C2 are coefficients of Muskingum routing 1 is the Muskingum input Q X is the Muskingum output They are expressed as C1 C2 C3 in the book Applied Hydrology Ven Te Chow ISBN 0 07 10810 2 P258 REAL K X INTERV C0 C1 C2 Q 0 2880 1 0 2880 Y 1 100 INTEGER INDEX J OOOO0000000000000000000O0O O 151
49. uses four basic assumptions to relate local downslope flow from a point to discharge at the watershed outlet Assumption 1 The dynamics of the saturated zone are approximated by successive steady state representations Assumption 2 The recharge rate r m h entering the water table is spatially homogeneous Assumption 3 The effective hydraulic gradient of the saturated zone is approximated by the local surface topographic gradient f Assumption 4 The distribution of downslope transmissivity m h with depth is an exponential function of storage deficit 19 TOPMODEL uses the distribution of the topographic index as an index of hydrological similarity which indicates the propensity of landscape areas to become wet jd ess 2 21 tan where a the area draining through a grid square per unit contour length tan j the local surface slope Under assumption 1 and assumption 2 the downslope subsurface flow rate per unit contour length q m h is 4 2 22 where r the recharge rate Under assumption 3 and assumption 4 q m h is also 4 tan f 2 23 where the lateral downslope transmissivity when the soil is just saturated S local storage deficit m model parameter controlling the rate of decline of transmissivity with increasing storage deficit By combining Equation 2 22 and Equation 2 23 the local soil moisture deficit S can be derived S mIn
50. wedge and prism During the advance of a flood wave inflow exceeds outflow producing a wedge of storage During the recession outflow exceeds inflow resulting in a negative wedge The prism is formed by a volume of constant cross section along the length of prismatic channel Figure 4 shows the prism and wedge storage in a channel reach Figure 4 The prism and wedge storage in a channel reach Chow et al 1988 The total storage is the sum of two components KX I Q 2 18 which can be rearranged to be the storage function S K XI 1 X Q 2 18b Equation 2 16b represents a linear model for routing flow in streams The channel outflow is expressed as Cal 2 19 where C are Muskingum coefficient and defined as T 2 20 2K 1 X At At 2KX 2K X At 2 20b 2 _2 At 2 20 18 2 6 TOPOGRAPHICALLY BASED BASE FLOW MODELING In areas that have much vegetation or consist of sandy soils base flow becomes important in total water balance The representative topographical based base flow model is TOPMODEL Beven 1995 Figure 5 illustrate the term definitions of TOPMODEL in a flow strip Ai Total area drained in flow strip ai area drained per unit contour length A w tan local surface slope Wi contour length Figure 5 Definition sketch for TOPMODEL flow strip Kirkby 1997 Modified TOPMODEL
51. 0 This section is to calculate the coefficients CoO 0 5 INTERV K X K 1 0 X 0 5 INTERV C1 0 5 INTERV K X K 1 0 X 0 5 INTERV C2 K 1 0 X 0 5 INTERV K 1 0 X 0 5 INTERV This section is to route and print out the results Q 0 0 DO 7 INDEX 1 2880 Q INDEX C0 l INDEX C1 I INDEX 1 C2 Q INDEX 1 IF Q INDEX GE 10000 OR Q INDEX LE 0 0001 THEN Q INDEX 0 END IF CONTINUE File 20 is the output file it contains Muskingum routing output OPEN 20 FILE AFTER STATUS UNKNOWN DO 8 INDEX 0 2880 WRITE 20 Q INDEX CONTINUE CLOSE 10 STATUS KEEP CLOSE 20 STATUS KEEP PRINT 98 FORMAT Calculation finished Please close the window PRINT 99 FORMAT and check the output files STOP END 153 OOO0O000000000000000000000 A 6 ADD F The program Highway Watershed Model HWM is organized as followings 1 SCS curve number method is used to generate excess rainfall EXCESSRAINFALL F Parameters needed to input CN Curve number for each sub watershed AMC Antecedent moisture conditions 2 SCS Unit hydrograph is used to generate hydrograph at the outlet HYDRO F Parameters needed to input Tc Time of concentration of the sub watershed Area Area of the sub watershed 3 Muskingum method is used to route hydrograph in channel MUSKINGUM F Parameters needed to input K Muskingum coefficient X Muskingum coefficient 4 Li
52. 015 0 64 2880 2005 Modeled 90542 0 70 2880 Deviation 1 72 9 37 0 min Mar 11 Measured 34977 0 45 2460 2005 Modeled 35800 0 44 2460 Deviation 2 35 2 22 96 0 min May 11 Measured 44466 0 43 2220 2005 Modeled 45542 0 42 2220 Deviation 2 42 9 2 33 0 min Tene D6 Measured 90631 1 08 2460 2005 Modeled 86472 1 10 2460 Deviation 4 59 1 85 0 min Sept 01 Measured 121958 1 36 2220 2005 Modeled 124077 1 33 2220 Deviation 1 74 2 21 96 0 min Average Absolute Perce 3 43 96 3 26 15 min As be seen from Table 13 all deviations of the modeled runoff total volume peak discharge value and peak discharge time are acceptable These results are much better than model results in WMS The average absolute percent deviation of the runoff volume deviations is 3 43 which is less than the deviation upper limit 15 Absolute means all negative deviations values are converted to positive before taking the average The absolute percent deviation of the peak discharge is 3 26 which is also within satisfactory limit 120 The average absolute deviation not percent for peak discharge is 15 minutes which is also satisfactory To compare the results the measured and modeled runoff volumes are shown in Figure 67 A trend line is added to see the modeled runoff volume deviation As can be seen from Figure 67 the perfect fit line should be with 1 while the actual fit line is Y 1 0312 X
53. 1 H1 EQ 2 H1 EQ 3 H1 EQ 4 RHYDRO A RHYDRO 1 TXT RHYDRO A RHYDRO 2 TXT RHYDRO A RHYDRO 3 TXT RHYDRO A RHYDRO 4 MEER 2 wa 155 IF H1 EQ 5 RHYDRO A RHYDRO 5 TXT IF H1 EQ 6 RHYDRO_A RHYDRO_6 TXT IF H1 EQ 7 RHYDRO A RHYDRO 7 TXT IF H1 EQ 8 RHYDRO A RHYDRO 8 TXT dig EQ 9 RHYDRO A RHYDRO 9 TXT IF H1 EQ 10 RHYDRO A RHYDRO 10 TXT F H2 EQ 1 RHYDRO B RHYDRO 1 TXT F H2 EQ 2 RHYDRO B RHYDRO 2 TXT F H2 EQ 3 RHYDRO_B RHYDRO_3 TXT F H2 EQ 4 RHYDRO_B RHYDRO_4 TXT F H2 EQ 5 RHYDRO_B RHYDRO_5 TXT F H2 EQ 6 RHYDRO_B RHYDRO_6 TXT F H2 EQ 7 RHYDRO_B RHYDRO_7 TXT F H2 EQ 8 RHYDRO B RHYDRO 8 TXT F H2 EQ 9 RHYDRO B RHYDRO 9 TXT F H2 EQ 10 RHYDRO B RHYDRO 10 TXT ee F H3 EQ 1 RHYDRO C RHYDRO 1 TXT F H3 EQ 2 RHYDRO C RHYDRO 2 TXT F H3 EQ 3JRHYDRO C RHYDRO 3 TXT F H3 EQ 4 RHYDRO C RHYDRO 4 TXT F H3 EQ 5 RHYDRO C RHYDRO 5 TXT C RHYDRO 6 TXT F H3 EQ 7 RHYDRO C RHYDRO 7 TXT F H3 EQ 8 RHYDRO C RHYDRO 8 TXT F H3 EQ 9 RHYDRO C RHYDRO 9 TXT F H3 EQ 10 RHYDRO_C RHYDRO_10 TXT F H4 EQ 1 RHYDRO D RHYDRO 1 TXT F H4 EQ 2 RHYDRO D RHYDRO 2 TXT F H4 EQ 3RHYDRO D RHYDRO 3 TXT F H4 EQ 4 RHYDRO D RHYDRO 4 TXT F H4 EQ 5 RHYDRO D RHYDRO 5 TXT IF H4 EQ 6 RHYDRO_D RHYDRO_6 TXT F H4 EQ 7 RHYDRO_D RHYDRO_7 TXT F H4 EQ 8 RHYDRO_D RHYDRO_8 TXT F H4 EQ 9 RHYDRO D RHYDRO 9 TXT F H4 EQ 10 RHYDRO_D RHYDRO_10 TXT F O
54. 1 1 2 1 4 4 days precipitation inch b Four day APD and CN Seven day CN AMC Relationship for Watershed SB10 11 110 Upstream CN Linear Upstream CN 100 90 0 5394 80 4 70 60 50 4 0 0 5 1 1 5 7 days precipitation inch 2 2 5 c Seven day APD and CN Figure 70 Up Stream sub watershed CN and AMC for eight events in WMS 126 Similar to analysis in WMS model Stream is chosen to analyze the CN AMC relationship in HWM Two day antecedent precipitation depth APD four day APD and seven day APD are chosen to be indicators of AMC Table 15 shows Up_Stream sub watershed CN and AMC for the eight storm events Figure 71 shows their relationship in graph format Since the two day APDs in many events are zero it may not be a good AMC indicator Most of early rainfall in seven day APDs is evaporated by sunshine and vegetation This may be the reason for the bad fit in Figure 71 c whose R square value is 0 6829 In contrast Figure 71 b which is the relationship of four day APDs and CN shows very good fit with R square value 0 9858 From Figure 71 a Figure 71 b and Figure 71 c it can be seen that four day APD may be a better indicator of AMC Table 15 Up Stream sub watershed CN and AMC for eight events in HWM PD amp CN 2 Day 4 Day 7 Day APD APD APD Oct 07 2005 0 0 0 65 Oct 25 2005 0 29 1 14 1
55. 2 69 70 60 min 60 90 90 120 60 90 90 90 Routing Right Highway4 Right Highway3 K min 20 20 20 40 20 20 20 20 X 0 2 0 2 0 2 0 2 0 2 0 2 0 2 0 2 Routing Right Highway3 Right Highway2 K min 20 20 20 40 20 20 20 20 X 0 2 0 2 0 2 0 2 0 2 0 2 0 2 0 2 Routing Right Highway2 Right Highwayl K min 20 20 20 40 20 20 20 20 X 0 2 0 2 0 2 0 2 0 2 0 2 0 2 0 2 Routing Right Highwayl SB10 K min 30 30 30 60 30 30 20 20 X 0 2 0 2 0 2 0 2 0 2 0 2 0 2 0 2 Routing Up Stream Down Stream K min 30 30 30 40 30 30 20 20 X 0 2 0 2 0 2 0 2 0 2 0 2 0 2 0 2 Routing Left Highway SBl1 K min 20 20 20 40 20 20 20 20 X 0 2 0 2 0 2 0 2 0 2 0 2 0 2 0 2 T dimensionless 12 14 13 18 10 17 10 12 K dimensionless 12 14 14 18 10 17 10 12 114 82 HWM RESULTS FOR WATERSHED TWO The Ecotones installed in the outlet flumes record water depth A rating curve is used to convert the water depth to the discharge and shown in Figure 42 Detailed information on all rainfall events can be found in Section 6 3 and Figure 41 Figure 59 to Figure 66 shows the comparison of measured and HWM modeled hydrograph Oct 07 2005 Hydrograph Comparison 2 0000 Measured HWM 1 8000 1 6000 1 4000 1 2000 1 0000 Discharge cfs 0 8000 0 6000 0 4000 0 2000 0 0000 0 12 24 36 48 60 72 84 96 Time Hr since 00 00 Oct 07 2005 Figure 59 Measured and HWM mod
56. 23 N SS d AO y ZEN SW 22 GRY a 25 mer 5 Ps 224 A OSA Figure 18 The imported DEM data for LPCW 5 2 2 Computing flow direction The flow direction should be computed in WMS The flow direction form a network of streams on top of the DEM WMS computes flow direction for individual DEM cells and creates streams based on these directions Figure 19 shows a flow direction of LPCW Figure 20 shows a stream network of LPCW 56 VAN 7 252 Figure 19 The flow direction of LPCW 57 SS Li SOO 9 LSS Dc d um pA Figure 20 The stream network of LPCW 5 2 3 Determining the outlet point and stream feature arcs The outlet point is determined according to project need Theoretically it can be any point in the watershed In this example a point in the stream near the lower left corner is selected By choosing a point on a lower stream branch a watershed outlet is defined WMS then uses the flow direction and accumulation data from Section 5 2 2 to convert the streams network into stream feature arcs Figure 21 1s the converted stream feature arcs in LPCW 58 2 22 ff eic cm 7 v x Figure 21 The converted stream feature arcs in LPCW 5 2 4 Defining the watershed boundary The stream feature arcs can be used to define the basin boundaries Because the DEM contains elevation data the mode
57. 25 Table 15 Up Stream sub watershed CN and AMC for eight events in HWM 127 Table 16 The comparison of the three criteria for Watershed Two with calculated n 133 Table 17 Input and output of EXCESSRAINFALL F eere 171 Table 18 Input and output of LINEAR EXP DELE iis pnn pant bete d 172 Table 19 Inputand output of HY DROP IR DH IPOD 173 Table 20 Input and output of MUSKINGUM F sese 174 Table 21 Input and output of ADDLE 175 Table 22 Input and output sss 176 Table 23 Input and output of HYDRO F 176 ix LIST OF FIGURES Figure 1 Main hydrological processes at a local 1 Figure 2 Conceptual view of surface 13 Figure 3 Soil Conservation Service synthetic unit hydrograph 15 Figure 4 The prism and wedge storage in a channel reach sss 18 Figure 5 Definition sketch for TOPMODEL flow strip 19 Figure 6 The schematic diagram of the representation of 21 Figure 7 Initial base flow 24 Figure 8 An example of watershed delineation using DEM see 32 Figure 9 An example of watershed delineation using TIN
58. 83 The Soil Conservation Service SCS curve numbers CN describe the surface s potential for generating runoff as a function of the soil type and land use on surface Curve numbers range between 0 lt CN lt 100 with 0 as the theoretic lower limit describing a surface that absorbs all precipitation and 100 the upper limit describing an impervious surface such as asphalt or water where all precipitation becomes runoff The 10 method computes the excess precipitation Pe generated for an incremental depth of precipitation falling on an area using the following relationship 2 a 2 4 where P the incremental precipitation depth inch the potential maximum retention inch The value 5 1 related to the curve number by _1000 where CN the Curve Number which is defined by SCS 5 10 2 5 Equation 2 4 applies only for gt 0 25 otherwise all the precipitation is assumed lost to infiltration The normal antecedent moisture conditions AMC II CN value is defined and tabulated by SCS based on different soil type and land use For dry conditions AMC 1 or wet conditions AMC equivalent curve numbers can be computed by 4 2CN IT 10 0 058CN IT 6 23 1 CN IIT 10 0 13CN IT 2 7 As a result the SCS method provides the depth of excess precipitation resulting from a given depth of precipitation falling over an area during a specific time interval The range
59. AL ANALYSIS BASED ON TIN DATA Although the structure of TIN file is different from DEM they represent the same reality If there are flat or pit cells in DEM there will be flat triangles or pit cells in corresponding TIN If the watershed delineation is incorrect in DEM the delineation is also incorrect in corresponding TIN Figure 33 is the TIN file for Watershed SB10 11 Figure 34 is the downstream part of TIN file in detail Figure 35 shows the TIN file with pit cells and flat triangles In the TIN file a cell at the left up is defined as the watershed outlet Figure 35 also shows the flow direction and pit cells in this watershed which indicates many flows go to pits and sink They do not flow to the outlet 69 Figure 33 The TIN file for Watershed SB10 11 PANES TINI 2 7 SAY AAA VAANAAAANAANAAY PE 2 20 KRREPRPUSRSERSSRERSISREREEE SPRKRPPRDARSRKKEKKKEKKARRPPPPOPPPPPRPRIEAISERIAK NA ININNIIEINZVINSNSSSSSNSSSSINNAVUdvwvveVId SSSRRESSSSSSEPREERPEREURRSESISISSSSSSSSSISSSSSERISRE 2
60. AM Oct 07 2005 and ended at 23 59 PM Oct 10 2005 The total rainfall depth of this event is 2 90 inches Figure 41 a is the half hour incremental rainfall data Figure 43 shows the comparison of measured and WMS modeled hydrograph It is seen that the hydrograph were predicted poorly Oct 07 2005 Hydrograph Comparison 2 0000 Measured 5 1 8000 1 6000 1 4000 1 2000 1 0000 Discharge cfs 0 8000 0 6000 0 4000 0 2000 0 0000 0 12 24 36 48 60 72 84 96 Time Hr since 00 00 Oct 07 2005 Figure 43 Measured and WMS modeled hydrograph for Oct 07 2005 Event 88 6 6 2 Watershed Two Event of Oct 25 2005 Oct 25 2005 Rainfall Event began at 00 00 AM Oct 25 2005 and ended at 23 59 PM Oct 29 2005 The total rainfall depth of this event is 0 64 inches Figure 41 b is the half hour incremental rainfall data Figure 44 shows the comparison of measured and WMS modeled hydrograph Oct 25 2005 Hydrograph Comparison Measured WMS o Discharge cfs P 0 2 0 12 24 36 48 60 72 84 96 108 126 Time Hr since 00 00 Oct 25 2005 Figure 44 Measured and WMS modeled hydrograph for Oct 25 2005 Event 6 7 ANALYSIS OF WMS RESULTS The most important criteria for comparing modeled hydrograph to measured hydrograph are the total volume of the runoff peak time and peak discha
61. C AFTER are file name representatives 20 BEFORE AFTER XX 1 100 C Read all parameters from a file OPEN 30 FILE PARAMETER TXT STATUS OLD DO 20 J 1 100 READ 30 END 21 XX J Y J 20 CONTINUE 21 LINE v 1 CLOSE 30 STATUS KEEP SBWSNUM Y 45 K Y 46 47 0 08333333 C Select the to read IF SBWSNUM EQ 1 THEN BEFORE HYDRO 1 TXT AFTER RHYDRO 1 TXT ENDIF IF SBWSNUM EQ 2 THEN BEFORE HYDRO 2 TXT AFTER RHYDRO_2 TXT ENDIF IF SBWSNUM EQ 3 THEN BEFORE HYDRO_3 TXT AFTER RHYDRO 3 TXT ENDIF IF SBWSNUM EQ 4 THEN BEFORE HYDRO 4 TXT AFTER RHYDRO 4 TXT ENDIF IF SBWSNUM EQ 5 THEN BEFORE HYDRO 5 TXT AFTER RHYDRO 5 TXT ENDIF IF SBWSNUM EQ 6 THEN BEFORE HYDRO 6 TXT AFTER RHYDRO 6 TXT ENDIF IF SBWSNUM EQ 7 THEN BEFORE HYDRO 7 TXT AFTER RHYDRO_7 TXT ENDIF IF SBWSNUM EQ 8 THEN BEFORE HYDRO_8 TXT AFTER RHYDRO 8 TXT ENDIF IF SBWSNUM EQ 9 THEN BEFORE HYDRO 9 TXT AFTER RHYDRO 9 TXT ENDIF IF SBWSNUM EQ 10 THEN BEFORE HYDRO 10 TXT AFTER RHYDRO 10 TXT 152 98 99 ENDIF File unit 10 is the input file it contains routing input required by Muskingum OPEN 10 STATUS OLD FILE BEFORE Initialize the input and output 1 is the Muskingum input Q is the Muskingum output DO 5 INDEX 0 2880 IINDEX 0 Q INDEX 0 CONTINUE Read data from the runoff txt file DO 6 INDEX 0 2880 READ 10 I INDEX CONTINUE K K 6
62. C Read all parameters from a file OPEN 30 FILEZ PARAMETER TXT STATUS OLD DO 20 1 100 READ 30 END 21 Y I 20 CONTINUE 21 LINE I 1 CLOSE 30 STATUS KEEP C OPEN 31 FILEZTEST TXT STATUS UNKNOWN C WRITE 31 LINE C DO 22 1 LINE C WRITE 31 Y I C22 CONTINUE C 31 STATUS KEEP AMC Y 2 SBWSNUM Y 3 PDUR Y 4 CN Y 5 PN PDUR 2 Conditions for AMC 1 dry OR 3 wet C RET is the potential max retention C OCNNis the corrected curve number for AMC 1 2 3 IF AMC EQ 2 CNN CN 1 0 IF AMC EQ 1 CNN 4 2 CN 10 0 058 CN IF AMC EQ 3 CNN 23 CN 10 0 13 CN RET 1000 CNN 10 C Readfrom RAINFALL TXT file and write to EXCESSACCUM TXT OPEN 70 FILEZ RAINFALL TXT STATUS z OLD OPEN 75 FILE EXCESSACCUM TXT STATUS UNKNOWN IF SBWSNUM EQ 1 OPEN 80 FILE EXCESS_1 TXT STATUS UNKNOWN IF SBWSNUM EQ 2 OPEN 80 FILE EXCESS_2 TXT STATUSZ UNKNOWN IF SBWSNUM EQ 3 OPEN 80 FILEZ EXCESS 3 TXT STATUSZ UNKNOWN IF SBWSNUM EQ 4 OPEN 80 FILEZ EXCESS 4 TXT STATUSZ UNKNOWN IF SBWSNUM EQ 5 OPEN 80 FILE EXCESS_5 TXT STATUSZ UNKNOWN IF SBWSNUM EQ 6 OPEN 80 FILEZ EXCESS 6 TXT STATUSZ UNKNOWN IF SBWSNUM EQ 7 OPEN 80 FILEZ EXCESS 7 TXT STATUSZ UNKNOWN pu o 2 DB BN Do i ee 144 IF SBWSNUM EQ 8 OPEN 80 FILE EXCESS_8 TXT STATUS UNKNOWN IF SBWSNUM EQ 9 OPEN 80 FILE EXCESS_9 TXT STATUS UNKNOWN IF SBWSNUM EQ 10
63. EVELOPMENT 93 71 MOTIVATION FOR DEVELOPING 93 72 WATERSHED 93 73 58 95 7 4 SCS AND LE UNIT 95 7 5 UNIT 100 7 5 1 Isochrone curve 100 7 5 2 ISO UH Geral 104 7 6 RUNOFF GENERATION AT EACH SUB WATERSHED 105 7 7 CHANNEL AND PIPE 105 7 8 RESERVOIR ROUTING 108 79 HYDROGRAPH ADDITION 111 7 10 ROUTING AND ADDING 112 80 APPLICATION HWM IN 1 99 PROJECT 113 8 1 PARAMETERS FOR WATERSHED TWO ALL
64. EVENTS 113 82 HWM RESULTS FOR WATERSHED 115 83 ANALYSIS OF HWM 5 5 119 84 RELATIONSHIP BETWEEN CN AND AM TC eerte enne tn nnne 123 85 COMPARISON WITH 5 130 8 5 1 Three indicators comparison cree ee ee eee eee 130 8 5 2 Comparison using parameters 4 ecce esee eren ener en eene en eee tn seen aseo 131 8 5 3 Comparison using AMC CN relationship e eeee eren 133 vii 8 5 4 Comments on WMS HWM software packages 133 9 0 CONCLUSIONS AND 5 135 91 CONCLUSIONS 135 92 RECOMMENDATIONS sssssssssssrsssssssscossssssssvssssssssnsssssosssssssosisessvsnssssiosssssise 136 APPENDIX A FORTRAN PROGRAMS FOR EACH MODULE OF HWM 138 U COC I Y y e 139 1 140 2 LINEAR EXP UB Bousitcscscsscsessassasssossssesssitenconboassensanessesnnbasennsabsneassisasensbuns 141 AS
65. Editor The XY Series Editor is a general purpose editor for entering curves or pairs of lists of data If the user wants to optimize the modeled hydrograph using an observed hydrograph the observed hydrograph can be input also using XY Series Editor 37 3 7 2 Precipitation Several options of precipitation can be defined One commonly used precipitation method is basin average precipitation With this method a time distribution can be entered via the XY Series Editor Several standard storm distributions can be loaded automatically from this editor The standard storm distributions often can not satisfy the user s requirement In this case distributions can be created by the user directly An average precipitation is also input to account for total rainfall The basin average method is convenient in small watersheds where the rainfall can be regarded as spatially uniform However rainfall is normally spatially non uniform in large watersheds where multiple rain gages are used A gage may be a storm total and or temporal distribution recording station type Recording stations allow for a continuous rainfall accumulation to be entered The storm total station only allows for a single rainfall value for the event Figure 14 shows a mix use of storm total and temporal distribution recording station Gage and Gage B are temporal distribution recording stations which are imaginary gages and do not participate building the Thiessen network
66. ITHYDRO J FIVE J INTERVAL INTERVAL WRITE 73 TEMP GOTO 31 END IF 30 CONTINUE 31 FIVE FIVE 0 083333333 END DO WRITE 73 0 CLOSE 73 5 5 SBWSNUM EQ 6 OPEN GG 5 2 412 42 4412 4 2 432 42 The following code convert the excess rainfall in different time into sub hydrograph and add them together to get hydrograph at the SBWS outlet IF SBWSNUM EQ 1 OPEN 74 FILE Z EXCESS 1 TXT STATUS OLD 148 SBWSNUM EQ 2 OPEN 74 FILE EXCESS_2 TXT STATUS OLD IF SBWSNUM EQ 3 OPEN 74 FILE EXCESS_3 TXT STATUS OLD IF SBWSNUM EQ 4 OPEN 74 FILE EXCESS_4 TXT STATUS OLD IF SBWSNUM EQ 5 OPEN 74 FILE EXCESS_5 TXT STATUS OLD IF SBWSNUM EQ 6 OPEN 74 FILE EXCESS_6 TXT STATUS OLD IF SBWSNUM EQ 7 OPEN 74 FILE EXCESS_7 TXT STATUS OLD IF SBWSNUM EQ 8 OPEN 74 FILE EXCESS_8 TXT STATUS OLD IF SBWSNUM EQ 9 OPEN 74 FILE EXCESS_9 TXT STATUS OLD IF SBWSNUM EQ 10 OPEN 74 FILE EXCESS_10 TXT STATUS OLD IF IF IF IF IF IF IF IF IF IF SBWSNUM EQ 1 OPEN 73 FILE UH_1 TXT STATUS OLD SBWSNUM EQ 2 OPEN 73 FILEZ UH 2 TXT STATUSZ OLD SBWSNUM EQ 3 OPEN 73 FILEZ UH 5 5 01 0 SBWSNUM EQ 4 OPEN 73 FILEZ UH 4 TXT STATUSZ OLD SBWSNUM EQ 5 OPEN 73 FILEZ UH 5 TXT STATUSZ OLD SBWSNUM EQ 6 OPEN 73 FILE UH_6 TXT STATUS OLD SBWSNUM EQ 7 OPEN 73 FILEZ UH 7 TX
67. LETNUM is the number of the outlets HYDRONUM is the number of routed hydrographs 154 22 21 R OOOO0O0000000000 C 5 H is the hydrograph counter when the added hydrograph is input H is the added input hydrograph num Z is the index FINAL is a variable to indicate whether the calculation is the final If it is final the output data is at one hour intervals If itis not the output data is at 5 minute intervals INTEGER OUTLETNUM HYDRONUM H H1 H2 H3 H4 Z FINAL OPEN 30 FILE PARAMETER TXT STATUS OLD DO 221 1 100 READ 30 END 21 X I CONTINUE LINE I 1 CLOSE 30 STATUS KEEP H is the hydrograph counter when the added hydrograph is input 0 FINAL Y 48 OUTLETNUM Y 49 HYDRONUM Y 50 H1 Y 51 H H 1 IF H EQ HYDRONUM GOTO 5 PRINT 4 FORMAT Please enter the next hydrograph READ 5 H2 H H 1 IF H EQ HYDRONUM GOTO 5 PRINT 4 READ 5 H3 H H 1 IF H EQ HYDRONUM GOTO 5 PRINT 4 READ 5 H4 H H 1 IF H EQ HYDRONUM GOTO 5 Set the total hydrograph file name IF OUTLETNUM EQ 1 HYDRO HYDRO_1 TXT IF OUTLETNUM EQ 2 HYDRO HYDRO 2 TXT IF OUTLETNUM EQ 3 HYDRO HYDRO 3 TXT IF OUTLETNUM EQ 4 HYDRO HYDRO 4 TXT IF OUTLETNUM EQ 5 HYDRO HYDRO 5 TXT IF OUTLETNUM EQ 6 HYDRO HYDRO 6 TXT IF OUTLETNUM EQ 7 HYDRO HYDRO 7 TXT IF OUTLETNUM EQ 8 HYDRO HYDRO 8 TXT IF OUTLETNUM EQ 9 HYDRO HYDRO 9 TXT IF OUTLETNUM EQ 10 HYDRO HYDRO 10 TXT Se a ee ee ee eee IF IF IF IF H1 EQ
68. Measured HWM 0 12 24 36 48 60 72 84 96 Time Hr since 00 00 June 26 2006 Figure 65 Measured and HWM modeled hydrograph for June 26 2006 Event 118 Sept 01 2006 Hydrograph Comparison Measured HWM Discharge cfs Time Hr since 00 00 Sept 01 2006 Figure 66 Measured and HWM modeled hydrograph for Sept 01 2006 Event 8 3 ANALYSIS OF HWM RESULTS As defined in Section 6 7 the most important criteria for comparing modeled hydrograph to measured hydrograph are the total volume of the runoff peak time and peak discharge values Table 13 shows these three criteria were satisfied Based on the project need a deviation within 15 on runoff total volume and peak discharge is regarded as satisfaction A deviation with 120 minutes equal two modeling time intervals on peak time is regarded as satisfactory 119 Table 13 The comparison of the three criteria for Watershed Two Total Runoff Peak Discharge Peak Time Volume ff cfs min Oct 07 Measured 142341 1 77 1440 2005 Modeled 152055 1 80 1440 Deviation 6 82 1 69 96 0 min Oct 25 Measured 77531 0 79 1020 2005 Modeled 74596 0 81 1080 Deviation 3 79 2 53 96 60 27 Measured 262528 3 12 4560 2005 Modeled 273125 3 00 4620 Deviation 4 04 3 85 60 min Jan 17 Measured 89
69. OTYPE gp 20 CONTINUE CLOSE 70 STATUS KEEP INTERVAL TTp 10 CLOSE 71 STATUS KEEP CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC C Readthe random interval unit hydrograph into an array OPEN 71 FILEZ UNITHYDRO TXT STATUS OLD DO 21 0 5000 READ 71 UNITHYDRO I 21 END DO CLOSE 71 STATUS DELETE CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC SBWSNUM EQ 1 SBWSNUM EQ 2 OPEN SBWSNUM EQ 3 OPEN SBWSNUM EQ 4 OPEN IF OPEN IF IF IF IF SBWSNUM EQ 5 OPEN IF IF IF IF 73 FILE UH_1 TXT SSTATUS UNKNOWN 73 FILE UH_2 TXT STATUS UNKNOWN 73 FILE UH_3 TXT STATUS UNKNOWN 73 FILE UH_4 TXT STATUS UNKNOWN 73 FILE UH_5 TXT STATUS UNKNOWN 73 FILE UH_6 TXT STATUS UNKNOWN SBWSNUM EQ 7 OPEN 73 FILE UH_7 TXT STATUS UNKNOWN SBWSNUM EQ 8 OPEN 73 FILE UH_8 TXT STATUS UNKNOWN SBWSNUM EQ 9 OPEN 73 FILE UH 9 TXT STATUS UNKNOWN IF SBWSNUM EQ 10 OPEN 73 0 10 TXT STATUS UNKNOWN UH 416 the 5 minute interval unit hydrograph for a certain watershed UNITHYDRO is the random interval unit hydrograph for a certain watershed The following codes convert UNITHYDRO to UH using linear interpolation Because UNITHYDRO is a random interval unit hydrograph we set it as a temporary file and do not store it WRITE 73 0 FIVE 0 083333333 4 0 DO WHILE J LE 5000 DO 30 J 0 5000 IF J INTERVAL LE FIVE AND J 1 INTERVAL GE FIVE THEN TEMP UNITHYDRO J UNITHYDRO J 1 UN
70. RINT Please enter the initial condition elevation again READ 5 INITIAL GOTO 100 END IF RESINTERVAL INDEX 1 DO 105 J 1 RESINTERVAL C The IF statement interpolates to get initial outflow and storage IF INITIAL GE ELE J AND INITIAL LE ELE J 1 THEN 1 STO J STO J 1 STO J INITIAL ELE J ELE J 1 ELE J Q1 DIS J DIS J 1 DIS J INITIAL ELE J ELE J 1 ELE J GOTO 106 END IF 105 CONTINUE 106 PRINT Calculation is in progress please wait C File unit 10 is the input file it contains routing input required by LEVEL POOL OPEN 10 STATUS OLD FILE BEFORE C Initialize the input and output 1 is the LEVEL POOL input Q is the LEVEL POOL output DO 5 INDEX 1 2880 IINDEX 0 Q INDEX 0 5 CONTINUE C Read data from the runoff txt file DO 6 INDEX 1 2880 READ 10 INDEX 6 CONTINUE ADDINPUT 1 0 DO INDEX 2 2880 ADDINPUT INDEX I INDEX I INDEX 1 END DO VARIABLE1 1 2 S1 300 Q1 VARIABLE2 1 0 Q 1 Q1 C This section is to route and print out the results DO INDEX 2 2880 VARIABLE2Z INDEX ADDINPUT INDEX VARIABLE 1 INDEX 1 162 DO 107 J 1 RESINTERVAL The IF statement interpolates to get outflow IF VARIABLE2 INDEX GE REL J AND VARIABLE2 INDEX LE REL J 1 THEN Q INDEX DIS J DIS J 1 DIS J VARIABLE2 INDEX REL J REL J 1 REL J IF Q INDEX GE 10000 OR Q INDEX LE 0 0001 THEN Q INDEX 0 END IF GOTO 108 END IF 107 CON
71. S Geology Survey http gisdata usgs net GeoCommunity GIS Data Depot http www gisdatadepot com Pennsylvania Spatial Data Access http www pasda psu edu etc Triangulated Irregular Networks TIN is another type of digital elevation map TIN can be used for visualization as background elevation maps for generating new TIN or DEM or perform basin delineation and drainage analysis in WMS 30 After DEM or TIN files are imported into WMS users can modify the elevation value of a certain point in WMS TIN files are not widely published on the web Therefore it is more difficult to find the proper TIN file than DEM file Fortunately TIN and DEM can be converted to each other Theoretically users can also create TIN file from the beginning manually However since watershed normally consists of thousands of points creating TIN files from scratch is not realistic 3 4 WATERSHED DELINEATION Both DEM and TIN are used as elevation information files to delineate a watershed First flow directions for individual DEM cells or TIN vertices are created By creating an outlet on a down stream branch stream network and watershed boundary are generated based on flow direction and stream threshold After the watershed is delineated the basin s characters such as area basin s slope maximum flow distance etc can be calculated automatically by WMS If the user is not satisfied with the automatically generated streams or water
72. T STATUSZ OLD SBWSNUM EQ 8 OPEN 73 FILEZ UH 8 TXT STATUSZ OLD SBWSNUM EQ 9 OPEN 73 FILE UH_9 TXT STATUS OLD SBWSNUM EQ 10 OPEN 73 FILE2Z UH 10 TXT STATUS OLD pP MP MP FLAG 1 1 0 DO WHILE FLAG LE 6000 READ 73 END 101 UNIT I 1 1 1 FLAG FLAG 1 END DO 101 UNITNUM I 1 FLAG 1 1 0 We do not know how long the two file are so we use EOF to determine when to stop reading it END LABEL Specifies a label to branch jump to if an END OF FILE EOF is reached READing past the end of file If no EOF reading will continue DO WHILE FLAG EQ 1 READ 74 end 40 EXCESS DO 102 J 0 UNITNUM HYDROARRAY I J 6 l EXCESS UNIT J 102 CONTINUE 1 1 1 40 CLOSE 73 STATUS DELETE CLOSE 74 STATUS KEEP OOO0O0O00 C Initialize the 1 D hydrograph DO 70 K 0 28800 HYDRO_ONE_D kK 0 70 CONTINUE Add the 2 0 hydrograph together into 1 D hydrograph DO 80 K 0 28800 DO 60 0 480 HYDRO_ONE_D K HYDRO_ONE_D K HYDROARRAY I K 149 60 CONTINUE IF HYDRO ONE D K GE 10000 OR HYDRO ONE D K LE 0 0001 THEN HYDRO ONE D K 0 END IF 80 CONTINUE IF IF IF IF IF IF IF IF IF IF SBWSNUM EQ 1 OPEN SBWSNUM EQ 2 OPEN SBWSNUM EQ 3 OPEN SBWSNUM EQ 4 OPEN 75 FILE HYDRO 1 TXT STATUS Z UNKNOWN SBWSNUM EQ 5 OPEN 75 FILE HYDRO_2 TXT STATUS UNKNOWN 75 FILE HYDRO_3 TXT STATUS UNKNOWN 75 FILEZ HYDRO 4
73. THE STUDY OF GIS BASED HYDROLOGICAL MODEL IN HIGHWAY ENVIRONMENTAL ASSESSMENT by Weizhe An B E Tianjin University 2000 M S Tianjin University 2002 Submitted to the Graduate Faculty of School of Engineering in partial fulfillment of the requirements for the degree of Doctor of Philosophy University of Pittsburgh 2007 UNIVERSITY OF PITTSBURGH SCHOOL OF ENGINEERING This dissertation was presented by Weizhe An It was defended on March 30 2007 and approved by Dr Rafael G Quimpo Professor Dept of Civil and Environmental Engineering Dr Ronald D Neufeld Professor Dept of Civil and Environmental Engineering Dr Jeenshang Lin Associate Professor Dept of Civil and Environmental Engineering Dr William Harbert Associate Professor Dept of Geology and Planetary Science Dissertation Director Dr Rafael G Quimpo Professor Dept of Civil and Environmental Engineering il THE STUDY OF GIS BASED HYDROLOGICAL MODEL IN HIGHWAY ENVIRONMENTAL ASSESSMENT Weizhe An Ph D University of Pittsburgh 2007 Highway construction often causes substantial adverse environmental effects both during and after the construction phases To assess the impact of highway construction on surrounding environment and mitigate its adverse influences I 99 Environmental Research is being conducted This study is a component of I 99 Environmental Research and mainly focuses on hydrological modeling of the
74. TINUE 108 C 97 98 99 VARIABLE INDEX VARIABLE2 INDEX 2 Q INDEX END DO File 20 is the output file it contains LEVEL POOL routing output OPEN 20 FILE AFTER STATUS UNKNOWN DO 8 INDEX 1 2880 WRITE 20 Q INDEX CONTINUE WRITE 20 0 CLOSE 10 STATUS KEEP CLOSE 20 STATUS KEEP CLOSE 30 STATUS KEEP CLOSE 40 STATUS KEEP CLOSE 50 STATUS KEEP CLOSE 60 STATUS KEEP PRINT 97 FORMAT PRINT 98 FORMAT Calculation finished Please close the window PRINT 99 FORMAT and check the output files STOP END 163 A 8 KINEMATIC_WAVE F The program Highway Watershed Model HWM is organized as followings 1 SCS curve number method is used to generate excess rainfall EXCESSRAINFALL F Parameters needed to input CN Curve number for each sub watershed AMC Antecedent moisture conditions 2 SCS Unit hydrograph is used to generate hydrograph at the outlet HYDRO F Parameters needed to input Tc Time of concentration of the sub watershed Area Area of the sub watershed 3 Muskingum method is used to route hydrograph in channel MUSKINGUM F Parameters needed to input K Muskingum coefficient X Muskingum coefficient 4 Linear reservoir or Level pool method is used to route hydrograph in reservoir LINEARRESERVOIR F n 1 K time of travel Parameters needed to input K Travel time of the reservoir LEVELPOOL F Parameters needed to input Initial
75. TXT STATUS Z UNKNOWN 75 FILE HYDRO_5 TXT STATUS UNKNOWN 75 FILEZ HYDRO 6 TXT STATUS Z UNKNOWN SBWSNUM EQ 7 OPEN 75 FILEZ HYDRO 7 TXT STATUSZ UNKNOWN SBWSNUM EQ 8 OPEN 75 FILEZHYDRO 8 TXT STATUSZ UNKNOWN SBWSNUM EQ 9 OPEN 75 FILEZHYDRO 9 TXT STATUSZ UNKNOWN SBWSNUM EQ 10 OPEN 75 FILEZ HYDRO 10 TXT STATUSZ UNKNOWN SBWSNUM EQ 6 OPEN IP TOP nnn OT 2 SF YS SES LIL wy C Write the 1 D hydrograph to file DO 90 K 0 28800 WRITE 75 HYDRO ONE D K 90 CONTINUE CLOSE 75 5 5 PRINT 98 98 FORMAT Calculation finished Please close the window PRINT 99 99 FORMAT and check the output files STOP END 150 5 MUSKINGUM F program Highway Watershed Model HWM is organized as followings 1 SCS curve number method is used to generate excess rainfall EXCESSRAINFALL F Parameters needed to input CN Curve number for each sub watershed AMC Antecedent moisture conditions 2 SCS Unit hydrograph is used to generate hydrograph at the outlet HYDRO F Parameters needed to input Tc Time of concentration of the sub watershed Area Area of the sub watershed 3 Muskingum method is used to route hydrograph in channel MUSKINGUM F Parameters needed to input K Muskingum coefficient X Muskingum coefficient 4 Linear reservoir or Level pool method is used to route hydrograph in reservoir LINEARRESERVOIR F n 1 K time of
76. The watershed area watershed length precipitation depth and temporal distribution are important to watershed modeling They are easy to estimate and errors are not large However some important parameters are very difficult to estimate These include the curve number for each land use the slope for each sub watershed the water flow velocity in Muskingum routing and the initial condition of reservoir Sometimes the parameters are different for different rainfall events even for the same watershed The reservoir elevation storage and elevation discharge characteristics are easy to obtain from the 83 design engineer However the reservoir will be partially filled after period of operation The reservoir initial conditions are also difficult to estimate The model is used to simulate different storm events To keep the model robust the watershed characteristics such as slope watershed length and area are all the same in different storm events The curve numbers are not the same for different storm events This is true because soil moisture content varies before different storm events Most parameters are determined by field survey These parameters include watershed length watershed area precipitation depth and temporal distribution reservoir characteristics and reservoir initial elevation However some other parameters cannot be determined accurately solely by field survey These parameters include curve number CN watershed slo
77. Total rainfall depth 1 00 inch 81 Half hr rainfall inch Half hr rainfall inch May 11 2005 Half Hour Incremental Rainfall 0 3 0 25 0 15 0 2 0 1 36 48 60 72 84 96 Time Hr since 00 00 May 11 2006 Figure 41 f Half hour incremental rainfall from May 11 to May 14 2006 Total rainfall depth 1 34 inch June 26 2006 Half Hour Incremental Rainfall 0 3 0 25 0 2 0 1 0 15 0 05 0 12 24 36 48 60 72 84 96 Time Hr since 00 00 June 26 2006 Figure 41 Half hour incremental rainfall from June 26 to June 29 2006 Total rainfall depth 1 31 inch 82 Sept 01 2006 Half Hour Incremental Rainfall 2 I Half hr rainfall inch o o R o pn o 2 Dy 1 24 36 48 60 72 84 96 Time Hr since 00 00 Sept 01 2006 S Figure 41 h Half hour incremental rainfall from Sept 01 to Sept 04 2006 Total rainfall depth 2 55 inch 64 PARAMETER SELECTION AND MODEL CALIBRATION The most important criteria for comparing model predictions to measured values are the total volume of the runoff peak time and peak discharge values The relationship between some important model parameters and model results are discussed in Section 3 11
78. UTLETNUM EQ 1 THYDRO HYDRO_1 TXT F OUTLETNUM EQ 2 THYDRO HYDRO_2 TXT F OUTLETNUM EQ 3 THYDRO HYDRO_3 TXT F OUTLETNUM EQ 4 THYDRO HYDRO_4 TXT F OUTLETNUM EQ 5 THYDRO HYDRO_5 TXT F OUTLETNUM EQ 6 THYDRO HYDRO_6 TXT F OUTLETNUM EQ 7 THYDRO HYDRO_7 TXT F OUTLETNUM EQ 8 THYDRO HYDRO_8 TXT F OUTLETNUM EQ 9 THYDRO HYDRO_9 TXT F OUTLETNUM EQ 10 THYDRO HYDRO_10 TXT Aimmmmmmnnmnm Initialize all variables to be zero DO 20 2 0 2880 Q1 Z Q2 Z 0 Q3 Z 0 156 Q4 Z 0 Q5 Z 0 20 CONTINUE C File unit 1 is the original HYDRO_ TXT file C RHYDRO and HYDRO are the original HYDRO_ TXT file OPEN 1 STATUS OLD FILE HYDRO IF HYDRONUM GE 1 OPEN 2 STATUS OLD FILE RHYDRO IF HYDRONUM GE 2 OPEN 3 STATUS OLD FILE RHYDRO B IF HYDRONUM GE 3 OPEN 4 STATUS OLD FILE RHYDRO C IF HYDRONUM GE 4 OPEN 5 STATUS OLD FILE RHYDRO D C Read the routed hydrograph into an array DO 6 2 0 2880 READ 1 Q1 Z 6 CONTINUE C number of rounted file is greater than 1 more statements need to be executed IF HYDRONUM GE 1 THEN DO 7 2 0 2880 READ 2 Q2 Z 7 CONTINUE ENDIF IF HYDRONUM GE 2 THEN DO 8 Z 0 2880 READ 3 Q3 Z 8 CONTINUE ENDIF IF HYDRONUM GE 3 THEN DO 9 Z 0 2880 READ 4 Q4 Z 9 CONTINUE ENDIF IF HYDRONUM GE 4 THEN DO 10 Z 0 2880 READ 5 Q5 Z 10 CONTINUE ENDIF C Adding hydrographs DO 11 2 0 2880 2 01 2 02 2 03 2 04 2 05 2 11 CONTINUE THYDRO is the final total hy
79. User needs to draw closed polyline assign it to be generic line and then build a polygon and assign it to be a drainage boundary type The outlet is a conceptual point connecting upstream flow and downstream flow Points are categorized into generic drainage outlet and route point The point type should be assigned to a drainage outlet One outlet must be accompanied with a basin to form the correct watershed model schematic structure A reservoir works as water storage or flood detention structure in the watershed Although an actual reservoir has a certain area and shape its function can be abstracted into an outlet in WMS model The reservoir s characteristics are input into outlet routing strategies Thus an outlet contains not only channel routing but also reservoir routing strategies A reservoir is not required in every outlet If an outlet does not have a reservoir only channel routing method is defined for the outlet 3 6 IMPORTING AND CREATING OF LAND USE AND SOIL DATA Land use file is a polygon schematic map overlapped onto the watershed boundary It has land use data properties and is defined in Land Use Layer Similarly soil data file is also a polygon schematic map overlapped onto the watershed boundary It has soil data properties and is defined in Soil Data Layer Land use and soil type files are used to calculate the composite curve number of sub watershed Most publicly available land use and soil data files are in Sh
80. WM BAT must be changed accordingly The input hydrograph file of channel routing and reservoir routing module is HYDRO TXT The output hydrograph file of channel routing and reservoir routing module is RHYDRO If two or more routings are connected the input file of later routing is the output file of previous routing Thus the original HYDRO_ TXT needs to be deleted and the routing output file RHYDRO TXT needs to be renamed to HYDRO ZTXT to meet the input name format requirement Since the modeled watershed contains two consecutive routings the deleting and renaming operations are required in the BATCH file Fortunately these operations can be easily accomplished by DOS command DEL and REN B 10 HWM EXECUTION With all the HWM modules HWM BAT file and parameter file well established the HWM execution is simple All that is needed is to double click the HWM BAT file The HWM BAT executes each module of HWM and output various text files The final output file contains coordinates of final outlet hydrograph in hourly interval For diagram view user needs to open the final output text file and copy all values into MS Excel Spread Sheet Although executing HWM using HWM BAT file seems easier the preparation works of it are much more than executing manually Furthermore once the automatic method is set it can only model the fixed watershed schematic If the 177 watershed schematic is changed most HWM modules HWM BAT file a
81. a spatially distributed velocity field Hydrological Processes Vol 10 831 844 1996 McCuen R H Hydrologic Analysis and Design 2 Edition Prentice Hall Upper Saddle River NJ 1997 Meybeck M Chapman D V and Helmer R Global Freshwater Quality a First Assessment WHO and UNEP Blackwell Ltd 1989 Miller J E Basic Concepts of Kinematic wave Models U S Geological Survey Professional Paper 1302 1984 Muzik I Flood Modeling with GIS derived distributed unit hydrographs Hydrological Processes Vol 10 1401 1409 1996 Nash J E The form of the instantaneous unit hydrograph C R et Rapports Assn Internat Hydrol IUGG Toronto 1957 Natural Resources Conservation Service Hydrology Section 4 National Engineering Handbook 2001 O Loughlin G Huber W and Chocat B Rainfall Runoff Processes and Modelling Journal of Hydrological Research Delft the Netherlands Vol 34 pp 733 751 1996 Quimpo G An W and Scheller A B I 99 Environmental Research Report Unpublished project report Appendix A Highway Watershed Model Users Manual 2007 Quimpo R G and Emerick J Resolution and accuracy in watershed response modeling with GIS Proceedings International conference on GIS and remote sensing in hydrology water resources and environment Three Gorges Dam Yichang P R China 2003 Quimpo R G I 99 Environmental Research progress report Unpublished project report 2005
82. ace other files relating discharge and storage to the selected elevations must be made Lastly a file containing the relationship between storage and discharge is created All of these files have the same number of entries which is equal to the number of elevation increments that were entered This process of relations is classically a graphical method where the storage at corresponding height is compared to discharge at the same height This regime of curves used to develop the storage outflow relationships and perform the routing procedure is shown in Section 7 7 All of equation calculations are completed within the program LEVELPOOL F 175 Once it has finished routing the flow through the pond the routed hydrograph must be added to the hydrograph of the adjacent downstream un routed hydrograph To do this the ADD F program Section B 6 is implemented The input and output file parameters are shown in Table 22 Table 22 Input and output of LEVELPOOL F File Input Output data Definition PARAMETERS TXT Pond number initial condition User defined input ELEVATION Pond elevation data User defined input DISCHARGE TXT Pond discharge data User defined input STORAGE TXT Pond storage data User defined input RELATIONSHIP Storage outflow function in Figure 58 User defined input HYDRO Sub watershed hydrograph Program defined input RHYDRO TXT Routed hydrograph after storage pond P
83. ameters estimation and job control setting are independent of the GIS data and can be implemented without any problems The watersheds contour maps structure layout maps and station numbers were obtained from Pennsylvania Department of Transportation PENNDOT The ponds characteristics were collected from ponds designers The characteristics of the structures such like pipe diameter location and slope are obtained from the designers The land use and soil type are obtained by our field survey Measured runoff data were obtained from Ecotone flumes of AWK Consulting Engineers Inc Measured rainfall data were obtained from raingages of Skelly and Loy Inc 72 6 1 MODEL ASSEMBLY FOR WATERSHED ONE Watershed One has an area of 0 085 sq mile 54 4 acres A scanned map was referenced to the local coordinate system by registering the map Three points were selected as base points The first point is at the right edge of Pond SB111 it has the coordinate of 586 8 ft 474 ft The second point is at the left boundary it has the coordinate of 430 ft 288 ft The third point is at the ridge of the watershed it has the coordinate of 2040 ft 913 6 ft The origin is selected to be the center of a north arrow in the map These points can be selected arbitrarily as long as their relative positions are correct Figure 36 shows the schematic layout for Watershed One The background map is hidden for clear display purpose The main layer dis
84. ameters from file and can only model a fixed watershed schematic Thus using HWM BAT can save much time for user but it is less flexible 178 BIBLIOGRAPHY Beighley R E and Moglen G E Trend Assessment in Rainfall Runoff Behavior in Urbanizing Watersheds Journal of Hydrologic Engineering Vol 7 No 1 pp 27 34 2002 Beven K J Lamb R Quinn P F Romanowicz and Freer J 1995 TOPMODEL In Computer Models of Watershed Hydrology Singh V P ed Water Resources Publications 627 668 Blazkova S Beven K Flood frequency prediction for data limited catchments in the Czech Republic using a stochastic rainfall model and TOPMODEL Journal of Hydrology 195 256 278 1997 Boyd M J Pilgrim D H and Cordery I A storage routing model based on catchment geomorphology J Hydrol Vol 42 pp 42 209 230 1979 Brimicombe A GIS Environmental Modeling and Engineering Taylor amp Francis 2003 Campling P Gobin A Beven K and Feyen J Rainfall Runoff Modelling of a Humid Tropical Catchment the TOPMODEL Approach Hydrological Processes Vol 16 pp 231 253 2002 Chen 7 M L Fukami K Yoshitani and Matsuura T Watershed Environmental Hydrology WEHY Model model application Journal of Hydrologic Engineering Vol 9 No 6 pp 480 490 2004b Chen Z Q Kavvas M L Yoon J Y Dogrul C Fukami K Yoshitani J and Matsuura T Geomorphic and soil
85. annot be removed easily Actually they should NOT be altered if they form a big pond Once they are altered the model can not reflect the real watershed characteristics While pits and flat terrains are very common in reality WMS cannot deal with it very well Sometimes users need to find out other methods to solve this problem 0222 ANS 1 p x qu STI NY ri ie Figure 8 An example of watershed delineation using DEM 32 Figure 9 An example of watershed delineation using TIN 35 DRAINAGE COMPONENT EDITING As stated above automatic delineation is not enough even for identifying a watershed Some model components must be edited manually Streams can be generated automatically or drawn by users Automatic streams are generated from DEM or TIN files If the automatically generated streams are not enough users need to draw the stream manually Streams are abstracted to be polylines in WMS Several types of polylines are employed in WMS model They are generic stream pipe lake and ridge After drawing a polyline using draw line tool user must assign it to be stream type The drawing direction of a stream must from downstream to upstream Other types of lines also should be assigned to proper line type The basins boundaries are polygon shaped Polygons are categorized into the following types generic lake reservoir and drainage boundary Polygons cannot be 33 drawn directly in WMS
86. ape file format First users should import them into WMS then connect the Shape files with their database to obtain land use and soil digital information Finally the Shape files must be converted to feature objects which are actually used in WMS Land use is classified into 20 types while soil type is classified into four types by SCS 1972 The relationship between curve number and land use soil type is described in Chapter Two Figure 10 Figure 11 Figure 12 and Figure 13 are illustrations of land use soil type map and their corresponding tables respectively The polygons in Figure 10 and Figure 12 represent different land use and soil type patches 34 LEVEL2 0 01577 VERGREEN FOREST LAND 0 04103 VERGREEN FOREST LAND 0 08092 SHRUB amp BRUSH RANGELAND 0 03276 SHRUB amp BRUSH RANGELAND 0 02251 IED RANGELAND 0 04703 IED RANGELAND 0 02518 ROPLAND AND PASTURE 0 10722 IED FOREST LAND 0 06161 IED RANGELAND 0 06353 IED FOREST LAND 0 05931 SHRUB amp BRUSH RANGELAND 0 03868 SHRUB amp BRUSH RANGELAND 0 08247 ROPLAND AND PASTURE 0 03269 SHRUB amp BRUSH RANGELAND 0 04243 SHRUB amp BRUSH RANGELAND 0 05665 SHRUB amp BRUSH RANGELAND n nc4 n Help 959 records Figure 11 Attribute table for land use map 35 SAS TEE pe 212 5 Mal A A Im E D Figure 12 Illustration of soil type map Attributes 1 Figure 13 Attribute table
87. ary array TEMP is a temporary value FIVE is five minutes in hour EXCESS is the excess rainfall in a certain half hour UNIT is the temporary variable to store the unit hydrograph REAL UNITHYDRO 0 5000 TEMP FIVE EXCESS UNIT 0 4200 Y 1 100 SBWSNUM is the watershed number and J are the index FLAG is a indicator UNITNUM is the number of unit hydrograph coordinate INTEGER SBWSNUM 4 FLAG UNITNUM LINE HYDROARRAY is the temporary array to store hydrograph HYDRO ONE Dis the temporary array to store one dimension hydrograph REAL HYDRO ONE D 0 28800 0 480 0 28800 CHARACTER 20 X 1 100 OOOOO000 C Read all parameters from a file OPEN 50 FILE PARAMETER TXT STATUS OLD DO 200 1 100 READ 50 END 201 200 CONTINUE 201 LINE I 1 CLOSE 50 STATUS KEEP 6 SBWSNUM zY 3 7 CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC tp 0 6 Tc 60 C TTpis the time of rise C We are generating half hour unit hydrograph so tr 0 5 tr 2 0 25 tr 0 5 0 25 tp ib 2 67 TTp C We use the English unit system The peak discharge unit is cfs qp 483 4 Area TTp UHDUR TTp 5 CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC C Basedon prototype unit hydrograph derive the real unit hydrograph 147 OPEN 70 FILE UHPROTOTYPE TXT STATUS OLD OPEN 71 FILE UNITHYDRO TXT STATUS UNKNOWN DO 20 0 5000 READ 70 PROTOTYPE WRITE 71 PROT
88. ated through vegetation root A watershed is a region of land where water drains down slope into a specified body of water such as a river lake ocean or wetland A watershed includes both the waterway and the land that drains to it A watershed boundary is determined by its topographic characteristics Ridges hills and mountains often play the role of delineating a watershed from other watersheds Based on the description above the main hydrological processes can be modelled by the following four modules Each module can be simulated by several methods This proposal considers only some representatives of each module 1 Precipitation loss module 2 Surface water flow module 3 Channel flow module 4 Base flow module 21 PRECIPITATION LOSS MODELING Rainfall runoff model computes runoff volume by computing the volume of water that is intercepted infiltrated stored evaporated transpired and subtracted from the precipitation The loss can be broadly categorized into infiltration down loss and evaporation up loss Infiltration from watershed area can be computed by the Horton Equation Green Ampt model and the Soil Conservation Service SCS curve number CN method SCS 1972 The Horton model is based on empirical observations showing that infiltration decreases exponentially from an initial maximum rate to some minimum rate over the course of a long rainfall event The model describes the infiltration capacity as a
89. atershed properties 53 1 99 DEM DATA GENERATION As stated in Section 5 1 the resolution of downloaded DEM file is too coarse compared to the small watershed area We created a 2x2 sq ft DEM file for Watershed SB10 11 from MicroStation DGN file provided by Pennsylvania Department of Transportation PENNDOT The DGN file only contains contour poly lines map There is no label polygon or points in the file The elevation information of each contour line is stored in the poly line s element information table but not displayed in the map The MicroStation 61 DGN format contour line file can be converted into DEM file through the following procedures 1 DGN file is imported into ArcGIS using Add Data function The DGN file is shown in Figure 24 Figure 24 The DGN file view in ArcGIS 2 DGN file is converted into TIN file in 3D Analyst an extension of ArcGIS The function to be used is Create TIN From Features The TIN file is shown as in Figure 25 62 Figure 25 The TIN file view in ArcGIS 3 TIN file is converted into GRID file in 3D Analyst using the function of 77N To Raster Resolution of the GRID file can be assigned in this procedure For example we can assign it as 2 2 sq ft or 5x5 sq ft The GRID file is shown as in Figure 26 63 Figure 26 The GRID file view in ArcGIS and WMS 4 Start WMS turn to the GIS module enable the ArcObject function add ArcGIS GRID file into WMS using Add Data functio
90. can be modeled and controlled by and K but can not be described in SCS UH 99 7 5 15 UNIT HYDORGRAPH Besides the SCS and LE unit hydrograph method a more complicated method the Isochrone Unit Hydrograph ISO UH is also employed in unit hydrograph development The Isochrone curve is the curve which connects points in the watershed with equal travel time to the outlet The ISO UH is constructed based on the isochrone curve 7 5 1 Isochrone curve generation To determine the isochrone curve detailed flow path distribution flow path length channel slope water velocity in a watershed must be determined The procedure of isochrone curve generation which is an example of sub watershed Right Highway is illustrated in the following 1 Each patch in the sub watershed is identified using the project land use and topographical map The patches are sliced small enough to ensure each patch can be represented by single slope single flow direction and single flow velocity coefficient K in Equation 7 3 The patch identification is illustrated by polygons in Figure 49 2 The flow path placement is determined based on topographical analysis The flow paths are displayed in Figure 49 using arrows 3 Slope and flow velocity coefficient K are calculated based on field survey They are shown in Figure 49 4 Flow velocity in each patch is calculated using Equation 7 3 This is illustrated in Figure 49 5 travel t
91. can obtain the average outflow at any time which is the ordinate of the ISO UH 7 6 RUNOFF GENERATION AT EACH SUB WATERSHED Once the unit hydrograph has been determined it may be applied to find the direct runoff and stream flow hydrograph For calculation convenience the time interval used in defining the excess rainfall hyetograph ordinates should be the same as that for which the unit hydrograph was specified The discrete convolution equation is described in Equation 2 14 77 CHANNEL AND PIPE ROUTING As shown in Figure 45 and Figure 46 runoff obtained at each sub watershed needs to be routed downstream Muskingum routing which is described in Chapter Two is used in channel routing To improve the modeling results kinematic wave routing is applied in pipe routing This is the case in Watershed One runoff from Up Stream sub watershed to Down Stream and in Watershed Two runoff from Up Stream sub watershed to Down Stream The diameter of the pipe used in Watershed One and Watershed Two is 18 inches and 30 inches respectively Although Watershed One is mentioned here it will not be modeled due to water diversion problem which 1 described in Section 6 4 The kinematic wave model is one of the distributed models It neglects the local acceleration convective acceleration and pressure terms in the momentum equation The kinematic wave model is defined by Equation 2 15 a and Equation 2 17 105 The assumptions and app
92. ce in total runoff was up to 16 the difference of peak discharges was up to 18 in peak times up to 2 5 hours Yue et al 2000 modeled the Kaifu River basin in Japan The difference in peak discharges was up to 15 in peak times up to 3 hours Whigham et al 2001 modeled the Namoi River catchment Australia The deviation between total runoff was 17 in peak discharges up to 26 Based on these it was decided that 15 deviation would be acceptable The above criteria were adopted in the rest of the study Table 9 The comparison of the three criteria in two events for Watershed Two Total Runoff Peak Discharge Peak Time Volume ft cfs min Oct 07 Measured 142341 1 77 1440 2005 Modeled 137675 1 99 1500 Deviation 3 3 12 4 60 min Measured 77531 0 79 1020 Oct 25 2005 Modeled 74786 11 840 Deviation 3 5 39 2 180 min 90 As we can see from Table 9 both deviations of the modeled runoff total volume are accepted within satisfactory one of two deviations of the peak discharge values is not satisfactory one of two deviations of the peak times is not satisfactory As mentioned before among the three criteria runoff total volume is easy to model However the peak discharge and peak time are difficult to model accurately There are several shortcomings of this model First although the calculation methods were chosen in each section of the model the WMS model does not provide cal
93. cient to describe various antecedent moisture conditions Among the parameters used in the models CN is explicitly related to AMC How to determine CN value becomes a big problem in the modeling To determine if CN values change in a systematic way an attempt was made to find out the relationship between CN and AMC In the studied watershed some sub watershed land uses are paved driveway Their CN values change 123 very little with Sub watershed Stream is large and mostly natural land Thus Up_Stream is chosen to analyze the CN AMC relationship It is difficult to measure the soil moisture condition After many attempts two day antecedent precipitation depth APD four day APD and seven day APD are examined as indicators of AMC CN AMC relationships from WMS and HWM are analyzed Table 14 shows Up_ Stream sub watershed CN and AMC for the eight storm events in WMS It should be noticed that CN in Table 14 only refer to CN in Up Stream sub watershed not the overall weighted CN in the model Figure 70 shows their relationship in graph format Since two day APDs in many events are zero it may not be a good AMC indicator Most of early rainfall in seven day APDs is evaporated by sunshine and vegetation This may be the reason for the poor fit in Figure 70 c whose R square value is 0 5394 Figure 70 b shows the plotted graph with R square value 0 7191 for four day APD and CN From Figure 70 a Figure 70 b and Figure 70 c
94. culation details which may be important to modeling results For example if the calculation time interval is changed the modeling results are also changed a little This behavior is not expected in modeling Since the WMS is an integrated model we do not know the program codes and do not know how the calculation interval influences the modeling results in algorithm Second the model has some restrictions For example only one routing method can be assigned to a channel However in reality one channel can have different routing methods Another example is the maximum limitation for the number of hydrograph ordinates The maximum limitation is 2000 If we have 5 minutes calculation time interval the maximum modeling time period is 2000 5 10000 minutes 166 67 hours 6 94 days This is a big restriction of the model Third to obtain modeled hydrograph that is close to measured hydrograph some parameters are selected unrealistic For example the water velocity in the channel is set to be 0 0016 ft sec This is much slower than real water velocity in the watershed channels The slope of the sub watershed is set to be 0 003 0 01 which is much milder than actual sub watershed slope However from Table 2 we can see that if the water velocity is chosen to be larger or the slope is to be chosen larger the modeled peak time will be early than measured the modeled peak discharge will also be higher than measured Sensitivity analysi
95. d a research model without source DEM file WMS was developed by Environmental Modeling Research Laboratory of Brigham Young University It is flexible in creating a practical model using various input source data or even creating a model from the scratch WMS is able to use Shape file ArcInfo Grid file DEM or TIN source data to create watershed delineation In case of none of the source file is available users can import aerial photographs or even scanned watershed 27 maps as referenced spatial data Although some GIS characteristics are missing in this case users are able to build a flexible practical model for watersheds where source data are not adequate GIS data such as land use and soil type files can be created by the user or imported from readily available data These techniques greatly enhance the applicability of WMS in watershed modeling and make WMS not only a research package but a pragmatic tool in watershed modeling project Another GIS environmental modeling package is Better Assessment Science Integrating Point and Non point Sources BASINS BASINS was developed by the U S Environmental Protection Agency EPA It takes advantage of developments in software and data management technologies and uses the ArcView3 X as the integrating framework to provide the user with a comprehensive watershed management tool In this manner it is like HECGEOHMS However BASINS focus on point and non point pollutant modeling inst
96. d assigning certain properties Soil type and land use data can be viewed in Figure 36 and Figure 38 Although these figures are mainly used for illustrating schematic layout of the watersheds the background gray polygons are soil type and land use data files As stated in Section 5 1 to create topographic GIS data DEM or TIN one needs to assign different values to thousands of pixels This cannot be accomplished manually Although GIS data are good resources relying solely on topographic GIS data could be misleading To overcome these difficulties some measures will be taken in building the model 71 6 0 1 99 ENVIRONMENTAL RESEARCH CASE STUDY Hydrological modeling is performed on the selected two watersheds These are approximately at about the stations of 400 SB111 Watershed One and 185 5 10 5811 Watershed Two in the construction project s alignment Because the topographic GIS data are not applicable in delineating the watershed boundary a schematic watershed boundary is drawn based on real watershed boundary Information related to elevation such as watershed slope and stream slope was also input manually based on field survey Other information such as watershed area watershed length and stream length were calculated in WMS automatically After the watershed is delineated the remaining procedures in runoff modeling such as drainage component editing basin parameters estimation channel and reservoir routing par
97. d hydrograph is 5 Hydrograph from sub watershed 6 H6 is routed to Pond SB 11 to become RH6 RH6 is routed to sub watershed 7 outlet through Pond SB 11 to become RRAH6 Routed hydrograph from upstream watershed or ponds RH5 RRAH4 and is added to hydrograph at sub watershed 7 H7 The added hydrograph is AH7 and is the final hydrograph for the whole watershed Similarly based on Figure 45 the modeling order for Watershed One can also be determined 112 8 0 APPLICATION OF HWM IN I 99 PROJECT Basic information on the project is shown in Chapter Four The model schematic of Watershed Two is shown in Section 7 2 and Section 7 9 The rainfall bar diagrams are displayed in Section 6 3 The ponds characteristics are shown in Section 6 1 and Section 6 2 This chapter only shows the modeling results The methods to determine parameters are similar to WMS model Some parameters are determined only by field survey These parameters include watershed length watershed area precipitation depth and temporal distribution reservoir characteristics and reservoir initial elevation The other parameters are determined by both field survey and trial and error method These parameters include curve number CN watershed slope watershed length water velocity in channel Muskingum K Muskingum As discussed in Section 7 4 HWM has extra parameters other than WMS These include time of concentration for each sub watershed relativ
98. days before each modeled rainfall event an initial condition of bottom elevation SB111 1204 ft is employed in modeling basin areas are calculated by WMS 1212 212 1211 1211 P s 1210 210 1209 1209 z c 8 1208 2 1208 oO m gt 9 1207 5 1207 51206 1206 gt 1205 g 1205 1204 Y 4204 0 25 50 75 100 125 150 175 0 0 0 5 1 0 15 20 25 Reservoir Outflow ft 3 s Reservoir Volume acre ft a Elevation outflow relationship b Elevation volume relationship Figure 37 Elevation storage outflow relationship of SB111 75 Because the watershed s area is small spatially uniform rainfall is used in the model Average precipitation and rainfall time distribution is input into the model For the unit hydrograph SCS dimensionless method is employed The most important parameters in this calculation are watershed length SCS curve number and watershed slope The watershed lag time is calculated using Equation 3 1 Watershed length and SCS curve number can be calculated by WMS using drainage land use and soil type layers since the coordinate system is already set 6 2 MODEL ASSEMBLY FOR WATERSHED TWO The procedure for constructing the second watershed is the same The second watershed has an area of 0 072 sq mile 46 08 acres Three points were selected as base points to register the map The first point is at the right edge of boundary it has the coordinate of 1675 ft 470 ft
99. de to evaluate WMS and HWM The AMC CN relationships were analyzed in Section 8 4 Although Figure 70 b appears to fit the data best compared to Figure 70 a and Figure 70 c its R square value is only 0 7191 In contrast the best fitting graph in Figure 71 has R square value of 0 9858 Thus the AMC CN relationship is better represented in the HWM model 8 5 4 Comments on WMS and HWM software packages The WMS software package used in I 99 Environmental Research was developed by Environmental Modeling Research Laboratory Brigham Young University It is a commercial software package and can be used in many situations WMS has the strength to handle many kinds of GIS data and has graphical user interface GUI However the GIS data in this research is not suitable for WMS The SCS UH method in WMS is also not suitable for the highway watershed response Because WMS is an integrated 133 commercial software package the details of the calculations in WMS modeling are not displayed to users We also can not insert our own model ideas such like LEUH in WMS The HWM package is developed by our research group Although it does not directly use GIS data it uses many parameters from GIS data analysis such as CN Muskingum K and Muskingum X The applicability of HWM to other watersheds needs to be tested At least in the 1 99 highway watersheds HWM produces satisfactory modeling results One of HWM modules utilizes LEUH instead of SCS UH
100. del results in one single sub watershed Generally the hydrograph comes from several sub watersheds outlets and reservoirs which have several sets of parameters In this case the model results are more complicated to anticipate 43 40 1 99 ENVIRONMENTAL RESEARCH OVERVIEW 41 PROJECT INTRODUCTION The Pennsylvania Department of Transportation PENNDOT is constructing the U S Route 220 1 99 State Route S R 6220 project that is a part of extending I 99 to I 80 at Bellefonte Figure 15 shows the I 99 project location Figure 16 shows the Environmental Impact Study EIS area boundary New I 99 US 220 Corridor Figure 15 The I 99 project location 44 Taylor Township EIS Project Area Boundary Construction Sections Approximate Limits of Work Roadway Right of way Roadway Centerline DRESSERS DES Sn Saab PR SLR oL NERA CAREY v Vu SD ES eO MES CH eC MOSH Figure 16 The Environmental Impact Study EIS area boundary 45 Figure 1 1 99 S R 6220 Relocation Project Blair and Centre Counties Highway construction often causes substantial adverse environmental effects both during and after construction Construction induced impacts include soil erosion resulting from clearing grubbing and earth movement and rainfall runoff Relocation of streams direct and indirect impacts to wetlands and encountering hazardous wastes are also the constructio
101. drograph OPEN 10 STATUS UNKNOWN FILE THYDRO IF FINAL EQ 0 THEN DO 30 Z 0 2880 WRITE 10 QT Z 30 CONTINUE ELSE DO 31 2 0 2880 12 WRITE 10 QT Z 31 CONTINUE 157 98 99 CLOSE 1 STATUS KEEP IF HYDRONUM GE 1 CLOSE IF HYDRONUM GE 2 CLOSE IF HYDRONUM GE 3 CLOSE IF HYDRONUM GE 4 CLOSE CLOSE 10 STATUSZ KEEP 2 STATUS KEEP 3 STATUS KEEP 4 STATUS KEEP 5 STATUSZ KEEP D PRINT 98 FORMAT Calculation finished Please close the window PRINT 99 FORMAT and check the output files STOP END 158 OOOO000000000000000000000 O LEVELPOOL F program Highway Watershed Model HWM is organized as followings 1 SCS curve number method is used to generate excess rainfall EXCESSRAINFALL F Parameters needed to input CN Curve number for each sub watershed AMC Antecedent moisture conditions 2 SCS Unit hydrograph is used to generate hydrograph at the outlet HYDRO F Parameters needed to input Tc Time of concentration of the sub watershed Area Area of the sub watershed 3 Muskingum method is used to route hydrograph in channel MUSKINGUM F Parameters needed to input K Muskingum coefficient X Muskingum coefficient 4 Linear reservoir or Level pool method is used to route hydrograph in reservoir LINEARRESERVOIR F n 1 K time of travel Parameters needed to input K Travel
102. e as channel routing That is if we encounter a reservoir routing we should consider it any another channel routing to process the model 110 7 HYDROGRAPH ADDITION The hydrograph after channel routing is still separate from other sub watershed s hydrograph In order to obtain the total hydrograph at the final outlet we should add the routed hydrograph to the proper downstream routed or un routed hydrograph This is done by simply adding discharges at the same time for different hydrographs Channel routing and hydrograph addition are operated interactively according to the schematic of the whole watershed The hydrograph from upstream sub watershed is routed to the downstream sub watershed The routed hydrograph is added onto the un routed hydrograph at the downstream sub watershed If routed hydrographs from more than one sub watershed meet at the same sub watershed all the routed hydrographs should be added onto the un routed hydrograph at the downstream sub watershed The added hydrographs are then routed further downstream as in the previous routing procedure As Section 7 7 states reservoir routing can be considered as another channel routing This routing and adding procedure is repeated until all the hydrographs are added to the most downstream outlet According to the above description different watershed schematics induce different routing and adding order Because the studied watersheds are fixed in schematic the
103. e calculated within the code and the initial discharge values are contained 173 within the input file that was generated from the previous program HYDRO f That is the inflow values into a specific reach are the outflow hydrograph coordinates from the previous watershed in the schematic The HWM is formulated so that there is a separate program for each reach of stream that must be routed Before a particular watershed is modeled one must first determine how many times the flow should be routed and the order of this procedure Then the programs can be executed in the correct order to ensure that flow is being modeled correctly in an upstream to downstream fashion Also after each channel routing the hydrograph addition must be executed The input and output file parameters are shown in Table 20 Table 20 Input and output of MUSKINGUM F File Input Output data Definition PARAMETERS TXT Muskingum Muskingum X User defined input HYDRO Sub watershed hydrograph Program defined input RHYDRO Coordinates of the routed Program defined hydrograph from each sub watershed output B 6 HYDROGRAPH ADDITION Program used ADD F The purpose of ADD f is to add the routed hydrograph to the direct un routed hydrograph of the adjacent downstream sub watershed The part is relatively simple and its working mechanism is illustrated in Section 7 8 The input of the program is one or more routed hydro
104. e channel Then it is routed to the detention pond through an underground pipe The watershed Up Side is disturbed by construction and is close to the highway so water from this part is dirty The sub watershed Highway collects dirty water from the road surface On the highway every 450 ft interval distance there are two catch basins used to collect dirty water The catch basins conduct water from the highway to the detention pond through an underground pipe The sub watershed Down Side is located at the lower side of the highway For the same reason water from this part is also dirty water The difference of this sub watershed from Up Side is that water flow to a highway ditch and then flows to the detention pond directly without flowing backward The pond SB111 is at the bottom of sub watershed Down Side Dirty water from the three sub watersheds stays in the pond for sedimentation purpose before flowing downstream The last sub watershed Down Stream is located at the bottom of the whole watershed Since it is far from highway and most area is covered by vegetation water from this part is clean and flows directly to the final outlet The delineated watershed and sub watersheds are assigned as the drainage layer for use in later modeling Each sub watershed has an outlet which is used to route its hydrograph to downstream The outlet names of the sub watershed are UpStrm UpSide Hiway DnSide and Final respectively Because water from Up Str
105. e channel water velocity CWV in the channel is set to be 0 0016 ft sec which is much slower than real CWV The Muskingum is calculated by Channel Length WV Using the under estimated CWV the modeled peak discharge and peak time are near satisfaction However we know from Equation 7 3 and Table 10 that ranges from 0 025 ft sec to 0 894 ft sec in 1 99 project If we use the calculated CWV from Equation 7 3 and Table 10 the Muskingum will be much smaller than values in Table 5 The modeled peak discharge will be much larger than measured The modeled peak time will be much earlier than measured Thus to obtain good modeling hydrograph results in WMS parameters are adjusted to unreasonable values Figure 72 and Figure 73 show the comparison of modeled hydrographs with measured hydrograph with CWV to be 0 1 ft sec which is about the real value of CWV In HWM LEUH can model different hydrologic responses of a watershed In each HWM model real calculated CWV is employed and the modeled results are satisfactory From the comparison of CWV in WMS and HWM we can find the necessity of LEUH method With appropriate LEUH parameter selection the peak discharge and peak time can be modeled well using reasonable values of CWV These results also question the applicability of SCS UH method in the studied watershed With the calculated CWV SCS UH method always results in higher peak discharge and early peak time than 131 measured Al
106. e model It may be specified as a flow rate 77 5 or it may be specified as a flow per unit area ff s mile 2 8 GIS BASED WATERSHED MODELING With the development of computer science hydrological models have been combined with Geographic Information System GIS technology GIS is a special type of information system in which the data source is a database of spatially distributed features and procedures to collect store retrieve analyze and display geographic data In other words a key element of the information used by utilities is its location relative to other geographic features and objects Shami 2002 It combines spatial locations with their corresponding various information GIS is a class of concepts instead of one product There are many kinds of GIS data which are supported by different software packages They may not be compatible with each other Shape files represent city park and airport using point feature They represent road river and pipe using polylines features They also represent watershed lake and country using polygon features This is not always the case In large scale for example a 24 city or an airport is often represented by polygons A feature object comprises entity with a geographic location typically describable by points arcs or polygons On the contrary Grid files represent everything using equal dimensional pixels In a certain scale map a large object is represented using
107. e peak time 7 and relative recess constant for the Linear Exponential Unit Hydrograph LEUH 8 1 PARAMETERS FOR WATERSHED TWO ALL EVENTS HWM has the advantage of putting all parameters in one text file which can be adjusted easily After several trial modifications of model parameters several sets of reasonable parameters are determined for Watershed Two Table 12 shows all event parameters for Watershed Two 113 Table 12 Important parameters used in specific storm events Oct 07 Oct25 27 Jan17 Marll June 26 01 2005 2005 2005 2006 2006 2006 2006 2006 Sub watershed Right Highway4 Weighted CN 80 98 94 89 90 85 93 80 min 30 40 40 60 20 40 60 60 Sub watershed Right Highway3 Weighted CN 80 7 98 94 89 90 85 7 93 80 min 50 70 70 90 40 70 70 70 Sub watershed Right Highway2 Weighted CN 80 9 98 94 89 90 85 9 93 80 min 50 70 70 90 40 70 70 70 Sub watershed Right Highwayl Weighted CN 80 9 98 94 89 90 85 9 93 80 min 40 60 60 80 30 60 40 40 Sub watershed Up Stream Weighted CN 65 98 68 80 66 65 96 85 min 40 60 60 80 30 60 60 60 Sub watershed Left Highway Weighted CN 81 7 98 94 89 90 86 7 93 80 min 100 150 150 200 100 150 150 150 Sub watershed Down Stream Weighted CN 70 94 75 87 7
108. ead data from the runoff txt file DO 6 INDEX 0 2880 READ 10 I INDEX CONTINUE This section is to route and print out the results 5 MIN interval LENGTH 26000 Q 0 0 TOTALTIME 0 0 DO 7 INDEX 1 2880 CALL GETSOLUTION I INDEX VELOCITY if no water totaltime is calculated in another way IF VELOCITY EQ 0 THEN TOTALTIME INDEX TOTALTIME INDEX 1 5 TRAVELTIME INDEX 0 ELSE TOTALTIME INDEX INDEX 5 LENGTH VELOCITY 60 TRAVELTIME INDEX LENGTH VELOCITY 60 ENDIF CONTINUE INDEX loop is for outflow DO 9 INDEX 1 2880 J loop is to determine the nearest outflow value DO 11 J INDEX 0 1 IF INDEX 5 TOTALTIME J GE 0 THEN SLP I J 1 I J TOTALTIME J 1 TOTALTIME J Q INDEX I J SLP INDEX 5 TOTALTIME J IF Q INDEX GE 10000 OR Q INDEX LE 0 0001 THEN Q INDEX 0 ENDIF GOTO 9 ENDIF CONTINUE CONTINUE File 20 is the output file it contains Muskingum routing output OPEN 20 FILE AFTER STATUS UNKNOWN DO 8 INDEX 0 2880 WRITE 20 Q INDEX CONTINUE CLOSE 10 STATUS KEEP CLOSE 20 STATUS KEEP 166 98 10 PRINT 98 FORMAT Calculation finished Please close the window PRINT 99 FORMAT and check the output files END This sub routine is to calculate the celerity SUBROUTINE GETSOLUTION input celerity input is the input discharge celerity is the water velocity considering kinematic wave temp123 is the temp variable used diff
109. ead of watershed modeling 28 3 0 GIS BASED HYDROLOGICAL MODEL WMS APPROACH As discussed in Chapter Two WMS is flexible in creating a practical model using various input source data or even creating a model from the beginning without any topological GIS data It may also be used for dealing with constructed watersheds In this environmental impact of highway assessment research WMS was tested because it has many desirable features This chapter will discuss the features of WMS model The author has devoted a lot of effort in examing whether it is suitable for the project 31 WMS INTRODUCTION WMS provides a platform for using various models such as HEC 1 National Flood Frequency Program NFF HEC RAS River Analysis System Hydrological Simulation Program FORTRAN HSPF and CE Qual W2 etc Each model is designed for particular purpose HEC 1 was developed by The Hydrologic Engineering Center HEC U S Army Corps of Engineering It performs flood hydrograph computations associated with a single recorded or hypothetical storm The main purpose in Task B of 1 99 project is to model the surface water in the construction site watershed Therefore model HEC 1 in the WMS package is mainly employed in this research 32 COORDINATE SYSTEM SETTING AND CONVERSION A digital image is very important in building WMS model An image consists of a collection of pixels each of which has its own value The resolution of the pixel 29
110. eam flows directly to the Final outlet a water diversion and return is used in UpStrm routing UpSide and Hiway outlet routings use pipe routing instead of open channel routing method The DnSide outlet uses regular 74 channel routing The Final outlet has no routing since it is at the end of the whole watershed The watershed s land use layer is divided into five parts and four categories The four categories are Up Stream Highway Down Stream and Highway Sides As their names indicate they are mainly distributed in the corresponding sub watersheds but not always strictly coincident For example the Up Side sub watershed may have small part of forest which is the land use of Up Stream The Up Side and Down Side sub watersheds share the same land use category Highway Sides The curve numbers of the corresponding land use are selected from National Engineering Handbook SCS 1972 The composite curve number of a sub watershed is calculated based on area weight of different land use inside the sub watershed The soil type layer of the watershed is set to unique type D loam due to its small area Another reason to use unique soil type is that curve number can be adjusted in land use layer design The detention pond SB111 is modeled as a reservoir Its characteristics are obtained from pond designer and are displayed in Figure 37 The reservoir is accompanied with the outlet DnSide Since there is no heavy rainfall in previous
111. elationship in HWM is 0 9858 The relationship between AMC and CN is better represented in HWM model than in WMS model 92 RECOMMENDATIONS Although HWM yields satisfactory results there are still several improvements that can be made 1 Due to data availability only eight storm events were modeled in WMS and HWM More storm events modeling are needed to further validate the models Since HWM is a newly developed model and LEUH is a newly developed unit hydrograph more watershed modeling tests are recommended to demonstrate its usefulness 2 Because of data availability only antecedent precipitation depth APD is used in discovering CN AMC relationship However CN may change due to many factors such as temperature humidity antecedent sunshine and evaporation vegetation etc More 136 studies should be carried out to explore CN changes according to these comprehensive factors This may require additional instrumentation to measure changes in soil moisture Figure 71 shows the AMC CN relationship for HWM Figure 71 b is the best fitting graph we can get However we are not certain if AMC and CN relationship is really linear The linear relationship is only an assumption to find out their relationship More rainfall and soil moisture data are needed to determine a better AMC CN relationship 3 In different events modeling of WMS and HWM 7 and Muskingum are adapted based on field survey and experience 7 and Muskin
112. eled hydrograph for Oct 07 2005 Event 115 Oct 25 2005 Hydrograph Comparison 0 9 Measured Discharge cfs 0 12 24 36 48 60 72 84 Time Hr since 00 00 Oct 25 2005 96 108 120 Figure 60 Measured and HWM modeled hydrograph for Oct 25 2005 Event Nov 27 2005 Hydrograph Comparison 3 5 Measured HWM Discharge cfs Time Hr since 00 00 Nov 27 2005 Figure 61 Measured and HWM modeled hydrograph for Nov 27 2005 Event 116 Jan 17 2006 Hydrograph Comparison 0 8 Measured HWM Discharge cfs 0 12 24 36 48 60 72 84 96 108 120 132 144 Time Hr since 00 00 Jan 17 2006 Figure 62 Measured and HWM modeled hydrograph for Jan 17 2006 Event Mar 11 2006 Hydrograph Comparison 0 5 Measured Discharge cfs 0 12 24 36 48 60 72 84 96 108 120 132 144 Time Hr since 00 00 Mar 11 2006 Figure 63 Measured and HWM modeled hydrograph for Mar 11 2006 Event 117 Discharge cfs Discharge cfs May 11 2006 Hydrograph Comparison 0 5 Measured HWM 0 12 24 36 48 60 72 84 96 Time Hr since 00 00 11 2006 Figure 64 Measured and HWM modeled hydrograph for 11 2006 Event June 26 2006 Hydrograph Comparison
113. emistry 6 Mammals 2 Hydrologic conditions 7 Benthic macro invertebrates 3 Vegetation community 8 Soil chemistry 4 Birds 9 Soil condition 5 Amphibians and reptiles 10 Adjacent land use and including dominant vegetation community The initial survey on the selected wetlands will include collection of data on the various animal classifications identified to provide a broad spectrum of baseline data on the community composition and population levels The subsequent field monitoring will focus on the benthic macro invertebrates and amphibians which are key bio indicator groups 51 An overall assessment of function and value will be completed for each monitored wetland for pre and post construction conditions and for post construction mitigation wetlands in accordance with the appropriate methodology These results will then be analyzed utilizing multiple linear regression ordination techniques or other appropriate ecologically valid statistical analyses to determine the relative importance of the monitored parameters in explaining observed changes in functions and values by wetland type and setting over time The results of the previous efforts will be synthesized to provide a regional framework for predicting construction impacts on wetlands by type and setting based on key indicators An important component of these analyses will be the development of a regional model that will predict the impact of construction on
114. enlarging all the ordinates to a constant for certain DUH while keeping the abscissas unchanged For example the area under the first DUH in Figure 47 is 1 So the ordinates of the first DUH should be multiplied by 1 33595 1 while the abscissas of it will be kept unchanged The area under the fourth DUH in Figure 47 is 15 So the ordinates of the fourth DUH should be multiplied by 1 33595 15 while the abscissas of it will be kept unchanged Figure 48 shows the normalized DUH for different T and K 96 q q peak Relative Discharge q q peak Relative Discharge Tr 0 Kr 1 Tr 0 Kr 10 Trz 10 Kr z 1 Tr 10 Kr 10 0 9 0 8 4 0 7 4 0 6 4 0 5 0 4 0 3 0 2 0 1 Relative Time Figure 47 Illustration of different combinations of T and Tr 0 Kr 1 Tr 0 Kr 10 Trz10 Krz 1 Trz 10 Kr 10 0 5 10 15 20 25 30 t Tp Relative Time Figure 48 Illustration of normalized different combinations of T and 97 After normalization the area under all DUHs is 1 33595 As we see from Figure 48 the normalized DUHs with different parameters can represent much different unit hydrograph styles The DUH in Figure 48 substitutes the DUH in SCS unit hydrograph method The value of g and in LEUH are estimated using
115. er Five illustrates some difficulties in the model building Chapter Six presents a case study on the selected watershed and the modeling results Chapter Seven develops the new model Highway Watershed Model HWM an alternative to the WMS model Chapter Eight gives the modeling results of HWM it also analyzes and compares the results from WMS and HWM The last chapter gives the conclusions of this research and recommendations to future study 2 0 THEORY AND METHODOLOGY For many years hydrologists have attempted to understand the transformation of precipitation to runoff in order to forecast stream flow for purposes such as water supply flood control irrigation drainage water quality power generation recreation and fish and wildlife propagation Since the 1930s numerous rainfall runoff models have been developed to simulate hydrologic cycle As shown schematically in Figure 1 water precipitates from cloud to land surface water evaporates from the land surface to become part of atmosphere Precipitation may be intercepted by vegetation become overland flow on the ground surface infiltrate into the ground flow through the soil as sub surface flow and discharge into streams as surface runoff Some of the intercepted water and surface runoff returns to the atmosphere through evaporation The infiltrated water may percolate deeper to recharge groundwater Groundwater may rise near to the land surface through capillary or be evapor
116. er method is used to generate excess rainfall EXCESSRAINFALL F Parameters needed to input CN Curve number for each sub watershed AMC Antecedent moisture conditions 2 SCS Unit hydrograph is used to generate hydrograph at the outlet HYDRO F Parameters needed to input Tc Time of concentration of the sub watershed Area Area of the sub watershed 3 Muskingum method is used to route hydrograph in channel MUSKINGUM F Parameters needed to input K Muskingum coefficient X Muskingum coefficient 4 Linear reservoir or Level pool method is used to route hydrograph in reservoir LINEARRESERVOIR F n 1 K time of travel Parameters needed to input K Travel time of the reservoir LEVELPOOL F Parameters needed to input Initial Initial condition of the reservoir elevation ADD F No parameters Only input hydrographs are needed If X 0 the Muskingum routing method becomes linear reservoir routing method LINEARRESERVOIR F program is similar to MUSKINGUM F Because a hydrograph may be routed many times through channel and reservoir it is very complicated to use different names at every routing Thus we use name HYDRO_ TXT at the outlet of a sub watershed and routing we use name RHYDRO_ TXT after each routing A hydrograph may be routed many times Each time before routing the hydrograph from RHYDRO_ TXT must be changed to YDRO_ TXT if needed kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk
117. eral outlets in the watershed based on rainfall land use soil type detention pond location stream distribution water velocity and basin slope etc For efficiency and cost effectiveness runoff prediction method and local applicability will be verified A successful model can reduce expensive monitoring instrumentation and personnel training cost in future projects The scope of this research will involve numerical computer simulations and field data collection assimilation and analysis GIS based rainfall runoff model will be developed using the Watershed Modeling System WMS platform and calibrated to simulate the hydrology and hydraulics phenomena along the stream system draining the selected constructed basin near 1 99 highway To compensate for the shortcomings the WMS model a new model Highway Watershed Model 48 developed The results from WMS and HWM will be analyzed and compared The relationship between antecedent moisture condition AMC and curve number CN will be investigated Highway watershed is more difficult to model than natural mountainous watersheds due to high human disturbance The watershed elevation is altered by human construction and hence the stream directions are changed The alteration makes elevation changes too mild on the highway surface for example or too steep at the mountain cut for example This research will discuss the methods dealing with these human interventions in the waters
118. ere is not always the real order of HWM module execution The real order of HWM changes with the watershed delineation schematic For I 99 highway watershed modeling the modules EXCESSRAINFALL F HYDRO F MUSKINGUM F and ADD F are executed several times For conciseness they are only explained one time in this manual 169 B 1 WATERSHED FORMULATION Before HWM can be utilized it is first required that the user identify the boundaries of the watershed separate it into smaller sub watersheds based on the topographical characteristics determine the size of each sub watershed and identify the path that water will flow through the sub watersheds to reach the common outlet It is important to identify the order in which water flows through the watershed The hydrologic methodology utilized in executing this program must be completed in a step wise manner in order to achieve accurate results That is discharge contributions from various locations throughout the area cannot simply be added together to obtain the total A complex routing of the data through the adjacent downstream basins or reservoirs is required to obtain the correct estimates of discharge The boundary of the watershed can be determined by several methods including utilizing topographic maps or using digital elevation model DEM data In this research topographic maps were used Once the watershed boundary is determined the sub watershed should be investigated thoroughly s
119. ethod which is described in Section 2 1 The program code requires certain input values and gives output values The input and output file parameters are shown in Table 17 Table 17 Input and output of EXCESSRAINFALL F File Input Output data Definition PARAMETERS TXT AMC CN sub watershed number User defined input precipitation duration RAINFALL TXT Half hour incremental rainfall User defined input EXCESS TXT Half hour incremental excess rainfall Program defined output With these data and the computation scheme outlined above the program may compute its output The HWM is set up so that a separate program is used to compute the excess rainfall for each sub watershed Each of these programs opens different parameters and records its output under a different name If the watershed contains seven sub watersheds five programs will run to compute excess rainfall for each of these The output will be in half hourly incremental excess rainfall and will be numbered after the corresponding sub watersheds From here on the symbol will be used to represent the number of the corresponding sub watersheds 171 DIMENSIONLESS UNIT HYDROGRAPH DUH GENERATION Program used LINEAR EXP UH F The theory of LEUH was explained in detail in Section 7 4 Once completed this portion of the model will generate text files containing the coordinates of the designed DUH of LEUH method This file will be stored
120. evapotranspiration and recharge rate The two improvements are tested by comparing the modelled total runoff and groundwater table with observed values at the watershed of Little Pine Creek Etna Pennsylvania Results show that the new version of VIC simulates the total runoff and groundwater table very well To investigate the influence of urban pavement and traffic on runoff water quantity Cristina et al 2003 developed a kinematic wave model which accurately captured the significant aspects of typical urban runoff The impacts of the paved urban surface and traffic were examined with respect to the temporal distribution of storm water runoff quantity The kinematic wave theory gave predictions of the time of concentration that were more accurate than other more common methods currently in use Campling et al 2002 developed TOPMODEL a semi distributed topographically based hydrological model and applied it to continuously simulate the runoff hydrograph of a medium sized 379km humid tropical catchment The researcher found that water tables were not paralle to the surface topography To increase the weighting of local storage deficits in upland areas a reference topographic index Agger was introduced into the TOPMODEL structure Not confined in deterministic modeling this research also assessed the performance of the model with randomly selected parameter sets and set simulation confidence limits by using generalized likelihood unce
121. f 78 Elevation storage outflow relationship 1 79 Half hour incremental rainfall for eight storm events sssssss 79 The rating curve for Ecotones in the two studied watersheds 88 Measured and WMS modeled hydrograph for Oct 07 2005 Event 88 Measured and WMS modeled hydrograph for Oct 25 2005 Event 89 Schematic diagram of Watershed One sese 94 Schematic diagram of Watershed 94 Illustration of different combinations of T and K e 97 Illustration of normalized different combinations of T and ET Illustration of isochrone curve generation 101 The travel time and contributing area diagram for Right Highway 102 The travel time and contributing area diagram for Right Highway 102 The travel time and contributing area diagram for Right Highway3 103 xi Figure 53 Figure 54 Figure 55 Figure 56 Figure 57 Figure 58 Figure 59 Figure 60 Figure 61 Figure 62 Figure 63 Figure 64 Figure 65 Figure 66 Figure 67 Figure 68 Figure 69 Figure 70 Figure 71 Figure 72 Figure 73 The travel time and contributing area diagram for Right HighwayA 103 The travel time and contributing area diagram for Up Stream 5 103
122. fall EXCESSRAINFALL F Parameters needed to input CN Curve number for each sub watershed AMC Antecedent moisture conditions 2 SCS Unit hydrograph is used to generate hydrograph at the outlet HYDRO F Parameters needed to input Tc Time of concentration of the sub watershed Area Area of the sub watershed 3 Muskingum method is used to route hydrograph in channel MUSKINGUM F Parameters needed to input K Muskingum coefficient X Muskingum coefficient 4 Linear reservoir or Level pool method is used to route hydrograph in reservoir LINEARRESERVOIR F n 1 K time of travel Parameters needed to input K Travel time of the reservoir LEVELPOOL F Parameters needed to input Initial Initial condition of the reservoir elevation ADD F No parameters Only input hydrographs are needed If X 0 the Muskingum routing method becomes linear reservoir routing method LINEARRESERVOIR F program is similar to MUSKINGUM F Because a hydrograph may be routed many times through channel and reservoir it is very complicated to use different names at every routing Thus we use name HYDRO_ TXT at the outlet of a sub watershed and routing we use name RHYDRO_ TXT after each routing A hydrograph may be routed many times Each time before routing the hydrograph from RHYDRO_ TXT must be changed to YDRO_ TXT if needed kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk Version HYDRO F Created b
123. for soil type map 36 The rectangular area inside is the un delineated watershed DEM file Normally the coverage area of the land use and soil type file is much bigger than studied watershed If land use and soil type files are not available the user can create them manually First the user must create land use and soil type coverages in WMS separately For each type of coverage land use and soil type polygons are created using polygon creating method described in Section 3 5 After creating polygons a database table regarding land use and soil type must be filled to connect the digital information with the polygon spatial area The database table works the same way as a database when Shape format soil and land use file are available 37 WATERSHED INFORMATION AND CALCULATION METHOD The watershed information required for modeling in WMS include four main groups 3 7 1 Basin data Basin data contain the basin s elementary characteristics The basin s name identifies it from other basins A descriptive name is helpful in building and running the model The basin s area is always calculated by WMS if the geo referencing information is correct If the basin s area is incorrect user should modify the geo reference information instead of changing area directly If a hydrograph is known for a given basin there is no need to compute a synthetic hydrograph This hydrograph can be input by defining the hydrograph using the XY Series
124. fort to extend I 99 to I 80 at Bellefonte Highway construction is often the cause of substantial adverse environmental effects both during the construction phase and during the operational phase To appraise the environmental influence of highway construction monitoring and evaluating the effectiveness of various mitigation techniques implemented are being done during the construction of 1 99 to enable improved management of corridor resources The research also includes developing enhanced capabilities to predict impacts and identifying suitable mitigation measures for future highway constructions The research includes four parts The first part is the evaluation of approved erosion and sediment controls to determine best management practice Intimately tied to the first part is the prediction of the runoff as a result of the rainfall on the construction project This is the second part of the project The third part is to monitor and assess the wetland hydro biological indicators for land use planning in the highway The last part is to evaluate the effectiveness and sustainability of stream restoration rehabilitation and relocation projects as part of mitigation for road construction This study focuses on the second part 13 OBJECTIVE AND SCOPE The objective of this research is to build a runoff prediction model using GIS techniques for a watershed affected by highway construction The model will be designed to predict runoff at sev
125. g identical sized square pixels In essence a raster file representing elevation is similar to DEM and Grid A raster file is also a regular grid data structure that contains a two dimensional array of elevations However since raster files grid files and DEM files are developed by 25 different agencies they are processed digitally differently Vector files represent objects similar to shape files Vector files may also represent rivers using polyline features and represent watersheds using polygon features However vector files and shape files are processed digitally computer differently Shape files grid files Triangulated Irregular Network TIN and Digital Elevation Model DEM files are supported by ArcGIS Environmental Systems Research Institute 1999 DEM files Raster files and Vector files are supported by IDRISI Eastman 1999 DEM files shape file and another type of TIN files are supported by Watershed Modeling System Environmental Modeling Research Laboratory Brigham Young University 1999 TIN files used in WMS are incompatible with TIN files used in ArcGIS DEM files used in ArcGIS are realized through grid files and are incompatible with DEM files used in IDRISI and WMS GIS based hydrological models utilize readily available digital geospatial information more expediently and more accurately than manual input methods Also the development of basic watershed information will help the user to estimate hydrolog
126. ghway cut areas The uniqueness lies in the minimum disruption of the hydrologic regimes prior to construction 50 4 2 3 Task Monitoring and assessment of wetland hydro biological indicator Task C will focus on the wetlands down slope of the cut areas in Section C10 Figure 16 and mitigation wetlands The environmental document compiled for the project through the National Environmental Policy Act NEPA process will be utilized to provide the initial baseline documentation of resources in the project area A GIS database will be compiled of project corridor wetlands Data will be organized to provide a clear illustration of each wetland s position in the landscape based upon watershed topographic setting and relationship to the new highway and other anticipated land use changes The database will include information concerning those features that may influence function and value These data includes wetland type topographic setting and geologic conditions hydrologic regime soil type adjacent land uses and soil types dominant vegetation species habitat value water quality issues and uniqueness Photographs of each wetland wetland delineation data forms and other relevant supporting information will be linked to this database Each monitoring wetland will be subject to periodic field surveys to assess parameters affecting function and value The following parameters will be monitored at the frequencies listed 1 Water ch
127. graphs and an un routed base hydrograph that needs to be added The output of the program is the total hydrograph after adding The input and output file parameters are shown in Table 21 174 Table 21 Input and output of ADD F File Input Output data Definition PARAMETERS TXT Routed and un routed hydrographs number User defined input RHYDRO TXT The routed total runoff hydrographs from Program defined input each sub watershed or from any reservoir HYDRO Sub watershed hydrograph before adding Program defined input HYDRO Sub watershed hydrograph after adding Program defined output B 7 RESERVOIR ROUTING Program used LEVELPOOL F Often storage ponds are included within a watershed in order to control runoff and sediment load This part the HWM deals with these ponds by modeling them using the level pool method Using this method and inflow hydrographs obtained from the previous sub program an outflow hydrograph will be determined for the outlet of the ponds This outlet hydrograph may then also be routed further downstream In order to complete this section of the model much information must be obtained and recorded concerning the design of the storage basins First a text file containing incremental elevations from the bottom to the top of the pond must be created The increments should be small enough to produce a detailed representation of the pond Once this file is in pl
128. gum may also change with APD temperature humidity antecedent sunshine and evaporation vegetation etc More studies are recommended to examine the effect of these factors on T and Muskingum 137 APPENDIX FORTRAN PROGRAMS FOR EACH MODULE OF HWM 138 PREFACE The original HWM consists of six modules which are flexible to model any number of sub watershed and arbitrary layout However it requires keyboard input and complicated layout combination Under Dr Quimpo s direction we re wrote the program using file input instead of keyboard input The current model reads all parameters from a file The final hydrograph can be obtained by double clicking a master file batch file However the flexibility is reduced This model can only model seven pre defined sub watershed layout situation If the user wants to model other layouts the program must be modified These programs source codes of the latest version of Highway Watershed Model are easy to run but less flexible We are able to modify the model to accommodate other watersheds configuration For conciseness only one program for each module is presented Detailed explanation of each module and HWM executing procedures are documented in Appendix B 139 1 echo off rem This Batch file is used to execute all program together 1 0LINEAR EXP UH EXE 1 1EXCESSRAINFALL exe 1 2EXCESSRAINFALL exe 1 3EXCESSRAINFALL exe 1 4EXCESSRAINFALL exe
129. he WMS model a new model the Highway Watershed Model HWM was developed HWM employs LEUH method instead of SCS UH to generate runoff LEUH performs better at describing different watershed responses using different dimensionless unit hydrographs Using the same 15 deviation criterion all total runoff volume and peak discharges are satisfactory With 120 minutes equal two modeling time intervals deviation as peak time acceptable criterion all modelled peak 135 times are satisfactory It was shown that in I 99 highway watershed modeling the results from HWM are better than those from WMS 3 The channel water velocity CWV that will produce acceptable results in WMS is much smaller than the calculated velocity Using a realistic CWV the peak discharges modeled from WMS are much larger than measured peak discharges The peak times modeled from WMS also occur earlier than measured peak times On the other hand using LEUH all results are satisfactory when real calculated CWVs are employed 4 The relationship between antecedent moisture condition AMC and curve number CN was investigated Two day antecedent precipitation depth APD four day APD and seven day APD were tried as indicators of AMC In both WMS and HWM modeling the best AMC indicator to fit AMC CN relationship is the four day APD The best R value of linear regression of AMC CN relationship in WMS is 0 7191 while the best R value of linear regression of AMC CN r
130. hed In applying GIS based model some GIS source data and watershed characteristics requirements must be available Unfortunately not all of them are available to this project A trade off to deal with GIS based model and traditional conceptual model applied in the practical watershed will be discussed This is also a reason to develop HWM model Also surface flow data and ground flow data will be collected to calibrate the model 14 LITERATURE REVIEW Extensive studies have been done on watershed modeling Generally models can be divided into two broad categories physically based model distributed model and conceptually based models lumped model A recent review on rainfall runoff modeling is given by O Loughlin et al 1996 Singh 1988 provides a general survey of most of the techniques available for modeling hydrological systems at that time Physical based models are one type of models that are based on physical laws and known initial and boundary conditions Presently quite a few physically based models have been developed and applied Physically based models are normally run with point values of precipitation evaporation soil moisture and watershed characters as primary input data and produce the runoff hydrographs They are generally accurate but difficult to use Many of the assumptions in these models cannot be satisfied in practice Users must determine a huge number of parameters which are often difficult to obtain In
131. hed Two will be discussed Table 3 shows the 84 runoff rainfall ratio for each storm event for Watershed Two SB10 11 Due to some shortcomings of WMS which are explained in Section 6 7 the modeling results are not all satisfactory Only two events will be discussed in this dissertation Table 3 Runoff Rainfall Ratio for Each Storm Event in Watershed Two Each usa Oct 07 Oct 25 Nov 27 Jan 17 Mar11 May 11 June 26 Sept 01 2005 2005 2005 2006 2006 2006 2006 2006 Depth grea 11 52 i 134 131 255 Rainfall Volume on the 485084 107053 468357 284360 167270 224142 219124 426540 Watershed ft Runoff Volume of the 142341 77531 262528 89015 34977 44466 90631 121958 Watershed ft S 0 8508 0 4634 1 5693 0 5321 02091 0 2658 0 5418 0 7291 0 2934 07241 0 5605 0 3130 02091 0 1984 04136 0 2859 65 PARAMETERS FOR WATERSHED TWO 6 5 1 Parameters for Watershed Two Oct 07 2005 Event The rainfall distribution and reservoir characteristics are shown before After several trial modifications of model parameters a set of reasonable parameters are determined for this watershed and event The watershed parameters used in Watershed Two Oct 07 2005 Event are listed in Table 4 85 Table 4 Watershed parameters for Watershed Two Oct 07 2005 Event
132. highway construction watersheds Recent research in basic hydrological theories and related fields were reviewed Several Geographic Information System GIS techniques in hydrological modeling were discussed Recent GIS based hydrological applications are mostly applied to large natural watersheds However the watersheds in this research are very small and their topographic characteristics are severely changed by construction There are a few difficulties in applying the GIS based watershed models in the project Several improvements were made to apply GIS based watershed model to highway watersheds using Watershed Modeling System WMS The WMS model employs Soil Conservation Service Unit Hydrograph SCS UH to generate hydrograph and has the shortcoming of predicting earlier peak time and higher peak discharge To overcome the WMS weakness a new model Highway Watershed Model HWM was developed The HWM model uses a new type of unit hydrograph the Linear Exponential Unit Hydrograph LEUH in generating runoff from rainfall Dimensionless Unit Hydrograph DUH in LEUH consists of linear rising part and exponential recession part HWM has the ability to describe different watersheds using different LEUHs which reflect the watershed unique hydrologic response characteristic In both WMS and HWM models an attempt was also made to find out the relationship between antecedent ill moisture condition AMC and curve number CN The diagram f
133. hydrographs such as Snyder unit hydrograph Clark unit hydrograph SCS dimensionless unit hydrograph have been developed The SCS dimensionless hydrograph is a synthetic unit hydrograph in which the discharge is expressed as a ratio of q to peak discharge and the time as the ratio of time t to the time of rise of unit hydrograph T Figure 3 a shows the SCS dimensionless hydrograph The values of g and may be estimated using a model of a triangular unit 14 hydrograph which is shown in Figure 3 b where the time is in hours and the discharge or cfs in Source Soil Conservation Service 1972 The Soil Conservation Service suggests the time of recession may be estimated as 1 67T qp can be expressed as CA q 2 12 where C 2 08 483 4 in the English system and A the drainage area in square kilometers square miles The time of rise T can be expressed in terms of lag time tp and the duration of effective rainfall t t D tf 2 13 The lag time ty can be approximately calculated by 0 67 where is the time of concentration of the watershed ITE UTp q q peak Direct Runoff a b Figure 3 Soil Conservation Service synthetic unit hydrograph a Dimensionless hydrograph b triangular unit hydrograph Source Soil Conservation Service 1972 Once the unit hydrograph has been determined it may be
134. ic parameters After obtaining adequate experience in GIS generated parameters users can make parameter estimation more efficiently GIS based hydrological models may use different GIS data as different layers To make different GIS data display and work in the correct location coincident spatial referencing is needed for different layers HEC GeoHMS was developed by U S Army Corps of Engineers Hydrological Engineering Center U S Army Corps of Engineers Hydrologic Engineering Center 2003 HEC GeoHMS links GIS tool ArcView3 2 and hydrologic model Hydrologic Modeling System HMS HEC GeoHMS combines the functionality of ArcInfo programs into a package that is easy to use with a specialized interface With the ArcView capability and the graphical user interface the user can access customized menus tools and buttons instead of the command line interface in ArcInfo The hydrologic algorithms in the model are the same as HEC HMS First HEC GeoHMS imports DEM data and fills sinks in the data Second it generates flow direction and 26 streams based DEM data Then the following procedure is to delineate watershed and sub watershed boundaries The newly generated files are stored in separate layers The pertinent watershed characteristics can be extracted from the source DEM data and the generated stream and boundary data After these processes a HEC HMS schematic map and project can be exported Other parameters such as meteorolog
135. ical routing and infiltration parameters need to be set before the project runs In fact HEC GeoHMS prepares the input file and schematic map for HEC HMS By using GIS data detailed watershed characteristics are obtained automatically for the HEC HMS model However the source GIS files such as DEM file are not generally available and difficult to generate from the beginning Quimpo et al 2003 develop a quasi distributed GIS based hydrologic model QD GISHydro The model consists of several separate modules which process data describing the spatial variation of watershed properties and compute the runoff time series at the watershed outlet Data processing and visualization is handled primarily by GIS software IDRISI32 while self written computer programs perform the bulk of the computations The model is designed to operate as simply and generally as possible requiring only four external data sets as input DEM land coverage soil coverage and incremental precipitation depths to create all other data needed to compute the direct runoff for the watershed under study The model is able to deal with non uniform excess rainfall for each watershed pixel Land use and soil type files are available for most of United State watersheds Incremental precipitation depth files can be created by the user easily Unfortunately DEM file is not always available and the model can only process DEM file as source elevation information Users cannot buil
136. ime interval of 10 minutes is used to divide the isochrone curves 6 Travel time of each sub patch with 10 minutes travel time interval is calculated 7 Contributing areas of each sub patch to each time interval are summed together to obtain the area for each time interval 8 A table showing the travel time and contributing area is displayed in Table 11 100 9 A diagram showing the travel time and contributing area is displayed in Figure 50 which is also called the isochrone diagram 0 10 min 1 0 32 ft sec x K1 2 0 H 6 0 52 ft sec Mar ae m 86 0 025 0 10 min 2 0 51 0 025 20 30 min i V2 0 24 1 10 20 min L6 1 70 ft V3 0 32 ft sec 0 10 min 16 2 30 ft 53 0 025 0 10 min 20 30 min K4 0 7 Sub watershed Outlet S4 0 5 e d 20 30 min V5 0 24 ft sec 55 0 025 Figure 49 Illustration of isochrone curve generation Table 11 The travel time and contributing area for Right Highway Time min Area sq ft 10 29801 20 106608 30 34626 40 3127 101 Right_Highway1 Time Area Diagram 120000 100000 80000 60000 40000 Contributing Area Square feet 20000 Travel Time mins Figure 50 The travel time and contributing area diagram for Right Highway The method to generate the isochrone diagrams for the other sub watersheds is
137. ion Thus subsequent use of the symbol 7 for rainfall intensity is really rainfall intensity minus evaporation rate The loss rate is computed by e A e k 2 8 where evaporation loss rate ff day surface area at the water level in the unit f e evaporation rate inch day and Ky evaporation conversion factor The values of e should be supplied for each interval of the simulation period 2 2 DISTRIBUTED SURFACE WATER MODELING The distributed surface water modeling is based on differential equations that allow the flow rate and water level to be computed as functions of space and time rather than of 12 time alone as in the lumped models The conceptual view of distributed surface runoff is illustrated in Figure 2 Each watershed surface is treated as a nonlinear reservoir Inflow comes from precipitation and upstream watersheds There are several outflows including infiltration evaporation and surface runoff The capacity of this reservoir is the maximum depression storage which is the maximum surface storage provided by ponding surface wetting and interception Surface runoff unit area occurs only when the depth of water in the reservoir exceeds the maximum depression storage dp in which case the outflow is given by Manning s equation RAINFALL EVAPORATION SNOWMELT INFILTRATION Figure 2 Conceptual view of surface runoff Depth of water over the sub watershed 4 in i
138. ion acceleration force force force term term term term term 16 The Saint Venant equations have three simplified forms i e dynamic wave model diffusion wave model and kinematic wave model Each of them defines a one dimensional distributed routing model The dynamic wave model considers all the acceleration and pressure terms in the momentum equation The accounted terms are labeled in Equation 2 15b The diffusion wave model neglects the local and convective acceleration terms but incorporates the pressure terms The simplified momentum equation of diffusion wave model is 2 16 Ox Pressure Gravity Friction force term force term force term The kinematic wave model is the simplest of the distributed model It neglects the local acceleration convective acceleration and pressure terms in the momentum equation The simplified momentum equation of kinematic wave model is g s S 0 2 17 Gravity Friction force term force term It assumes Sp Syand the friction and gravity forces balance each other Solutions to the distributed model can be found in many references Fread 1973 Chow et al 1988 2 5 LUMPED CHANNEL ROUTING Level pool routing method linear reservoir model and the Muskingum method belong to lumped flow routing The Muskingum method is a commonly used hydrologic routing 17 method for handling a variable discharge storage relationship The model considers two components of storage
139. itting of AMC CN from HWM is better than that from WMS It is recommended that this issue may be studied further using additional instrumentation to measure the time variation of soil moisture conditions Although the WMS is widely used HWM produces more reliable and better results than WMS in the studied watershed The peak discharge and peak time are difficult to simultaneously model perfectly iv TABLE OF CONTENTS ACKNOWLEDGEMENTS xvi 10 INTRODUCTION 1 Li BACKGROUND 1 12 PROBLEMS STATEMENT 2 13 OBJECTIVE AND SCOPE RUIN PAS M MEER DOE 3 14 LITERATURE REVIEW 4 15 LAYOUT OF THIS 155 7 2 0 THEORY AND 8 2 1 PRECIPITATION LOSS 9 22 DISTRIBUTED SURFACE WATER 12 23 LUMPED SURFACE WATER 14 2 4 DISTRIBUTED CHANNEL
140. jectives of this project part is to reduce instrumentation and data collecting expenses Due to high cost of buying and installing the instruments only the two test watersheds have Ecotone recorders The model built on these two watersheds will be applied to other watersheds with some site specific modifications A key feature of this highway watershed design is the inclusion of infiltration galleries under the roadway which catch intercepted groundwater from areas upslope Runoff from newly impervious surfaces resulting from construction would be collected and routed to storm water management ponds This slows down runoff production through reduced transport rate and also improves its quality through detention in the ponds catching the first flush Runoff from undisturbed land is channeled directly to receiving streams as clean water This is achieved by routing the clean runoff directly to downstream outlet without passing the intermediate watersheds A rain gage was installed in Port Matilda a town near the watersheds Because the watershed is not too large only one rain gage was used The location of rain gage is illustrated in Figure 16 The model focuses on the hydrologic phenomenon of a system designed to incorporate an infiltration stratum under the roadway This project presents a unique opportunity to test the new concept in design to minimize adverse impacts on the environment particularly with respect to hydrologic regimes in hi
141. key issue for this task is to conduct field reconnaissance monitoring of field sites under 46 normal and high rainfall and assess the results in a final report The research includes the following work 1 Periodic site visits with professional observations reporting and digital pictures 2 Digital photographs will be taken and logged with narrative Digital pictures will be stored electronically to be retrieved as needed for study and comparison incorporated into a GIS database and incorporated into the final project report GIS mapping will be linked to a database including modeling results and to digital photographs 3 The field crew will identify selected samples that to be analyzed for turbidity analysis trace heavy metals and filtered COD Field measurements of pH and temperature will be taken Such studies provide new insight into the behavior of BMPs subjected to runoff containing residuals typical of motorized vehicle traffic 4 A qualitative risk based evaluation method will be prepared The evaluation aims at the relative environmental impacts associated with the ineffectiveness or failure of the BMPs on downstream receiving waters including wetlands and streams The method will address modes likelihood and consequences of failure and will consider reliability longevity costs environmental benefits and liability 4 2 2 Task Hydrologic monitoring and modeling Task B is the prediction of the quantity of runoff o
142. kkkkkkkkk Version EXCESSRAINFALL F Created by Weizhe An April 09 06 The program reads the half hour accumulative rainfall txt file and generates a half hour cumulative excess rainfall text file for different sub watershed because different SBWS have different CNs The RAINFALL TXT file contains cumulative half hourly rainfall kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk Code inputs Files RAINFALL TXT User Antecedent soil moisture condition 1 2 or 3 Curve number SBWS number rainfall duration Code output Files EXCESSACCUM TXT EXCESS_ TXT kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk 143 C RET is the potential max retention CN is the original input curve number C OCNNis the corrected curve number for AMC 1 2 3 C TEMPPREC and PREVIOUS are temporary variables used to convert EXCESSACCUM to EXCESSPREC C Seethe program for details REAL TEMPPREC PREVIOUS CN CNN RET EXCESSACCUM is temporary variable then it is written to EXCESSACCUM TXT PRECIPITATION is temporary variable it is read from RAINFALL TXT REAL EXCESSACCUM EXCESSPREC PRECIPITATION 1 100 is the antecedent soil moisture condition SBWSNUM is the sub watershed number PDUR is the storm duration PN is the interval num of the storm Because the rainfall is at half hour intervals PN PDUR 0 5 PDUR 2 INTEGER AMC SBWSNUM PDUR PN LINE CHARACTER 20 X 1 100
143. l Protection Agency 600 3 88 001a Athens Georgia 1988 Kavvas M L Chen Z Q Dogrul C Yoon J Y Ohara N Liang L Aksoy H Anderson M L Yoshitani J Fukami K and Matsuura T Watershed Environmental Hydrology WEHY Model based on upscaled conservation equations hydrologic module Journal of Hydrologic Engineering Vol 9 No 6 pp 450 464 2004 Kilgore J L Development and evaluation of a GIS based spatially distributed unit hydrograph model Unpublished master s thesis Virginia Polytechnic Institute and State University VA 1997 Kirkby M J TOPMODEL a personal view Hydrological Processes Vol 11 pp 1087 1097 1997 Liang X and Xie Z Important factors in land atmosphere interactions surface runoff generation and interactions between surface and groundwater Global and Planetary Change Vol 38 1 2 pp 101 114 2003 Lid n and Harlin J Analysis of Conceptual Rainfall Runoff Modelling Performance in Different Climates Journal of Hydrology Vol 238 pp 231 247 2000 Linsley R K Kohler M A and Paulhus J L H Hydrology for Engineers McGraw Hill New York NY 1982 Madsen H Wilson G and Ammentorp H C Comparison of Different Automated Strategies for Calibration of Rainfall Runoff Models Journal of Hydrology Vol 261 pp 48 59 2002 181 Maidment Olivera F Calver A Eatherall A Fraczek W Unit hydrograph derived from
144. l can be used to calculate the basin properties such as watershed area slope and average overflow distance etc It is not just a schematic of the watershed Figure 22 show the delineated watershed boundary and some of the basin properties where A watershed area BS watershed slope AOFD average overflow distance L watershed length MSL maximum stream length MSS maximum stream slope 59 6220 a ASTO 01592 _ 83 74 1 MSL 26424 04 ft i ey tit SIC n 5 WEEN Figure 22 The delineated watershed boundary and some of basin properties 5 2 5 Creating sub watersheds In order to create sub watersheds additional drainage outlets need to be defined The new drainage outlets must be on the stream After several nodes or vertices along the stream arcs are defined into drainage outlets the same method defining watershed boundaries can be used again to define sub watersheds Figure 23 shows the re defined sub watershed boundaries and watershed properties Due to space availability Figure 23 only shows two properties of the watershed boundaries However all properties in Figure 22 can be shown for each sub watershed 60 A 1 10 2 N ES N A 4 COL 07 C EE mM m T Y y E Es p OF mi 2 gt TING E en LC Figure 23 The re defined sub watershed boundaries and w
145. l rainfall using SCS abstraction method which is described in Chapter Two HWM utilizes half hour accumulative total rainfall data to generate incremental excess rainfall data 7 4 SCS AND LE UNIT HYDROGRAPH The unit hydrograph method is used to produce hydrograph at outlet of each sub watershed Excess rainfall from Section 7 3 is used as input in unit hydrograph method The SCS Unit Hydrograph SCS UH is employed in WMS model in Chapter Six The SCS UH method assumes the dimensionless unit hydrograph DUH shapes are all the same for any shaped watershed The DUH 18 shown in Figure 3 a This assumption does not consider the influence of watershed shape on the DUH which may be one reason for the unsatisfactory fit For example the DUH for a long narrow watershed is quite different from a square watershed But in SCS UH method they are the same Although the SCS UH is widely used it lacks flexibility in describing hydrological response for different shapes of sub watershed The profile of dimensionless unit hydrograph is always same no matter what is shape of the sub watershed it applies to This is obviously not suitable and cannot reflect the hydrological response characteristics of the sub watershed To solve this problem a new DUH of linear exponential unit hydrograph LEUH is employed 95 In SCS UH the DUH always reaches peak when the relative peak time T 1 The DUH always recedes near to zero when
146. models researchers have developed object oriented software to model rainfall runoff relationship Garrote et al 1997 presented a software environment for real time flood forecasting using distributed models The system Real time Interactive Basin Simulator RIBS provides an object oriented framework for implementation of a class of distributed rainfall runoff models satisfying certain formal requirements RIBS manages process organization and data handling facilitation of user interaction and result visualization and provision of access to model structure hydrologic processes and model inference Other widely used packaged software include Watershed Modeling System WMS developed by Environmental Modeling Research Laboratory Brigham Young University Storm Water Management Model SWMM developed by U S Environmental Protection Agency EPA Hydrologic Engineering Center Hydrological Modeling System HEC HMS developed by U S Army Corps of Engineering and Hydrological Simulation Program FORTRAN HSPF developed by U S EPA 15 LAYOUT OF THIS DISSERTATION The dissertation is organized as follows Chapter Two contains basic theories on watershed modeling both physical based and conceptual based model theories Chapter Three reviews the procedures for developing the GIS based model WMS model which the author investigated in detail but found to be inadequate Chapter Four gives an overview of the studied watershed Chapt
147. n The GRID file appearance in WMS is the same It is also shown in Figure 26 5 The GRID file is converted into DEM format using Convert To DEM function The DEM file is shown in Figure 27 After DEM file is obtained the watershed delineation can be performed in WMS This is illustrated in the following section Section 5 4 64 54 WATERSHED DELINEATION IN I 99 BASED ON DEM DATA As illustrated in Section 5 3 resolution of 2x2 sq ft DEM file is derived from PENNDOT MicroStation DGN file for Watershed SB10 11 Figure 27 shows the original DEM file in WMS Figure 28 shows the DEM file with the flow direction the stream networks and stream feature arcs in an enlarged scale Although these procedures work fine the generation of watershed is a big problem The real watershed is disturbed by construction Many man made channels and underground pipes were built to drain water The watershed elevation is also altered to form a shape showed in Figure 38 The automatically generated watershed boundary is shown in Figure 29 The WMS tutorial states Watershed delineation from DEMs is straightforward and relatively simple provided the project area is not entirely flat or completely dominated by manmade structures you can t expect the DEM method to work if there is no relief in the DEM elevations themselves Environmental Modeling Research Laboratory Brigham Young University 2004 However I 99 project area DEM file contains man
148. n environmental impacts Highway constructions may also unintentionally damage site of archeological and culture significance During the operation phase highways affect the environment through the introduction of pollutants in storm water runoff permanent changes in land use and resulting ecological consequences The objective of the I 99 environmental research is to monitor and evaluate the effectiveness of various mitigation techniques implemented during the highway construction to provide an improved management of the highway and to develop enhanced capabilities to predict impacts and identify suitable mitigation measures for future highway projects in Pennsylvania Quimpo 2004 The project will provide immediate benefits in helping to minimize the construction and operational impacts of I 99 It will provide long term benefits by developing Best Management Practices BMPs for Pennsylvania highways and through the development of models that can be used throughout Pennsylvania to predict construction impacts and mitigation success These models will provide for greater accuracy and reliability in future designs while reducing the cost of expensive field and laboratory investigations 42 PROJECT COMPONENTS 4 2 1 Task A Evaluation of erosion and sediment controls As stated in Chapter One this environmental research includes four tasks The primary focus of Task A is to continue the research on Best Management Practices BMPs The
149. n the complex construction project The primary focus of Task B is to perform monitoring and modeling to evaluate the hydrologic regime associated with the highway cut area the down slope wetlands and the mechanism used to maintain groundwater flow to the wetlands ie infiltration galleries The model which is to be calibrated using the field monitoring data will be used to evaluate explain and predict the effectiveness of the infiltration galleries in maintaining groundwater flow to the down slope wetlands The objective is to develop a model that can be applied at the I 99 project to reliably predict future hydrologic impacts to the wetlands and thereby reduce costly monitoring efforts The model may then be used in the design of other projects with similar conditions Runoff prediction techniques for the specific local construction site will be built and verified To reduce expensive 47 monitoring instrumentation at other projects the model should be portable which means the procedures can be used at other construction sites with adjustments for site specificity The portability requirement is an important criterion in the selection and choice of model As part of the monitoring effort included in Task B water level recorders were installed at several locations The recorders are classified into three categories The first category which is called Well Logger is used to record the ground water table changes The second category Dee
150. nches is continuously updated with time 1 in seconds by solving numerically a water balance equation over the sub watershed The non linear reservoir is established by coupling the continuity equation with Manning s equation Continuity may be written for a sub area as ar os ieee pO 2 9 dt dt where V D volume of water on the sub area ff D water depth inch time sec surface area of sub area f i rainfall excess rainfall snowmelt intensity minus evaporation infiltration rate inch sec Q outflow rate cfs 13 The outflow is generated using Manning s equation Q l p g 2 2 10 where n manning s roughness coefficient D depth of depression storage ft R hydraulic radius Area WetPerimeter ft S sub watershed slope 7 77 Equations 2 9 and 2 10 be combined into one non linear differential equation that may be solved for one unknown the depth d This produces the non linear reservoir equation P circo hugs 2 11 Equation 2 11 is solved at each time step by means of a simple finite difference scheme Huber et al 1988 2 3 LUMPED SURFACE WATER MODELING The lumped surface water modeling is accomplished by the unit hydrograph method The unit hydrograph of a watershed is defined as a hydrograph resulting from one inch spatially uniform excess rainfall over the watershed at a constant rate for an effective duration Several types of unit
151. nd parameter file have to be revised to fit the updated schematic If the user wants to execute the model manually the user must determine the order of each module execution Most parameters are input by keyboard instead of file In case of consecutive routings the user must delete and rename the appropriate output text files manually The preparation works is less than automatic ways but the total time spends in this manner is much longer than using HWM BAT file In model calibration process user needs to change parameters quite often Even if only one parameter is changed the model must be implemented again to obtain new results Since automatic method reads parameters from files while manual method reads parameters from keyboard automatic execution can save much time for user especially in model calibration process The manual method has merit of flexibility i e if the watershed schematic is changed all HWM modules and parameter file are kept unchanged The order of executing HWM modules should be changed but this order is controlled by user instead of HWM modules and parameter file It must be pointed out that the final results whether using HWM BAT or executing modules separately are the same For the same watershed schematic the order of HWM module execution is also the same Section 7 9 shows the execution order for Watershed One and Watershed Two The only difference is that HWM BAT executes all modules automatically reads par
152. ndition of bottom elevation SB10 1325 ft SB11 1321ft is employed in modeling Spatially uniform rainfall is used in the model SCS dimensionless unit hydrograph method is employed 1335 1334 1333 1332 1331 2 1330 oO 1329 4328 2 1327 1326 1325 0 50 100 150 Reservoir Outflow ft 3 s Reservoir Volume acre ft 200 250 0 00 025 0 50 0 75 100 125 150 175 200 a Elevation outflow relationship b Elevation volume relationship Figure 39 Elevation storage outflow relationship of SB10 78 1331 1331 1330 1330 1329 1329 1328 1328 1327 21327 8 1326 8 1326 1325 1325 1324 1324 8 1323 8 1323 8 1322 1322 Y 4321 1321 0 50 100 150 2 0 250 0 0 05 10 15 20 25 30 35 40 45 50 Reservoir Outflow ft 3 s Reservoir Volume acre ft a Elevation outflow relationship b Elevation volume relationship Figure 40 Elevation storage outflow relationship of SB11 63 MODELED RAINFALL EVENTS For this research eight significant stormwater events during the period from Oct 2005 to Sept 2006 were analyzed Figure 41 a to Figure 41 h show the bar graph for the eight stormwater events Half hr rainfall inch Oct 07 2005 Half Hour Incremental Rainfall 0 2 0 1 4 0 05 4 0 4 0 12 24 36 48 60 72 84 96 Time Hr since 00 00 Oct 07 2005
153. near reservoir or Level pool method is used to route hydrograph in reservoir LINEARRESERVOIR F n 1 K time of travel Parameters needed to input K Travel time of the reservoir LEVELPOOL F Parameters needed to input Initial Initial condition of the reservoir elevation ADD F No parameters Only input hydrographs are needed If X 0 the Muskingum routing method becomes linear reservoir routing method LINEARRESERVOIR F program is similar to MUSKINGUM F Because a hydrograph may be routed many times through channel and reservoir it is very complicated to use different names at every routing Thus we use name HYDRO_ TXT at the outlet of a sub watershed and routing We use name RHYDRO_ TXT after each routing A hydrograph may be routed many times Each time before routing the hydrograph from RHYDRO_ TXT must be changed to YDRO_ TXT if needed kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk Version ADD F Created by Weizhe An April 11 06 kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk Q is the original hydrograph data array QT is the total hydrograph data array REAL Q1 0 2880 Q2 0 2880 Q3 0 2880 REAL Q4 0 2880 Q5 0 2880 QT 0 2880 Y 1 100 RHYDRO is the routed hydrograph from upstreams HYDRO is the hydrograph file at the question SBWS THYDRO is the final total hydrograph CHARACTER 20 HYDRO RHYDRO A RHYDRO B RHYDRO C RHYDRO D THYDRO CHARACTER 20 X 1 100 OUT
154. o the TOPMODEL is not used in the studied watershed 22 Another reason not to use TOPMODEL is that many parameters are difficult to obtain in I 99 Project For example one of the key parameters in TOPMODEL is the index of hydrological similarity A of each grid square which depends on the area drained per unit contour length a and the local surface slope tan To determine 4 of each grid square a and tan of each grid square are needed This includes tremendous calculation which is not practical for 1 99 Project 27 SIMPLER LUMPED BASED FLOW MODELING A simpler lumped model the exponential recession model is available to describe the base flow The recession model has been used to explain the drainage from natural storage in a watershed Linsley et al 1982 It defines the relationship ofQ the base flow at anytime f to an initial value as O Q k 2 32 where Q initial base flow at time zero k recession constant The base flow is illustrated in Figure 7 The shaded region represents base flow in this figure the contribution decays exponentially from the starting flow The total flow is the sum of the base flow and the direct surface runoff 23 Discharge Direct surface runoff Baseflow Time Figure 7 Initial base flow recession k is defined as the ratio of the base flow at time to the base flow one day earlier The starting base flow value Q is an initial condition of th
155. o Equation 7 8 we get 2 3 1 2 0 59 89 4 2 OU 3 0 710 where 1 2 jp 7 11 2 Put 7 11 into 7 10 we get 1 2 MUN NE LE 0 14 s ES r 112 n r All variables in Equation 7 12 should be known except 0 Given any discharge at the pipe inlet 0 can be determined by trial and error Theoretically the flow can submerge the pipe However in this project reality such a large storm almost never happens So it is not necessary to consider the submerged situation The kinematic wave can be obtained by 107 m TET 1 2 7 13 3 3 r 1 cos0 2 After 0 is determined c can be obtained from 7 13 The routing procedure calculates the outlet discharge using inlet discharge Suppose the inlet discharge is Q t which can be represented by discrete input Q tj Then the outflow discharge can be calculated as 117 Qj t where T L cy is the kinematic wave travel time in the pipe or channel Chow 1988 For each Q tj and T can be calculated through above method 7 8 RESERVOIR ROUTING If the flow passes through a pond or reservoir the reservoir routing is needed to run the model The level pool reservoir routing and linear reservoir routing is employed in HWM Level pool routing is a procedure for calculating the outflow hydrograph from a reservoir with an assumed horizontal water surface given its inflow hydrograph and storage outfl
156. o that different parameters can be determined for each sub watershed These parameters include the Curve Number CN Time of Concentration T and the Antecedent Moisture Condition AMC Breaking up the large drainage basin into these smaller sub areas will make for a much more detailed and accurate model An example of this can be seen in Figure 36 and Figure 38 where the large area has been divided into the five and seven sub watersheds Also note the locations of reservoirs which will be modeled later Based on the general slope and topography of the area a framework for the direction of water flow can be determined This framework should be identified using a flow chart For instance Figure 45 and Figure 46 show the flow chart for the test watersheds shown in the Figure 36 and Figure 38 This framework must be followed when ordering the routing sequence 170 B 2 EXCESS RAINFALL GENERATION Program used EXCESSRAINFALL F Once the watershed framework and basic parameters are determined and recorded the computations can be begun The first step in this process is determining the amount of excess rainfall that results from a specific storm event Excess rainfall is defined as the direct runoff from a precipitation event It is the depth of water that does not infiltrate into the soil evaporate or get used by plant life It flows on the surface of the watershed until it is discharged at the outlet HWM model utilize SCS abstraction m
157. odeling period ranges from several hours to a few days In contrast continuous model simulates storm events over a long time period The modeling period ranges from several days to a few months While the event modeling is sufficient for project need there is another reason to build event modeling in this research The models WMS and HWM are designed mainly for event modeling The main runoff generation method that we used is the Curve Number CN method The runoff volume peak discharge peak time is mainly controlled by CN In different storm events the CN for a certain sub watershed is different because of different Antecedent Moisture Conditions AMC In the modeling CN for each sub watershed is selected based on AMC and is fixed once the model procedure starts If multiple events are modeled continuously CN needs to be adjusted for different events This can not be accomplished in WMS or HWM Even in events modeling the choice of CN is the most difficult task As stated in Section 2 1 CN can be found in National Engineering Handbook SCS 1972 based on soil type and land use For different AMC Soil Conservation Service 1972 also classified AMC into three types normal condition AMC II dry condition AMC 1 and wet condition AMC III The classification of AMC is shown in Table 1 Section 2 1 Equivalent CN can be computed by Equation 2 6 and Equation 2 7 However in the research we found only three kinds of AMC were not suffi
158. ow characteristics Chow 1988 The time horizon is broken into intervals of At indexed by i that is t 0 At 2At 1 DAt The continuity equation for the reservoir is dS I t Q t 7 14 dt where 5 the reservoir storage f reservoir input discharge at time and Q t reservoir output discharge at time 1 Integrating Equation 7 14 at i th time interval we got Si i 1 At 141 At 48 I t dt O t dt 7 15 S iAt 108 The inflow values at the beginning and end of the i th time interval are J 7 respectively Similarly the corresponding values of the outflow are and Q If the variation of inflow and outflow over the interval is approximate linear the change in storage over the interval S S can be found by re writing Equation 7 15 as LI 12S E EA At Q 1 5 1 7 16 The values of 7 are input discharges and are known The value of and 5 known at the i th time interval from calculation during the previous time interval Multiplying Equation 7 16 through 2 41 and re arranging the results we can isolate the two unknowns Q and S 25 25 Cu ead U se 0 7 17 25 In order to calculate the outflow Q a storage outflow function relating m 0 and Q is needed The method for developing this function using elevation storage and elevation outflow relation
159. p Ecotone is used to record the sub surface flow in the down stream watershed The last category Shallow Ecotone is employed to obtain water depth in the watershed outflow flume Ecotone is the brand of the instruments The Shallow Ecotone instrument is a Parshall flume Figure 17 is an illustration of a Parshall flume which has a contraction in the middle Parshall Flume Figure 17 An illustration of a Parshall flume When water flows through the flume the contraction forces the water flow from sub critical status to critical flow status At the critical depth the specific energy is minimized and discharge is uniquely related to the water depth Equation 4 1 shows the specific energy expression 28 4 1 where specific energy h water depth discharge 48 cross section area g gravity acceleration To get the minimum of Equation 4 1 is differentiated and assigned to be zero LEN 2080 4 2 dh where B flume width Equation 4 2 can be solved by substituting flow velocity V Q A and water depth h A B 2 1 0 4 3 Then the flow velocity and discharge can be calculated by V gh 4 4 O B Jg h 4 5 Theoretically the discharge can be calculated from depth directly In practice the relationship of water depth and discharge is calibrated and provided by manufacturer Once the relationship between water depth and discharge is determined we do not need
160. pe watershed length water velocity in channel Muskingum K Muskingum X For example CN the watershed slope and watershed length are used to calculate the lag time of a watershed CN is used to calculate the excess rainfall Water velocity in channel Muskingum K and Muskingum X are used to route hydrograph in channel CN is determined based on land use soil type and antecedent moisture condition AMC It is difficult to decide the accurate CN by only surveying and looking up tables The same reasons exist for watershed slope and watershed length The watershed slope is the average slope of a watershed However the watershed is irregular The slope varies from one part to another part The average slope is difficult to determine Water velocity in channel depends on many factors such as channel slope roughness and channel shape The channels shape slope and roughness in the watershed are very irregular It is difficult to determine these parameters accurately only by field survey One solution to determine these parameters is to combine field survey with the trial and error method First parameters rough value is estimated by field survey Then these parameters are adjusted in order to fit modeled hydrograph to measured hydrograph Ecotone water stage recorders were installed at the outlets of Watershed One and Watershed Two They are used to collect runoff data to calibrate the model Although two watersheds were selected only Waters
161. ph for Oct 07 2005 Event with edad 132 Measured and WMS modeled hydrograph for Oct 25 2005 Event with Calculated WY 132 xli LIST OF SYMBOLS Infiltration capacity into soil Minimum or ultimate value of f at Maximum or initial value of at t 0 Time Hydraulic conductivity Muskingum proportionality coefficient Coefficient of contraction flow velocity coefficient Recession constant Initial effective saturation Effective porosity Wetting front soil suction head The incremental precipitation depth excess rainfall The potential maximum retention watershed slope watercourse storage The Curve Number Evaporation loss rate Watershed area channel cross section area Evaporation rate Evaporation conversion factor Volume of water Water depth Rainfall excess Inflow rate Outflow rate Manning s roughness coefficient xiii AOFD MSL MSS NSTPS APD Hydraulic radius Conversion constant Muskingum coefficient The area draining through a grid square per unit contour length The local surface angle The local surface slope Index of hydrological similarity The lateral downslope transmissivity when the soil is just saturated Local storage deficit Model parameter controlling the rate of decline of transmissivity with increasing storage deficit in TOPMODEL The downslope subsurface flow rate per unit contour length Peak discharge Time of ri
162. played is the drainage layer which shows the sub watersheds streams and outlets position The gray segment lines and polygons under the drainage layer are land use and soil type layer which are inactive in the display Deep Ecotone Shallow Econtone Down_Stream Well Logger CN 820 N id Y CN 810 7 0 01 2 Zi Highwe gg CN 80 pl AO Dij A 0 00 mi 2 2 L 763 L 710 80 ft Soil type data file Lp Stream CN 81 0 A 0 07 mi 2 141 NN Land use data file Figure 36 Schematic layout for Watershed One 73 Based the topography re built channel and the flow of water in the watershed the whole watershed is divided into five sub watersheds Up Stream Up Side Highway Down Side Down Stream From the overall view the water flows from south east to north west As it name indicated Up Stream is located in the upper part of the watershed and occupies about 75 area of the whole watershed Most of Up Stream is undisturbed forest so water collected from this part 18 clean The clean water flows through a lateral channel and then goes to the most downstream outlet by an underground pipe without passing the intermediate downstream watershed The underground pipe is modeled as water diversion in WMS Up Side 18 located at the upper side of the highway Because the highway pavement is higher than other land the overland water from this part flows backward to the highway bas
163. res The area of Watershed Two is about 0 072 sq mile 46 08 acres Although DEM files are available online they cover large areas normally in 10 to 100 sq miles The resolution of the DEM is 30x30 sq meters The studied watersheds are only a few points in this kind of DEM file Detailed watershed delineation cannot be performed in such coarse DEM files Since DEM files are coarse the converted TIN files also cannot be used The same problems exist in the downloaded land use and soil type files Land use and soil type files are even in larger scale usually in 100 to 1000 sq miles If the online land use and soil type files are used probably the whole watershed falls in only one type of soil and land use 2 The watershed geomorphological characteristics and land uses have been changed recently by construction The online data do not reflect the updated elevation and land use changes For example during or after the construction land use in the watershed land use changes from uncultivated land or forest to paved highway Streams are created or covered Stream flow directions are changed Elevations hence the water flow channel 53 are also changed due to construction The nature stream is sinuous and coarse The water flow velocity in nature watershed is slow Constructed channels or streams are generally straight and smooth hence water velocity is greatly increased These changes cannot be reflected simultaneous on the downloading GIS
164. reservoir characteristics are shown before The watershed area basin length and overland slope are the same as in previous events The only different parameters are curve numbers After several trials a set of reasonable CNs are determined for this watershed and event Table 7 displays the CN for this event Table 7 Curve Number for Watershed Two Oct 25 2005 Event Up Left Right Right Right Right Down Stream Highway Highwayl Highway2 Highway3 Highway4 Stream Composite CN 98 98 98 98 98 98 98 There are five outlet channel flow routings Their parameters are listed in Table 5 The curve numbers for each land use type are listed in Table 8 Table 8 CN for each land use for Watershed Two Oct 25 2005 Event Index Land use name CN value for Soil Type D 0 Up Stream 98 1 Highway 98 2 Down Stream 98 3 Highway Sides 98 6 66 WMS RESULTS FOR WATERSHED TWO The Ecotones installed in the outlet flumes record water depth A rating curve is used to convert the water depth to the discharge Figure 42 shows the rating curve for flumes used 87 Rating Curve for Flume at Outlet 2 0 999 Q 0 0106H 0 0487H R 0 999 Discharge Q cfs Water Depth H inch Figure 42 The rating curve for Ecotones in the two studied watersheds 6 6 1 Watershed Two Event of Oct 07 2005 Oct 07 2005 Rainfall Event began at 00 00
165. rge values Table 9 shows the comparison of these three criteria for the two events modeled Based on the project need a deviation within 15 on runoff total volume and peak discharge is regarded as satisfactory A deviation within 120 minutes equal two modeling time intervals on peak time is regarded as satisfactory The hydrological modeling object is a watershed which contains various kinds of land use soil type vegetation coverage irregular surface slope 89 complicated stream networks and channels Although the hydrological theory works well in laboratory many uncertain factors and unavailable parameters in the watershed may influence the modeling results Rainfall spatial distribution may also add inaccuracy in the modeling There is no standard criterion in watershed modeling to evaluate the modeling quality The criteria adopted in this research were selected based on other researchers experience cited in the literature Quinn et al 1993 modeled the discharge for the River Severn watershed at Plynlimon Wales The difference between observed and predicted peak discharge was 19 the difference in peak time was up to 5 hours Campling et al 2002 modeled the River Ebonyi headwater watershed in Nigeria The difference between observed and calculated total runoff was about 15 in the peak discharge it was 31 the deviation of peak times was up to 3 hours Muzik 1996 modeled Waiparous Creek in the Alberta Canada The differen
166. rogram defined output B 8 KINEMATIC ROUTING Program used KINEMATIC_WAVE F The function of this module is the same to module B 5 except that this module uses the kinematic wave method while module B 5 uses Muskingum method The pipe s geometric characteristics such like pipe diameter pipe slope roughness are needed in kinematic wave method Since only one pipe routing is employed in HWM we integrated the specific pipe s geometric data in the program KINEMATIC WAVE F The detailed theory of kinematic wave is illustrated Section 7 6 The input and output file parameters are shown in Table 23 Table 23 Input and output of HYDRO F File Input Output data Definition KINEMATIC WAVE F Pipe diameter pipe slope roughness User defined input HYDRO Sub watershed hydrograph Program defined input RHYDRO TXT Coordinates of the routed hydrograph Program defined from each sub watershed output 176 B 9 MASTER FILE Program used HWM BAT This file is a computer BATCH file instead of a FORTRAN program It contains no calculations The task of this file is to execute different HWM modules consecutively without human intervention To achieve correct modeling results HWM modules for each sub watershed must be built and put into the same directory The correct order of HWM modules must be placed in HWM BAT file If the schematic of the watershed is changed the order of HWM modules in H
167. roximations made in kinematic wave theory is that is assumed to be a function of x alone This means that S Sp the other three slope terms secondary terms in Equation 2 15b are negligible Thus the bed slope is assumed to be large enough The water wave is assumed long and flat enough so that the change in depth and velocity with respect to distance 2 and 2 and the change in x x velocity with respect to time 2 are negligible when subtracted from S in Equation t 2 12b Henderson 1966 p 364 showed that the value of the secondary terms are small if the channel slope is about 10 feet per mile 0 189 or more Gunaratnam and Perkins 1970 p 45 also found the similar behavior In the project the slopes of the two steep underground pipes are 16 67 and 29 81 which is much larger than 0 189 This validates the kinematic wave application In order to use kinematic wave method kinematic wave celerity should be obtained Chow 1988 presented that kinematic wave celerity can be expressed as Quom Z 7 7 We have 22 S A R 7 8 where R the hydraulic radius ck kinematic wave celerity Q pipe discharge n Manning coefficient A flow cross section area S pipe slope For circular pipe 106 24 4 0r 7 9 where 9 the wetted angle indicated in Figure 57 r is the pipe radius lt 2 Figure 57 Pipe cross section illustration Put Equation 7 9 int
168. rtainty estimation GLUE framework The model simulated the fast subsurface and overland flow events superimposed on the seasonal rise and fall of the base flow very well It was also found that there was increased uncertainty in the simulation of storm events during the early and late phase of the season Conceptual based lumped models are well known for their simplicity They are also applied widely by many researchers Fontaine 1995 evaluated the accuracy of rainfall runoff model simulations by using the 100 year flood of July 1 1978 on the Kickapoo River in southwest Wisconsin as a case study The accuracy of a simple analysis 18 compared to that of an elaborate labor intensive analysis The more elaborate modeling approach produces more accurate results Fontaine concluded that the error in the precipitation data used for calibrating the model appears to be the primary source of uncertainty Lid n 2000 did an analysis of conceptual rainfall runoff modeling performance in different climates It was found that the magnitude of the water balance components had a significant influence on model performance Beighley 2002 presented a method for quantifying spatially and temporally distributed land use data to determine the degree of urbanization that occurs during a gauge s period of record Madsen 2002 presented and compared three different automated methods for calibration of rainfall runoff models Besides building mathematical
169. s for each sub watershed These files will be stored for later use in the program and can be viewed and analyzed at any time Table 19 Input and output of HYDRO F File Input Output data Definition PARAMETERS TXT Te sub watershed area User defined input UHPROTOTYPE TXT DUH abscissas and coordinates Program defined input EXCESS 8 Half hour excess rainfall Program defined input HYDRO TXT Coordinates of the total runoff hydrographs Program defined computed at each sub watershed output B 5 MUSKINGUM ROUTING Program used MUSKINGUM F Once the outflow hydrographs have been determined at each sub watershed for a particular storm event they must be added together in order to determine the total outflow hydrograph at the watershed outlet However hydrographs within a watershed cannot simply be added they must be first routed downstream in order to account for time delays and parameters specific to the channels within each sub watershed This program utilizes the Muskingum Method of channel routing in order to combine hydrographs This method models a flood wave propagating down a channel The detailed theory was described in Section 2 5 Based on Muskingum method parameters an iterative method can be completed in which the inflow hydrograph will produce the coordinates of the routed outflow hydrograph Equation 2 19 and Equation 2 20 are executed in this program The coefficients in the equations ar
170. s proves this behavior 91 Furthermore some of the modeling results are not satisfactory and need to be improved As we can see from Table 9 one of two deviations of the peak discharge values is not satisfactory one of two deviations of the peak times is not satisfactory The modeled hydrograph shapes do not fit the measured shapes very well To compensate for the above shortcomings and get better results a new model Highway Watershed Model HWM will be developed and presented in Chapter Seven It will be applied in the project in Chapter Eight 92 7 0 HIGHWAY WATERSHED MODEL HWM DEVELOPMENT 7 4 MOTIVATION FOR DEVELOPING HWM Although WMS 18 widely used in watershed modeling it may not be suitable for the present case Sensitivity analysis indicates the total discharge is mainly related to curve number the hydrograph shape is mainly related to the watershed slope Other parameters influence the hydrograph very little In some cases in WMS no matter how the parameters are adjusted the modeled hydrographs still do not match the measured hydrograph very well This may be the shortcoming of WMS As discussed in Section 6 8 there are some shortcomings and restrictions in manipulating in WMS To make the model more flexible and to have full control in its implementation a new model the Highway Watershed Model HWM was developed by writing completely new programs Because this model is developed directly for 1 99 Environmental
171. se Lag time Duration of effective rainfall Time of concentration Unit hydrograph Muskingum weighting factor The lag time Watershed length Acceleration of gravity Water pressure head before or after the contraction part Relative peak time Recession constant Watershed slope Average overflow distance Maximum stream length Maximum stream slope The number of integer steps for the Muskingum routing Antecedent precipitation depth xiv Pipe radius the recharge rate in TOPMODEL Ck Kinematic wave celerity 0 wetted angle in pipe flow Specific energy B Flume width CWV channel water velocity XV ACKNOWLEDGEMENTS I would especially like to thank my advisor Dr Rafael G Quimpo for his constant support and guidance throughout the duration of my Ph D study I would also like to give special thanks to Dr Ronald D Neufeld Dr Jeen Shang Lin Dr William Harbert and Dr Xu Liang for their mentorship in my graduate work Special gratitude is extended to colleagues and staff in the Department of Civil and Environmental Engineering for their invaluable support and assistance provided throughout my study I would also express gratitude to my parents and younger sister for their consistent support from my family Thanks are also given to all my friends who have helped me in my study and research xvi 10 INTRODUCTION 11 BACKGROUND Hydrology is the scientific study of water and
172. see 33 Pieure 10 of land Use NNNM M MEME 35 Figure 11 Attribute table for land Use uo caede ER EDS 35 Figure 12 Illustration of soil type 36 Figure 13 Attribute table for soil type tap vee ies rne rtr trn poen Levi bord 36 Figure 14 A mix use of storm total and temporal distribution recording station 39 I5 The I 99 project locaton Da NUN I 44 Figure 16 The Environmental Impact Study EIS area boundary 45 Figure 17 An illustration of a Parshall 48 Figure 18 The imported DEM data for LPCW 56 Fig re 19 The flow direction Of LECW auod ov n RM cw pU Pap MEME 97 Figure 20 The stream network of 58 Figure 21 The converted stream feature arcs in 39 Figure 22 The delineated watershed boundary and some of the basin properties 60 Figure 23 The re defined sub watershed boundaries and watershed properties 61 Figure 24 The DGN file view in ArcGIS ugs bi David pel eno eio iR Due epit be aia 62 Fiebre 25 The TIN tle view in ArcGIS 63 Figure 26 Figure 27 Figure 28 Figure 29 Figure 30 Figure 31 Figure 32 Figure 33 Figure 34
173. shed boundaries he can add streams and outlet manually Also users are free to combine adjacent sub watersheds into one and divide a big sub watershed into several However all operations must have solid practical basis instead of only imagination An example of watershed delineation using DEM and TIN file is shown in Figure 8 and Figure 9 respectively Although it is convenient to generate watershed delineation using DEM or TIN files there are some limitations In a real watershed there may be some spikes or pits A spike is a cell whose elevation is higher than the surrounding cells A pit is a cell whose elevation is lower than the surrounding cells Flat terrains flat channels also exist in reality While a spike is generally not a serious problem in hydrologic analysis a pit or flat element on the other hand can be This can be problematic because the water flows into the pit and never flows out Thus the flow path is discontinued The model cannot determine the flow direction if flat terrains are encountered In order to perform any type of hydrologic analysis pits and flat elements must be removed WMS program has tools 31 to remove a small amount of error elements by changing their values through interpolation However these tools are only useful when a few errors happen If huge numbers of pits flat terrains congregate together to form a big pond their elevation values cannot be altered though interpolation Thus they c
174. ship is shown in Figure 58 The elevation storage relationship and elevation discharge relationship can be derived from reservoir design data The value of At is taken as the time interval of the inflow hydrograph For a given value of water surface elevation the value of storage S and discharge are determined Figure 58 a and Figure 58 b then the value of 2S 4t Q is calculated and plotted on the horizontal axis of a graph with the value of the outflow Q on the vertical axis Figure 58 c In routing the flow through time interval i all terms on the right side of Equation 7 17 are known and so the value of 2 At Q can be computed The corresponding value of Q can be determined from the storage flow function 2S 4t Q versus To set up the data required for the next time interval the value of 25 A4t is calculated by 25 d 7 18 id 109 The computation is then repeated for subsequent routing periods b torage Outflow a Water surface Figure 58 Development of the storage outflow function for level pool routing on the basis of storage elevation and elevation outflow curves Chow 1988 Linear reservoir routing is the simplified Muskingum routing which is discussed in Chapter Two If we take Muskingum parameter X 0 we obtain linear reservoir routing method Although the algorithm of reservoir routing is different from channel routing it is regarded as similar procedur
175. ter table levels The watershed flux of water entering the water table 0 is calculated by assuming the of each topographic index class 0 4 4 2 29 Output from the saturated store is represented by the base flow term which can be calculated using a subsurface storage deficit discharge function of the form O e 2 30 where e is discharge when S is zero The watershed average deficit S is updated by subtracting the unsaturated zone recharge and adding the base flow from the previous time step 5 1 Qu Qul 2 31 The initial base flow and the initial root zone storage deficit 5 0 are input at the start of the modeling Experience in modeling the Booro Borotou watershed in the Cote d Ivoire Quinn 1991 and watersheds in the Prades mountains of Cataluna Spain suggests that TOPMODEL will only provide satisfactory simulations once the watershed has wetted up In many watersheds that tend to receive precipitation in short high intensity storm or receive low precipitation the soil seldom reach a wetted state and the response may be controlled by the connectivity of any saturated downslope flows Short high intensity storm may lead to the production of infiltration excess overland flow which is not usually included in TOPMODEL The watersheds in 1 99 Environmental Research often receive such kind of rainfall Some assumptions are violated in the studied watershed s
176. the slope in interperlation linear function LENGTH is the length of the pipe REAL VELOCITY TOTALTIME 0 2880 TRAVELTIME 0 2880 SLP LENGTH INTEGER INDEX J BEFORE AFTER are file name representatives CHARACTER 20 BEFORE AFTER XX 1 100 Read all parameters from a file OPEN 30 FILE PARAMETER TXT STATUS OLD DO 20 J 1 100 READ 30 END 21 XX J Y J CONTINUE LINE J 1 CLOSE 30 STATUS KEEP SBWSNUM Y 72 73 74 Select the file to read IF SBWSNUM EQ 1 THEN BEFORE HYDRO_1 TXT AFTER RHYDRO_1 TXT ENDIF IF SBWSNUM EQ 2 THEN BEFORE HYDRO_2 TXT AFTER RHYDRO_2 TXT ENDIF IF SBWSNUM EQ 3 THEN BEFORE HYDRO 3 TXT AFTER RHYDRO 3 TXT ENDIF IF SBWSNUM EQ 4 THEN BEFORE HYDRO 4 TXT AFTER RHYDRO 4 TXT ENDIF IF SBWSNUM EQ 5 THEN BEFORE HYDRO 5 TXT AFTER RHYDRO 5 TXT ENDIF IF SBWSNUM EQ 6 THEN BEFORE HYDRO 6 TXT AFTER RHYDRO 6 TXT ENDIF IF SBWSNUM EQ 7 THEN BEFORE HYDRO 7 TXT AFTER RHYDRO_7 TXT ENDIF IF SBWSNUM EQ 8 THEN BEFORE HYDRO 8 TXT AFTER RHYDRO 8 TXT ENDIF IF SBWSNUM EQ 9 THEN BEFORE HYDRO 9 TXT AFTER RHYDRO 9 TXT ENDIF IF SBWSNUM EQ 10 THEN 165 BEFORE HYDRO_10 TXT AFTER RHYDRO_10 TXT ENDIF File unit 10 is the input file it contains routing input required by Kinematic OPEN 10 STATUS OLD FILE BEFORE Initialize the input and output 1 is the Kinematic input Q is the Kinematic output DO 5 INDEX 0 2880 IINDEX 0 Q INDEX 0 CONTINUE R
177. though SCS UH is widely used it appears to be unsuitable for I 99 highway watershed modeling Oct 7 2005 Hydrograph Comparison 3 5000 Measured WMS 3 0000 2 5000 2 0000 Discharge cfs 1 5000 1 0000 0 5000 0 0000 Time Hr since 00 00 Oct 7 2005 Figure 72 Measured and WMS modeled hydrograph for Oct 07 2005 Event with calculated CWV Oct 25 2005 Hydrograph Comparison Measured WMS Discharge cfs 0 12 24 36 48 60 72 84 96 108 12C Time Hr since 00 00 Oct 25 2005 Figure 73 Measured and WMS modeled hydrograph for Oct 25 2005 Event with calculated 132 Table 16 The comparison of the three criteria for Watershed Two with calculated CWV Total Runoff Peak Discharge Volume ft cfs 8 Peak Time min Measured 142341 1 77 1440 Oct 07 2005 Modeled 137365 3 06 1260 Deviation 3 50 96 72 88 96 180 min Measured 77531 0 79 1020 Oct 25 2005 Modeled 74761 1 92 540 Deviation 3 57 143 04 480 min As we can see from Figure 72 Figure 73 and Table 16 with calculated CWV the modeled total runoff volumes do not change much However the peak discharges are greatly increased and peak times are greatly advanced These results show the SCS UH may not be suitable in I 99 highway watershed modeling 8 5 3 Comparison using AMC CN relationship Another comparison will be ma
178. tion of the reservoir elevation ADD F No parameters Only input hydrographs are needed If X 2 0 the Muskingum routing method becomes linear reservoir routing method LINEARRESERVOIR F program is similar to MUSKINGUM F Because a hydrograph may be routed many times through channel and reservoir it is very complicated to use different names at every routing Thus we use name HYDRO_ TXT at the outlet of a sub watershed and routing we use name RHYDRO_ TXT after each routing A hydrograph may be routed many times Each time before routing the hydrograph from RHYDRO_ TXT must be changed to YDRO_ TXT if needed kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk Version NewUH F Created by Weizhe An June 28 06 Considering the limitations of SCS Dimensionless UH method a new UH is developed under Dr Quimpo s guidance The new UH assumes that Dimensionless UH consists two of parts The first part is linear uprising The peak time is Tp as explained in SCS Dimentionless UH method The second part is exponential decrease from peak to zero This program generates the Dimensionless UH by calculating 51 points of the UH curve kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk Code inputs parameters Files Two parameters in file PARAMETER txt User They are both read from PARAMETERS TXT file Although the theoretical range of Tp is 0 5 the practical range is 0 5 2 141
179. to get discharge from the instrument Instead we get water depths and convert them into outflow discharges in the hydrological analysis using the relationship The Well Logger Deep Ecotone and Shallow Ecotone instruments automatically record water levels at six hour intervals one hour intervals and one hour intervals respectively The data will be used in Task B for calibrating the model and evaluating model prediction results and in task C for assessing wetland conditions and key wetland indicators The locations of monitoring instruments for Watershed One and Watershed Two are illustrated in Figure 36 and Figure 38 respectively The Environmental Impact Study EIS is about 10 miles long and 1 mile wide Because the EIS area does not belong to one watershed it is divided into several sections 49 Along the highway length marks are coded from 0 to 535 One unit mark s distance interval is 100 ft Hydrological modeling is performed in the selected two watersheds which are at about the length mark of 185 and 400 For purposes of Task A ponds were constructed downstream of the highway at several locations The corresponding ponds in the two watersheds are SB111 around length mark 400 and SB10 SB11 around length mark 185 These two watersheds were selected because PENNDOT constructed special underground filter galleries in the watersheds Also Ecotones were installed at these two watersheds outlets As stated above one of the ob
180. to produce hydrograph LEUH is shown to be a better unit hydrograph method than SCS UH Another strength in using HWM is that it is developed by our research group and we know all the calculation details It is easier for us to change to the most suitable calculation method which 18 restricted by an integrated software 134 9 0 CONCLUSIONS AND RECOMMENDATIONS 91 CONCLUSIONS The objective of this research is to build a runoff prediction model using GIS techniques for a watershed affected by highway construction The model was designed to predict runoff at several outlets in the watershed based on rainfall land use soil type detention pond location stream network distribution water velocity and basin slope etc The local applicability efficiency and runoff prediction method were verified Based on the results the following conclusions can be made 1 A GIS based rainfall runoff model was developed using the Watershed Modeling System WMS platform and calibrated to simulate the hydrology and hydraulic behavior along the stream system draining selected watersheds near I 99 highway construction site Because of GIS data problems the watershed delineation was carried out manually instead of using GIS based topographical data With 15 deviation as accepted criterion the modeling results of WMS show all total runoff volumes are satisfactory but the prediction of peak discharge is not satisfactory 2 To address the shortcomings t
181. ugh model structures and development procedures of WMS and HWM are different the most important parameter that controls the total runoff volume is the curve number CN The model calibration is implemented mainly based on net rainfall equality principle i e excess rainfall equals measured total runoff volume This is the reason that total runoff volume is easy to model The peak discharge and peak time are controlled by many factors such as CN watershed slope Muskingum shape of dimensionless unit hydrographs etc of these factors can be changed in HWM However the shape of DUH is fixed in WMS This is the main difference between HWM and WMS and 18 the motivation to develop HWM Modeling results show this change is valid and successful With the total 130 runoff volume unchanged the peak discharge and peak time change interactively with the change of those controlling factors For example if the watershed slope is increased the peak discharge will increase but the peak time is advanced simultaneously If the 7 parameter in Linear Exponential Unit Hydrograph LEUH is increased the peak discharge will decrease while the peak time is delayed simultaneously With the application of LEUH HWM extends the ability of modeling different watershed hydrological responses 8 5 2 Comparison using parameters The model WMS and HWM can be compared by examining their parameter suitability As we can see from Table 5 th
182. ulation and are not specific to any basin or reach in the channel These parameters are defined in WMS job control module model s title ID author and short description can be filled in the first part Then the modeling event starting date and calculation unit should be filled The most important data here are the computational interval and the number of hydrograph ordinates They determine how long the resulting hydrograph should be displayed If the display time is too short the hydrograph will not be shown completely If the display time is too long the hydrograph shown is to rough and many details are missed Proper computational interval and the number of hydrograph ordinates are needed to get good modeling results They can be estimated by observing similar outflow records As stated in 3 7 1 the user has the option to optimize unit hydrograph and loss rate parameters in the modeling so the calculated hydrograph will match the observed hydrograph User also can optimize routing parameters using observed inflow and outflow hydrographs and a pattern lateral inflow hydrograph for the routing reach They are also set in job control module 41 3 10 DISPLAY OUTPUT The model results are detailed hydrographs at each outlet At the outlet where reservoir is located both hydrographs flowing into and flowing out can be displayed The display formats can be diagram text format Excel format etc For direct view a diagram is often
183. used to calculate lag time defined by SCS 1000 Ho 10 1 98 x 3 1 1900x 4 5 where Trag the lag time L the watershed length CN curve number S watershed slope in percent 38 CHANNEL AND RESERVOIR ROUTING The hydrographs from the upper basins would be combined with the lower basin hydrograph at the watershed outlet Routing parameters should be determined to compute lag and attenuation on the upper basin hydrographs before adding them to the lower hydrograph The Muskingum method is often used in channel routing The method is dependent primarily upon the following factors the number of integer steps for the routing Muskingum K coefficient in hours and Muskingum X coefficient The algorithm is explained in Chapter Two The integer step number and K coefficient are determined by water flow velocity in the channel 40 A reservoir is placed at an outlet to model water storage and retention Although the reservoir does not occupy area in the model its characteristics can be defined using a table The important reservoir routing data are elevation discharge relationship elevation storage relationship and initial condition Using these data reservoir routing can be performed without knowing reservoir s area 39 JOB CONTROL SETTING Most of the parameters required for HEC 1 model are defined for basins outlets and reservoirs However there are some global parameters that control the overall sim
184. wetland species diversity relative abundance of domain classification and the performance of uncommon or unique species This model will be developed for use as a tool in assessing impacts of future highway projects utilizing key indicators and standardized measures of diversity 4 2 4 Task D Evaluation of stream restoration rehabilitation and relocation The objective of Task D is to assess the effectiveness of stream restoration stabilization and relocation practices for highway construction and their ability to sustain a complex ecologically diverse healthy stream system over the long term Highway constructions often impact streams directly and indirectly These construction projects typically require some type of mitigation which includes stream bank stabilization stream relocation stream restoration and possibly mitigation elsewhere to compensate for impacts of the project 52 5 0 DIFFICULTIES IN MODEL BUILDING 5 1 DIFFICULTIES STATEMENT This research focuses on Task B the prediction of runoff on the complex construction site Hydrological modeling is performed in the selected two watersheds which are approximately at about the stations of 400 58111 Watershed One and 185 SB10 5811 Watershed Two in the construction project s alignment Due to the following features this construction watershed is difficult to model 1 The watershed areas are very small The area of Watershed One is about 0 085 sq mile 54 40 ac
185. with R 0 9971 Similarly scatter plot for measured and modeled peak discharge is shown in Figure 68 The perfect fit line should be Y X with 1 while the actual fit line is Y 0 9829 X with R 0 997 For peak time modeling Figure 69 shows the scatter diagram for measured and modeled peak time The perfect fit line should be Y X with R 1 while the actual fit line is Y 1 0062 X with 0 9993 300000 Actual fit line 250000 200000 Perfect fit line 150000 2 1 100000 Modeled runoff volume m 3 50000 0 50000 100000 150000 200000 250000 300000 Measured runoff volume 133 Figure 67 Scatter plot for measured and modeled runoff volume 121 35 Actual fit line 0 9829 Perfect fit line 2 1 Modeled peak discharge cfs 0 05 15 2 25 3 35 Measured peak discharge cfs Figure 68 Scatter plot for measured and modeled peak discharge 5000 Actual fit line 10062 R 0 9993 4000 3000 Perfect fit line 2000 X Modeled peak time min 1000 0 1000 2000 3000 4000 5000 Measured peak time min Figure 69 Scatter plot for measured and modeled peak time 122 84 RELATIONSHIP BETWEEN CN AND Based on the length of the modeling period we can categorize our model an event model instead of a continuous model An event model simulates storm events one by one The m
186. y Weizhe An April 10 06 The program reads the half hour incremental excess rainfall txt file generates half hour SCS unit hydrograph and generates hydrograph at the outlet at the sub watershed s outlet The EXCESS_ TXT file contains the incremental half hourly rainfall for the corresponding sub watershed kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk Code inputs Files EXCESS_ TXT UHPROTOTYPE TXT User Time of concentration of each sub watershed Area of the sub watershed Output Files UNITHYDRO TXT UH_ TXT HYDRO 4 146 C UNITHYDRO TXT and UH_ TXT are both half hour unit hydrograph but they are in different coordinate scale C UNITHYDRO TXT are in natural coordinate UH_ TXT are in 5 min interval coordinate Be careful C kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk The following parameters are adopted from Applied Hydrology Ven Te Chow ISBN 0 07 010810 2 Page 229 Tc is the time of concentration tp is the lag time TTp is the time of rise tr is the duration of unit hydrograph 0 5 hr tb is the duration of the direct runoff qp is the unit hydrograph peak discharge PROTOTYPE is the original SCS unit hydrograph by proportion not real values UHDUR is the unit hydrograph duration 0 5 hr 30 min INTERVAL is the time interval of the prototype unit hydrograph REAL Tc TTp tr tb Area PROTOTYPE UHDUR INTERVAL UNITHYDRO 5000 is a tempor
187. y flat areas and pits It is almost dominated by manmade structures like channels pipes and highways Figure 29 also shows the DEM with flat and pit cells The shaded areas are flat or pit cells 65 NS ie 2 1 Figure 27 The DEM file for I 99 Environmental Research Figure 28 The DEM file with the flow direction the stream networks and stream feature arcs 66 Figure 29 The automatically generated watershed boundary and DEM with flats and pit cells Trimming a profile like the actual watershed to form a proper watershed shape does not solve this problem The inner flat and pit cells remain unchanged Actually the man made structures are not reflected in the DEM file yet The watershed delineation does not coincide with the actual one Figure 30 shows the original DEM file for Watershed SB10 11 Figure 31 shows the DEM file with flow direction stream networks and the stream feature arcs Figure 32 shows the automatically generated watershed boundary the flat and pit cells The shaded area are flats or pits cells In comparison the LPCW DEM file contains no flat or pit cells 67 Figure 30 The original DEM file for Watershed SB10 11 Figure 31 The DEM file with the flow direction the stream networks and stream feature arcs for Watershed SB10 11 68 Figure 32 The automatically generated watershed boundary flats and pit cells for Watershed SB10 11 55 TOPOGRAPHIC
188. ype of flow regime An equation similar in form to the Manning s equation be used to calculate the flow velocity 5 7 3 where flow velocity ft s coefficient based on the flow type S slope in percent McCuen 1989 and SCS 1972 provided values of K for several flow situations which are listed in Table 10 With different velocities in different segments can be obtained Table 10 Coefficients of velocity ft s versus slope relationship for estimating travel velocities McCuen 1989 SCS 1972 K Land Use Flow Regime 0 25 Forest with heavy ground litter hay meadow overland flow 0 5 Trash fallow or minimum tillage cultivation contour or strip cropped woodland overland flow 0 7 Short grass pasture overland flow 0 9 Cultivated straight row overland flow 1 Nearly bare untilled overland flow alluvial fans in western mountain regions 1 5 Grassed waterway 2 Paved area sheet flow small upland gullies For different land uses and slopes the water flow velocity ranges from 0 025 ft sec to 0 894 fi sec LEUH is better than SCS unit hydrograph method in that it can describe different sub watersheds response using different DUHs For example some watersheds starts to produce runoff quite quickly but the recession time is very long While some watersheds start to produce runoff very slowly but the recession time is short This

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