Rioni_river_Practica..
Contents
1. TT Computation Level Output Detailed Output Interval 6 Hour v DSS Output Filename D Dropbox G eorgia Practical RioniHR RioniHR dss i Mixed Flow Regime see menu Options Mixed Flow Options TI Ending Date Computation Settings Computation Interval Modelers are reluctant to establish fix water levels as BC This BC forces to measure cross sections to a place where no change in water elevation happens regardless of the discharge This might be deep in the sea A better solution could be a rating curve at the outlet although in this case this was not available Notice that by fixing the water elevation we state that the profile in the last downstream sections do not change with the discharge This is erroneous if the last cross section is constrained between banks not reaching open water yet The boundary condition downstream will affect the results The advice is to establish a reasonable BC and later compare the rating curve produced by HecRas with measurements in the field Figure 46 Interface to run the unsteady state Page 22 of 27 HEC RAS analysis 23 27 MATRA Project Running the model and analyzing the results ITC WRS Gabriel N Parodi Calibration and validation can only be done with independent measurement sources This information is not available at the present stage of the study Comparison of rating curves could be an easy asset to achieve validation Unsteady flow 33 To run the He2. a process that escapes the objective of this exercise In our case we will adopt that all channel sections have a Manning equal to 0 035 and the Left and Right overbanks 0 050 This kind of generalization is not proper during real modeling There are some sections in the river where there is a flow division The channel splits in two sections and the river flows in 2 parallel sub channels Those are the cases of at least 2 stations 987 and 984 in the Upper Rioni depicted in Figure 22 and Figure 23 For these cases the horizontal variation of the Manning needs more than 3 options HecRas can be instructed to account for that from the cross section data editor 14 At the cross section that requires this option from the cross section editor select Options Horizontal variation of n values A new column n Val is added to the Cross Section Coordinates The user can enter now a horizontal variation of n zola Exit Edit Options Plot Help Rive Rioni x Apply Data Val i Plot Cotone Ba S IM Keep Prev XS Plots Clear Prev Reach Upper z River Sta 387 DIRE RioniHR Plan E Te IF H J k os 035 os TEE E fa roun Mannina s n Values Bank Sta m E 2 B gt 2 w 5 28 63675 6 33 60304 0 7 38 58931 8 43 55561 9 48 54188 10 53 50818 11 58 49445 3 12 59 83628 4 i Station m 13 121 9851 1A 169 OR75 R Figure 22 The flow happens over 2 sections in station 987 The
3. Select flow file for plan Figure 36 Interface to run the steady state 50 cm elevation at the downstream ends 32 Select Subcritical flow regime and press compute Calculations will be finished in seconds Result analysis A deep analysis requires time and verifications It is not expected to cover all of them in this exercise A reduced check list of controls are the following a Verify that the regime type subcritical is the adequate b Review the summary of errors warning and notes with extreme care In general there might errors that require attention cross sections additions and changes in the conveyance reqiring the verification of cross sections adequacy c Verify the adequacy of the selected profiles d Verify the adequacy of the boundary conditions e Verify the adequacy of the extent of the cross sections Some of them might have been extended vertically to allow the model to flow This is unacceptable f Calibrate the model with available information rating curves or water marks This option may require refinements like the addition of structures g Dothe modification analysis as required In the following and indication of every step is given Page 19 of 27 HEC RAS analysis 20 27 MATRA Project Running the model and analyzing the results ITC WRS Gabriel N Parodi Verifying the flow regime The verification of the flow regime can be done in several ways e Pressing the icon v
4. 1783 082478 22 Foni LowerPo 98 23 Roni LowerPoti 97 1853 850981 1818 788981 1769 296505 25 Ron LowerPo 97 24 Roni LowerPo 96 345 9986364 342 5203532 339 50095 24 Rioni LowerPo 96 25 Reni LowerFo i 95 968 3809893 984 7772646 1003 713871 25 Foni LowerPo 95 26 Roni LowerFo i 94 529 1454756 527 895999 526 9300397 31 Foni Lower 496 33 Roni Lowerkeft _300_ 717 1371224 898 3780316 1068 176710 _ TRini LowerLeit 300 Rni Lowerleft _250 140277 140277 140277 To operate with this table as an example we take the first line below the heading At the Rioni River in the upper section from station 999 to 998 the distances are highlighted in dark yellow Figure 11 shows the schematics between the 2 sections and it can be seen that indeed the LOB distance is smaller than the other 2 12 From the Geometric Data Editor menu select Tables Reach Lengths A table opens and the user can copy the distances from the excel sheet and paste it directly in this table Use the column Station as the reference key column This table is an addition to HECRAS that allows entering all the section distances at once At the end of the copy and paste process the Interface for the Rioni Upper should look like in Figure 12 Last section of each reach should be set distance 0 Press OK to save the data and the repeat the procedure for all branches Figure 13 to
5. 4669788 4669791 4669795 4669798 Tools Editors _ Inline Structure Lateral Structure Saaga Area Storage Area Conn g Pump Ri Son Pum n v Draw l Autoshapeso a FO fd Or 2 A gt z Ready NUM CALG 48 4669760 od Figure 8 The verification of one XS The coordinates in the CSV file for a selected cross section coincides with the coordinate in the geometric data editor This can be checked in the lower right sector of the Geometric data editor were the coordinate appear 1 or 2 meter error is normal Adding cross sections In the previous section all XS were added by importing from an excel file This would be enough for this exercise However in real situations there are many options to enter XS in HECRAS The most common case is that the XS survey in the field produces a number of XS that prove not to be in enough number to make the HR model stable In these cases it is recommended to come back to the field measure some more XS and incorporate them in the model Md To add XS manually click the button in the geometric data editor As from this point follow the instruction in the HECRAS User Manual Chapter 4 Entering Cross section Data Understanding this procedure is required for the multiple editions that are normally required before getting a successful run Fine tuning the input XS Up to now the input limits to the geometry of individual cross sections that fit in the r
6. At the end of the data input the interface should look like in Figure 33 Notice that the initial discharge is repeated twice to help in the stabilization of the model before the wave comes in The boundary condition downstream is again controlled by the water head at the Black Sea 18 27 MATRA Project ITC WRS Gabriel N Parodi Table 7 Observed flood in 1987 and estimated Recurrence intervals after Tsamalashvili 2010 Notice that the shape of the hydrograph is associated to the available flood of 1987 1987 Observed Discharge m s m f o 226 asa are os a ein ri scare EEA e Lio Lion 60 anr Ome 595 634 roo 761 ese 420 500 see 27 686 As the last cross section available is not yet at the sea it is perhaps better to select a normal depth for boundary condition instead of fixing the water level In this example we could try a normal depth of 0 001 and then change to water head fixed if the results are not satisfactory The most ideal case would be to extend the cross sections towards the sea till there is certainty that the water level in the section is not influenced by the channel constriction As cross sections did not get the sea the selected boundary condition remains to be tested 28 Select the three boundary conditions downstream Flow Hydrograph 29 for the ending reaches and set normal depth equal 0 001 in all three cases At the end of the input the interface shoul
7. Figure 16 show the outcome of this last procedure Figure 11 The distance between 999 and 998 is different for the LOB channel and ROB The ROB is the longest Page 8 of 27 HEC RAS analysis 9 27 MATRA Project Input ITC WRS Gabriel N Parodi River Rioni z ev Edit Interpolated XS s River Rioni 2 Bal Bi Edit Interpolated XS s Reach Upper Reach Ea aai Selected Area Edit Options aaa i i i Selected Area Edit Options Add Constant Multiply Factor Set Values Replace Add Constant _ Multiply Factor Set Values Replace River Station Channel ROB 1716 976 2137 524 i 681 9819 742 1292 1313 814 1192 651 869 7734 1779 681 1783 083 1334 632 1883 481 2928 122 i 1818 789 1769 297 2371 593 1902 833 1686 062 342 5204 339 5009 1558 788 1571 991 1592 671 984 7773 1003 714 2444 867 2051 115 1525 432 i 527 896 526 939 1000 601 1584 693 2307 155 0 0 1901 778 1356 33 734 4262 2174 922 2170 695 2133 19 Figure 13 Final distances between the cross sections for the 1290 883 1800 615 2302 573 LowerPoti reach 2165 729 1844 135 1569 479 1845 056 1646 182 1437 074 2060 426 2371 554 2754 611 14 985 1954 076 2063 064 2376 288 15 984 2346 902 1863 115 1746 972 16 983 1900 676 1108 248 828 4783 17 982 1673 173 1791 341 1883 443 18 981 3515 382 3272 886 3227 601 19 980 0 0 0 Figure 12 Final distances between the cross sections for the Upper reach Edit Downstream Reach Lengths Edit
8. Figure 17 Correcting an error in a cross section Step 1 in the cross section editor select the station with the wrong information in the graphic Each point is linked to the table and the corresponding line illuminates River Rioni oly Data Vel ta Plot Options Ba l Keep PrevXS Plots _ Clear Prev 994 Reach LowerPoti z River Sta 99 z atl RioniHR Plan RioniHR 30 06 2011 993 Description i 992 ee Del Row Ins Row aise wns I Reach Len oa 05 035 05 gt 19 Cross Section Coordinates L08 Channel __ ROB 3 fi 1774 558 fi 1779 681 fi 1783 083 I n 10 143 a i 39 147 2 41 7872 1 28 LOB Channel ROB er ve 3 67 41922 1 37 loo oos 005 n JO 8 4 74 25162 0 25 x 5 79 33682 0 43 Main Channel Bank Stations 87 2 6 82 90002 0 83 __LeftBank RightBank__ 986 AR 7 87 90002 1 53 74 25162 147 8988 I 8 92 90002 1 73 Cont Exp Coefficient Steady Flow filed 51 50 9 97 90283 1 76 10 102 9028 298 Al 11 11 107 9028 3 33 N aa 12 112 9028 3 38 13 117 9056 3 25 982 74 141127 208 2R z a pa me a L i Station m to O gt Cross Section Data RioniHR_reach z Le Bat Edit Options Plot Help pe tate EEE River Rio a Boot pia lf 00 Phat Raf B I Keep Prevx Pris _ Clear Prev Rioni LowerRight 350 131 3298 481 2428 pasci Ciro A er S18 52 a Wi t RioniHR Plan RioniHR 30 06 2011 Rioni Low erLeft 157 5632 4
9. X Y Z Format OK SI metric units next 10 3 Unselect all the River Reach Stream lines were digitized and they will not be imported next 10 4 Unselect Bridges and Culverts Inline Structures and Lateral Structures Leave all other options 10 5 Click Finish Import Data As you finish with the import the plan should look like Figure 7 Imported cross sections into HECRAS Notice that the cross sections are imported in the right position Verification of the positions of the XS For the sake of verification look at the csv file locate any XS and compare the coordinates of the XS ends with the position in the Geometric Data editor To do that just place the arrow as good as possible on top or the end and compare the coordinates See Figure 8 Page 5 of 27 HEC RAS analysis 6 27 Input MATRA Project ITC WRS Gabriel N Parodi Ej Microsoft Excel XsecHECRAS csv Insert Format Tools Data Window Help 10 x Berea ee amp File Edit 210 x LI Options View pre Tor ols GIS Tools Help 89 File Edit View x dI E g 100 Bis 3 Go to Office Live LowerPoti LowerPoti LowerPoti LowerPoti LowerPoti LowerPoti LowerPoti LowerPoti LowerPoti LowerPoti LowerPoti LowerPoti LowerPoti LowerPoti 721479 5 721473 4 721472 5 721470 5 721466 9 721463 3 721459 7 721456 2 721452 6 721449 721445 4 i 4669762 4669768 4669769 4669771 4669774 4669778 4669781 4669785
10. dele cei iaia 19 Verilying he low regimea L ole a a te oad E a E allodole lea 20 Errors wafnings and NOTOS ccleaner 20 Ability of cross section interpolatioNs i 20 Verification of the adequacy of the profileS 21 Control ofhe DoundarnyCONdiNioNS rire lalla 22 ASIC AG iMille iaia 23 Evaluation oftne critical s amp GHONS setole lello eifel ia edita 24 SPEGCIAL INHECRAS ilaria 25 Goal of this practical To set up a basic HEC RAS model for the Rioni river in Georgia execute an initial run and evaluate the errors and results The river produces flooding during summer time as a consequence of a combination of situations melting of snow insignificant slope and the Black sea boundary condition plus eventual rainfall Secondary objectives Use georeferenced background maps to support the river network construction Input of georeferenced cross section x y Z Input of hydraulic parameters of the cross section Steady state analysis input of profiles and boundary conditions Unsteady state analysis input of hydrograph and other boundary conditions Modelling lateral inflow if any Model run and analysis of errors A glance to bridge and culverts input Separated exercise optional NOTES This practical concentrates on the HECRAS model input analysis and output No use of the GEO HECRAS interface is made Page 1 of 27 MATRA Project ITC WRS Gabriel N Parodi HEC
11. reaches In the Figure 1 and Table 2 we describe the identifiers for the project Table 2 River amp branches Branch Upper Lower LowerRight LowerLeft LowerPoti There is one river Rioni divided in 5 sections branches as schematically described in Table 2 and Figure 1 There are 2 junctions in the model Table 3 Table 3 Junctions in the model representation In the geometric data interface select the pencil river reach and carefully digitize the Rioni upper branch Always the digitizing should be made from upstream to downstream You can use tools as zoom in out panning from the context sensitive menu and add points and move points from the Edit menu IMPORTANT 7 1 You digitize the deeper section in the river however this remains as a schematics 7 2 The cross sections will always be perpendicular to this river reach 1 3 The digitizing ends with a double click at the end of the branch or at the junction 8 When you end up the digitizing process you will be requested with the name of the river and the name of the branch Write down the names given in Table 2 It is Case sensitive so type it as it is given in the Table 2 respect the Capital letters and with no spaces 8 1 When you start or end in a junction the name of the junction will be requested by the software At the end of the digitalization process a portion of the upper reach should be like this Page 3 of 27 MATRA Project ITC W
12. should make specific notes on which is the beginning and end of the channel and the overbanks In this way the process of informing this to HECRAS is easier an accurate Photo 1 gives some guidelines on channel determination and roughness Page 9 of 27 HEC RAS analysis 10 27 MATRA Project Input ITC WRS Gabriel N Parodi 4 7 Guia o n x n itato LN a ta T ni Pietra a woe as AOE EN LP Se 2 N gt v Cad Photo 1 A river section seen from the point of view of HECRAS The river was flowing from right to left The dashed redlines show the position of the channel area At the moment of the photo the water was not covering the whole channel Left and right of the channel area are the Left and Right overbanks The characterization of the Manning is shown with the vertical color lines On the left there are 3 different Mannings for the LOB channel and ROB To to right a more detail characterization of the Manning where the surveyor observed more than one Manning at the overbank The three photographs to the left are details of the roughness For this specific exercise the surveyor was instructed to make one leveling station at the site were the water start flowing at the channel banks while doing the XS This is not strictly needed In some occasions this was not explicitly indicated so for this exercise we will use the banks available in the Bank_position xls file as depicted in Table 5 13 From the Geom
13. shows how the Steady Flow Boundary condition interface opens Internal boundaries are all set The user need to add a boundary condition to the three downstream reaches only as we assume subcritical flow Page 16 of 27 HEC RAS analysis 17 27 MATRA Project Input ITC WRS Gabriel N Parodi Figure 31 shows the interface that ESNI opens when the Known W S button is Set boundary for all profiles C Set boundary for one profie St a tine pressed The Water Elevation absolute elevation referred to the Datum of the project as the cross sections are In the first run we set everything to 0 elevations and in a second run it will be set to 0 3 m After the Boundary conditions are settled the interface should look like in Figu re 32 Steady Flow Heach Storage Area Optimization Select Boundary condition for the downstream side of selected reach Once the Flow data is completed it can Figure 30 Interface for Steady Flow Boundary condition Downstream be saved from the Steady Flow Data conditions should be established if subcritical flow is assumed Click In the Interface File Save As and enter a Se indicated in the figure and then click on Known W S This operation will na be repeated for the other downstream reaches proper name for this flow data condition k l e BC_steady00 m MI Set known water surfaces for flows i 9 The second Flow Data Condition in a steady state is exactly the same as t
14. simulate a flood wave coming in the system hydrograph It is the standard analysis performed over a flood event Initial Conditions refer to the discharge flowing at the beginning of the simulation time 0 It is common practice that the system is allowed to flow at steady state for few hours before receiving the wave front in unsteady modeling This prevents some instability in the process Results of a steady flow analysis may be used as initial conditions in an unsteady flow analysis as well Steady flow analysis There are four kinds of boundary conditions in HECRAS for the steady state Known water surface critical depth normal depth and rating curve The outlet of the system is the Black Sea The level of the Black Sea is affected by tides and inputs and outputs although the water elevation amplitude of the Black Sea is small compared to oceans The Known Water Surface condition is then appropriate for the downstream outlets in both steady and unsteady situations Upstream several profiles can be selected Profiles are just discharges entering the upper section of the system that the user selects based on importance Each profile is treated independently by the software if you enter 4 profiles discharges there will be 4 independent runs with 4 independent results although the user can display the results simultaneously for comparison Normally Profiles are discharges associated to return periods There is evidence of a statis
15. user manual 11 3 If any error happens the program will stop Warnings must be checked carefully and not necessarily mean that actions need to be taken Notes indicate information on how the model operates E c Q v gt 2 Ww If the energy drops or increase more than 70 or 140 between one section and the next one respectively of the conveyance sections change too much irregular sections then additional cross sections are normally required This might indicate that more survey is needed HecRas has some tools to artificially interpolate the cross sections see below Errors are written by profile as the results are independent Ability of cross section interpolations HecRas can geometrically interpolate cross sections in order to artificially create more sections than the surveyed ones The interpolation can be cancelled back to original at any time and it is performed by a sophisticated algorithm that interpolate among two XS shapes both geometry and roughness User selects the maximum distance between two sections and if it will be done for two consecutive sections a reach a subreach or a river Particularly when interpolating between 2 cross sections the user has the option to force interpolation lines between the sections This feature allows the intervention of the user to avoid wrong interpolations done by the fully automatic procedure Figure 38 and Figure 39 Show the interpolation options available i
16. 19 5128 Description This XS had an eror in the qAPply the data on this window _ RS 99 05 une os Rioni LowerLeft __250 157 5632 419 5128 Rioni LowerPoti 100 11 98201 153 2415 Rioni LowerPoti 99 74 25162 147 8988 Rioni LowerPoti 98 50 06245 _143 542 Rioni LowerPoti 97 21 74888 99 82433 Downstream Reach Lengths LOB Channel ROB Del Row Ins Row u se Tien 3 67 41922 4 74 25162 0 25 5 79 33682 0 43 Main Channel Bank Stations 6 82 30002 0 83 Rioni LowerPoti 96 11 35721 99 15968 7 87 90002 1 53 3 2 oa E Rioni LowerPoti _ 95 26 98104 90 65729 Gus dr Roni JLowerPo i 94 6 614233 100 5253 11 107 9028 3 33 12 112 9028 3 38 moe 13 117 9056 3 25 102 90 2 98 TAITA 28 0 50 100 150 2 Station m Figure 18 Replace 2 98 by 2 98 and press Enter and Apply Data The correction is done Figure 19 shows a case where the measured cross sections banks fit perfectly well the maps This give as confidence that the section is stable and the input was done correctly in HecRas Figure 20 shows a deposition area or a sand dune in the topographic map at the position where the actual water section is now flowing Figure 21 shows the actual channel shifted from the original position This could be a mistake product of inverting the stationing data the XS was input from right to left It could also be another kind error that ma
17. 723355 6 723358 8 723362 723387 9 723386 5 723385 2 723383 8 723382 5 723381 1 723379 8 723378 4 723377 5 723373 8 723049 8 723009 7 722985 1 722978 5 722973 6 Y 4674005 4674016 4674018 4674019 4674023 4674027 4674031 4674034 4674038 4674042 4673901 4673906 4673911 4673916 4673920 4673925 4673930 4673935 4673938 4673951 4673347 4673359 4673366 4673368 4673369 MATRA Project ITC WRS Gabriel N Parodi column with the Column with the Column with the coordinates X river name reach name Y and the depth Z referred to a Figure 6 Single excel file containing the information of the stations of a certain number of cross sections The first line is the heading and it is fixed Then there is one line for every single station The first column is the river the second the river branch the third the XS number the fourth and fifth the X and Y coordinates and the sixth is the depth with respect to an arbitrary datum in this case The file can be imported into HECRAS in a single move It is very important to check the integrity and correctness of the csv file There should be no mistake in the river reach or branch names User must respect the exact names as entered in the river sketch as they are Case sensitive 10 To import the XS from the Geometric Data interface select File import geometric data CSV Comma Separated Value 10 1 Select the XsecHECRAS csv file and click OK 10 2 Select
18. Downstream Reach Lengths River E GYM EditinterpolatedXS s River Rioni Ra E EdiInterpolatedXS s Resch IEEE Resch REM Selected Area Edit Options aaa Selected Area Edit Options Add Constant Multiply Factor Set Values Replace Add Constant Multiply Factor Set Values Replace LOB Channel ROB River Station LOB Channel ROB 1402 77 1402 77 1402 77 400 1462 8 1462 8 1462 8 0 0 0 350 0 0 0 Figure 14 Final distances between the cross sections for the Figure 15 Final distances between the cross sections for the LowerLeft reach LowerRight reach Edit Downstream Reach Lengths River ion gt S Baj GYM Edit Interpolated xs s Reach Selected Area Edit Options Add Constant Multiply Factor Set Values Replace 715 7173 730 0241 726 7054 1543 646 1582 264 1688 316 1555 101 1548 582 1534 845 0 0 Figure 16 Final distances between the cross sections for the Lower reach Left and right banks The next step is the establishment of the left and right banks LB and RB By default HECRAS assumes that the first and last station of each XS is the LB and RB respectively This must be corrected in order to assign the correct roughness Keep in mind that the channel is not the area where the water was flowing in the survey but the area where the water could flow without producing a flooding to the overbanks During the XS survey the surveyor
19. RAS analysis 2 27 Acknowledgments We make use of HECRAS 2011 version 4 1 0 for this exercise Acknowledgments Some information in this practical was extracted from the Msc Thesis of Tamar Tsamalashvili ITC 2010 ESA department She also translated this exercise into Georgian language to be use at CENN training course in Bachulari Green Center Georgia Much of the material suggestions and advices for this exercise were done by Dr Menno Straatsma from ESA department ITC Netherlands To Tamar and Menno offer my sincere gratitude Data available for this practical e Rioni Georeferenced topographic map of the Rioni Downstream basin containing all the available cross sections measured in a local Survey e Cross sections There are 44 cross sections for this exercise Cross sections are named with numbers from upstream higher numbers to downstream lower numbers They are in a csv format so readable with Excel software The format of these files looks like in Table 1 The first 2 columns are the X and Y coordinates of the levelled station UTM WGS84 zone 37 the third column the elevation from a predefined datum and the fourth column is the progressive across the section This format in excel allows direct import into HECRAS The following figure shows the location of the cross sections and the sketch of the river the sketch is shifted for clarity Cross sections are shown with a colour look up table that shows highe
20. RS Gabriel N Parodi HEC RAS analysis 4 27 Input Figure 2 Aspects of the digitalization of the Rioni Upper 9 Repeat the procedure for the other 4 branches At the end of the process all river and branches should look like in Figure 3 Figure 4 and Figure 5 show a detail of the junctions ar ae ci ak Figure 4 Detail of the junction downstream Figure 5 Detail of the junction upstream This ends up the graphical input of the river reaches Importing the cross sections In the following we will import from one 1 csv file all cross section XS into the HECRAS project Cross sections have been surveyed in the field with high precision instruments A single Excel file can be created containing the geometry of each XS see Table 1 The format of this Excel file should follow some specifications to facilitate the input into Hec Ras In the following we look at one of import methods into HECRAS Open the file XsecHECRAS csv from your working directory Excel will be the default software to open the file The file looks like in Figure 6 Page 4 of 27 HEC RAS analysis Input 5 27 Cross section number Reach Lower Lower Lower Lower Lower Lower Lower Lower Lower Lower LowerPoti LowerPoti LowerPoti LowerPoti LowerPoti LowerPoti LowerPoti LowerPoti LowerPoti LowerPoti LowerPoti LowerPoti LowerPoti LowerPoti LowerPoti X 723331 4 723340 3 723342 2 723342 8 723346 723349 2 723352 4
21. Right Max WS Surface Area Volume Stream Power TO Da 0 for 3c E cee S n E j lt oO S g E Cd v l 3 20000 Main Channel Distance m Figure 50 Longitudinal information of a hydraulic variable In this case is the maximum speed in a cross section Notice that the calculation is done at cross sections only and since no interpolation was done the estimation have errors Figure shows maximum speed in the channel and the LOB and ROB This ends up the basic HecRas analysis in this exercise Many options remain in the software to further analysis and research The user should investigate the list of Error warnings and notes and do some interpolations in the model Users are strongly suggested to review the user manual to discover those features that are essential for their projects Special in HecRas HecRas has a complete set of tools to e Incorporate structures in the model Bridges culverts storage areas and complex in line and lateral structures e To analyze the result of possible remedial structures and compare to the original case Those are special features in engineering and require special attention to be modeled correctly The reading of the User and Hydraulic manuals are essential Users are invited to review the HecRas example 2 in steady state Single Bridge to model bridges The user is requested to follow the Example 2 of the Application Guide on HecRas Page 25 of 27
22. Rioni River Georgia Study case in Hec Ras Practical el Parod Gabriel Parodi 7 1 2011 Rioni River Study case in HECRAS 1 27 MATRA Project Goal of this practical ITC WRS Gabriel N Parodi Rioni River Study case in HECRAS RIONI RIVER STUDY CASE IN HEGRAS ui 1 GOALOF THIS PRACTICA Larraia a A A ANA 1 SECONDAR OBJECTIVE Sacri a a a aa Lita 1 NOTE eee AO ee A ee eee ee 1 ACKNOWCEDGNENTS ail 2 DATA AVALABLEFORTHISPRAGTICAL LZ LL N 2 HEGRAS ANALYSBS ibn 2 INPUT na LI rat 2 Entering the background image and the river sketch iii 3 IMPONING the CYOSS SCCUONS osse ar ale E a a Hane 4 Verification of the positions of tne XS ale an 5 AGGdING CCOSS SEGHONS 3 ac RA es eh state etl iui lei deve ie leader de edile am lu 6 FING TURING TAS puerta elise eee lana 6 SIOPpeSsicuc nali etilico 6 Rescnessnieonoleaia ae ria i are 7 Lell ane rightbanks ec gate ees ste cas a ens tine tae ed ahaa te E iene ala 9 AO CONMCCINOS S s 222 se etext soot E elle 10 Mannino COGMICICIILG zitta ice it a di teebela noci eri tibi ia Sidia 11 SUNCIONS s cicale ala ele ii 14 Boundary and Nar CONGIIONS gt lola aio 14 Steady TOW AMIS Sn site ce ares eee tea a a a at ec o asest 15 ASSUMpPUON Ol Me TOW PalONS sareen ee iiss shan a a O a a Ea as 16 Unsteady Flow analysis jsf ce ila etiam iii 17 RUNNING THE MODEL AND ANALYZING THE RESULTS 0 19 Steady FIOW rurale aliena 19 REST anas S enice E AE
23. cRas in unsteady flow select the icon perform a unsteady flow simulation Figure 46 shows the input information for the unsteady flow simulation Notice that the date and time of the simulation is stated in here and it should coincide with the information provided in the input hydrograph Observe the format of the Date and Time fields as well The hydrograph information is every 24 hs The calculation interval in this case is set to 10 minutes HecRas interpolates the 24 hs hydrograph for the calculations Despite that the calculations are done every 10 minutes the software produces an output every 6 hours selected by user from the interface In unsteady flow there are several options for the calculation User may opt for different tolerances methods to calculate friction slopes pre runs to optimize the backwater effect recommended when flowing towards the sea and more User needs to read the manual for advance features 34 Input the data as stated in Figure 46 and then press compute The kinds of verifications to be profile Plot 0 ea made are similar to the case of File Options Help steady flow In a real case the t Profiles P T Plot Initial Conditions Reload Data modeler should prevent the anes Voc YoniHR Plan RioniHR_ 29062011 al use of the unsteady option dui Ina without validating the steady Erin ee case 5 ioe Ground 35 From the main menu select the icon view profiles Add the reache
24. d look like in Figure 34 Information The button Add RS allows the user to input a hydrograph structure or restriction at any station in the system It works similarly as in the steady case Any mechanism of input or output of water in and out from the system can be simulated using this option In the Unsteady flow Data interface select the Initial Conditions tab We are going to assume that the initial conditions before the storm are as expressed in Figure 35 Page 18 of 27 River Rioni Reach Upper RS 9 Read from DSS before simulation Select DSS file and Path lt path TT TTT Enter Table Data time interval 1 Day v Select Enter the Data s Starting Time Reference Time Use Simulation Time Date Time C Fixed Start Time Date No Ordinates Interpolate Missing Values Del Row Ins Row Date Simulation Time Flow hours m3 s 00 00 TT 24 00 i 2 3 4 5 6 7 8 21 6 00 240 00 264 00 288 00 Time Step Adjustment Options Critical boundary conditions Monitor this hydrograph for adjustments to computational time step Min Flow Multiplier Plot Data OK Cancel Figure 33 Flow hydrograph data input HEC RAS analysis Running the model and analyzing the results 19 27 MATRA Project ITC WRS Gabriel N Parodi AB Unsteady Flow Data A Unsteady Flow Data Unsteady Flow 01_FS_0 H elp File Options Help SS py Boundary Conditions Initial Cond
25. elected steady flow conditions for this exercise User can change them at Reach Boundary anytime Conditions button Select river for adding a new flow change location All internal boundaries Junctions are already established and ready It remains the definition of the downstream boundaries at the Black sea and the upstream boundary at the Upper Rioni Reach e Ifthe system is fully subcritical then the Upstream boundary is not needed e Ifthe system is fully supercritical then the downstream boundary is not needed e If the system has sections in subcritical and others in supercritical both boundary conditions are needed mixed flow Normally the user would assume that the system is subcritical if the slopes are very gentle i e lt 1 2 In any case the user can assume any regime and after the run will immediately verify if the assumption was right or needs other assumptions There is clear evidence that the lower Rioni is fully subcritical and then we need to enter only the downstream boundary conditions Out of the four options we could assume a water elevation in the Black sea and set it to the last XS of the LowerRight LowerLeft and LowerPoti reaches The higher the water level at the Black Sea the more the backwater effect and the more difficult the drainage Then this boundary condition is essential to flood analysis We will set the BC at 0 level and at 0 5 m in two different runs as example Figure 30
26. etric Data Editor menu select Tables Bank stations A table opens and the user can copy the LOB and ROB from the excel sheet Bank_positions xls and paste it directly in this table The user can and normally should enter the bank stations from the Cross section editor as the control is easier XS correctness All cross sections should be correctly entered in HR Parameters to check are altitude progressive position of the banks and to ensure that the sections are entered in HR from Left to Right while looking at the section from upstream These lasts two must be checked by the surveyor The Surveyor of the Project Mr Beso Kavtaria informed that XS 99 in the LowerPoti has an error in elevation at station 102 90 that was not corrected in the CSV file with the cross sections The elevation was wrongly set to 2 98 meter when it should be 2 98 m Figure 17 and Figure 18 indicates how the correction is done Page 10 of 27 HEC RAS analysis 11 27 MATRA Project Input ITC WRS Gabriel N Parodi These days we could use actual remote sensing imagery to Tables Location af the eta right banks check for some inconsistencies for the exercice We have imposed the surveyed sections over the topographic sheets of the region The topographic sheets are rather old when compared to the time needed for river shifting after flood events e Cross Section Data RioniHR_reach Exit Edit Options Plot Help
27. g the model and analyzing the results 22 27 MATRA Project ITC WRS Gabriel N Parodi the cross section where the levee is located from the Geometric data editor The XS is then edited and the levee can be installed from option levee See Figure 45 Exit Edit Options Plot Help River Riri v Malo Plot Options Reach Upper v River Sta 98 sit Description ae E Del Row Ins Row Cross Section Coordinates Station Elevation gl Keep Prev XS Plots Clear Prev RioniHR Plan RioniHR_plan2 08 07 2011 RS 988 0s gt 035 gt 05s Downstream Reach Lenaths LOB Channel ROB 2165 729 1844 135 1569 479 Manning s n Values 9 LOB Channel 0 05 0 035 0 05 Main Ch Xs vee Dats T Left Bank 336 399 3 135 0433 4 175 2776 5 268 5167 6 274 5978 7 300 1385 8 315 0656 9 334 9706 10 336 399 01 11 337 8839 HALALA Ome lr a rs Enter station and elevation points to mark levee on cross section Left Right 268 5167 Elevation 6 4 300 400 OK Cancel Defaults Clear Figure 45 Levees are created from the cross section editor with the option option levee Cont Exp Coe fj Contractia Station Station m For profile 6 3000 m s the left overbank is flooded The left bank survey needs to be extended horizontally till a position where flood does not happen The present survey is not extended enough and the s
28. he si one above except that the elevation STO downstream is 0 5 instead of 0 ess Downstream TIP To save time open the Steady Bm ae fo ein Flow Data just recently saved and ioni unction e ioni unction __ save as again with other proper name SS that represents the new BC Later open this newly created dataset and replace the BC downstream for 0 5 tWord 21 From the Stream Flow Data Tebe windo Oeil exes menu File Save Flow Data as Figure 31 Once clicked Known W S the elevation of the water in the and give a proper name for the downstream boundary condition must be entered for any profile Set water new Flow data l e BC_steady05 level equal 0 for all profiles and all reaches The only change is the Reach Boundary _ew conditions downstream Set boundary for all profiles Set boundary for one profile at a time 22 Press the Reach Boundary aU IER USARE RT Condition button 23 Double click on each Known WS downstream BC and change the 0 ioni ppe Junction Junetion 1 i JunctionsJunction 1 elevation by 0 5 3 24 Once is finished Save the Steady lai Flow Data File save At the end of this process two Steady Flow Data cases will be available to compute in HecRas Figure 32 Final look of the interface Steady Flow Feach Storage Area Optimization a a Cancel Help ep changes and dose This procedure of build
29. horizontal variation of Manning allows to design appropriate Manning s for each portion of the progressive Page 12 of 27 HEC RAS analysis 13 27 Input MATRA Project ITC WRS Gabriel N Parodi Exit Edit Options Plot Help River FERA Sel Plot Options 4 Keep Prev XS Plots Clear Prev Reach Upper River Sta 984 jie RioniHR Plan Description A f Del Row Ras 05 35 ol oasi A Cross Section Coordinates Station Downstream Reach Lenaths Channel Ground Bank Sta 1746 972 4 2 Manning s n Values 4 21 2 16 4 51 91807 0 97 5 56 90872 0 91 6 61 91308 1 16 Z 66 91743 1 21 8 71 92179 1 36 9 76 91756 1 44 10 81 92191 1 5 03 11 86 91257 1 66 l 600 1 5 Station m 13 96 92128 1 39 TAL1N1 917 171 Elevation m an location Figure 23 This is a case of parallel flow HecRas can handle these situations but roughness partition in three is not enough for this section Figure 22 and Figure 23 show 2 cases where parallel flow happens and then Manning needs to be better distributed Both figures show the changes in the Manning already made The user may try to reproduce them The user only needs to enter the new Manning at the stations where there is a change The other stations are handled by the software Look at the graphical part of Figure 22 and Figure 23 In the upper part the new distribution of the Manning is already indicated The user should try to reproduce
30. iew profile in the main HR interface brings a view similar to Figure 37 Reaches and profiles up to 6 in this case can be added pressing goa Fc esa the corresponding buttons seen in _ _ amp the figure les T Plot Initial Conditions Reload Data e From the options variables ioni Upper SO O ER E n on aaa te eo ie nike Lom Plan RioniHR 29 06 2011 selected If the critical depth line is iO a l M Rioni __LowerRight below the water surface line at any progressive then the regime is Crt PFA subcritical In any other case the Ground regime has to be modified with implications in the boundary conditions Sometimes HR does not display the full critical line except when incompatibilities occur So if you dont see the critical line in the figure the regime 0 20000 40000 mig ht be correct Main Channel Distance m 298 51 1 74 e Other option is to open the view summary output look up tables Figure 37 Longitudinal profile plot can be used to identify irregularities icon The table summarizes some and the correctness of the flow regime hydraulic properties of every cross section The last column is Froude number in the channel Be certain that is less than 1 at all sections to ensure subcritical flow Errors warnings and notes From the main menu click the icon Summary of errors warnings and notes At this stage it is strictly necessary to read the corresponding section in the
31. ing a scenario from scratch saving it and re saving with other name to later modify it and build a second scenario is available everywhere in HecRas It saves time and prevents errors up to certain extent Unsteady Flow analysis Tsamalashvili 2010 study the hydrographs records available and the recurrence intervals of big floods see Table 7 The table shows that only average daily values have been recorded Hourly values or less might be needed to record the maximum instantaneous peak discharge that will eventually produce outbreaks In this exercise we will work with 10 years hydrograph as it will be introduced in the model The boundary condition upstream is the flow hydrograph that should be applied to the Upstream of the Upper reach of Rioni river CHECK POINT of the exercise Students should finish here the second day Page 17 of 27 HEC RAS analysis Input 25 Select the icon Edit Enter unsteady flow data The Unsteady Flow Data editor opens As you click in any boundary condition cell the choices of possible boundary condition options highlight 26 Select The Rioni Upper boundary condition cell and then the highlighted Flow Hydrograph option The exact date of the event is not relevant as such but it has to be consistent during the whole project The event happened between 31 January to 11 February and we will take these dates as modeling period 27 Enter the flow hydrograph data 21 1
32. itions Initial Flow Distribution Method C Use a Restart File Enter Initial flow distribution File Options Boundary Conditions Initial Conditions Filename Boundary Condition Types Stage Hydrograph Flow Hydrograph Stage Flow Hydr Normal Depth steral Inflow Hudr ae Farai ra Rating Curve Add Boundary Condition Location Boundary Condition Flow Hydrograph Normal Depth Normal Depth Normal Depth Initial Elevation of Storage Areas Figure 34 Boundary conditions for the unsteady case selected for the first model run Figure 35 Initial conditions for Unsteady state Assumed Running the model and analyzing the results Steady Flow 30 To run the HecRas in steady ElHecrassso SteadyFlowAnaysis fc flow select the icon File Edit Run View Options GISTools File Options Help t i T EE AN ior I Plan RioniHR O Shoib fRioniHR perform a steady flow ACKER AA a a va Di ti si Fi 3 6 Project eometty Fie RioniHR_reach simulation Figure 36 cee Perform a steady flow simulationhdy Flow Fie Ena 31 As the Steady Flow cem Fini FipiviRegime Eat Desoizton in Steady Flow Flow 01_Ocm Subcritical Analysis interface appears Unsteady Flow Unsteady Flow 01_FS_0 c ea select the ad equate Description Edit enter geometric data C Mixed geometry file and Steady flow file There should be 2 steady flow files one for 0 elevations and the other for
33. ive sections are aligned then the 3 distances are identical Figure 10 Distances between XS X1 and X2 in the LOB Channel and ROB are different LOB distance is the shortest and ROB the longest The distances are to be measured along the centerlines of the LOB channel and ROB The spreadsheet distances xls contains the distances between the cross sections in the three sectors The spreadsheet contains the information depicted in the following Table 4 Page 7 of 27 HEC RAS analysis 8 27 MATRA Project Input ITC WRS Gabriel N Parodi Table 4 Distances between the cross sections Colors indicate the group of distances composing each reach for easier visualization Lines in white are used to enter the distances between the cross sections at the junctions and not at the reaches From soctonin River Section psen to scenon iRiver Section Sisvioni LoBdist cnan Dist Felde Rioni Upper 999 Rioni Upper doni Rioni _ Upper _ Roni Upper il E 7 3 o ei oer BO 76 Fil Lower 60 007038 reais 34202208 ST oni owe ie 32 Fino argh 400 143 051706 1029 544152 8294170596 Roijen 400 Remi LowerRight 350 14628 14028 14028 m Fini Upper 980 20 FRenil LowerPot 100 2578695645 380 9107522 503 5348788 Foni LowerPo 100 21 Roni LowerPott _99__ 575 4102042 681 9810538 742 1202232 21 Foni LowerPo _99_ 22 Roni LowerFo i 98 1774 558498 1779 680911
34. iver schematics There are several additions modifications and verifications to incorporate at every XS The main ones are Check of the slope correctness Lengths of the downstream reaches LOB channel ROB Establishment of the exact left and right banks Verification of the XS correctness Manning coefficients LOB channel ROB Eventually some modification to the sections as levees flow impediments ineffective flows Slopes The slope is the most sensitive parameter in any hydraulic model Slope is not directly input in HECRAS but it is calculated based on the XS elevation and the distances between the XS From upstream to downstream all cross sections should reduce elevation 11 Inthe Geometric Data Editor Press the Cross section button Figure 9 shows the cross section data editor and the option Keep Prev XS Plots This option leave on cross section on the screen and plot the next one selected by the user In the case of the Figure 9 the most upstream section of Rioni Upper is compared to the most downstream of this reach It can be observed the vertical differences between these 2 positions Only 4 1 CHECK POINT of the exercise Students should finish here the first day Page 6 of 27 HEC RAS analysis 7 27 MATRA Project Input ITC WRS Gabriel N Parodi few meters in about 33 km if banks are available for one profile then the conveyance section can also be compared This check is essential as the slopes shou
35. j f f 29 LowerRight 400 n oos oossfoo f 30jLowerRight sso n oos5 oos5joos 31 Lower 49 n oosfoossjoos f f 32 Lower 498 n oo oos5joos J 33 Lower 497 n oosjoossfoos 34 Lower 4 n oosfoossjoos Page 13 of 27 0 05 0035 0o05 f f o oe 86 DD 903 3 3 3 HEC RAS analysis 14 27 MATRA Project Input ITC WRS Gabriel N Parodi already entered The table should look similar to Table 6 but it is not essential This concludes the input of the cross section data Junctions There are 2 junctions in the model In the junctions the user has to enter the reach lengths across the junction the tributary angle and the calculation method All this information can be 4 i 376 54 m read in the User Manual of HecRas 16 Press the Junction button in the Geometric Data editor The first Junction appears 16 1 Enter Description Division Upper into Lower and LowerPoti Description is only for information 16 2 There are two lengths to input 16 2 1 From Rioni Upper to Rioni Lower Poti 380 91 m There is an angle of 30 between the Rioni Upper and the Rioni Poti The angle will be used in case that Momentum computation mode is selected 16 2 2 From Rioni Upper to Rioni Lower 376 54 m The mentioned distances can be obtained also from Table 4 The selection of the Method for the Junction calculation must be read from the manual For steady flow we will selec
36. ld be accurate Cross Section Data RioniHR_reach Exit Edit Options Plot Help River Rioni Apply Data gal lt ata Plot Ootions 4 Fr Keep Prev XS Plots _ Clear Prev Reach Upper River Sta EEN 4 Description Del Row Ins Row _ Channel Ground e Bank Sta 5 78 39517 6 83 39281 7 88 39563 8 93 39327 9 98 38692 10 103 3937 11 108 3914 12 113 3942 13 118 3918 14 123 3946 15 128 3923 16 133 3951 17 138 3927 18 143 3904 19 148 3932 20 153 3908 Elevation m 400 600 800 1000 1200 1400 1600 1800 Station m Select river station for cross section editing Figure 9 In the cross section data editor the option Keep Prev XS Plots allows the user to see elevations of related cross sections in one display Adequate to check relative altitude and compare the capacity carrying Reaches The downstream reach is the distance m between one XS and the next one downstream There are 3 distances to be entered One for the Left OverBank LOB for the main Channel and for the Right OverBank ROB To define left or right for a XS HECRAS always assume that you observe the corresponding XS while standing upstream of it and looking downstream This is essential otherwise all the cross sections will be reverted Why three distances HECRAS divides the flow into three sections flow in the channel and flow in the right and left banks to calculate different conveyances If the consecut
37. n HecRas Decisions taking by the user on forcing an interpolation can be substantial in the results Figure 40 Figure 41 and Figure 42 shows also two options of displaying the interpolated cross sections Notice that being a 1 D model either option is for displaying purposes only Calculations in either case are identical Page 20 of 27 HEC RAS analysis Running the model and analyzing the results Figure 38 Interpolated cross sections between river stations 986 and 985 without forcing lines Figure sections Figure 40 Planimetry of the cross sections 986 and 985 interpolate cut lines from bounding XS s on 41 5 21 27 MATRA Project ITC WRS Gabriel N Parodi Figure 39 Interpolated cross sections between river stations 986 and 985 with 4 forcing lines interpolated cross with the option Linearly Figure 42 5 interpolated cross sections with the option Generate for display as perpendicular segments to reach inverter on The user should incorporate the interpolated cross sections and repeat the calculations and control the errors and warning tables Verification of the adequacy of the profiles HecRas is robust software and sometimes produces artificial changes that allow ending the hydraulic calculations without halting Any kind of change done by HR will be reported as a warning Figure 43 shows station 988 in the upper Rioni For the profile 1 500 m s the river flows in the cr
38. nction the sum of the input flow should equal the sum outflow In this case Qin Qoutt Qout2 For each individual branch i in a junction Q A Vi constant As the river is subcritical and the slope negligible in order to estimate the flow partitions it was adopted that the water speed is similar in the three branches With this assumption Ain Aouti Aout2 For the sake of this exercise we assume that the LowerRight and LowerLeft branches have similar cross sections and that the LowerPoti area is 20 and the Lower reach 80 of the upper reach So if X is the flow upstream of the upper Rioni into the system 0 2 X goes into Rioni Poti 0 8 X into the lowerRioni and 0 5 0 8 X into both the lowerRight and lowerLeft branches The user can change these assumptions at any time At the end of the input the Steady Flow Data Flow 03 interface should look like in Sect eer ay Figure 29 Enter E dit Number of Profiles 25000 max 6 Reach Boundary Conditions Apply Data Locations of Flow Data Changes tt River GM Ci Add Multiple The Add Flow Change Reach Upper v River Sta 999 Add A Flow Change Location Flow Change Location Profile Names and Flow Rates Location button allows the user to add or withdraw discharges at any selected station This allows the simulation of small tributaries or watersheds without a formal design in HecRas 20 From the Steady Flow Data interface select the Figure 29 S
39. of the highest flood It gives a reference of the elevation of the lateral structures energy causing bank erosion A 1 D model like HecRas has several limitations in terms of detail analysis A 1D model always assumes that the velocity in a cross section is uniform in width and depth As such the software displays the average value of the speed at the cross section A second limitation is that as the model is 1 D it actually calculates as if the river is on a straight line so differential forces happening in a cross section in turns and meanders are not calculated 36 Select the icon View General Profile Plot From the Standard plots select Velocity and from Reaches select Upper Lower and LowerRight Figure 50 shows the longitudinal plotting of hydraulic variables In this case is the flow speed The plotting is not smooth because the model requires more cross sections Notice that the information is multi temporal The graph shows the maximum speed in the XS that happened during the period of the run and not an instantaneous value Page 24 of 27 Special in HecRas 25 27 MATRA Project Running the model and analyzing the results ITC WRS Gabriel N Parodi General Profile Plot Velocities o f File Options Standard Plots User Plots Help Plot Initial Conditions Reload Data RioniHR Plan RioniHR 30 06 2011 Top Width Rioni Upper Weighted n Froude Vel Chnl Max WS Hydraulic Depth Vel Left Max WS Shear Vel
40. oftware rises an artificial vertical wall at progressive 0 to continue the calculation This indicates that the section needs to be surveyed again till completeness and that this cross section is compromised and probably requires the construction of lateral protection structures like dikes Control of the boundary conditions The selection of adequate boundary conditions is crucial for the modeling success In general modelers prefer to establish the system under 4 Vnsteady Flow Analysis study far away from the boundaries In this case if errors happen they will be in the vicinities of the boundaries but the inner model system will have better results This might not be the case in areas without slope or in case of subcritical flows with extensive backwater effects In the particular case of the Rioni river the boundary downstream is the water level of the Black Sea In this exercise a water level was supposed to be 0 and 0 5 m to evaluate the differences but in the real case it is needed a better measurement File Options Help Plan Short ID O Geometry File RioniHR_reach v Unsteady Flow File Unsteady Flow 01_FS_0 v Plan Description Programs to Run J MW Geometry Preprocessor MV Unsteady Flow Simulation MW Post Processor Simulation Time Window Starting Date 31JAN1987 T Starting Time 0000 11feb1987 T Ending Time 0000 10 Minute v DS doro Output Interval 6 Hour v
41. orking directory and type a title and the file name for the project l e RioniHR for both OK In the following we will enter the geometric data of the project Entering the background image and the river sketch 5 Press the icon Edit enter geometric data The geometric user interface appears 6 Enter the georeferenced background for the project by pressing the Add Edit background picture for the schematics Select the Geotif file Rionitopo tif and add it to the project The image has coordinates but HECRAS may display a coordinate extension that extends much beyond the boundary coordinates of the image This is not a critical issue but is convenient to correct it 6 1 Say yes if you are asked to extend the coordinates of the map Close the add background user interface 6 2 The map might not display and the working area remains blank To solve it anywhere in the working area right click and type Set Schematics Plot Extent Set to Computed Extents OK After that the topographic map should be visible You can use the context sensitive menu to do panning zooming and other visualization options on the map Notice that the map has coordinates 6 3 Warning Notice that despite that the map has coordinates the map remains as a background object only for displaying purposes This means that extreme care should be placed during the input of cross sections data In the following we will create the schematics of the river and
42. oss sectional area Again in Figure 43 for profile 4 2000 m s the water overflows the left bank This is impossible as in the progressive 268 52 m the elevation of the embankment is 6 12 m meaning 0 12 m higher than the elevation of the water This is standard behavior in HecRas By default HR will inundate adjacent areas having elevation lower than the water level despite that the connectivity does not allow it To prevent this the user must establish a levee at that point in the cross section XS 998 station 268 52 Figure 44 shows the calculation of HECRAS when a levee is established There is no flooding of the left overbank for profile 4 To impose a levee the user must select RioniHR Plan RioniHR_plan2 RS 988 05 _ 035 gt e 0s gt 08 07 2011 Legend WS PF 6 WS PF 4 WS PF 1 Bank Sta round 268 52 6 30 Elevation m 300 Station m 400 283 78 4 86 Figure 43 Three profiles represented in the cross section For profile 1 the water level remains in the channel For profiles 4 and 6 the software rises an artificial wall to the left of the left overbank to prevent overflooding and continues the calculation RioniHR se e e Plan RioniHR 29 06 2011 Legend Elevation m 300 400 700 Station m 269 13 5 98 Figure 44 Same calculation as before but now with the levee established Page 21 of 27 HEC RAS analysis Runnin
43. r elevated points in red lower in blue 123342 8 123346 123349 2 123352 4 123355 6 Xsection 19 723331 4 723340 3 723342 2 4674005 4674016 4674018 4674019 4674023 4674027 4674031 4674034 3 25 2 13 0 64 0 22 0 43 0 49 0 51 0 6 Table 1 format of the cross section information 0 13 95869 16 87948 17 7386 1 22 14233 21 13963 32 74335 37 14065 and intermediates in a scale from red to blue Cross sections Rioni delta Y coor m LowerRight Upper Lower pma LowerLeft LowerPoti 735000 745000 750000 X coor m 720000 725000 730000 740000 Figure 1 Cross sections measured in the Rioni river HEC RAS analysis The following sections summarize the steps in the HECRAS software to model the section of the Rioni river mentioned earlier The HECRAS manual is required for consultation and details Input 1 Make a working directory in your hard drive with Windows explorer or other File manager create the directory RioniHR in the D drive Use the C drive if D is not available For this exercise this directory will be already created after unzipping the packed exercise file 2 Open HecRas 4 1 0 3 Select metric units for the entire project Options Unit System select System International metric OK Page 2 of 27 HEC RAS analysis 3 27 MATRA Project Input ITC WRS Gabriel N Parodi 4 Creating a new project From main menu File New Project Navigate to your recently created w
44. s as in Figure 47 35 1 Right click inside the graph select variables and choose Left and right banks and the water surface Main Channel Distance m 954 65 66 gt To verify the boundary conditions in the unsteady state normal depth Figure 47 plots a longitudinal profile from o Elevation m i n 20000 Figure 47 Longitudinal plot of the Upper Lower and LowerLeft Rioni The sloppy water profile at the end section may indicate a wrong selection of the boundary conditions the upper to the LowerLeft tz Profile Plot o e ends File Options Help The selection of a normal Reaches t Profiles e T Plot Initial Conditions Reload Data depth boundary condition uu ZioniHR Plan RioniHR 29 06 2011 E fixed to 0 001 01 Rioni 1LowerPoti produces a discontinuity in the i cn Tossss profile that indicates an 5 Ground inadequacy see the cursor arrow in the figure Figure 48 shows the results of the modeling after the friction slope was reduced ten times 0 0001 The backwater effect produced by the Black Sea is then controlling the situation Elevation m i n E 20000 As expressed above a rating curve is perhaps the most adequate alternative as lower end BC although the selected Figure 48 Modification of the boundary condition downstream from 0 001 to 0 0001 Boundary Conditions are affect the profile at the lower end of the system adequate if the sy
45. ss Junction Junction Add Weight system under analysis and the Length sprosi dunctor ten J A m Unsteady Flow Computation Mode elements composing the external Rioni 1029 54 ee influence over the system under To Rioni LowerL ef 898 38 Energy Balance Method analysis The system is analized in isolation but boundary conditions are K Cancel _Hep Edit Junction Description required to impose the constraints and ET E EEE pee forces that the external influences subject the system Figure 27 Junction 2 input In this exercise two situations will be analyzed steady and unsteady flow The steady flow assumes that at any section in the river system the discharge is constant in time Two cross sections may have different discharge values but they will remain always invariable in time Steady Page 14 of 27 HEC RAS analysis 15 27 MATRA Project Input ITC WRS Gabriel N Parodi flow analysis assumes that a constant flow enters the river system for a long period of time till the system stabilizes input output As such it assumes that all sectors able to store water will be filled In this way steady flow analysis could picture very well the hypothetical case of a long term long lasting flood For the same reason steady flow is not normally used to analize flood peak discharges as this might result in a unreasonable flood estimation Floods last less than the time to stabilize the peak Unsteady analysis is done to
46. stem under Main Channel Distance m 286 40 17 Page 23 of 27 HEC RAS analysis 24 27 MATRA Project Running the model and analyzing the results ITC WRS Gabriel N Parodi analysis is restricted to the upper lower and RioniPoti reaches Evaluation of the critical sections In this particular project the vulnerability to flood is intimately related to the lateral protection Figure 49 is a profile plot showing a longitudinal profile where the left and right channel bank elevations plot together with the maximum water elevation during the imposed flood along the Rioni This gives an indication of the kind of effort to be done in the protective structures to contain the water laterally The modeler should review each cross section to identify compromised dikes in the same way as it was done in Figure 43 and Figure 44 Sectors where the model imposed a vertical extension of the cross section are critical and need further analysis In many occasions is not elevation the cause of problem but other hydraulic variable like velocity or ey Profile Plot File Options Help Reaches 3 f Profiles Plot Initial Conditions Reload Data Rioni Upper ee CC E Cee seo sel e il ETTI RioniHR Plan RioniHR 29 06 2011 Rioni LowerPoti Rion Upper Rioni LowerLeft Rioni LowerRight WS Max WS Ground oi E c 2 gt 2 w D o D 20000 Main Channel Distance m En Figure 49 Longitudinal profile
47. t the energy method and for unsteady flow the new energy balance method to overcome the problem that the sections at the junctions are measured very far apart XS should be measured close to the junction without overlapping 380 91 m Figure 25 Distances in the Junction 2 When all data is added to HECRAS the user interface for Junction 1 should look like in Figure 26 17 Repeat the same procedure for Junction 2 17 1 Enter a description and the rest of the information At the As cu end of the process the data JunctionName Junction 1 a I pox reer input should be like in Figure Description Division Upper into Lower and LowerPoti J Momentum 27 If Momentum method is Be Add Friction Lenath across Junction Junction Add Weight not selected the input From Rioni Upper sati Unsteady Flow Computation Mode angles will not be stored C Force Equal WS Elevations ea Energy Balance Method This is OK Figure 27Figure 27 shows the final outcome Cancel Help Edit Junction Description Figure 26 Junction 1 input Boundary and initial conditions The success or failure in a hydraulic model is tight to the selection of adequate boundary conditions BC mento ESS Do Seed Fon Computation Modo The river system is composed by two n dine f Description Junction 2 Lower to LowerLeft amp LowerRight J C Momentum exclusive or environments the PE Add Fiction enath acro
48. these changes The objective af these changes is that a Manning of 0 035 should be assignes where the water flows and a value of 0 05 should be assigned at the islands Table 6 Adopted Manning coefficients J Reach River Station Frein mmg n 41 n 2 n 3 n nas n 6 a oe so n oos ooss oo _ 2 upper ove n 005 005 00 _ Pal uber sor n o0s ooss oo _ oper e n _ oos oossfoos _ S upper sw n 006 005 00 _ 6 e 3 31313153 6 Upper 3 n oo oossjoos f 7 Upper 992 n oosjoosjoos f 8 Upper 991 n foos oossjoos f f Upper 90 n foo oosjoos Lio Upper 989 n oosjoosjoos f n foosfooss oos j f o o35 o5 f 0 035 o5 J 0 35 0 05 0 035 0 05 U U U 3 33131313 o o35 o5 f 0035 o5 fJ 0 035 o5 f 0 035 o5 f Check all cross sections and note down those that this alternative could be needed Table 6 is the first attempt of Manning s for this model and will be used in this exercise River stations 987 and 984 have more than 1 channels as the flow is divided as it is seen in Figure 22 and Figure 23 15 From the Geometric Data Editor menu select Tables Bank stations A table opens and the user can verify the Mannings U vosos _ 0 035 o5 0 035 o5 f 0035 o o5 f 0 05 0 035 0 05 f f 26 LowerPoti 94 n oos oossjoosj f f 28 LowerLeft 250 n oos oossjoos
49. tical increase of the annual peak discharges in the last years Flood records are available from 1939 to 1990 In this example we will set 6 profiles starting at 500 m s and ending at 3000 m s with jumps of 500 m s 18 In HR main menu select the icon Edit Enter steady flow data The user should read the user manual for this critical step hn 19 The interface asks for a number of profiles 2 Return Discharge m s and the corresponing flow rates at every mos Ay Period 1939 1990 reach Assuming that in the upper Rioni a fix amount of discharge enters the system i e 500 m s the distribution of this amount between the lower and Poti will depend on the hydraulics of the system or man made operation of the system The same for the second junction between the lower and the lowerLeft and lowerRight reaches The user has two options 19 1 Impose a flow in every reach default regardless of the mass balance at the junction 19 2 Give and estimation of the flow at every reach and let HecRas to optimize the hydraulic to a proper partition of the flow at every junction We will see both alternatives In either case the estimated initial flow at every reach needs input Figure 28 Gumbel extreme probabilistic plot It states the historical records of floods Page 15 of 27 HEC RAS analysis 16 27 MATRA Project Input ITC WRS Gabriel N Parodi Assumption of the flow partitions In steady flow and in a ju
50. y lead to review the pre processing done to the raw point survey data or eventually it would be necessary to repeat the XS INFORMATION ONLY There is an option in HR to reverse the stationing order from the Geometric Editor Data Tools Reverse stationing data In our case we are confident that all the sections are well input in HR and the mismatch is product of river dynamic shifts Manning coefficients The next step is the assignation of the Manning coefficients of roughness Manning coefficients can be assigned in two ways in HECRAS a One single Manning for LOB ROB and Channel per cross section is adopted At the end 3 Manning s in total per XS b Manning can change along the progressive of the section regardless the position Page 11 of 27 HEC RAS analysis 12 27 MATRA Project Input ITC WRS Gabriel N Parodi See an example in Photo 1 and read the HECRAS User manual about these alternatives Ma E a AS NA n aa PIC mo Re a 7 ata dati Figure 19 Correct banks Figure 20 river shifting Figure 21 Is a river shifting or a reverse stationing An error During preliminary studies Manning coefficients are obtained from tables available elsewhere In the HECRAS reference manual there is a standard table where Manning coefficients can be assigned after a description of the river bed at every cross section After the model runs it is very common to fine tune the model by re adapting the Manning values This is
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