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OFAT User Guide - Government of Ontario

1. 51 Figure 11 Three Flood Frequency Regions 55 Figure 12 Six Low Flow REGIONS vacant ee ee eee 60 Figure 13 Flood hazard criteria Zones 69 Figure 14 IDF Curve of Toronto Lester B Pearson International 17 List of Tables Table 1 Parameter Range Statements for OFAT Regional Hydrology Models 26 Table 2 Descriptions of pour point fields in PourPoint dbf 35 Table 3 Descriptions of watershed polygon fields in Watershed dbf 36 Table 4 Descriptions of characterization fields in CharacterizationTable dbf 36 Table 5 Descriptions of flood flow fields in lndesvEbpA dt 37 Table 6 Descriptions of landcover fields in Landcovertable dbf 37 Table 7 Descriptions of mean annual flow fields in MAF dbf 37 Table 8 Descriptions of graphical index method fields in MOEGI dbf 37 Table 9 Descriptions of low flow regression method fields in MOERegression dbf 38 Table 10 Descriptions of flood flow regression fields in MoinShawRegression dbf 38 Table 11 Viewing options for export file types 38 Table 12 Coefficients of the Regression Eouatons 52 Table 13 Table 14 Table 15 Table 16 Table 17 Table 18 Table 19 Table 20 Table 21 Table 22 Table 23 Table 24 Table 25 Table 26 Table 27
2. OFAT im Find information Markup and Printing Find Gh E N Ud a watershed Button Characterization Hydrology Models Flow Statistics Precipitation Statistics Find Watershed Figure 8 Find Watershed Tool Steps to run the Find Watershed tool Click the OFAT tab Click the Find Watershed button to open the tool window Optionally you can enter part of a watershed name or ID in the text box to filter the list Click the Zoom button beside the desired watershed name or ID The map will zoom to and highlight the selected watershed Click the Clear Highlighted Watershed button to remove the highlight 33 4 0 Exporting Watershed Information All watersheds watershed characterizations and hydrology model outputs can be exported downloaded from the OFAT website Lines in the export list that are grey and not selectable have not had the outputs created Run the characterization and hydrology model tools to produce outputs available for export Watershed Watershed 2 Row for each Watershed 1 M Watershed area and pour point geometry sei EM Watershed area geometry KMZ file L Characterizatons table calculated values only LJ Land cover table areas and percentages LL Land cover raster GRID files Export List Hydrology model tables LL Mean Annual Flow MNR 2003 C Low Flow Graphical index Method MOEE 1995 LJ Low Flow Regression Method MOEE 1995 C Flood Flow Index Fiood Method
3. Table 14 Ratio of the Frequency Values Region Q1 25 Q2 Q5 Q10 Q20 Q50 Q100 Q200 Q500 Q2 Q2 Q2 Q2 Q2 Q2 Q2 Q2 Q2 1 0 95 1 00 1 24 1 43 1 62 1 86 2 04 2 23 2 48 2 0 94 1 00 1 29 1 52 1 74 2 04 2 25 2 45 2 72 3 0 93 1 00 1 33 1 62 1 89 2 25 2 54 2 82 3 19 4 0 93 1 00 1 32 1 57 1 80 2 13 2 37 2 60 2 92 5 0 94 1 00 1 27 1 50 1 74 2 06 2 34 2 62 2 96 6 0 91 1 00 1 43 1 78 2 13 2 60 2 96 3 33 3 84 7 0 94 1 00 1 27 1 47 1 66 1 90 2 07 2 24 2 47 8 0 92 1 00 1 43 1 85 2 30 2 96 3 46 4 00 4 77 9 0 94 1 00 1 27 1 50 1 72 2 02 2 26 2 49 2 80 10 0 95 1 00 1 20 1 35 1 48 1 64 1 77 1 90 2 07 11 0 93 1 00 1 33 1 62 1 90 2 32 2 67 3 05 3 55 12 0 94 1 00 1 22 1 38 1 52 1 68 1 80 1 90 2 05 Another feature of this study was the introduction of the expected probability concept The expected probability is defined as the average of the true probabilities of all magnitude estimates for any specified flood frequency that might be made from successive samples of specified size It incorporates the effects of uncertainty in application of the curve The Province of Ontario has adopted the policy where all frequency curves will be adjusted for the expected probability computations 53 The average record length is employed to adjust the probabilities for each of the regions N represents the number of years of record Table 15 Expected probability Exceedance Probability Expected
4. Table 28 Table 29 Table 30 Table 31 Table 32 Table 33 Table 34 Table 35 Table 36 Table 37 Table 38 Table 39 Table 40 Table 41 Range of Drainage Area Values for the Regression Equations 52 Ratio of the Frequency Values 2 222 2 c ceceeecececeeeceeececenececeeecececeees 53 Expected probability eeben ag AER eebe Egger eebe eme intra EE 54 Variables used in the Moin amp Shaw 1985 Regression Equation 56 All Ontario regression Ree E le 56 Region A regression co efficients eeEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEE 57 Region B regression co efficient 22 22 2 c cscecececeeecececeeenececeeenececeees 57 Region C regression co efficients ss 57 All Ontario multiple regression equation parameters 58 Region A multiple regression equation parameters 58 Region B multiple regression equation parameters ss ssssennnesreeeserrrrrre1ne 58 Region C multiple regression equation parameters 59 Regression equations of the Index Flood Method 7Q2 61 Regression equation variables for NE and NW regions 62 Coefficients of multiple regression equations for 7Q2 sesssesssnnnneeeeeennnn 62 Coefficients of multiple regression equations for 7Q20 62 Regression equation va
5. 0 7217 0 1799 0 0202 no data 0 15 0 87 Q20 0 2311 0 7461 nodata 0 0197 0 0081 0 15 0 87 Q50 0 3659 0 6989 no data 0 0275 no data 0 15 0 85 Q100 0 4471 0 6839 no data 0 0276 no data 0 16 0 83 Table 20 Region C regression co efficients Flow m3 a0 a1 a3 a4 a5 a6 a8 SE R2 sec Q2 1 7155 0 8734 nodata 0 0167 nodata 0 5580 nodata 0 22 0 82 Q5 1 7967 0 9031 0 1721 0 0180 nodata 0 5424 nodata 0 21 0 83 Q10 1 6547 0 8897 0 1841 0 0177 nodata 0 5261 nodata 0 21 0 82 Q20 1 5499 0 8786 0 1937 0 0174 nodata 0 5173 nodata 0 22 0 81 Q50 1 1793 0 8759 no data no data 0 0337 0 4698 0 0800 0 23 0 79 Q100 1 1375 0 8676 no data no data 0 0349 0 4804 0 0811 0 23 0 78 57 The range of input values for the parameters of the Multiple Regression Equation are presented in the following tables Table 21 All Ontario multiple regression equation parameters Variable Q2 Q20 Q2 Q20 Q50 Q1 00 Q50 Q1 00 Minimum Maximum Minimum Maximum DA 13 9 60100 0 13 9 395 5 BFI 0 15 1 0 0 15 0 56 SLP 0 02 9 42 0 02 1 22 ACLS 0 00 122 00 0 0 10 50 MAR 137 0 626 0 137 0 363 50 MAP 500 0 1000 0 500 0 840 0 Table 22 Region A multiple regression equation parameters Variable Q2 Q20 Q2 Q20 Q50 Q1 00 Q50 Q1 00
6. 1 T P The same definition is applied to low flow frequency analysis as well The major difference from flood frequency is that instead of using the exceedance probability the non exceedance probability is used to obtain the probabilities This is because the return period event is the value that will not be exceeded The streamflow statistics include e The flood magnitude with recurrence intervals of 1 2 1 2 33 1 5 1 10 1 20 1 25 1 50 1 100 1 200 and 1 500 year e The n day drought severity 1 3 7 15 and 30 days with recurrence intervals of 1 2 1 5 1 10 1 20 1 50 1 100 year e The 3 day flood magnitude with recurrence intervals of 1 10 year 28 To ensure that fish passage is adequate over the desired range of flows 3Q10 high and 3Q10 low streamflow magnitudes are used as the range The 3Q10 high was found using the Consolidated Frequency Analysis CFA software and the 3Q10 low using Low Flow Frequency Analysis LFA program Water Survey of Canada s HYDAT gauge streamflow data was used for the analysis Flow Duration Curve The Flow Duration Curve represents the relationship between magnitude and frequency of streamflow exceedance It disregards the sequence of occurrence It is drawn with streamflow values arranged from highest to lowest y axis and percent exceedance x axis at each interval Exceedance Probability P is expressed as P 100 M n 1 e P the probability that a given streamflow will b
7. Name Watershed 3 Coordinate System Pour poirt coordinates Coordinate k Section Oum Create trom Map Point Cancel Zoom in to activado creston from map point Row foreach Watershed x B xX D Pour Point rt Watershed Polygon Figure 3 Create Watershed Tool Steps to run the Create Watershed tool Click the OFAT tab Click the Create Watershed button The Create Watershed tool window will appear on the left side of the screen A default name of Watershed 1 will appear in the text box This can be changed at this time if desired The name cannot be changed after the watershed is created Create a pour point with one of two methods Enter the coordinates of the pour point in the text boxes of the coordinate section of the tool window One of three coordinate systems can be specified The entered coordinates must be within 90 metres of a mapped hydrology feature Click the Create button 19 e Create a pour point by a mouse click on a mapped hydrology feature To do this zoom in until the Create from Map Point button becomes enabled turns from grey to black The mouse click must be within 90 metres of a mapped stream or lake Failure to be within 90 metres of a mapped hydrology feature will return a warning message e The generated watershed is added to the bottom row of the tool window and the map display zooms to the watershed extent e Multiple watersheds can be created Each additional watershed will be
8. 00034 14 2 0 1 6 1 1 1 Max 1020 350 516 0 00747 3960 0 8 190 5 100 100 65 Mean Annual Flow MAF Model Currently OFAT contains the Isoline Method Environment Canada 1986 to estimate mean annual flow cms The original provincial isoline map for mean annual runoff mm was first digitized and then a continuous surface a map with 1km 1km cell resolution was created from the isolines The mean annual runoff mm for the watershed is calculated by averaging all the cell values within the watershed boundary which can be converted into mean annual flow cms 66 Appendix 2 Provincial Application Areas of OFAT Permit To Take Water 2007 Sections 34 Ontario Water Resources Act R S O 1990 and Water Taking Regulation O Reg 387 04 Permit to Take Water Guideline recommendation for Surface Water Taking of Category 2 is River and Streams 8rd order or higher order takings less than 5 of 7Q20 Approval of Sewage Works 2010 Sections 53 Ontario Water Resources Act R S O 1990 a Industrial Sewage Works Under the Environmental Impact Analysis of Surface Water Impact states the limiting conditions as Limiting conditions within the receiving water body including Low flow conditions in the receiving water body e g the 7Q20 for a stream i e the 7 day average low flow occurring once in 20 years b Municipal and Private Sewage Works Under the Envir
9. 1 20 000 scale in northern Ontario e The raster hydrology elevation and derivative data layers were developed in a UTM projection 4 zones which critically limits spatial watershed representation across UTM zones e The data holdings were not Provincial in scope a usable hydrology base in the far north was absent A major undertaking to address these issues has now been completed by producing GIS hydrology elevation and hydrology derivative datasets in a seamless standardized Lambert Conformal Conic LCC projection for the entire province The base hydrology data in this projection allows users to work in a seamless data environment To address base data scale differences all developed raster data layers have been created at a uniform 30 metre grid resolution This seamless LCC data is employed as the backbone of OFAT 14 A detailed data description and links to metadata are provided in Section 5 0 1 5 Website The OFAT 3 release is a spatial web application Deployment in a web environment offers numerous advantages over that of a desktop application or GIS extension including Only a web browser is needed to use OFAT The user doesn t need GIS software Updates and additions to the tools can be implemented without the need of any action from the user group Improved data can be updated on the web server No need for users to handle large amounts of input data Output data can be downloaded for those that wish to ana
10. 1964 The frequency factor depends on the type of distribution It is expressed mathematically as y y oK Index Method The Index method was developed by Dalrymple in 1960 A summary of this method as given in the U S Geological survey is given below 47 Initially single hydrometric station analysis is carried out and the corresponding frequency is developed The variable used for single station analysis is the maximum instantaneous peak flow of the annual series Then single station frequency curves are combined to give the regional frequency curves This is completed in two steps The first step is the development of the dimensionless frequency curve which represents the ratio of the flood of any frequency to an index flood known as mean annual flood The second step is the development of the relationship between mean annual floods to the drainage area of the basin The procedure for the development of the frequency curve for any location is a find the mean annual flood corresponding to the drainage area of the watershed b from the first curve select ratios of peak discharge to mean annual flood for the selected recurrence interval c multiply these ratios by the mean annual flood and plot the resulting discharges of these ratios by the mean annual flood and plot the discharge of known frequency to define the frequency curve The procedure is explained in the upcoming section The mean annual flood is used to make the dimensi
11. 50 and 100 year return periods are shown on IDF curves Rainfall Intensities for the province of Ontario can be found in MTO IDF Curve Lookup http www mto gov on ca IDF_Curves Duration 5 minutes 10 minutes 15 minutes 30 minutes 1 hr 2 hr 6 hr 12 hr 24 hr Recurrence Interval 2 5 10 25 50 100 years Environment Canada National Climate Data Archive Free download FTP site ftp arcdm20 tor ec gc ca pub dist IDF Duration 5 minutes 10 minutes 15 minutes 30 minutes 1 hr 2 hr 6 hr 12 hr 24 hr Recurrence Interval 2 5 10 25 50 100 years 76 Short Duration Rainfall Intensity Duration Frequency Data 2010 04 13 Donn es sur l intensit la dur e et la fr quence des chutes de pluie de courte dur e 600 500 TORONTO LESTER B 400 PEARSON INTLA ON 300 6158733 200 1950 2003 x 51 years ans Latitude E x E CG 43 41 N E 70 Longitude D gt 60 79 38W 2 50 Elevation Altitude 5 40 x 173m 2 30 20 E E 2 19 Ei Return Periode 5 E P riodes de retour E 6 Years ans 5 100 59 4 25 10 3 x 5 2 x 2 1 5 10 15 30 60 2 6 12 24 Minutes Hours Heures Duration Dur e ser Bal ia Szenen Canada Figure 14 IDF Curve of Toronto Lester B Pearson International L Version 1516 1 78
12. Arterial and Collector Roads 25 year 50 year Local unpaved Roads and 10 year 25 year Resource Access Temporary Detours 1 to 5 year 1 to 10 year Flooding Hazard Limit Natural Hazard Policies of the Provincial Policy Statement of the Planning Act 2002 River System Flood Standards Zone 1 the peak flow resulting from the Hurricane Hazel1 Storm or the 100 year flood whichever is greater Zone 2 the 100 year flood Zone 3 the peak flow resulting from the Timmins2 Storm or the 100 year flood whichever is greater depending on the location in the province 68 Flood Hazard Criteria Zones of Ontario Veit and Conservation Authorities ZONE 3 Lake Huron ees Approximate acurcaries ot ths loco Zeres Flood Procuced by Hurricars Hazel Storr ZONE 1 oy thw 499 Ywa Flood whishuvet s twat ZONE 2 The 100 Year Flood ZONE 2 Fland Pradinas sy the Timmins Storm or the TIO Year flood whistever is greater Bt Ze Date not depicted on this mar Lasshead Region and Sault Ste Maris Region Web Coneervaticr Auticrities nol d Part emh Figure 13 Flood hazard criteria zones Adaptive Management Natural Channel System Adaptive Management of Stream Corridors in Ontario The full regime flows should be included Low flow 7Q2 7Q10 7Q20 biological requirements Bankfull flow 1 1 5 to 1 5 year event geomorphology requirements Riparian flow 1 10 to 1 25 year event biology
13. Flow Index with Expected Ares Limit Drainage Area Parameter in not in range Probability for model Adjustment EPA Fe Parameters DA SLP ACLS BFI MAR are Flood ae EC RngQ2Q20 or in outside of the range used to create this Multiple Regression RngQ50Q100 madel Acronyms used in parameter range statements DA Drainage Area LNTH Length of Main Channel SLP Slope of Main Channel BFI Base Flow Index MAR Mean Annual Runoff ACLS Area of Lakes and Swamps 26 3 3 2 Notes about Flow Prediction Models All model output units are cubic metres per second cms Most models included in OFAT are regional hydrologic models To estimate flows for a watershed OFAT uses a model specific region data set e g low flow regions or flood regions to determine automatically which region or sub region the watershed is located Then appropriate sets of equations relationships are used to calculate the desired flow information Each flow model in OFAT has its own limitations This means that the models included in OFAT should only be used for a watershed within the ranges of the parameters e g drainage area that were originally used for developing the models Use of the equations relationships is not encouraged outside of their parameter ranges It is strongly suggested that the original model document be referred to or consult with a water professional before using generated flow values for any decision making purpose Val
14. Great Lakes St Lawrence Watershed Systems November 2014 https www javacoeapp lrc gov on ca geonetwork srv en main home uuid bf69cb35 ec1f 472d 89f7 4084f94e4472 44 6 0 References This help document contains some content from the original Users Manual for Ontario Flow Assessment Techniques OFAT where applicable Chang C F Ashenhurst S Damaia and W Mann 2002 Ontario Flow Assessment Techniques OFAT Hydraulic Information Management Editors Brebbia C A and W R Blain WIT Press Ashurst Southampton U K pp 421 431 Kenny F M Matthews B 2005 A methodology for aligning raster flow direction data with photogrammetrically mapped hydrology Computers amp Geoscience 31 6 768 779 Kenny F M Matthews B and Todd K 2008 Routing Overland Flow through Sinks and Flats in Interpolated Raster Terrain Surfaces Computers amp Geoscience 34 2008 pp 1417 1430 DOI information 10 1016 j cageo 2008 02 019 MOEE 1995 Regionalization of Low Flow Characteristics for various regions in Ontario Ministry of Environment and Energy MOEE Ontario Canada Moin S and M Shaw 1985 Canada Ontario Flood Damage Reduction Program Regional Flood Frequency Analysis for Ontario Streams Volume 1 2 and 3 Environment Canada Ontario Canada WRIP Technical Release 2012 Ontario Integrated Hydrology Data Elevation and Mapped Water Features for Provincial Scale Hydrology Applications Zh
15. Minimum Maximum Minimum Maximum DA 62 9 60100 0 62 9 118000 0 BFI 0 36 1 0 0 36 1 0 SLP 0 02 4 14 0 02 4 14 ACLS 0 0 100 0 0 0 100 0 MAR 193 0 598 0 193 0 598 00 MAP N A N A 500 0 1000 0 Table 23 Region B multiple regression equation parameters Variable Q2 Q20 Q2 Q20 Q50 Q1 00 Q50 Q1 00 Minimum Maximum Minimum Maximum DA 13 9 3810 0 13 9 4770 0 BFI 0 26 0 82 0 26 0 90 SLP 0 14 5 77 0 02 5 77 ACLS 0 0 97 0 0 0 100 0 SHP 1 41 42 14 1 38 42 14 58 Table 24 Region C multiple regression equation parameters Variable Q2 Q20 Q2 Q20 Q50 Q1 00 Q50 Q1 00 Minimum Maximum Minimum Maximum DA 14 2 5910 0 14 2 5910 0 BFI 0 15 0 81 0 15 0 81 SLP 0 21 9 42 0 21 9 42 ACLS 0 0 122 0 0 0 122 0 MAR 137 0 527 0 137 0 527 00 Low Flow Models The Graphical Index Method MOEE 1995 and the Regression Method MOEE 1995 implemented in OFAT were developed by Cumming Cockburn Limited for the Ontario Ministry of Environment and Energy The estimated output parameters from the Graphical Index Method MOEE 1995 Low Flow model are 102 105 1010 1020 1050 10100 302 305 3010 3020 3050 30100 702 705 7010 7020 7050 70100 1502 1505 15010 15020 15050 150100 3002 3005 30010 30020 30050 300100 The estimated output parameters from the Regression Method MOEE 1995 Low Flow model are 302 3020 3050 702 7020 7050 3002 30020 30050 59 Six L
16. Watershed Characterization Tool 3 2 1 Steps to run the Watershed Characterization tool e Atleast one watershed must be generated before using the Watershed Characterization tool e Click the OFAT tab e Click the Watershed Characterization button to open the tool window The tool window contains a Characterization tab and a Land Cover tab 22 Physiographic Characterization 15 physiographic characterizations can be computed for each generated watershed by e Click the Characterization tab in the tool window e Click the desired watershed row to calculate in the bottom section of the tool window The selected watershed row will be highlighted in blue e Click the Calculate button next to the desired characterization or click the Calculate All button The resulting values are displayed next to the characterization name To calculate and view the characterizations for a different watershed repeat the steps above for the desired row in the tool window The values will be updated with the values of the selected highlighted watershed row For processing efficiency some characterizations will be calculated at the same time Clicking Calculate for one characterization may trigger the calculation of others Land Cover Classification 30 land cover classes can be extracted and summarized for each generated watershed by e Click the Land Cover tab in the tool window e Click the desired watershed row to summarize in the bottom s
17. and rivers and wetlands within the watershed The Ontario Hydro Network OHN Waterbody data was the source for lakes and rivers https Awww javacoeapp rc gov on ca geonetwork srv en main home uuid 3ebaf6b2 6dd6 4ebb a6bb 4fc7 78426709 The Wetland data from the LIO Warehouse was the source for wetland https www javacoeapp rc gov on ca geonetwork srv en main home uuid 04e466a9 7731 438c a37a 38fde98202b7 Both datasets were converted from vector polygons to 30 metre cell rasters The two rasters were then merged into a single integer raster In areas where the two original datasets overlapped the lakes and major rivers took precedence over wetland Annual Mean Temperature The data source was Environment Canada historic normal data from 1981 2010 in an 8 2 kilometre cell resolution raster The median of the cell values is reported if 20 or more cells fall within the watershed The mean of the cell values is reported if less than 20 cells fall within the watershed http climate weather gc ca climate_normals normals_documentation_e html docID 1 981 Annual Precipitation See description for Annual Mean Temperature 5 4 Data Used in Watershed Land Cover Summary The Ontario Land Cover Compilation serves as a consistent land cover map for the entire province to meet regional to landscape level analysis 1 50 000 1 100 000 This product is comprised of three separate land cover databases each with separate c
18. corresponding drainage area range are given in Table 12 This method developed two equations e Drainage area greater or less than 60 square kilometres for region 1 This approach overcomes the limitation of the drainage area range to a certain extent e The dimensionless ratio of the regional frequency curves for each region is given in Table 13 Twelve Flood Frequency Regions REGION W i EH PS a4 EE 200 100 0 200 400 600 800 Bn ON eters Figure 10 Twelve Flood Regions of Index Flood Method Moin amp Shaw 1985 51 General form of equation Q2 CA where Q2 2 year return period 3PLN flood A Drainage Area C Constant n exponent slope Table 12 Coefficients of the Regression Equations Region Constant C Exponent n 1 a 0 22 A lt 60 km2 1 000 1 b 0 73 A gt 60 km2 0 707 2 0 51 0 896 3 0 20 0 957 4 0 71 0 842 5 0 45 0 775 6 0 41 0 806 7 1 13 0 696 8 0 73 0 785 9 0 40 0 81 10 0 28 0 849 11 0 38 0 706 12 0 59 0 765 Table 13 Range of Drainage Area Values for the Regression Equations Region Minimum km2 Maximum km2 1 0 11 9270 2 76 1 3816 3 86 0 3960 4 2 5 5910 5 14 2 4300 52 Region Minimum km2 Maximum km2 6 5 2 697 7 63 5 293 8 4 9 800 9 24 3 1520 10 18 6 11900 11 0 7 24200 12 4250 94300
19. flow BH estimates between Q50 and Q100 FF Q x Flood Flow Quantity for specific return period x 4 4 Viewing Options for Exported Files The following table contains suggested viewing options for the various export package file types Table 11 Viewing options for export file types File Type Viewing Options and Notes Open the kmz file from Windows explorer to view in Google Earth ne Must have Google Earth installed on computer Shapefiles can be viewed in many GIS packages ArcGIS explorer is free GIS viewer that can load shapefiles Do not alter the associated files that have the same name with different extensions dbf prj shx to prevent corrupting the GIS file collection Shp DataBase File can be opened by database GIS or spreadsheet dbf software 38 File Type Viewing Options and Notes ESRI GRID s are raster files that are opened by GIS software The Land Cover is extracted in OFAT without the generation of me pyramids Pyramids can be generated for the Land Cover Grid with ArcCatalog for faster viewing in ArcMap An ESRI Layer file used to color code the Land Cover Raster for lyr map display Add the layer file into ArcMap and set the data source as the land cover GRID 39 5 0 Metadata This section contains the metadata for the datasets used in OFAT analysis operations Where possible metadata links and document references are provided
20. geomorphology Valley flow flood plain 1 100 to Regional event Design Flood for River and Stream Crossing based on Risk MTO Drainage Management Manual 1997 Risk is usually expressed as a probability P that a flood will be exceeded in any one year period and can be expressed as P 1 1 1 Tr n where e Tr return period of the storm in years e n life of the structure in years 69 Table 41 Percent probability of exceedance during life of structure Average bead 2 3 years 5 years 10 years 25 years 50 years 100 years Years 2 33 73 94 100 100 100 100 5 41 67 89 100 100 100 10 22 41 64 93 99 100 25 9 18 34 64 87 98 50 5 9 18 41 64 87 100 2 9 22 40 64 1000 0 1 1 3 5 10 Peak Flow Rate Criteria Storm water management planning and design manual 2003 Generally accepted criteria are that maximum peak flow rates must not exceed pre development values for storms with return periods ranging from 2 to 100 years Peak flow rates must be determined on a site by site basis Existing rates can be determined utilizing computer simulation modelling or by transposing a frequency analysis of measured peak flow rates on a unit area basis to a site Ontario Low Water Response Indicator thresholds for Low Water Conditions Level I Voluntary Conservation e Precipitation is less than 80 of average e Spring monthly streamflow is less than 100
21. of the watershed in square kilometres ShapFactr re of the length of the main channel divided by the rainage area Average elevation value of the DEM within the delineated MeanElevM watershed Maximum elevation value of the DEM within the delineated MaxElevM watershed MeanSlpPc Average slope of the watershed calculated using the slope grid LeOMChKm Length of the main channel or longest flow path in kilometres MaxChElvM Maximum channel elevation in metres at the most upstream point of the flow path MinChElvM Minimum channel elevation in metres at the pour point ChSip M Km Channel slope in metres kilometre most upstream point of flow path to the pour point Channel slope in percent most upstream point of flow path to Chsip_ rent the pour point Area covered by Lakes Rivers and Wetlands within the WatrAreaKm watershed in square kilometres OpWAreaKm Area in the watershed covered by open rivers and lakes WetlAreaKm Area in the watershed covered by wetlands MeanTemp Annual Mean Temperature AnnPrecipt Annual Precipitation 36 Table 5 Descriptions of flood flow fields in IndexEPA dbf Field Name Description OFATID Auto generated OFAT ID Model Name of the model Units Units AreaLimit Result of the model input parameter watershed area range test Table 6 Descriptions of landcover fields in Landcovertable dbf Field Name Description Value Grid cell value Area Area of
22. rather than duplicating published material in this guide The OFAT base map is made up of a variety of data from the Ontario Land Information LIO Data Warehouse and is not discussed in this document For more information about LIO data visit Land Information Ontario s webpage http www ontario ca page land information ontario 5 1 Ontario Integrated Hydrology Data The Ontario Integrated Hydrology OIH data is a collection of related elevation and mapped water features that are used in combination for generating watersheds and to support hydrology applications Because the amount of data for the province is so large the OIH has been subdivided into 9 separate packages Each package covers a different part of the province and the data in each package can be updated independent of the others View the OIH metadata record on the Ontario Metadata Management Tool https www javacoeapp lrc gov on ca geonetwork srv en main home uuid 5383ed26 4a12 4026 b624 65c2e431c861 The OIH metadata record contains transfer download options for e Packages Map and Watersheds Table Map illustrating the 9 data packages as well as a table listing the watersheds in each package e Package Index Shapefile e OIH Data Technical Specifications Provides a detailed description of OIH data including creation specifications uses limitations considerations etc e 9separate data packages 40 5 2 Data Used in Watershed Delineation The OI
23. within this zone there is a severe shortage of flow monitoring data Understanding our water resources in this part of the province requires a heavy reliance on modelled approaches At the core of OFAT 1 and 2 was the automated implementation of 18 existing regional hydrologic models and empirical relationships pertaining to flow estimation in Ontario In recognition that many of these models equations are now dated and or rarely used in Ontario it was decided early in the project that an independent evaluation of regional models empirical relationships would be conducted by Trent University s Institute of Watershed Science This evaluation and consultation with the hydrology community to gauge the applicability value of the individual models led to the implementation of five regional hydrology models for OFAT 3 The hydrology models currently in OFAT are e Flood Flow Index Flood with Expected Probability Adjustment Moin amp Shaw 1985 e Flood Flow Primary Multiple Regression Method Moin amp Shaw 1985 e Low Flow Graphical Index Method MOEE 1995 e Low Flow Regression Method MOEE 1995 e Mean Annual Flow Mean Annual Flow MNR 2003 12 1 3 Use and Limitations of OFAT The most fundamental function of OFAT is to generate a watershed from a pour point within 90 metres m of a watercourse in Ontario Watersheds can be included in a wide variety of planning and analysis Most often streamflow statistics
24. 00058893 0 6295 3Q50 0 1331 0 00045199 0 5160 30Q2 0 7119 0 0022380 1 6806 30Q20 0 3275 0 00097749 0 9305 30Q50 0 2839 0 00087086 0 8045 Table 31 Multiple regression equation coefficients for southeastern region Flow m3 sec a0 at a2 7Q20 0 5084 7 6323E 11 1 1460 7Q2 0 9018 1 3049E 10 2 2728 3Q2 1 0351 1 2409E 10 2 3828 3Q20 0 6133 7 0980E 11 1 2527 3Q50 0 6226 6 5153E 11 1 2372 30Q2 1 0195 1 4637E 10 2 6144 30Q20 0 5196 8 5495E 11 1 3062 30Q50 0 4643 7 9836E 11 1 1773 Southwestern and West Central Regions Table 32 Regression equation variables used in WC and SW regions Variables Symbol Drainage Area km2 ES Base Flow Index dimensionless BFI Length of Main Channel km LNTH Mean Annual Runoff mm MAR Mean Annual Snow cm MAS The general form of multiple regression equation for the Southwestern and West central Regions Y ao a DA ap BFI as LNTH Table 33 Multiple regression equation coefficients for WC and SW region Flow m3 sec a0 al a2 a3 7Q2 0 190 1 24E 10 1 67 8 35E 5 7Q20 0 166 9 03E 11 1 10 4 67E 5 7Q50 0 160 8 54E 11 1 02 3 92E 5 3Q2 0 183 1 21E 10 1 55 7 81E 5 3Q20 0 158 8 57E 11 0 99 4 30E 5 3Q50 0 150 7 92E 11 0 91 3 64E 5 30Q2 0 233 1 29E 10 2 12 1 12E 4 30Q20 0 227 9 58E 11 1 52 no data 30Q50 0 078 1 25E 10 1 44 no data Each
25. 08 54 Low Flow Mode IS nes edad TS Ti SATA ITA AA AT 59 Index Method MOEE 1005 ee 61 Regression Method MOEE 1995 61 Appendix 2 Provincial Application Areas of OFAT ea 67 Permit To Take Water 2007 67 Approval of Sewage Works 2010 ccccccccceccceseceneceneceneecheceneceneceneceneceneeeneceneeeneceneconee 67 Approval under the Lakes amp Rivers Improvement Act GO10 67 Flooding fe ER e E 68 Adaptive Management assi ates ed os antes ped pi pi ane ate ed teeta 69 Design Flood for River and Stream Crossing based on Risk 69 Peak Flow Rate Criteria EE 70 Ontario Low Water Response 70 Water ET ceee AP PP A epee ds A VR ettii 71 Climate Changes acer casar ainiai eh es ea CAN A AO eh ee ee 72 Other Areas Indirectly Connected to Streamflow 73 Ee 74 Appendix 3 Other References ssesssssrnrrtrtttettttrrttttttttttr rtt tttttnnnnnn Ettr Ernnnenn rnn E reee 76 List of Figures Figure 1 OFAT ln 16 Figure 2 OFAT Map E RE 17 Figure 3 Create Watershed WEE 19 Figure 4 Watershed Characterization Tool 22 Figure 5 Hydrology Models Tool az iccccsecuccnececcccneceeecenecencsceynteencevnteveteysteesenveteueteeeeeeneeee 25 Figure 6 Flow Duration EE 30 Figure 7 Flow Statistics KEE 31 Figure 8 Find Watershed Tal EE 33 Figure 9 Exporting Watershed Information 34 Figure 10 Twelve Flood Regions of Index Flood Method Moin amp Shaw 1985
26. 30 metres upstream of the confluence to delineate a watershed for only one of the contributing streams OFAT can generate a watershed from a pour point within a waterbody lake or large river The underlying stream network contains virtual lines that connect flow though 20 waterbodies The virtual lines are not visible on the map The user defined pour point must fall within 90 metres of a virtual line to generate a watershed Because the lines are not visible on screen the pour point may not fall within the tolerance which will result in a warning message This should only be an issue with very large hydrographic features The virtual lines will typically be near the centre of the waterbody A waterbody may contain many virtual lines that represent flow from contributing streams Water flow does not start or stop at the borders of Ontario The input data that OFAT uses to generate watersheds does not always extend beyond the borders of Ontario Full watersheds will be created along the Quebec border in the area north of the Ottawa River Watersheds along the Ottawa River and the United States will only represent the Ontario portion 21 3 2 Watershed Characterization Watershed OFAT III Tab Characterization Button age Map Layers OR Find nfomaton 1 Bs D Tool Window Sope of Man Channel mim Sope of Man Channel Ares Lames Wears ur Zeen Lames raf Row foreach Watershed Figure 4
27. 5 times per year to 2 8 times per year Other Areas Indirectly Connected to Streamflow Average Annual Water Yield the amount of freshwater derived from unregulated flow m3 s 1 measurements for a given geographic area over a defined period of time Used to estimate stocks of water assets for the Water Accounts component of Statistics Canada s environmental accounting framework the Canadian System of Environmental and Resource Accounts Yearly runoff surfaces were then averaged to produce the thirty year surface and scaled back to a volume based on the resolution 100 km2 of the surfaces producing the water yield estimate 73 References Government of Ontario Ministry of the Environment Stormwater Management Planning and Design Manual 2003 http www archive org details stormwatermanageOOtorouoft Government of Ontario Ministry of Transportation MTO Drainage Management Manual 1997 Government of Ontario Ministry of Natural Resources Technical Guidelines and Requirements for Approval under the Lakes amp Rivers Improvement Act http www ontla on ca library repository mon 9000 246477 pdf Government of Ontario Ministry of Environment Guide to Permit to Take Water Application 2007 Government of Ontario Ministry of Natural Resources Adaptive Management of Stream Corridors in Ontario 2001 Government of Ontario Ministry of Natural Resources Technical Guide River and Streams Hazard F
28. AR a7 MAR agLog ACLS 1 ag MAP ajo SF Regression co efficients of the Multiple Regression Equations are listed below in the series of Tables Table 17 All Ontario regression co efficients Geo a0 a1 a3 a4 a7 SE R2 Q2 1 5689 0 8509 0 1635 0 0339 0 0013 0 22 0 95 Q5 1 3629 0 8370 0 2023 0 0341 0 0012 0 21 0 85 Q10 1 2251 0 8261 0 2154 0 0341 0 0012 0 21 0 84 Q20 1 1478 0 8205 0 2353 0 0333 0 0012 0 21 0 84 Q50 0 8744 0 8006 0 2315 0 0359 9 7E 4 0 21 0 84 Q100 0 7947 0 7950 0 2424 0 0357 9 3E 4 0 22 0 83 56 Table 18 Region A regression co efficients ae mie a0 al a2 a7 a8 a9 SE R2 Q2 0 5473 0 9418 2 3038 0 0011 no data no data 0 13 0 95 Q5 0 4916 0 8952 1 7518 0 0012 0 1007 nodata 0 12 0 96 Q10 0 6927 0 8859 1 8087 0 0010 0 0907 nodata 0 12 0 96 Q20 0 8670 0 8767 1 8563 8 5E 4 0 0819 nodata 0 13 0 95 Q50 1 0335 0 9005 2 3169 no data no data 5 2E 4 0 13 0 94 Q100 1 0929 0 8889 2 2764 no data no data 5 1E 4 10 15 0 93 Table 19 Region B regression co efficients Fow o a0 a1 a3 a4 a10 SE R2 Q2 0 2143 0 7464 0 2172 0 0194 0 0077 0 14 0 91 Q5 0 2746 0 7443 0 1961 0 0198 no data 0 14 0 89 Q10 0 3795
29. H Stream Geometric Network and Enhanced Flow Direction grid are used for watershed delineation in OFAT 5 3 Data Used in Watershed Characterization Watershed Shape Factor square of the length of the main channel divided by the drainage area Watershed Mean Elevation average of the OIH Digital Elevation Model DEM values within the watershed Watershed Maximum Elevation maximum OIH DEM value within the watershed Watershed Mean Slope average Slope Percent grid value within the watershed The slope percent grid was created with ESRI s Spatial Analyst Slope function on the OIH DEM Length of Main Channel Upstream Flow Length grid value at the pour point The Upstream Flow Length grid was created with ESRI s Spatial Analyst Flow Length function on the OIH Enhanced Flow Direction EFD grid Maximum Channel Elevation OIH DEM elevation value at the most upstream point along the main flow path Minimum Channel Elevation OIH DEM elevation value at the pour point Slope of the Main Channel m km Rise divided by run The difference in the OIH DEM elevation values at the pour point and the most upstream point along the main flow path determine the rise The Upstream Flow Length as determined in Length of the Main Channel is the run Slope of the Main Channel The slope of the main channel m km divided by 1 000 metres to get common units and then multiplied by 100 for percent 41 Area of Lakes and Wetlands Area of lakes
30. Method Moin amp Shaw 1985 has estimated parameteres of Q2 Q5 Q10 Q20 Q50 Q100 Index Flood Method Moin amp Shaw 1985 For the study the province was divided into 12 regions based on the study conducted by Sangal and Kallio 1977 and a homogeneity test was conducted The regions are shown in Figure 12 The variable used for single station analysis is annual peak instantaneous flow Where this value is not available the analysis uses the hydrograph method described by Sangal 1981 A total of 247 hydrometric stations with a record length of 10 or more years were used for the study These stations have either natural or minimal regulation in flow The data was fitted to the Three Parameter Log Normal Distribution Split sample testing Jack Knife method was done to validate the model Eleven hydrometric stations from the total were kept aside These stations were not used in developing the regional curve or in establishing drainage area versus mean annual flood relationships The testing stations were treated as ungauged and the results of the single station analysis of these stations were compared with the regional model The percentage error was tabulated and it is seen that Index Flood method gave predicted values which were quite reasonable except for two stations when compared to those obtained by the single station analysis 50 The flow versus drainage area relationship is shown below The equations coefficients and the
31. Probability 0 005 0 005 1 52 N1 16 0 01 0 01 1 26 N1 16 0 05 0 05 1 6 N1 04 0 1 0 1 1 3 N1 04 0 3 0 3 1 0 46 N0 925 Multiple Regression Method Moin amp Shaw 1985 The Multiple Regression Method was also included for the flood mapping studies along with the Index Method As in the Index Method the variable used for single station analysis is annual peak instantaneous flow Where this value is not available the analysis uses the hydrograph method described by Sangal 1981 Gauging stations in Ontario were classified according to the degree of regulation Regulated gauging stations are included in the 50 and 100 year return period with the premise that regulation has less impact on large events Frequency curves were developed for gauging stations with more than 10 years of historic data For 50 and 100 year return periods 270 gauging stations were used and for 2 5 10 and 20 year return periods 217 gauging stations with natural flow or minor regulation were used The main feature of this method is the delineation of homogenous regions within Ontario using the standardized residuals from the 100 year return level Three homogenous regions where found by grouping the residuals of similar magnitude and sign These regions are shown in Figure 11 Regression equations were developed for each of the three homogeneous regions The parameters significant in the regression equations in the order of import
32. R Table 27 Coefficients of multiple regression equations for 7Q2 Region a0 at a2 a3 a4 a5 a6 a7 1 35 766 no data 0 8628 no data no data 4 130 no data 0 000353 2 21 65 0 00337 no data no data no data 4 791 0 18088 no data 3 7 506 no data no data 1 581 10 7 no data 0 5491 0 0156 no data LS and 3 DA lt 3 15 0 00323 no data no data 0 01898 no data 0 00756 no data 17000 km2 Table 28 Coefficients of multiple regression equations for 7Q20 Region a0 at a2 a3 a4 a5 a6 a7 1 25 718 no data 0 5587 no data no data 2 89 no data 0 000272 2 8 124 0 00125 no data no data no data 0 796 0 0104 no data 3 0 4185 no data no data 9 777 10 8 no data 0 3403 0 0055 no data 1 2 and 2 45 0 0016 no data no data 0 0021 no data 0 0047 no data 3 DA lt 17000 km2 62 Central and Southeastern Regions Table 29 Regression equation variables used in Central and SE regions Variables Symbol Drainage Area km2 ES Base Flow Index dimensionless BFI The general form of multiple regression equation Y ao a DA a2 BF1 Table 30 Multiple regression equation coefficients for central region Flow m3 sec a0 at a2 7Q20 0 2134 0 00066184 0 7022 7Q2 0 7216 0 0018060 1 7386 3Q2 0 5398 0 0016260 1 2856 3Q20 0 1841 0
33. added to a new row at the bottom of the tool window and to the map e Several options are available for each watershed row e Click on a row to select The selected watershed row will be highlighted in blue The map display will zoom to the selected watershed e The watershed can be turned on and off in the map display by clicking the On Off checkbox This is useful when there are multiple overlapping watersheds in the map display e The watershed and pour point can be deleted by clicking the Delete icon e The watershed and pout point can be downloaded by clicking the Export icon See section 4 0 Exporting Watershed Information for details on how to export and download 3 1 2 Notes about Watershed Generation Each watershed generated in OFAT is independent of any other watershed generated This allows watersheds to overlap e g nested sub watersheds Caution should be taken when placing a pour point near a stream confluence where two streams meet and merge into one stream to achieve desirable results OFAT uses a 30 metre cell resolution raster Enhanced Flow Direction Grid in generating the watershed Due to the 30 metre raster resolution stream confluences within the grid are in the area of the mapped stream confluence that is shown on the map Place the pour point at least 30 metres downstream of the confluence to include the stream junction and all contributing streams in the watershed delineation Place the pour point at least
34. ance are Drainage Area Base Flow Index Slope of the Main Channel Area Controlled by Lakes and Swamps Mean Annual Runoff Mean Annual Precipitation and Shape Factor 54 Three Flood Frequency Regions REGION EA EH B EE c 200 100 O 800 Kilometers Figure 11 Three Flood Frequency Regions Regression equations developed were tested on measure of performance as expressed as percentage in difference from the single gauge analysis sensitivity analysis of dependent variables regression analysis R2 of the equation error analysis same as Index method and testing of regression equations with two stations each from each region The test results indicated good prediction of estimates with acceptable error The model is calibrated for all the independent variables of the regression equation The governing equations and the information are given below in Table 16 55 Table 16 Variables used in the Moin amp Shaw 1985 Regression Equation Variable Symbol Drainage Area km2 DA Mean Channel Slope m km SLP Index of Area Controlled by Water amp Wetland ACLS Shape Factor dimensionless LNTH2 DA where LNTH length SF of main channel km and DA drainage area km2 Base Flow Index dimensionless BFI Mean annual Runoff mm MAR Mean Annual Precipitation mm MAP The regression equation is Log QT ao a Log DA a gt BF1 1 2 as SLP 1 3 a4 ACLS 1 2 as SLP agLog M
35. ao J Todd K Hogg A and Kenny F 2008 Improving Ontario s Provincial Digital Elevation Model Internal Report Water Resources Information Program Ministry of Natural Resources 90p 45 Appendix 1 Regional Hydrological Models Introduction Frequency analysis is conducted for gathering inference about streamflow To measure streamflow hydrometric gauging stations are installed These stations are installed along the stream reach But not all the locations of a stream reach are gauged Estimates will be biased if flows are pro rated with the nearby gauge stations beyond 25 drainage area Hence in order to estimate the high low flow n year return level values at any location of a stream reach regional hydrologic models have been developed The regional hydrologic models usually use stochastic modelling techniques The commonly used stochastic modelling techniques are regression transfer functions neural networks and system identification Mathematical and statistical theories and concepts are used to estimate the parameters Among the above methodologies the regression models namely the Index Method and the Multiple Regression Method are widely used in hydrology These models resolve the problem by trading space for time Hosking and Wallis 1997 The underlying principle is to transpose the historic streamflow records of the region to the location of interest This is achieved by building models that combine streamflo
36. are required in areas where streamflow gauges do not exist OFAT generates modelled streamflow statistics for any mapped stream reach in Ontario Depending on the use of the output field verification may be appropriate e Among other applications baseline flow information is needed to e Design hydraulic structures such as culverts bridges dams etc e Protect or enhance fish habitat e Support an ecosystem approach to land and water management e Water use and wastewater permitting analysis e Support various academic studies Provincial specific application areas of OFAT are listed in Appendix 2 The generated streamflow statistics from the models assume natural flow conditions within the watershed of interest Influences that regulate flow in any way such as dams or withdrawals can significantly alter the flow quantity Also the flow models require certain ranges of input parameters such as drainage area of the watershed If parameters fall outside of the range required for the model such as the drainage area for a very small watershed results may contain small to large errors OFAT model outputs include a statement on the status of input parameter ranges for the particular model OFAT obviously cannot provide tools for all water related applications which is why all data generated in OFAT can be downloaded for further analysis The spatial watershed boundary and its associated physical characteristics that are implemented in OFAT pro
37. as pr Ontario User Guide for Ontario Flow Assessment Tool OFAT Spatial Data Infrastructure Mapping and Information Resources Branch Corporate Management and Information Division Ministry of Natural Resources and Forestry 2015 09 23 Disclaimer This technical documentation has been prepared by Her Majesty the Queen in right of Ontario as represented by the Ministry of Natural Resources and Forestry the Ministry No warranties or representations express or implied statutory or otherwise shall apply or are being made by the Ministry with respect to the documentation its accuracy or its completeness In no event will the Ministry be liable or responsible for any lost profits loss of revenue or earnings claims by third parties or for any economic indirect special incidental consequential or exemplary damage resulting from any errors inaccuracies or omissions in this documentation and in no event will the Ministry s liability for any such errors inaccuracies or omissions on any particular claim proceeding or action exceed the actual consideration paid by the claimant involved to the Ministry for the materials to which this instructional documentation relates Save and except for the liability expressly provided for above the Ministry shall have no obligation duty or liability whatsoever in contract tort or otherwise including any liability or negligence The limitations exclusions and disclaimers expressed above
38. details about each individual model please refer to the original literature listed in the references section Low Flow Prediction Models LOF This type of model generates low flow predictions such as mQn representing m day low flow in an n year return period For example 7Q20 represents the 7 consecutive day average low flow in a 20 year return period The low flow prediction models provided in OFAT are e Graphical Index Method MOEE 1995 e Regression Method MOEE 1995 Flood Prediction Models HIF This type of model generates flood flows such as Qn representing the flood flow in an n year return period For example Q10 represents the flood flow in a ten year return period The flood flow prediction models provided in OFAT are e Index Flood Method With Expected Probability Adjustment Moin amp Shaw 1985 e Primary Multiple Regression Method Moin amp Shaw 1985 24 Mean Annual Flow Prediction Model MAF This type of model generates the mean annual flow for the watershed e lsoline Method MNR 2003 OFAT Ill Tab D Navigation Map Layers OFATI Find Information N Q CG Hydrology Models Create Watershed Watershed Charactenzation Hydrology Models Button E Mean Annual Flow MNR 2003 Run Model aa index Method Run Model d NEEN Method with EPA Run Model Flood Flow Primary Multiple Regression Moin amp Shaw 1985 Run Model Tool Window View hydrology models note Run All Mod
39. e equaled or exceeded of time e M the ranked position on the listing dimensionless e n the number of events for period of record dimensionless The Flow Duration Curve is one of the versatile analytical tools used in watershed studies as it has a wide range of applications including characterizing flow regime design of hydropower facilities water budget studies and comparison of different watersheds 29 e 04CA002 Flow Duration Curve 10 T T T T T T T T T Discharge m sec L L L l L L L 0 10 20 30 40 50 60 70 80 90 100 Percent Exceedance Figure 6 Flow Duration Curve Historic daily streamflow records from the Water Survey of Canada HYDAT data base from January 1970 onwards were used for generating flow duration curves Active gauges with more than 20 years of record both regulated and natural were selected for their creation The minimum years of record required to ensure data quality is 20 years Active gauges with more than 10 years of record are also included for reference For these gauges it is highly recommended to use the data with caution Results include the tabular values of annual and monthly Flow Duration Curves and the associated graphical output The Flow Duration Curves were created by the Period of Record method 30 OFAT III Tab A Map Layers GRATIN Find Information Markup and Printing Flow Do Flow Stabstes Pre ATTAWAPISKAT RIVER BELOW MUKETEI RIVER Natura
40. ection of the tool window The selected watershed row will be highlighted in blue e Click the Extract Land Cover The resulting values are displayed next to each land cover type summarized by area km2 and percent coverage within the watershed To calculate and view the characterizations for a different watershed repeat the steps above for the desired row in the tool window The values will be updated with the values of the selected highlighted watershed row The extraction could take several minutes depending on the size of the watershed The land cover can be viewed on the map by selecting the View Land Cover Layer The viewable layer is for the entire province not just the watershed 23 Export Download and Metadata e See Section 4 0 Exporting Watershed Information for details on how to export and download characterization results e See section 5 0 Metadata for descriptions of the individual characterizations and data used in calculating the values 3 3 Flow Prediction Regional Hydrology Models OFAT contains a series of regional hydrologic models and empirical relationships that generate water flow information Flow regimes can be determined for a watershed after the watershed has been generated and the required characterizations computed OFAT currently contains three flow model categories Each category contains one or more models See Appendix 1 for a description of each of the models currently in OFAT For further
41. els 24 3 3 1 Steps to run the Hydrology Models tool 25 3 3 2 Notes about Flow Prediction Models 27 34A Flow Statistics ip 27 3 4 1 Steps to run the Flow Statistics tool aa 32 3 5 Find Watershed EE 33 3 5 1 Steps to run the Find Watershed tool 33 4 0 Exporting Watershed Information aa 34 4 1 Steps to export watershed information nnna 34 4 2 Contents of the Download Package arara 34 4 3 Field Descriptions for Exported Tables 35 4 4 Viewing Options for Exported Files 38 90 cite o ANA Jp PORRA e RS PS susan O Gece Sdn IR OO RR RT RS RN OR 40 5 1 Ontario Integrated Hydrology Data 40 5 2 Data Used in Watershed Delineation 41 5 3 Data Used in Watershed Characterization 41 5 4 Data Used in Watershed Land Cover Summary 42 5 5 Data Used in Hydrology Models 43 5 6 Data Used in Streamflow Statistics 44 BC Referentes ee 45 Appendix 1 Regional Hydrological Models aerea 46 lire eiert BEE 46 Governing Equations for Return Period Return Level 47 NGSX En e e os vas POOR E PDR RR RD NR SAND NR RR PR DR cent 47 Multiple Regression Method 49 Flood Fow Oe 50 Index Flood Method Moin amp Shaw 1985 50 Multiple Regression Method Moin amp Shaw 1
42. els Row foreach Watershed Figure 5 Hydrology Models Tool 3 3 1 Steps to run the Hydrology Models tool e Atleast one watershed must be generated before using the Hydrology Models tool e Click the OFAT tab e Click the Hydrology Models button to open the tool window 25 e Click the desired watershed row to calculate in the bottom section of the tool window The selected watershed row will be highlighted in blue e Click the Run Model button next to the desired model or click the Run All Models button Click the View Flows button to the right of each model name to view the results of each of the executed hydrology models The values shown are associated with the selected highlighted in blue watershed row in the tool window Input parameter values for Low Flow and both Flood Flow models are checked with appropriate range values The results of the input parameter tests are stated at the bottom of the table shown when the View Flows button is clicked Hover the cursor over the lower row s of the results column to see the full statement regarding the parameter test results Table 1 Parameter Range Statements for OFAT Regional Hydrology Models Model Field Name Parameter Range Statements Low Flow Aree Limit Drainage Area Parameter in not in range Graphical Index for model Law Flow Parameters DA LNTH BFI MAR are e Range Limit in outside of the range used to create this Regression Method model Flood
43. ge bookmarks OFAT tab The OFAT toolset is explained in the next section Find Information tab Search by text coordinates address assessment parcel or township lot concession and zoom to location Measure tools distance or area Markup and Printing tab Various options for scale file type and adding text or basic drawings to the map to highlight information on the print out Map Layers tab Turning map layers on and off or viewing the legends There are 2 legends The OFAT legend will be displayed when the Map Layers tab is opened There 16 is a toggle button at the bottom of the legend to switch between the OFAT and Base Data legends 2 1 OFAT Legend descriptions Diversion Identifies a location where water is being diverted from the natural flow This may be a dam that is blocking flow or a location where water is now flowing through Waterbody Outlet Identifies where water is flowing out of a lake or river This can aid in deciding where to create a pour point for a watershed by identifying the direction of flow Dam Dams have been categorized into 5 ownership classes which are Conservation Authority Provincial Federal Ontario Power Generation OPG and Other HYDAT Gauge Identifies Water Survey of Canada HYDAT Streamflow gauges HYDAT Gauges that belong to the Reference Hydrometric Basin Network RHBN will be displayed on the map as a red symbol with RHBN after the gauge name Gauges that are not part
44. hed drainage point on a mapped hydrology feature such as a stream river or lake anywhere within the land boundary of Ontario including Ontario s Far North The resulting watershed polygon can then be used within OFAT to summarize key watershed characteristics The watershed boundary and characteristics are used in Flood Flow Low Flow and Mean Annual Flow models The user can view all spatial and tabular outputs online and download the outputs for further specialized viewing or analysis A standard Internet browser is required to use OFAT Table of Contents DU MNO E 2 Additional ge e ln E 2 Executive SUMMATY regeert 3 Key VO a a e a oe nd UR 3 EE 3 Table Ol Ee EE 4 LISTON e 7 IST Ol ADI ae aa ed 7 Bee 9 1 0 Overview ER E 11 1 1 Background E 11 1 2 Functionality EE 12 1 3 Use and Limitations of OFAT EE 13 14 Data Te 14 To WY SING outa a a a en oo 15 1 6 Future EnMaANEeMents nn es 15 ZONA Wy ie gt ne DD E moon 16 2 1 OFAT Re nee eene Rasetenddasesenbiasetenadanetens 17 3O OFAT TN EE 18 3 1 Create Watershed saine iii Nm 18 3 1 1 Steps to run the Create Watershed tool 19 3 1 2 Notes about Watershed Generation 20 3 2 Watershed Characterization eeeerereeeaaee na aanereeea 22 3 2 1 Steps to run the Watershed Characterization Tool 22 3 3 Flow Prediction Regional Hydrology Mod
45. l Active Accordion Section Accordion Row End Year 2011 Number of Years 38 Figure 7 Flow Statistics Tool 31 3 4 1 Steps to run the Flow Statistics tool e Click the OFAT tab e Click the Flow Statistics button to open the tool window e Selecting a gauge to query can be accomplished using one of two methods e Click the combo box drop down arrow at the top left of the Flow Statistics tool window and then select a gauge by its HYDAT ID It is possible to type in the combo box to narrow the selection e Click on the Flow Statistics identify button at the top right of the tool window and then click on a stream gauge symbol on the map As you zoom in on the map the stream gauge name will appear The selected gauge will highlight on the map and the flow statistics will be displayed in the accordion section of the tool window Click on an accordion row to view the flow values The gauge name regulation type and status will be displayed below the combo box Click on the Flow Duration Curve accordion row to view a period of record length summary for the selected gauge Then click the View FDC button to display the graph Hover the cursor over the curve on the graph to display the value at that point You can download a table containing annual and monthly flow values for each percent exceedance for the currently selected gauge station by clicking the Download FDC Data button 32 3 5 Find Watershed OFAT III Tab v
46. lass structures and which have been rationalized into a single classification The Ontario Land Cover Compilation combines the Provincial Land Cover Database Far North Land Cover and the Southern Ontario Land Resource Information System Each of these separate land cover databases were resampled to a common pixel 42 spacing 15 metres re projected to a common projection NAD83 Lambert Conformal Conic and reclassified into a common class structure Data Specification documentation is available for download from the metadata record https www javacoeapp lrc gov on ca geonetwork srv en main home uuid 46be851e efc3 4511 bf45 7ac5eb8fd459 5 5 Data Used in Hydrology Models Hydrology models in OFAT use information as required from derived watershed characteristics There are additional data layers required for the regression models Additional data include Mean Annual Runoff The OFAT Mean Annual Runoff Surface is a 1 kilometre resolution raster data set that represents the mean annual runoff in millimetres at a particular location This grid was created by North East Science and Information Branch of MNR The source data to create the grid was taken from Moin and Shaw Regional Flood Frequency Analysis for Ontario Streams 1985 Hard copy maps were digitized to create a mean annual runoff contour dataset which were then interpolated into a surface using TOPOGID This data is stored in MNRF Lambert Conformal Conic Projection SDI i
47. lood Limit 2001 Government of Ontario Ministry of Environment Guide for Applying for Approval of Sewage Works 2010 Government of Ontario Ministry of Natural Resources Ministry of Environment Ministry of Agriculture and Food Ministry of Municipal Affairs and Housing Ministry of Enterprise Opportunity and Innovation Association of Municipalities of Ontario Conservation Ontario Ontario Low Water Response 2003 Statistics Canada 2009 Technical Paper The Water Yield for Canada as a Thirty year Average 1971 to 2000 Concepts Methodology and Initial Results Robby Bemrose Laura Kemp Mark Henry and Fran ois Soulard http www statcan gc ca pub 16 001 m 16 001 m2009007 eng pdf 74 Government of Ontario Ministry of Natural Resources Ministry of Environment Water Budget and Water Quantity Risk Assessment Guide Drinking Water Source Protection Program 2011 http www waterbudget ca waterbudgetguide The Ontario Ministry of Natural Resources and Ministry of the Environment in partnership with Credit Valley Conservation Guide for Assessment of Hydrologic Effects of Climate Change in Ontario 2010 http www waterbudget ca climatechangeguide 15 Appendix 3 Other References IDF Curves An Intensity Duration Frequency curve IDF curve is a graphical representation of the probability that a given average rainfall intensity will occur It characterizes the rainfall pattern of the area Usually 2 5 10 25
48. low flow region uses a different range of hydrologic parameters to develop models limiting their use Ranges of input parameters for each region are shown in the following tables 64 Table 34 Region 1 range of input parameters Variable MAP MAS MAR EVA DA BFI LNTH ACLS Min 500 190 108 340 401 0 25 0 Max 830 305 456 450 94300 1 476 3 100 Table 35 Region 2 range of input parameters Variable MAP MAS MAR EVA DA BFI LNTH ACLS Min 695 190 154 490 744 0 68 4 0 Max 790 230 406 515 50200 0 99 238 1 100 Table 36 Region 3 range of input parameters Variable MAP MAS MAR EVA DA BFI LNTH ACLS Min 695 190 154 490 744 0 68 4 0 Max 790 230 406 515 50200 0 99 238 1 100 Table 37 Region 4 Central range of input parameters Variable MAP MAS MAR SLP EVA DA BFI LNTH ACLS Min 780 120 189 0 02 665 24 3 10 17 9 0 Max 1000 300 527 9 434 830 1520 0 82 94 3 100 Table 38 Region 5 Southeastern range of input parameters Variable MAP MAS MAR SLP EVA DA BFI LNTH ACLS Min 800 170 260 0 14 635 7 0 3 5 0 Max 920 200 540 12 19 790 4120 0 88 112 4 100 Table 39 Region 6 Southwestern range of input parameters Variable MAP MAS MAR SLP EVA DA BFI LNTH ACLS Min 780 90 137 0
49. lowest average summer month flow e Other times monthly flow lt 70 of lowest average summer month flow 70 Level Il Conservation and Restrictions on Non Essential Use e Precipitation is less than 60 of average weeks with less than 7 6 mm e Spring monthly streamflow is less than 70 of lowest average summer month flow e Other times monthly streamflow is less than 50 of lowest average summer month flow Level III Conservation Restriction Regulation e Precipitation is less than 40 of average e Spring monthly streamflow is less than 50 of lowest average summer month flow e Other times monthly streamflow is less than 30 of lowest average summer month flow An indication of streamflow approaching the minimum needed to maintain the ecosystem is the statistical flow value 7Q20 Comparing the value of the current flow with the historic low value will determine when the streamflow is approaching the 7Q20 Streams in the headwaters or those having high width to depth ratio are expected to be more sensitive to low flows An indication of streamflow approaching the minimum needed to maintain the ecosystem in these streams is the statistical flow value 7Q2 Water Budget Section 15 2 Clean Water Act 2006 Water Budget and Water Quantity Risk Assessment Guide 2011 Water Budget Components Analyse Streamflow QSW The analysis will include estimates of streamflow statistical paramete
50. lts table e MoinShawRegression dbf Moin amp Shaw Flood Flow Primary Multiple Regression results table 4 3 Field Descriptions for Exported Tables Most tables will contain the OFATID attribute which is automatically generated when the user defines a pour point The ID is carried through to the watershed characterizations and hydrology model outputs The OFATID can be used to organize or link tables and geometries The following tables contain field names and descriptions for each of the OFAT output tables Table 2 Descriptions of pour point fields in PourPoint dbf Field Name Description Shape Geometry of the GIS file The value will be Point OFATID Auto generated OFAT ID WTertiary Tertiary watershed identifier where the pour point is located Latitude Latitude in decimal degrees NAD 83 Longitude Longitude in decimal degrees NAD 83 X_LCC X coordinate in Lambert Conformal Conic NAD 83 35 Field Name Description Y LCC Y coordinate in Lambert Conformal Conic NAD 83 Table 3 Descriptions of watershed polygon fields in Watershed dbf Field Name Description Shape Geometry of the GIS file The value will be Polygon OFATID Auto generated OFAT ID Table 4 Descriptions of characterization fields in CharacterizationTable dbf Field Name Description OFATID Auto generated OFAT ID AreaKm Area
51. lyze further Metadata is available in the online user guide 1 6 Future Enhancements OFAT is a dynamic application and enhancements are regularly in progress The Spatial Data Infrastructure SDI Unit of the Mapping and Information Resources Branch MIRB of the MNRF are willing to entertain any partnerships or suggestions that are compatible with the vision of OFAT 15 2 0 OFAT Interface Only an internet browser is required to run OFAT No GIS software is needed Upon starting OFAT the user is presented with a full view of Ontario along with the surrounding provinces and states The OFAT tools are functional only within the Ontario portion of the map display Five Tabs are placed horizontally across the screen below the OFAT banner Each tab has a set of associated tools MINISTRY OF NATURAL RESOURCES AND FORESTRY LC Ontario Ontario Flow Assessment Tools III Powered by Land Information Ontario OFAT III Find Information Markup and Printing 2a Le Oo Remove Bookmark Go To Out Pan Provas Bookmarks Map Navigation Figure 1 OFAT Interface Tools associated with the Navigation Map Layers Find Information and Markup and Printing tabs are briefly explained below More detailed explanations can be found in the Make a Topographic Map user guide https www sse gov on ca sites MNR PublicDocs EN CMID Make 20A 20Topo 20Map 200nline 20Help 20English pd f Navigation tab Zoom and pan around the map and mana
52. nstant n exponent Table 25 Regression equations of the Index Flood Method 7Q2 Region Equation 1 7Q2 8 681 0 00208 DA 2 7Q2 2 494 0 00325 DA 3 7Q2 1 341 0 00353 DA Central 7Q2 0 383 0 00161 DA Southeastern 7Q2 1 60 0 00251 DA Combined Central and Southeastern 7Q2 0 118 0 00205 DA Regression Method MOEE 1995 Watershed characteristics Drainage Area Length of Main Channel Mean Annual Runoff Base Flow Index and Mean Annual Snowfall were used to make the regression equations This method also develops two equations for the regions 1 2 and 3 for drainage areas greater or less than 17 000 km2 This approach overcomes the limitation of the drainage area range The equations for each region their coefficients and the calibrated watershed values are given in the following tables Sensitivity analysis of the watershed parameters show that the drainage area to be the most sensitive Nash Sutcliff coefficient of 0 68 and 0 86 were obtained for 7 day 2 and 20 year recurrence intervals 61 Northeastern and Northwestern Regions Table 26 Regression equation variables for NE and NW regions Variables Symbol Drainage Area km2 DA Length of Main Channel km LNTH Mean Annual Runoff mm MAR The general form of multiple regression equation for 7Q2 and 7Q20 is Y a ta DA a2 DA a3 DA a4 LNTH as LNTH 2 a MAR a7 MA
53. of the RHBN will be displayed as a blue symbol Diversions Waterbody Outlet Conservation Authority Dam Provincial Dam Federal Dam OPG Dam Other Dam HY DAT Gauge HY DAT Gauge RHBN Y A A A A A 9 9 Figure 2 OFAT Map Legend 17 3 0 OFAT Toolset This section explains how to use the OFAT tools and limitations that uses should be aware of 3 1 Create Watershed OFAT is capable of delineating a watershed from any user defined point in Ontario that satisfies certain criteria Generating a watershed is the initial point of the work flow for many of the functions A watershed is required to perform the subsequent operations in the work flow such as generating watershed characteristics and executing the hydrology models A watershed is created in OFAT by defining a pour point a point through which all overland flow of the watershed will drain through A pour point must be created on a mapped hydrology feature lake or stream and must exist within the land boundary of Ontario A point within the Great Lakes St Lawrence Ottawa River St Clair Hudson Bay James Bay or similar area will not generate a watershed 18 Create Watershed OFAT Ill Tab Button Navigation Map Layers OPATEM Findinomaton Markup and Printing O Ab AY wech Create Watershed Watershed Characterization Hydrology Models Flow Statsics Precg aton Statistics Find Watershed Tool Window gt Create watershed al e E A
54. onless frequency curve Mean annual flood index flood is defined as the flood having a recurrence interval of 2 33 years The premise for using the mean annual flood as the index flood is as follows The magnitude of the mean annual flood is affected by both physiographic and meteorological factors of the drainage basin A method to account for the composite effect of these factors is determined by dividing the study region into homogeneous hydrologic regions and correlating it to the most significant factor the drainage area The Index Method assumes that the flow is natural or with minimum regulation and the region is homogeneous There is no limit to the drainage area of the homogeneous region The recurrence intervals are computed with a minimum of 10 years of record 48 The Index method is popular as it is simple and most importantly it requires only the drainage area of the watershed making it suitable for watersheds where physio meteriological data are sparse The Index method was first introduced for flood flows and then later applied for low flows The scientific principles remain the same for both flood and low flows Multiple Regression Method Multiple linear regression is a multivariate statistical technique for examining the linear correlations between two or more independent variables IVs and a single dependent variable DV Multiple linear regression models are useful for e predicting unobserved values of the
55. onmental Impact Analysis of Surface Water Impact states the limiting conditions as Limiting conditions within the receiving water body including Low flow conditions in the receiving water body e g the 7Q20 for a stream i e the 7 day average low flow occurring once in 20 years Approval under the Lakes amp Rivers Improvement Act 2010 Sections 14 and 16 Lakes and Rivers Improvement Act LRIA 1927 and Ontario Regulation 454 96 Flow recommendations as given in the technical guidelines are The design flow for fish passage should not exceed a frequency of a 1 10 year 3 day delay This is the flow that is exceeded on average every ten years for three consecutive days 67 The PMF probable maximum flood is not normally used for channel design The channel capacity may be designed for less than the 25 year flood e g 10 5 or 2 year flood but the combined capacity of the channel and flood plain must meet the design flood criteria for small dams in the table Bankfull discharge of a river natural flow channel usually corresponds to the 1 2 33 year to the 1 5 year return period depending upon the stream type and basin conditions Table 40 Minimum design floods for road crossing Road Classification Total Span up to 6 0 metres Total Span over 6 0 metres Freeways and Urban 100 year or Regulatory e 50 year Flood depending on local Arterial Roads conditions Rural
56. ow Flow Regions Region 1 CR 3 E 4 CP EM 6 C Ontario 200 100 0 200 400 600 800 Ben Lloret Figure 12 Six Low Flow Regions As all methods were undertaken by the same consultant the methodology for the single gauge station analysis and the generation of homogeneous regions remains the same A total of 344 stations with more than 10 years of record were used for the study Variables are extracted in two steps First the moving average low flows n day were determined and then from that extreme low values are extracted for each year of the available data base For the Index method for each n day 1 3 7 15 and 30 duration frequency curves were developed for each station For the regression method only 7 day duration is used The data is fitted to the Weibull Distribution and then frequency curves of these stations were developed The Province was divided into six hydrological homogeneous regions by grouping similar meteorological and physiographic characteristics These homogeneous regions are depicted in Figure 12 60 Index Method MOEE 1995 Equations that relate the frequency with the drainage area the calibrated values range of drainage area are given in Table 25 Application of the Index method resulted in a Nash Sutcliff coefficient of 0 92 and 0 87 for 7Q2 and 7Q20 respectively General form of the equation Q2 CA where Q2 2 year return period 3PLN flood A Drainage Area C Co
57. response y x for new x e understanding which terms aj x have greatest effect on the response coefficients a with greatest magnitude e finding the direction of the effects signs of the ai e to what extent do x1 x2 and x3 IVs predict y DV Here the first use is being implemented The governing equation is of the form where y dependent variable T year flood flow actual or transformed ao regression constant a regression coefficient s x independent variable s basin parameter actual or transformed p no of independent variables used The assumption of the analysis is that the residuals are normally distributed and have a straight line relationship with predicted DV scores and the variance of the residual about the predicted scores is the same for all predicted scores 49 Flood Flow Model In 1978 the Government of Canada and the Province of Ontario entered into An Agreement Respecting Flood Risk Mapping and Other Flood Damage Reduction Measures The Index Method with Expected Probability Adjustment Moin amp Shaw 1985 and the Secondary Multiple Regression Method Moin amp Shaw 1985 commissioned by the Steering Committee are implemented here The flood flow model Index Flood Method With Expected Probability Adjustment Moin amp Shaw 1985 has estimated parameters of Q1 25 Q2 Q5 Q10 Q20 Q50 Q100 Q200 Q500 The flood flow model Secondary Multiple Regression
58. riables used in Central and SE regions 63 Multiple regression equation coefficients for central region 63 Multiple regression equation coefficients for southeastern region 63 Regression equation variables used in WC and SW regions eeeeeeeeeee 64 Multiple regression equation coefficients for WC and SW region 64 Region 1 range of input parameters 65 Region 2 range of input parameters 2 222 2222 2 csceceeeeeeeeeteeseeeeneeeeeeeneeeeee 65 Region 3 range of input parameters 65 Region 4 Central range of input parameters rnn nnne 65 Region 5 Southeastern range of input parameters 65 Region 6 Southwestern range of input parameters 65 Minimum design floods for road crossing 68 Percent probability of exceedance during life of structure 70 List of Acronyms CFA Consolidated Frequency Analysis DEM Digital Elevation Model EPA Expected Probability Adjustment FDC Flow Duration Curve GIS Geographic Information Systems HIF Flood Prediction Models HYDAT Environment Canada s Hydrometric database IDF Intensity Duration Frequency LCC Lambert Conformal Conic LFA Low Flow Frequency Analysis LOF Low Flow Prediction Models MAF Mean Annual Flow Prediction Model MIRB Mapping and Information Resources Branch MNRF Ontario Ministry of Nat
59. rk began on OFAT 2 but was never fully completed A major innovation with OFAT 2 was the inclusion of a Daily Flow Toolkit Using the refined and quality controlled time series flow data from Environment Canada s Hydrometric HYDAT database this Toolkit contained the functionality to derive 6 daily flow calculations The provincial need for OFAT like functionality across Ontario has not diminished over the intervening years evidenced by regular requests for OFAT and OFAT outputs In the far north of Ontario this need was heightened with the initiation of land use planning activities across this zone These factors led the MNR s Water Resources Information Program WRIP with support from the Far North Branch Integration Branch and the Land and Resources Cluster to build OFAT 3 11 1 2 Functionality A central requirement of any spatial hydrology modelling tool is the ability to accurately delineate and characterize watersheds An objective of the OFAT 3 project was to develop such a tool that was easily and openly accessible for widespread application via the Internet Such an application serves the needs of the flow modelling community and can be actively employed to support science and policy groups across the Ontario Public Service OPS and beyond that require access to authoritative watershed definitions and characteristics For example the Ontario s Far North planning area represents 44 of the province and
60. rs i e QP90 QP50 Qavg where continuous records exist analysis of spot flow measurements or pro rating of data from nearby gauges The analysis may also include baseflow separation at gauged surface water stations Surface Water Supply Estimation Methods The 30Q2 flow provided by OFAT is an estimate of average annual baseflow Pryce 2004 This flow could be considered as 71 the water supply for each month as the tools in OFAT cannot provide monthly low flow estimates OFAT cannot account for flow augmentation and regulation controls Therefore the team must understand its limitations in estimating baseflow Tier One Surface Water Monthly Water Reserve Estimation Methods When a continuous stream gauge is available the surface water reserve may be calculated for each month as the monthly lower decile flow QP90 or the flow that is exceeded 90 of the time for each month nm o Surface Water Stress Assessment Surface water reserve is calculated as the monthly lower decile flow Q90 at the outlet of the subwatershed for Tier Two The water reserve estimate may be the same in Tier One where a reliable surface water gauge is located at the outlet of the subwatershed nm o Significant Risk Circumstances Groundwater Under scenario G existing plus committed plus planned demand the municipal takings result in measurable and unacceptable impacts to other uses For cold
61. s not the custodian of this data set Base Flow Index The OFAT Base Flow Index Surface is a 1 kilometre resolution raster data set that represents the portion of flow in a stream derived from soil moisture or groundwater baseflow The grid value in any one location represents the ratio of base flow to total flow volume dimensionless This grid was created by North East Science and Information Section of MNR The source data to create the grid was taken from Moin and Shaw Regional Flood Frequency Analysis for Ontario Streams 1985 Tabular data from this study was used to create point values which were then interpolated into a continuous surface raster using TOPOGRID The grid does not cover the entire province This data is stored in MNRF Lambert Conformal Conic Projection SDI is not the custodian of this data set 43 5 6 Data Used in Streamflow Statistics The data product geodatabase and accompanying technical document are available through the following links Flood Flow and Low Flow Statistics For the Southwestern Hudson Bay and Nelson River Watershed Systems February 2013 https www javacoeapp Irc gov on ca geonetwork srv en main home uuid 1bcabfe3 47ed 461b ac00 653c365b53f2 Baseline Hydrology For the Southwestern Hudson Bay and Nelson River Watershed Systems March 2014 https www javacoeapp lrc gov on ca geonetwork srv en main home uuid b6bb27d4 1a28 4ce1 8195 1caa0b2cced2 Flood Flow Statistics For the
62. shall apply irrespective of the nature of any cause of action demand or action including but not limited to breach of contract negligence strict liability tort or any other legal theory and shall survive any fundamental breach or breaches Cette publication sp cialis e n est disponible qu en anglais Additional Information This document contains detailed help for using OFAT to the specifics around input data and models OFAT uses to produce the generated outputs Please refer to the original documentation or speak with an expert in this area before using the information for decision making purposes For more information or if persistent problems occur with the application or the data that OFAT uses or if anything is omitted from this Help document please email Spatial Data Infrastructure SDI at sdi ontario ca Executive Summary Key Words Ontario Flow Assessment Tool Abstract Ontario Flow Assessment Tool version 3 OFAT is an online spatially based application which automates several technical and labour intensive hydrology tasks It allows the user to view select hydrology information such as stream flow statistics OFAT calculates flow quantity estimation values and several intermediate outputs such as watershed delineation and characterization These derivatives can be used by a variety of users and applied to many water related applications Using a base map for reference the OFAT user defines a waters
63. the land cover classification within the watershed in m2 Percentage of area of the land cover classification within the Percentage watershed Class Name Land cover classification Table 7 Descriptions of mean annual flow fields in MAF dbf Field Name Description OFATID Auto generated OFAT ID Model Name of the model Units Units MAF Mean annual flow quantity estimation Table 8 Descriptions of graphical index method fields in MOEGI dbf Field Name Description OFATID Auto generated OFAT ID Model Name of the model Units Units AreaLimit Result of the model input parameter watershed area range test LF_ x Q y Low Flow Quantity averaged over x days for a specific return period y 37 Table 9 Descriptions of low flow regression method fields in MOERegression dbf Field Name Description OFATID Auto generated OFAT ID Model Name of the model Units Units RangeLimit Result of the input parameters range test LF_ x Q y a Quantity averaged over x days for a specific return Table 10 Descriptions of flood flow regression fields in MoinShawRegression dbf Field Name Description OFATID Auto generated OFAT ID Model Name of the model Units Units Result of the model input parameters range test for the flow eeng estimates between Q2 and Q20 Result of the model input parameters range test for the
64. ues of 9999 will be inserted for some flow values if the model does not accommodate the specific input parameters for the particular area of the province These values do not represent an error 3 4 Flow Statistics OFAT contains estimates of streamflow statistics for select Water Survey of Canada s HYDAT gauges in the Southwestern Hudson Bay the Nelson River and the Great Lakes St Lawrence River watershed systems that lie within the Province of Ontario The resultant streamflow statistics include Mean Annual Flow Mean annual streamflow cubic meter per second is the average streamflow if there are daily streamflow values for the complete year The calculation is performed on a calendar year basis with historic data from January 1970 inclusive onwards The average value for the number of years of record available is reported 27 Flood Flow and Low Flow A recurrence Interval or Return Period for flood flow is defined as An annual maximum event has a return period or recurrence interval of T years if its magnitude is equalled or exceeded once on the average every T years The reciprocal of T is the exceedance probability 1 F of the event that is the probability that the event is equalled or exceeded in any one year Bedient 2002 The probability P that an event F will occur in any year T expressed mathematically as P F L Return Period is the reciprocal of probability and expressed mathematically as
65. ural Resources and Forestry MOEE Ministry of Environment and Energy NESI North East Science and Information OFAT Ontario Flow Assessment Tool OIH Ontario Integrated Hydrology OPG Ontario Power Generation OPS Ontario Public Service RHBN Reference Hydrometric Basin Network SDI Spatial Data Infrastructure UTM Universal Transverse Mercator WRIP Water Resources Information Program 10 1 0 Overview of OFAT 1 1 Background When initially released in 2002 the Ontario Flow Assessment Techniques 1 OFAT 1 developed by the Ministry of Natural Resources North East Science and Information NESI was a system ahead of its time OFAT 1 was visionary providing automated implementation of existing very labour intensive manual hydrology calculations Chang et al 2002 This system provided users with the potential to estimate flow regimes representing low flows e g 7Q2 7Q10 7Q20 etc flood flows e g Q2 Q10 Q25 Q100 etc mean annual flows minimum instream flow requirements and bankfull flows for watersheds in Ontario outside the extent of the far north of the province This functionality allowed users to compare and explore obtained results across regional models with the confidence of standardized Geographic Information System GIS processes and attribute handling OFAT 1 was a customized add on to proprietary GIS software Updates to newer versions of GIS software necessitated a re work of OFAT In 2003 wo
66. vide nearly instant accurate results that otherwise could be a significant undertaking 13 1 4 Data History As OFAT was first being developed in 2000 base data projects were underway to create the provincial hydrology elevation and derivative GIS datasets necessary to support spatial hydrology analysis In the absence of yet established provincial datasets WRIP developed a full suite of required data layers as one off products strictly to support OFAT and OFAT users While this was a practical response to the data gap it was not optimal in terms of data quality data updating and longer term ability to integrate with other data Since the initial OFAT development these required datasets have been produced in Universal Transverse Mercator UTM projections in a more rigorously standardized and quality controlled environment Kenny and Matthews 2005 Kenny et al 2008 WRIP 2008a 2008b 2008c Zhao et al in press These data products are substantially refined and are now openly available to Ontario s water management community As refined and useful as these hydrology and elevation data holdings are there were still several limitations to using these data uniformly across the province in a modelling environment that might encompass watersheds that span more than half the province These challenges include e The scale of provincial base data and derived data was variable The base data was 1 10 000 scale in southern Ontario and
67. w at known locations with the corresponding physio meteriological factors The above mentioned two methods are also recommended by WMO 1994 for frequency studies Amongst the two the Index method is the simplest method The steps involved in developing regional models are e Develop a Single Station Frequency Curve e Delineate Homogenous Regions e Develop Regional Frequency Curves that are evaluated against the methodology scientific principles used 46 Governing Equations for Return Period Return Level Recurrence Interval or Return Period is defined as An annual maximum event has a return period or recurrence interval of T years if its magnitude is equalled or exceeded once on the average every T years The reciprocal of T is the exceedance probability 1 F of the event that is the probability that the event is equalled or exceeded in any one year Bedient 2002 The probability P that an event F will occur in any year T is expressed mathematically as 1 Return Period is the reciprocal of probability and is expressed mathematically as WE D Recurrences intervals return periods usually calculated are 1 5 2 2 33 5 10 25 50 100 200 and 500 years annual exceedance probabilities of 0 6667 0 50 0 4292 0 20 0 10 0 04 0 02 0 01 0 005 and 0 002 respectively General equation for estimating the return level is in terms of the frequency factor for hydrological studies is given by Chow
68. water streams an unacceptable impact is defined by a circumstance where groundwater discharge is reduced by more than 20 as compared to the existing estimated monthly streamflow Qp80 the flow that is exceeded 80 percent of the time or the average monthly baseflow of the watercourse or another threshold that has already been defined as a condition in an existing permit In situations where another threshold has been defined that threshold would be used to identify a significant risk Climate Change Guide for Assessment of Hydrologic Effects of Climate Change in Ontario 2010 Summary of hydrologic change metrics Mean Flows Mean annual flow Mean monthly flows Mean seasonal flow Peak Flow Statistics Recurrence Interval peak flows e g 2 Year 100 Year Flow Distribution Flow frequency duration curve Low Flow Statistics 1Q10 7Q10 7Q20 72 After selecting the hydrologic metrics the study team must decide how to compare the climate change impacts to the reference regime The following methods can be used to compare the estimated impacts with each metric Absolute Change Estimate the absolute change in the hydrologic metric e g 7Q10 decreases from 10 L s to 7 L s Relative Change Estimate the percent change in the hydrologic metric eg 7Q10 decreases 30 Frequency Change Estimate the change in the frequency of exceedance for a metric e g frequency of overbank flow increases from 2
69. with EPA Moin amp Shaw 1985 L Flood Flow Primary Multiple Regression Moin amp Shaw 1985 Create Package Download Package Cancel Figure 9 Exporting Watershed Information 4 1 Steps to export watershed information e Click the Export icon in a watershed row of an OFAT tool to export the data for that particular watershed e Check each desired items to include in the export e Click Create Package button e Click the Download Package button 4 2 Contents of the Download Package Extract the contents of the download package compressed zip file The following list describes the folders and files that can be downloaded 34 e kmz folder e Watershed1 kmz Google Earth kmz file e landcoverGRID folder e info this folder is required for GIS software e landcovr landcover raster in ESRI GRID format e OntarioLandcover lyr GIS layer file to be used as a legend file in ArcGIS e shape folder e PourPoint shapefile 5 files user defined watershed pour point GIS file e Watershed shapefile 5 files watershed GIS file e CharacterizationT able dbf watershed characterization results table e IndexEPA dbf Moin amp Shaw Flood Flow Index with EPA results table e landcovertable dbf summary by area of the land cover within the watershed table e MAF dbf Mean Annual Flow values table e MOEGI dbf MOE Low Flow Graphical Index results table e MOERegression dbf MOE Low Flow Regression resu

OFAT User Guide - Government of Ontario

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