Water Quality Assessment Data and Results

Transcription

1 I Water Quality Assessment Data and Results WinSLAMM Program Description and WinSLAMM Features and Uses WinSLAMM Reference Documents Obtained from the programs Website: Table I1: Water Quality Results (WinSLAMM) Table I2: Comparison between Highest Practical SWM with EoPs and Existing Conditions Table I3: Comparison between Moderate SWM Implementation and Existing Conditions Table I4: Comparison between Public Property SWM Implementation and Existing Conditions Table I5: Comparison between HP SWM NO EoPs and Existing Conditions Assessment of the Relative Impact of SWM Retrofit Alternative Developed for the Pinecrest Creek (Baird & Associates Ltd., February, 2011) Wastewater & Drainage Services Stormwater Facility Annual Performance Summary (City of Ottawa) Water Quality Summary Table (City of Ottawa) Summary of Pollutant EMCs in Stormwater Runoff: WinSLAMM Parameter Value Adjustments (Center for Watershed Protection, 2007) WinSLAMM Pollutograph Results (Included in Appendix R: CD) Pinecrest_Stormwater.xls Surface Water Quality Monitoring Data Received from the City of Ottawa Feb 8, 2010 (Included in Appendix R: CD)

2 August 14, 2009 WinSLAMM, the Source Loading and Management Model WinSLAMM, the Source Loading and Management Model was developed starting in the mid-1970 s as part of early EPA street cleaning and receiving water projects in San Jose (Pitt 1979) and Coyote Creek (CA) (Pitt and Bozeman 1983). The primary purpose of the model is to identify sources of urban stormwater pollutants and to evaluate the efficiency of control practices. During the mid 1980s, the model was expanded to include more management options beyond street cleaning, including wet detention ponds, infiltration and grass swales. The Nationwide Urban Runoff Program (NURP) projects (EPA 1983) provided a large data set for the model, especially, Alameda Co. CA (Pitt and Shawley 1983); Bellevue, WA (Pitt and Bissonnette 1983); and Milwaukee, WI (Bannerman, et al 1983). Research funded by the Ontario Ministry of the Environment (Ottawa) (Pitt 1987) and the Toronto Area Watershed Management Strategy study in the Humber River (Pitt and McLean 1986) also provided much information on bacteria sources in urban areas. During the mid-1980s, the model started to be used by the Wisconsin Department of Natural Resources (WDNR) in their Priority Watershed Program (Pitt 1986). The first Windows version of the model was developed in 1995 and the current version is 9.3.0, released in April The model is continuously being updated based on user needs and new research (recent and current support from Stormwater Management Authority of Jefferson County, AL; the TVA, Economic Development group; WDNR; the USGS; and Imbrium). The next version currently being developed will include drag and drop watershed elements and more complete routing options. Over the years, WinSLAMM has been extensively revised and expanded and now includes a wide range of capabilities. The following lists several important model features: The model can evaluate a long-series of rain events. One to five years of typical rains are used, but several decades of rains can be evaluated The model is based on actual field data. For example, street dirt accumulation and washoff equations and direct runoff from paved surfaces are based on many thousands of measurements from actual rain events The effects of compacted urban soils are considered Uncertainties of many modeling parameters are represented by built-in Monte Carlo components Costs of control practices can be directly calculated and considered in model runs Runoff flow-duration probability distributions and associated receiving water biological conditions are calculated based on site conditions and the control measures being used The model can be interfaced with several other models for more detailed drainage system and receiving water evaluations. Prior descriptions of WinSLAMM have been presented during the Engineering Foundation and in the Urban Water Modeling Conference series, and in other publications (Pitt 1986; 1997; 1999; Pitt and Voorhees 2002 for example). The model web site ( ) also contains further model descriptions and references. Applications of WinSLAMM include: Permit Compliance Municipal Pollutant Loadings and Discharge Reductions Evaluate Alternative Stormwater Controls City-wide

3 Watershed Site Development Identify critical drainage areas Identify critical land uses Identify critical source areas Assist with cost-sharing Identify the most cost-effective stormwater control and development scenarios WinSLAMM is an urban stormwater model (it does not directly address agricultural areas, natural areas, etc.). It is designed to be an effective multi-scale model (individual lots to whole communities), and can calculate annual or seasonal pollutant loads. It evaluates individual or multiple stormwater control scenarios (source area, land use, drainage, outfalls), as shown highlighted in the following table: WinSLAMM Treatment Practice Options by Source Area Hydrodynamic Device Wet Detention Street Cleaning Biofiltration/ Rain Gardens Porous Pavement Rain Barrels/ Tanks Grass Swales Catchbasin Cleaning Drainage Disconnection Roof Paved Parking/Storage Unpaved Parking/Storage Playgrounds Driveways Sidewalks/Walks Streets/Alleys Undeveloped Areas Small Landscaped Areas Other Pervious Areas Other Impervious Areas Freeway Lanes/Shoulders Large Turf Areas Large Landscaped Areas Land Uses Drainage System Outfall The effectiveness of the control practices are calculated based on the size and other attributes of the devices, the source area or outfall location characteristics, and the calculated runoff characteristics. The model does a complete mass balance and routing of water volume and particulate mass, considering the combined effects of all controls. Hydraulic and particle size routing occurs for each device individually, although serial effects of multiple devices are being expanded for these parameters in an upcoming version. The effects of the sedimentation controls are calculated using modified Puls hydraulic routing with surface overflow rate particulate routing. The performance of wet ponds have been verified by extensively monitoring several ponds (WI DNR and USGS, with documentation at: d%20documentation.pdf ). The infiltration and biofiltration devices use a combination of hydraulic routing with infiltration and evaporation losses, plus any pumped withdrawals. Evapotranspiration Page 2

4 losses are being added to the devices in the next model update. Underdrain filtering in biofilters is based on extensive tests of media filtration. Grass swale performance is calculated based on extensive laboratory and outdoor testing of particulate trapping of shallow flowing water and infiltration losses (Kirby 2005; Johnson, et al. 2003; Nara and Pitt 2005). Porous pavement performance is calculated based on infiltration losses and clogging effects. Street cleaning and catchbasin benefits are based on extensive EPA research, and newer updated research that has examined modern street cleaning equipment. Hydrodynamic devices are based on the basic sedimentation processes, but have been verified by tests conducted by the USGS and the DNR, plus continued tests at the University of Alabama. The following figure shows some example screen shots used to enter information for some of the controls. Example Control Practice Input Screens for WinSLAMM Hydrodynamic Device Input Screen Main Wet Detention Pond Input Screen Porous Pavement Input Screen Street Cleaning Input Screen Page 3

5 Biofilter Input Grass Swale Input Screen Each land use is described by characterizing elements for each source area within the land use, including source area and land use controls. Outfall and drainage system controls are described using the drop down menus. A new drag and drop interface is currently being developed that will allow greater efficiency and flexibility for control placement, and for using multiple land use source areas. The following figures show a screen from the most current version (v 9.40) and from the interface under development. WinSLAMM Version 9.40 Source Area Screen and Version 10 Interface (Under Development) The calculated outputs from WinSLAMM are organized in several tiers. The first output the model shows is a summary table with the results of the most commonly analyzed pollutants (runoff volume and particulate solids). The data in the summary table includes the following information: Page 4

6 Runoff Volume (ft 3, percent reduction; and R v, runoff coefficient) and Particulate Solids (lbs and mg/l) for: - Source area total without controls - Total before drainage system - Total after drainage system - Total after outfall controls Total control practice costs: - Capital costs - Land cost - Annual maintenance cost - Present value of all costs - Annualized value of all costs Receiving water impacts due to stormwater runoff: - Calculated R v with and without controls - Approximate biological condition of receiving water (good, fair, or poor) - Flow duration curves (probabilities of flow rates for current model run with and without controls) The flow duration curves are included on an optional second page, as shown on the following figure. Summary Table with Detailed Output Tabs (need updated picture, attached) Flow-Duration Summary Output Option The tabs along the top of the summary table display additional results for runoff volume (ft 3 ), particulate solids (lbs and mg/l), and the analyzed pollutants (lbs and mg/l). Results are shown: - By source area for each rain event - Land use total - Summary for all rains - Total for land use and for each event - Outfall summary, before and after drainage system and before and after outfall controls - R v (runoff volume only) - Total losses (runoff volume only) - Calculated CN (runoff volume only) Page 5

7 An example of the detailed data for runoff volume is shown in the following figure. Runoff volume detailed WinSLAMM output. Another group of output options are one-line per event data sets. This data is saved in a *.csv file format that can be opened in a spreadsheet for viewing and further data manipulation. These files can also be examined by selecting the utilities/view file/use notepad or use Windows view pull down menu option from the main WinSLAMM page. The data presented in these files includes One-Line per Event Runoff Details, with data for each event and statistical summaries for all events (number of events, total, equivalent annual total, minimum, maximum, average of all events, median, standard deviation, and coefficient of variation). The available data includes: - Rain duration (hours) - Rain interevent period (days) - Runoff duration (hours) - Rain depth (inches) - Runoff volume (ft 3 ) - R v - Average flow (cfs) - Peak flow (cfs) - Suspended solids (lbs and mg/l) One of the main features of WinSLAMM is to identify the sources of pollutants for different rain conditions for a specific development. The following example plot shows how runoff volume originates from different sources in a medium density residential area for different categories of rains. This type of plot is very useful when determining the most likely effective locations for stormwater controls, or for changes in development characteristics. Page 6

8 A powerful feature of WinSLAMM is the batch processor that enables many control options to be quickly compared for an area. The batch processor can analyze runoff volume and pollutants and also combine unit cost data to evaluate the cost effectiveness of control options. The following plot of the cost-performance data for one study site shows the unit costs associated with preventing particulate solids from being discharged from an area. References Narayanan, A. and R. Pitt. (2005). Costs of Urban Stormwater Control Practices. Stormwater Management Authority of Jefferson County, AL Pitt, R. Demonstration of Nonpoint Pollution Abatement Through Improved Street Cleaning Practices, EPA-600/ , U.S. Environmental Protection Agency, Cincinnati, Ohio. 270 pgs Page 7

9 Pitt, R. The incorporation of urban runoff controls in the Wisconsin Priority Watershed Program. In: Advanced Topics in Urban Runoff Research, (Edited by B. Urbonas and L.A. Roesner). Engineering Foundation and ASCE, New York. pp Pitt, R. Unique features of the Source Loading and Management Model (SLAMM). In: Advances in Modeling the Management of Stormwater Impacts, Volume 6. (Edited by W. James). Computational Hydraulics International, Guelph, Ontario and Lewis Publishers/CRC Press. pp Pitt, R. Small storm hydrology and why it is important for the design of stormwater control practices. In: Advances in Modeling the Management of Stormwater Impacts, Volume 7. (Edited by W. James). Computational Hydraulics International, Guelph, Ontario and Lewis Publishers/CRC Press Pitt, R. and J. Voorhees. SLAMM, the Source Loading and Management Model. In: Wet-Weather Flow in the Urban Watershed (Edited by Richard Field and Daniel Sullivan). CRC Press, Boca Raton. pp Page 8

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11 Brief Summary of WinSLAMM Features and Uses Robert Pitt Dept. of Civil, Construction, and Environmental Engineering University of Alabama Tuscaloosa, AL John Voorhees PV and Associates Madison, WI WinSLAMM Weaknesses: Not used for peak flow predictions or flood analyses. Can be integrated with other models and tools to address fate and transport in receiving waters (such as QUAL2E, HSPF) Doesn t calculate construction erosion, but does calculate rainfall energy for post processing Doesn t include snowmelt Can be used with SWMM to evaluate combined sewer Is not a lifestyle, but can be integrated with models that are connected to Youtube, etc What WinSLAMM is: Urban stormwater model (does not address agricultural areas, etc.) Designed as multi-scale model (individual lots to whole communities) Annual or seasonal pollutant loads and event pollutant probability distributions using long-term rainfall records Evaluates individual or multiple stormwater control scenarios (source area, land use, drainage, outfalls), such as: Wet detention ponds Biofiltraiton and bioretention devices Catchbasins Proprietary devices Porous pavements Street cleaning Cisterns and rain barrels for water reuse Grass swales Rain gardens Development options (pavement and roof disconnections, etc.) Applications of WinSLAMM Permit Compliance Municipal Pollutant Loadings and Discharge Reductions Evaluate Alternative Stormwater Controls: City-wide Watershed Site Development Identify critical drainage areas ID critical land uses ID critical source areas Assist with cost-sharing Identify the most cost-effective stormwater control and development scenarios 1 DRAFT

12 Background & History Development Began in mid-1970 s Early EPA street cleaning and receiving water projects San Jose and Coyote Creek (CA) Primary Purpose: Identify Sources of Urban Stormwater Pollutants Evaluate Efficiency of Control Practices Mid-1980 s - Model used in Agency Programs: Toronto Area Watershed Management Strategy Background & History Mid-1980 s: Model expanded to include more management options beyond street cleaning Nationwide Urban Runoff Program (NURP) projects provided large data set for model, especially: Alameda Co. CA; Bellevue, WA; and Milwaukee, WI Ontario Ministry of the Environment (Ottawa) Background & History Model Applications Large Scale, City-wide Analysis Example Wis. Dept. of Natural Resources: Priority Watershed Program First Windows Version Developed in 1995 (Currently developing Windows version 9.4) Continuously being updated based on user needs and new research (recent and current support from Stormwater Management Authority of Jefferson County, AL; the TVA, Economic Development group; WI DNR; and the USGS) City-wide sediment load and runoff volume analysis for Wausau, WI (EarthTech) 2 DRAFT

13 Model Applications Site Development Analysis Example Porous Pavement Biofilter Infiltration/Detention Pond Catchbasin with Sump Grass Swales CFD Modeling to Calculate Scour/Design Variations We are using CFD (Fluent 6.2 and Flow 3D) to determine scour from stormwater controls; results being used to expand WinSLAMM analyses This is an example of the effects of the way that water enters a sump on the depth of the water jet and resulting scour Model Applications Detailed Practice Analysis Examples Develop and analyze new controls this inlet has a prototype upflow filter installed Wet Detention Pond Analyze the performance of a specific pond for a specific site (WinSLAMM or WinDETPOND) WinSLAMM integrates site and development information: Landuse Area Rainfall Soil Type Development Characteristics WinSLAMM Runoff Volume and Pollutant Loads Control Practices 3 DRAFT

14 Residential Land Use Source Areas Pitched Roofs Driveways Sidewalks Small Landscaped Areas Medium Density Residential Shopping Center Commercial Commercial Land Use Source Areas Flat Roofs Parking Driveways Sidewalks Small Landscaped Areas Probability distribution of rains (by count) and runoff (by depth). Birmingham Rains: <0.5 : 65% of rains (10% of runoff) 0.5 to 3 : 30% of rains (75% of runoff) 3 to 8 : 4% of rains (13% of runoff) >8 : <0.1% of rains (2% of runoff) Low Density Residential Storm Sewer Outfall Residential Land Use Source Areas Pitched Roofs Driveways Sidewalks Small Landscaped Areas Park Other Urban Land Use Source Areas Playground Sidewalks Large Landscaped Areas Important WinSLAMM Features Hydrology stresses small and intermediate-scaled processes that are most important for water quality analyses. Sediment accumulation and washoff processes based on huge number of field observations from throughout North America. Stormwater control performance calculations based on extensive field observations; most are driven by site hydraulics and sediment characteristics. Stormwater controls can be evaluated in many combinations and located at many areas. Construction and operating costs of stormwater controls are calculated for most US locations. Model output can be exported to support further postprocessing (integrated with detailed drainage system models, receiving water models, and decision analyses models). Many types of runoff monitoring used to calibrate and verify WinSLAMM, from small source areas to outfalls. 4 DRAFT

15 Street dirt washoff and runoff test plot, Toronto Example runoff plot for small paved area. Pitt 1987 Pitt 1987 Infiltration Measurements for Noncompacted, Sandy Soils Pitt, et al Infiltration Rates in Disturbed Urban Soils (AL tests) Sandy Soils Clayey Soils Field research has shown that the infiltration rates of urban soils are strongly influenced by compaction, probably more than by moisture saturation. Pitt, et al Infiltration Measurements for Compacted, Sandy Soils Pitt, et al DRAFT

16 Pitt, et al A Nice Example of Runoff Model Verification using WinSLAMM Observed vs. Predicted Runoff at Madison Maintenance Yard Outfall Observed Runoff (in) 6 - Predicted Runoff (in) Another Good Verification Example Bannerman, et al Pollutant Probability Distributions (used in Monte Carlo Calculations) Depicts the pollutant concentrations for source areas and land uses DRAFT

17 WinSLAMM uses an Extended Rainfall Period, Usually from One Year to Several Decades Long Observed Particulate Removal by Street Cleaning Referential removal of large particulates by street cleaners Measured Street Particulate Loading, Keyes Smooth Asphalt Test Area Street cleaning days Changes in particle sizes Street dust and dirt loading saw-tooth pattern Pitt < Overall > Percentage of Particle Sizes Removed by Street Sweeping < Overall > Very Rough Streets Particle Sizes Ranges (microns) Percentage of Particle Sizes Removed by Street Sweeping -20 Smooth Streets Particle Sizes Ranges (microns) Observed Washoff of Street Dirt by Particle Size, Bellevue, WA Preferential removal of small particles by rains Pitt 1985 DRAFT

18 ,000 1,250 1,500 1,750 2,000 2,250 2,500 Air Sweeper Control Modeled Post Sw eeping Pre Sw eeping Measured Versus Modeled Street Loads With Mechnical Broom Street Cleaning - Residential 2004 T F Low-Frequency Broom High-Frequency Broom Wisconsin DNR and USGS Recent Street Cleaning Tests A R D Bedload sampler installations. About 5% of annual sediment was in bedload fraction. Fugitive dust losses from streets account for excessive material that is not washed off during rains. Particle Resuspension of Street Dirt Caused by Vehicle Passage for an Asphalt Road lb /cu rb -m ile 8

19 Annual TSS Reductions, %, for Vacuum Assisted Cleaner With & Without Parking Control Land Use Parking Density With Parking Controls 1 \ Week 1\ Month Without Parking Controls 1 \ Week 1 \Month Med. Den Res. High Den Res. Strip Comm Med. Med. Med Downtown Exten Light Indus. Med Date: 10/11/ ft 75 ft TSS: 10 mg/l TSS: 20 mg/l 25 ft TSS: 30 mg/l 6 ft 3 ft 2 ft TSS: 63 mg/l TSS: 35 mg/l Head (0ft) TSS: 84 mg/l TSS: 102 mg/l Pollutant Control in Grass Swales Runoff from Pervious/ impervious area Reducing runoff velocity Trapping sediments and associated pollutants Sediment particles Infiltration Reduced volume and treated runoff Settling of Different Sized Particulates as a Function of Flow Characteristics (depth and velocity), Particle Settling Characteristics and Grass Type and Height Ratio: Ratio: Ratio: Total Dissolved Solids (<0.45 µm) Settling frequency 9 DRAFT Percent reduction (%)

20 Low Flow vs. Historical Stillwater, OK, Retardance Curves Relatively short urban landscaping grasses (2 to 6 inches tall) Kirby 2006 From such graphs swale hydraulic characteristics can be predicted d on the basis of flow rate, cross sectional geometry, slope, and vegetation type. Wet Detention Pond Data Entry Form - particle size distribution - stage-area info - initial stage conditions - inflow hydrograph shape factors or actual hydrograph in DETPOND) - many outlet options (including conventional hydraulic outlets, beneficial use withdrawals, seepage, evaporation, pumped outlet, stone weepers, etc.) Three Components to Modeling Wet Detention Ponds 1. Pond Geometry 2. Flow, Initial Stage and Particle Size Data 3. Outlet Information 10 DRAFT

21 Measured Particle Sizes, Including Bed Load Component, at Monroe St. Detention Pond, Madison, WI Vortechs Monitoring Site Proprietary devices modeled using basic settling methods with bypass; scour currently being added to model. Suspended Solids Control at Monroe St. Detention Pond, Madison, WI (USGS and WI DNR data) Consistently high TSS removals for all influent concentrations (but better at higher concentrations, as expected) TSS Load Reduction Results Used for Model Verification Sum of Loads; TSS Loads, kg Vortechs (18 events, no bypass) Stormceptor (15 events, bypass) Influent Effluent DRAFT

22 Biofilter Data Entry Form Sources of Cost Data Pre-Determined Costs SEWRPC 1991 Cost Report Costs Updated Using ENR Cost Indices Cost Indices Available for 20 Cities 12 DRAFT Construction Cost Index by City Atlanta, GA Baltimore, MD Birmingham, AL Boston, MA Chicago, IL Cincinnati, OH Cleveland, OH Dallas, TX Denver, CO Detroit, MI Kansas City, MO Los Angeles, CA Minneapolis, MN New Orleans, LA New York, NY Philadelphia, PA Pittsburgh, PA San Francisco, CA Seattle, WA St.Louis, MO Cost Index Value

23 WinSLAMM v 9.2 Output Summary Model Input/Output Example plots showing runoff percentage contributions from different source areas. Detailed Model Input/Output Data Available for: Runoff volume Particulate solids concentration Particulate solids yield Pollutant concentration Pollutant yield Many export options to link to other models Example Flow Duration Curves Use these curves to compare the attenuation of the control practices at the outfall to a no controls condition. 13 DRAFT

24 Example Flow-Duration Curves for Different Stormwater Conservation Design Practices 140 Flow Duration Curves are Ranked in Order of Peak Flows Top Set: No Controls Swales Middle Set: Pond Pond and Swales % Greater than Discharge Rate 14 Discharge (cfs) Bottom Set: Biorentention Swales and Bioretention Pond and Bioretention Pond, Swales and Bioretention Example Cost Effectiveness Plot of Stormwater Control Practices for Runoff 80 Volume Reductions 70 Pond Pond and Swale Swale Pond and Bioretention Bioretention Pond, Swales and Bioretention $/1000 cu. Ft Reduced Current and Planned Expansions to WinSLAMM Based on recent research results and field verification Expand full routing capabilities in grass swales and incorporate advanced particulate trapping algorithms (current). Will expand to grass filtering stormwater controls. Add more detailed ET analyses and pollutant trapping processes to bioretention and biofiltration devices (current). Will expand to green roofs. Adding scour removal of particulates from hydrodynamic devices (current). Will expand to ponds. Currently developing drag and drop front-end to model to enable more flexible placement of controls. Other enhancements as requests, data, and resources allow! Swales and Bioretention Max % Runoff Reduced Selected WinSLAMM General Descriptions DRAFT Pitt, R. and J. Voorhees. Using decision analyses to select an urban runoff control program Chapter 4 in: Contemporary Modeling of Urban Water Systems, ISBN , Monograph 15. (edited by W. James, E.A. McBean, R.E. Pitt, and S.J. Wright). CHI. Guelph, Ontario. pp Pitt, R., R. Bannerman, S. Clark, and D. Williamson. Sources of pollutants in urban areas. In: Effective Modeling of Urban Water Systems, Monograph 13. (edited by W. James, K.N. Irvine, E.A. McBean, and R.E. Pitt). CHI. Guelph, Ontario, pp Pitt, R., D. Williamson, and J. Voorhees. Review of historical street dust and dirt accumulation and washoff data. Effective Modeling of Urban Water Systems, Monograph 13. (edited by W. James, K.N. Irvine, E.A. McBean, and R.E. Pitt). CHI. Guelph, Ontario, pp Pitt, R. and J. Voorhees. SLAMM, the Source Loading and Management Model. In: Wet-Weather Flow in the Urban Watershed (Edited by Richard Field and Daniel Sullivan). CRC Press, Boca Raton. pp Pitt, R. Small storm hydrology and why it is important for the design of stormwater control practices. In: Advances in Modeling the Management of Stormwater Impacts, Volume 7. (Edited by W. James). Computational Hydraulics International, Guelph, Ontario and Lewis Publishers/CRC Press Pitt, R. Unique Features of the Source Loading and Management Model (SLAMM). In: Advances in Modeling the Management of Stormwater Impacts, Volume 6. (Edited by W. James). Computational Hydraulics International, Guelph, Ontario and Lewis Publishers/CRC Press. pp Pitt, R. The Incorporation of Urban Runoff Controls in the Wisconsin s Priority Watershed Program. In: Advanced Topics in Urban Runoff Research, (Edited by B. Urbonas and L.A. Roesner). Engineering Foundation and ASCE, New York. pp

25 Table I1 Water Quality Results (WinSLAMM) Existing Conditions Total Yield and Concentrations Rain from 1980 Typical year April 15 to November 8 Data Source Outfalls Total Drainage Area (ha) Runoff Volume (m3) Yield of TSS (kg) Conc of TSS (mg/l) E.Coli Counts E.Coli (Cts/100m L) Yield of TP (kg) Conc of TP (mg/l) Pinecrest Creek E E E E WinSLAMM Summary of Ottawa River Results E E E E Outfalls from Westboro Existing Conditions Within Monitored Pinecrest Creek from Data Monitoring Data WinSLAMM Existing Conditions and Scenario Comparisons 1. Comparison Between Highest Practical SWM with EoP Implementation and Existing Conditions Scenario (Percent Change) Data Source WinSLAMM Results Outfalls Total Drainage Area (ha) Runoff Volume Yield of TSS Conc of TSS E.Coli Counts E.Coli Conc Yield of TP Conc of TP Pinecrest Creek % 43% 25% 35% 14% 32% 10% Summary of Ottawa River Outfalls from Westboro % 46% 23% 54% 33% 34% 5% 142 mg/l mg/l Predicted TSS & TP Concentrations (mg/l) within Pinecrest Creek 2. Comparison Between HP SWM No EoP and Existing Conditions Scenario (Percent Change) Total Runoff Yield of Conc E.Coli Data Source Outfalls Drainage Volume TSS of TSS Counts Area (ha) WinSLAMM Results E.Coli Conc Yield of TP Conc of TP Pinecrest Creek % 11% 19% 24% 1% 12% 17% Summary of Ottawa River Outfalls from Westboro % 15% 23% 28% 4% 15% 22% 224 mg/l mg/l Predicted TSS & TP Concentrations (mg/l) within Pinecrest Creek 3. Comparison Between Moderate SWM Implementation and Existing Conditions Scenario (Percent Change) Total Runoff Yield of Conc E.Coli E.Coli Data Source Outfalls Drainage Volume TSS of TSS Counts Conc Area (ha) WinSLAMM Results Yield of TP Conc of TP Pinecrest Creek % 35% 26% 26% 15% 25% 14% Summary of Ottawa River Outfalls from Westboro % 42% 30% 46% 35% 28% 13% 140 mg/l mg/l Predicted TSS & TP Concentrations (mg/l) within Pinecrest Creek 4. Comparison Between Public Property SWM Implementation and Existing Conditions Scenario (Percent Change) Total Runoff Yield of Conc E.Coli E.Coli Yield Data Source Outfalls Drainage Conc of TP Volume TSS of TSS Counts Conc of TP Area (ha) WinSLAMM Pinecrest Creek % 39% 35% 22% 18% 25% 21% Summary of Ottawa River Results % 40% 35% 42% 38% 24% 19% Outfalls from Westboro Predicted TSS & TP Concentrations (mg/l) mg/l within Pinecrest Creek mg/l Note: A negative number indicates that the Proposed value is higher than Existing Conditions value. J.F. Sabourin and Associates Inc. JFSAinc. Ref: Water Resources and Environmental Consultants 2/1/2011 Ottawa, Ontario Page 1-3

26 Table I2 Comparison Between Highest Practical SWM With EoPs and Existing Conditions (Percent Change) Table I3 Comparison Between Moderate SWM Implementation and Existing Conditions (Percent Change) Subwatershed Land Use Area Runoff Volume Average E.Coli Coliforms Yield of TSS Yield of Phosphorus Subwatershed Land Use Area Runoff Volume Average (ha) (m3) (#) (kg) (Kg) (ha) (m3) (#) (kg) (Kg) Pinecrest Residential + Other Urban % 24.6% 8.4% 11.4% Pinecrest Residential + Other Urban % 14.8% 5.0% 6.2% Industrial % 9.5% 55.2% 96.6% Industrial % 17.4% 62.8% 100.4% Institutional % 33.2% 14.2% 11.7% Institutional % 21.7% 12.2% 9.7% Commercial % 14.8% 5.6% 0.7% Commercial % 10.2% 3.0% 1.2% Freeways % 0.0% 0.0% 0.0% Freeways % 0.0% 0.0% 0.0% Total Before Drainage System % 23.3% 7.2% 9.5% Total Before Drainage System % 14.1% 4.1% 4.8% Total After Outfall Controls % 34.8% 43.2% 32.0% Total After Outfall Controls % 25.7% 35.4% 24.8% WBoO4298 Residential + Other Urban % 19.8% 11.2% 13.5% WBoO4298 Residential + Other Urban % 10.9% 5.0% 6.2% Institutional % 26.8% 5.7% 3.0% Institutional % 17.8% 4.0% 1.9% Commercial % 20.1% 12.3% 7.1% Commercial % 15.9% 9.5% 5.4% Total Before Drainage System % 20.2% 11.5% 10.9% Total Before Drainage System % 13.1% 7.1% 5.7% Total After Outfall Controls % 20.3% 13.5% 12.3% Total After Outfall Controls % 13.1% 7.1% 5.7% WBoO4299 Residential + Other Urban % 29.9% 14.4% 17.3% WBoO4299 Residential + Other Urban % 18.7% 7.5% 9.2% Commercial % 20.6% 9.5% 3.5% Commercial % 10.2% 4.2% 0.8% Total Before Drainage System % 29.9% 14.3% 17.2% Total Before Drainage System % 18.7% 7.4% 9.1% Total After Outfall Controls % 30.5% 14.8% 17.8% Total After Outfall Controls % 18.7% 7.7% 9.3% WBo04300 Residential + Other Urban % 28.3% 13.4% 16.1% WBo04300 Residential + Other Urban % 17.2% 6.8% 8.3% Institutional % 29.3% 8.6% 6.4% Institutional % 18.3% 5.1% 3.3% Commercial % 24.5% 14.1% 9.8% Commercial % 18.3% 10.9% 7.3% Total Before Drainage System % 27.8% 13.1% 14.3% Total Before Drainage System % 17.5% 7.7% 7.7% Total After Outfall Controls % 63.9% 57.6% 42.1% Total After Outfall Controls % 58.7% 53.9% 36.6% WBo04301_Split Residential + Other Urban % 26.9% 12.4% 15.9% WBo04301_Split Residential + Other Urban % 15.6% 6.0% 8.1% Total Before Drainage System % 26.9% 12.4% 15.9% Total Before Drainage System % 15.6% 6.0% 8.1% Total After Outfall Controls % 27.2% 12.8% 16.2% Total After Outfall Controls % 15.8% 6.2% 8.4% WBo04307_Split Residential + Other Urban % 27.5% 13.0% 15.6% WBo04307_Split Residential + Other Urban % 16.6% 6.6% 8.0% Industrial % 17.1% 16.7% 7.5% Industrial % 8.7% 10.0% 4.2% Institutional % 28.4% 8.4% 5.9% Institutional % 17.7% 4.9% 3.1% Commercial % 24.2% 13.3% 8.1% Commercial % 18.3% 10.2% 6.1% Total Before Drainage System % 27.2% 13.0% 13.8% Total Before Drainage System % 16.7% 7.2% 7.3% Total After Outfall Controls % 63.7% 56.6% 39.8% Total After Outfall Controls % 58.4% 53.6% 34.9% WBo04313 Residential + Other Urban % 30.1% 14.5% 17.4% WBo04313 Residential + Other Urban % 18.6% 7.5% 9.2% Institutional % 30.4% 9.4% 7.1% Institutional % 18.9% 5.4% 3.6% Commercial % 26.8% 16.1% 11.5% Commercial % 20.2% 12.2% 8.8% Total Before Drainage System % 30.0% 14.0% 16.3% Total Before Drainage System % 18.7% 7.5% 8.6% Total After Outfall Controls % 30.1% 16.4% 17.7% Total After Outfall Controls % 18.7% 9.8% 10.0% WBo04490 Residential + Other Urban % 30.4% 15.1% 18.9% WBo04490 Residential + Other Urban % 18.5% 7.8% 10.1% Commercial % 17.4% 7.8% 4.4% Commercial % 11.7% 6.1% 3.5% Total Before Drainage System % 30.3% 14.8% 18.5% Total Before Drainage System % 18.4% 7.7% 9.9% Total After Outfall Controls % 30.4% 17.6% 20.1% Total After Outfall Controls % 18.5% 7.8% 10.0% E.Coli Coliforms Yield of TSS Yield of Phosphorus Note 1 A negative number indicates that the Proposed value is higher than Existing Conditions value. Note 2 "Residential" and "Other Urban" have been compared as one area because some of the areas within the Residential land use in the existing conditions model had to be moved to the Other Urban land use for all the Proposed models due to WinSLAMM modelling limitations. Note 3 There has been no change for Freeways, as there were no controls implemented for Freeways in any of the Proposed models. J.F. Sabourin and Associates Inc. JFSAinc. Ref: Water Resources and Environmental Consultants 2/22/2011 Ottawa, Ontario Page 2-3

27 Table I4 Comparison Between Public Property SWM Implementation and Existing Conditions (Percent Change) Table I5 Comparison Between HP SWM NO EoP and Existing Conditions (Percent Change) Subwatershed Land Use Area Runoff Volume Average E.Coli Coliforms Yield of TSS Yield of Phosphorus Subwatershed Land Use Area Runoff Volume Average (ha) (m 3 ) (#) (kg) (Kg) (ha) (m 3 ) (#) (kg) (Kg) Pinecrest Residential + Other Urban % 7.9% 2.5% 1.9% Pinecrest Residential + Other Urban % 14.8% 5.0% 6.2% Industrial % 20.7% 73.5% 104.2% Industrial % 13.8% 17.3% 7.5% Institutional % 33.2% 16.0% 12.5% Institutional % 27.8% 7.9% 5.1% Commercial % 2.3% 5.9% 5.6% Commercial % 23.5% 13.4% 8.0% Freeways % 0.0% 0.0% 0.0% Freeways % 0.0% 0.0% 0.0% Total Before Drainage System % 8.4% 1.7% 1.3% Total Before Drainage System % 23.9% 10.5% 11.9% Total After Outfall Controls % 22.1% 38.8% 24.7% Total After Outfall Controls % 24.1% 11.1% 12.3% WBoO4298 Residential + Other Urban % 4.8% 2.5% 1.6% WBoO4298 Residential + Other Urban % 10.9% 5.0% 6.2% Institutional % 26.7% 0.2% 0.9% Institutional % 26.8% 5.7% 3.0% Commercial % 1.0% 1.2% 0.8% Commercial % 20.1% 12.3% 7.1% Total Before Drainage System % 4.3% 1.8% 1.3% Total Before Drainage System % 20.2% 11.5% 10.9% Total After Outfall Controls % 4.3% 1.8% 1.3% Total After Outfall Controls % 20.3% 13.5% 12.3% WBoO4299 Residential + Other Urban % 7.0% 3.6% 2.4% WBoO4299 Residential + Other Urban % 18.7% 7.5% 9.2% Commercial % 0.2% 1.2% 2.0% Commercial % 20.6% 9.5% 3.5% Total Before Drainage System % 7.0% 3.5% 2.4% Total Before Drainage System % 29.9% 14.3% 17.2% Total After Outfall Controls % 7.0% 3.6% 2.4% Total After Outfall Controls % 30.5% 14.8% 17.8% WBo04300 Residential + Other Urban % 10.3% 3.9% 2.8% WBo04300 Residential + Other Urban % 17.2% 6.8% 8.3% Institutional % 29.3% 8.7% 6.9% Institutional % 29.3% 8.6% 6.4% Commercial % 6.5% 1.7% 2.1% Commercial % 24.5% 14.1% 9.8% Total Before Drainage System % 11.0% 3.8% 3.0% Total Before Drainage System % 27.8% 13.1% 14.3% Total After Outfall Controls % 55.5% 51.9% 33.1% Total After Outfall Controls % 27.8% 15.3% 15.7% WBo04301_Split Residential + Other Urban % 7.8% 4.3% 3.6% WBo04301_Split Residential + Other Urban % 15.6% 6.0% 8.1% Total Before Drainage System % 7.8% 4.3% 3.6% Total Before Drainage System % 26.9% 12.4% 15.9% Total After Outfall Controls % 7.9% 4.4% 3.6% Total After Outfall Controls % 27.2% 12.8% 16.2% WBo04307_Split Residential + Other Urban % 9.6% 3.4% 2.4% WBo04307_Split Residential + Other Urban % 16.6% 6.6% 8.0% Industrial % 9.4% 1.8% 1.7% Industrial % 17.1% 16.7% 7.5% Institutional % 28.4% 8.5% 6.2% Institutional % 28.4% 8.4% 5.9% Commercial % 5.8% 1.9% 1.7% Commercial % 24.2% 13.3% 8.1% Total Before Drainage System % 10.4% 3.5% 2.6% Total Before Drainage System % 27.2% 13.0% 13.8% Total After Outfall Controls % 55.3% 51.7% 31.4% Total After Outfall Controls % 27.3% 13.2% 14.0% WBo04313 Residential + Other Urban % 11.8% 4.2% 3.1% WBo04313 Residential + Other Urban % 18.6% 7.5% 9.2% Institutional % 30.4% 9.5% 7.7% Institutional % 30.4% 9.4% 7.1% Commercial % 9.0% 3.1% 3.4% Commercial % 26.8% 16.1% 11.5% Total Before Drainage System % 13.0% 4.8% 3.5% Total Before Drainage System % 30.0% 14.0% 16.3% Total After Outfall Controls % 13.0% 4.8% 3.5% Total After Outfall Controls % 30.1% 16.4% 17.7% WBo04490 Residential + Other Urban % 10.4% 4.4% 3.1% WBo04490 Residential + Other Urban % 18.5% 7.8% 10.1% Commercial % 0.1% 0.6% 0.9% Commercial % 17.4% 7.8% 4.4% Total Before Drainage System % 10.3% 4.2% 3.1% Total Before Drainage System % 30.3% 14.8% 18.5% Total After Outfall Controls % 10.3% 4.1% 3.1% Total After Outfall Controls % 30.4% 17.6% 20.1% E.Coli Coliforms Yield of TSS Yield of Phosphorus Note 1 A negative number indicates that the Proposed value is higher than Existing Conditions value. Note 2 "Residential" and "Other Urban" have been compared as one area because some of the areas within the Residential land use in the existing conditions model had to be moved to the Other Urban land use for all the Proposed models due to WinSLAMM modelling limitations. Note 3 There has been no change for Freeways, as there were no controls implemented for Freeways in any of the Proposed models. J.F. Sabourin and Associates Inc. JFSAinc. Ref: Water Resources and Environmental Consultants 2/22/2011 Ottawa, Ontario Page 3-3

28 w w w. b a i r d. c o m Baird o c e a n s engineering l a k e s design r i v e r s science w a t e r s h e d s construction Assessment of the Relative Impact of SWM Retrofit Alternatives Developed for the Pinecrest Creek Study February N a v i g a t i n g N e w H o r i z o n s

29 w w w. b a i r d. c o m Assessment of the Relative Impact of SWM Retrofit Alternatives Developed for the Pinecrest Creek Study Prepared for City of Ottawa Infrastructure Services and Community Sustainability Infrastructure Policy Unit Prepared by W.F. Baird & Associates Coastal Engineers Ltd. For further information please contact Michael Fullarton at (905) Revision Date Status Comments Reviewed by Approved by 0 10-Nov-2010 Draft DMF 1 15-Nov-2010 Draft Includes City Comments DMF 2 11-Feb-2011 Final Final City Comments DMF This report was prepared by W.F. Baird & Associates Coastal Engineers Ltd. for the City of Ottawa. The material in it reflects the judgment of Baird & Associates in light of the information available to them at the time of preparation. Any use which a Third Party makes of this report, or any reliance on decisions to be made based on it, are the responsibility of such Third Parties. Baird & Associates accepts no responsibility for damages, if any, suffered by any Third Party as a result of decisions made or actions based on this report. N a v i g a t i n g N e w H o r i z o n s

30 TABLE OF CONTENTS 1.0 INTRODUCTION LOADING CONDITIONS FOR THE SWM RETROFIT ALTERNATIVES NUMERICAL ANALYSIS CONCEPTUAL DESIGN OF A STORMWATER IMPOUNDMENT Review of Existing DFBS at Bluffers Park, Toronto Proposed System for the Westboro Area Design Conditions Outfall Discharge Water Levels Currents Ice Protection Toe Scour Protection Structure Cross Section Position and Layout of Proposed Facility Facility Cost CONCLUSIONS REFERENCES APPENDIX A - STORMWATER VOLUMES AND E.COLI CONCENTRATIONS TO RIVER APPENDIX B - MIKE3 MODEL RESULTS A s s e s s m e n t o f t h e R e l a t i v e I m p a c t o f S W M R e t r o f i t T a b l e o f C o n t e n t s

31 1.0 INTRODUCTION Baird & Associates (herein referred to as Baird) was retained by the City of Ottawa (herein referred to as the City), to assist with an assessment of the relative impact of storm water management (SWM) retrofit alternatives, for Pinecrest Creek and contributing outfalls, on Ottawa River water quality. Note that this investigation has focused on bacterial contamination, specifically, Escherichia coli (E.coli), at Westboro Beach in order to evaluate various SWM retrofit alternatives. A total of seven stormwater outfalls and one creek were considered in the assessment. These sources discharge directly to the Ottawa River and all are situated within a 3 km section of shoreline, upriver of Westboro Beach. Figure 1.1 provides an overview of the study area. Note that OUT04313 represents two storm catchment systems and two outfalls; that is, the Highland Park East and West outfalls. The development of the SWM objectives, targets and scenarios as well as the hydrological and fluvial geomorphological analyses were undertaken by J.F. Sabourin & Associates Inc. (JFSA) and JTBES Environmental Systems. The SWM retrofit measures considered for implementation included: Lot level/source control - downspout redirection, porous pavement, rain gardens, rain barrels, cisterns, and street cleaning Conveyance - street narrowing, infiltration trenches, and grass swales End-of-pipe (EoP) - oil and grit separators and surface ponds (wet and/or dry). The following provides a summary of the scenarios considered in this study. Existing Conditions The Existing Conditions scenario represents the land use and the storm drainage/stormwater management (very limited) that currently exist in the study area. Information on existing conditions was derived from City of Ottawa land use and infrastructure data and a series of lot level inventories using Google Street view, Bing 3D aerial views and window shield surveys. The Existing Conditions scenario is the study area s baseline scenario. It reflects the impact of current practices and was used to determine areas where retrofit measures could be implemented for overall SWM improvements. A s s e s s m e n t o f t h e R e l a t i v e I m p a c t o f S W M R e t r o f i t P a g e 1

32 Highest Practical Implementation The Highest Practical Implementation scenario is composed of the existing land use with the implementation of all the study s selected BMPs. Highest practical indicates the highest level of implementation presumed to be feasible. The percentage uptake of lot level measures was based on data collected from other SWM retrofit studies and the study area s characteristics. The level of implementation of the EoPs, including oil and grit separators (O&Gs) and SWM ponds was determined by screening a list of possible EoP sites. The sites were screened for space limitations, servicing conflicts, aesthetics, natural features and property ownership. Six (6) EoP sites were selected. Highest Practical Implementation without End of Pipe Facilities This is the Highest Practical scenario without any end-of-pipe facilities. This scenario provides an indication of the improvements achieved by implementation of lot level and conveyance measures only. Moderate Implementation The Moderate Implementation scenario is comprised of the same types of measures and EoPs as the Highest Practical scenario, however, the extent of the implementation is at a moderate rather than high level. The moderate implementation percentages were also derived from other SWM retrofit studies and study area conditions. The Moderate scenario implementation percentages are based on a 5-30% reduction from the Highest Practical percentages. Four (4) of the six EoPs were chosen for this scenario (a surface pond and an O&Gs were eliminated). Public Property Only Implementation The Public Property Only scenario includes only measures located on publicly-owned lands. Public lands were defined for this scenario as municipal, federal, provincial and local institutional (school boards and schools) lands. As all EoPs are located on public lands, all the EoPs included in the Highest Practical scenario are included in the Public Property Only Implementation scenario. The implementation percentages used in this scenario are the same as used in the Highest Practical scenario. This scenario provides an indication of the improvements that can be achieved without requiring participation from private landowners and individual homeowners. For each retrofit alternative, predicted hydrographs and E.coli pollutographs were developed at all outlets in order to support the in-river analysis that was undertaken in this study. The hydrological assessment of SWM alternatives was conducted using three rainfall events from 1980, which is considered to be an average year in terms of rainfall. Table 1.1 summarizes the three rainfall events used in the study. These events represent a cross-section of storms that range from a moderate A s s e s s m e n t o f t h e R e l a t i v e I m p a c t o f S W M R e t r o f i t P a g e 2

33 rainfall (Event 13), which would occur every two to three weeks, to more significant, less frequent rainfall events (Event 20), which would occur every two to three months (Stantec, 2005). Table Rainfall Events 1980 Rainfall Events Date & Time of Rainfall Event Duration of Event (hours) Rainfall Accum (mm) Ottawa River Flow at Britannia (m 3 /s) Return Frequency (PACP 1 ) Event 13 June 20, Event 20 July 8, Event 22 July 14, PACP - per average control period which is taken as April 15 to November 15 The hydrographs and pollutographs generated from these events were used to define the wet weather inflows and loadings in the three-dimensional hydrodynamic and transport model of the Ottawa River that was developed as part of the Westboro Beach water quality study (Baird, 2008). This model was then used to conduct an assessment of the relative impact of various retrofit options on river water quality at Westboro Beach. A general assessment of the feasibility of implementing a Dunker's flow balancing type solution for some of the larger outfalls upstream of Westboro Beach was carried out at the request of the City. This preliminary investigation included a review of the performance of the existing Dunker's Flow Balancing System (DFBS) that was constructed at Bluffers Park in Toronto, Ontario. A coastal engineering assessment of the potential site for a similar system on the Ottawa River was carried out and included the development of a conceptual design and associated (preliminary) construction cost estimate. The Dunker's system is discussed in Section 4.0. A s s e s s m e n t o f t h e R e l a t i v e I m p a c t o f S W M R e t r o f i t P a g e 3

34 Figure 1.1 Overview of Study Area A s s e s s m e n t o f t h e R e l a t i v e I m p a c t o f S W M R e t r o f i t P a g e 4

35 2.0 LOADING CONDITIONS FOR THE SWM RETROFIT ALTERNATIVES Loadings estimates were derived for existing conditions and each retrofit alternative using the predicted hydrographs and pollutographs provided by JFSA for three separate storm events from Figure 2.1 shows the stormwater volume and E.coli loading contribution to the river by point source based on the cumulative volumes and loads from all three rainfall events. Pinecrest Creek generates approximately 75% of the total stormwater volumes and loading to the river, which is not unexpected given the watershed is an order of magnitude larger than the stormwater catchments. The Wavell (OUT4307), Ardmore (OUT4300) and Highland Park (OUT4313) outfalls are also key contributors to the river. Figure 2.2 summarizes the average percent reduction in stormwater volume and E.coli loadings to the river for each retrofit scenario based on all three rainfall events. A summary of volumes and loads from individual sources is provided in Appendix A. The most significant reduction in stormwater volumes is generated by the Highest Implementation scenarios (24%). The Moderate Implementation and Public Property scenarios reduced storm volumes by 13% and 5%, respectively. With respect to E.coli loads, the Highest Implementation (which included end-of-pipe facilities), generated the largest reduction in bacterial loads to the river (35%). The Moderate Implementation and Public Property scenarios utilized the same types of end-of-pipe facilities resulting in lower loads relative to the Highest Practical with no end-of-pipe scenario, thus illustrating the benefits of these types of stormwater management measures. A s s e s s m e n t o f t h e R e l a t i v e I m p a c t o f S W M R e t r o f i t P a g e 5

36 Figure 2.1 A breakdown of Storm Volume and E.coli Load by Point Source under Existing Conditions (Results are based on the cumulative volumes and loads from three storm events) A s s e s s m e n t o f t h e R e l a t i v e I m p a c t o f S W M R e t r o f i t P a g e 6

37 Figure 2.2 Percent Reduction in Stormwater Volume and E.coli Loads for Each Retrofit Scenario (Results are based on the average reductions from all three storm events) A s s e s s m e n t o f t h e R e l a t i v e I m p a c t o f S W M R e t r o f i t P a g e 7

38 3.0 NUMERICAL ANALYSIS A numerical analysis was conducted to support the assessment of various SWM retrofit alternatives by examining the relative impacts of each alternative on river water quality. Note that this investigation has focused on bacterial contamination in the Ottawa River, specifically, Escherichia coli (E.coli). The analysis utilized the existing three-dimensional hydrodynamic and transport model MIKE3, that was previously developed as part of the Westboro Beach study (Baird, 2008). The following is a brief overview of the model. MIKE3 is a comprehensive software system designed for the simulation of three-dimensional flows and environmental processes. Developed by the Danish Hydraulic Institute (DHI), the package includes unsteady three-dimensional flows, taking into account density variations, bathymetry and external forcing such as meteorology, water levels, currents, point sources such as outfalls, and other hydrographic conditions. MIKE3 has different configurations for its grid system, including the original regularly spaced finite difference grid, and the more recently developed model that is based on a flexible mesh approach. The Westboro model utilized the flexible mesh approach; one of the strengths of this model is that it allows for increased resolution in areas of interest and less resolution in less critical areas. The domain of this model extends from the Deschenes Rapids to just downstream of Westboro Beach as shown in Figure 3.1. The resolution of the mesh varies from 100m in the main channel down to 15m along the south shore of the river, and 5m near the beach area. In 2005, the hydrodynamic model was calibrated against measured current data and subsequently used to simulate steady state current patterns for various flow conditions. The transport model was used to help identify contaminant pathways of bacterial plumes and provide an indication of the potential impact at the beach. For this study, the model was setup to simulate the discharge from eight point sources including seven storm outfalls and Pinecrest Creek. Three separate rainfall events from 1980 were considered in the analysis; note that the year 1980 was used as it is representative of an average rainfall year. Hydrographs and pollutographs were developed by JFSA for each retrofit scenario, this information was then used to define the point source conditions in the Westboro model. An assessment of the relative impact of each retrofit scenario was conducted by examining the predicted E.coli concentrations at Westboro Beach. Figure 3.2 shows a typical 2D model output result of the effluent plumes from all sources for the July 7, 1980 rainfall event under existing conditions. Table 3.1 and Figure 3.3 summarize the relative impact of each retrofit scenario based on the MIKE3 model results at Westboro Beach. The model results for all retrofit scenarios are presented in Appendix B in the form of timeseries plots of predicted E.coli concentrations at Westboro Beach. Peak concentrations from individual sources were also tabulated in order to assess the relative impact of each retrofit alternative. A s s e s s m e n t o f t h e R e l a t i v e I m p a c t o f S W M R e t r o f i t P a g e 8

39 Figure 3.1 MIKE3 Model Domain A s s e s s m e n t o f t h e R e l a t i v e I m p a c t o f S W M R e t r o f i t P a g e 9

40 Figure 3.2 Typical MIKE3 Model Output (E.coli Plumes for the July 7, 1980 event under Existing Conditions) A s s e s s m e n t o f t h e R e l a t i v e I m p a c t o f S W M R e t r o f i t P a g e 1 0

41 Figure 3.3 Percent Reduction in Peak E.coli Concentration at Westboro Beach (Results based on average of all three 1980 storm events) Table 3.1 Percent Reduction in Peak E.coli Concentration at Westboro Beach by Point Source (Results based on average of all three 1980 storm events) Highest Practical SWM Highest Practical SWM Moderate Public Property ID Description No EOP with EOP SWM Only 4490 Workman Outfall 5% 5% 3% 2% 4313 Highland Park Outfall 20% 20% 13% 9% 4301 Mansfield Outfall 2% 2% 1% 1% 4307 Wavell Outfall 18% 44% 41% 39% 4300 Ardmore Outfall 15% 36% 33% 31% 4299 Pooler Outfall 0.48% 0.48% 0.48% 0.13% 4298 Orchard Outfall 0.09% 0.09% 0.20% 0.02% Pinecrest Pinecrest Creek 11% 16% 10% 8% Combined Concentration 22% 42% 36% 33% Note that these model results include background concentrations, which were based on the monthly geometric mean calculated from daily E.coli concentrations measured at both the Britannia and Lemieux Island Water Purification Plants (WPPs) from For June and July, background concentrations were determined to be 30 counts/100ml and 25 counts/100ml, respectively. A s s e s s m e n t o f t h e R e l a t i v e I m p a c t o f S W M R e t r o f i t P a g e 1 1

42 It should also be noted that the transport module of MIKE3 has not been calibrated; therefore, the predicted concentration levels at Westboro Beach should not be taken as an absolute value. The strength of this model is in its ability to readily assess the relative impacts and trends for a range of potential mitigation measures both on land and in the water. It would be difficult to predict E.coli concentrations at Westboro Beach with any degree of accuracy given the high variability associated with bacteria. This is illustrated in Figure 3.4, which compares rainfall accumulation against measured E.coli concentrations at Westboro Beach. The concentration levels predicted by the MIKE3 model for the three 1980 storm events were also presented in the graph. Figure 3.4 Comparison of Rainfall Accumulation and E.coli Concentrations at Westboro Beach The model results tend to fall within the scatter of the measured data, which can range by an order of magnitude under most rainfall conditions; this provides a level of confidence in the model predictions at Westboro Beach. There are numerous potential explanations for the variability observed in the measured data, including the spatial and temporal characteristics of the rainfall events, actual E.coli concentrations at each outfall, river flow conditions, background concentrations, and impacts from other sources such as waterfowl, to name a few. As a result it would be difficult for the model to accurately predict E.coli concentrations for a specific rainfall event. A s s e s s m e n t o f t h e R e l a t i v e I m p a c t o f S W M R e t r o f i t P a g e 1 2

43 The following observations were made based on the findings from the model results: For all scenarios considered, Wavell (OUT4307), Highland Park (OUT4313), Ardmore (OUT4300) and Pinecrest Creek represented the top four most significant contributors of E.coli to the river and ultimately at Westboro Beach. Although Pinecrest Creek represented approximately 75% of the total load to the river, outfalls such as Wavell (OUT4307), Highland Park (OUT4313) and Ardmore (OUT4300) had more significant impacts at Westboro Beach due to proximity; all three outfalls are situated within 1.5 km of the beach, as compared with Pinecrest Creek, which is approximately 3 km upstream of the beach area in a sheltered bay. In general, the stormwater plumes from Pinecrest would impact Westboro Beach much later than the three big outfalls, as eddy currents within the bay and proximity to the beach result in an increase in travel time. The inclusion or exclusion of SWM retrofit alternatives in the Pinecrest Creek sub-watershed would not have an effect on the initial wave of bacterial plumes experienced at the beach, which is due to the Wavell, Ardmore and Highland Park outfalls. However, implementation of retrofit alternatives in the sub-watershed will obviously mitigate the second wave of bacterial plume that impacts the beach from the creek. All retrofit alternatives that were considered in this study resulted in a reduction in E.coli concentrations at Westboro Beach ranging from 22% to 42%. The most notable reductions occurred for those options that included end-of-pipe facilities. The prioritization of key contributors also changed with the implementation of end-of-pipe facilities as Highland Park (OUT4313) became the most significant contributor at the beach. The Highest Practical scenario generated the largest reduction in E.coli loads to the river (38%) and in E.coli concentrations at Westboro Beach (42%). The most noticeable reductions were observed in the Wavell (OUT4307) and Ardmore (OUT4300) catchments, where endof-pipe facilities, such as storm ponds, are proposed for this alternative. The Moderate and Public Property scenarios are comprised of the same types of measures and end-of-pipe facilities proposed for the Highest Practical scenario; as such, these two scenarios represent the second and third most effective stormwater management alternatives. A s s e s s m e n t o f t h e R e l a t i v e I m p a c t o f S W M R e t r o f i t P a g e 1 3

44 4.0 CONCEPTUAL DESIGN OF A STORMWATER IMPOUNDMENT A general assessment of the feasibility of implementing a Dunker's flow balancing type solution for some of the larger outfalls upstream of Westboro Beach was carried out at the request of the City. This assessment included: 1) a basic review of the design and performance of the existing Dunker's Flow Balancing System (DFBS) operated by the City of Toronto at Bluffers Park, 2) a coastal engineer assessment of the potential site on the Ottawa River and 3) development of a conceptual design of the proposed system and a preliminary construction cost estimate. 4.1 Review of Existing DFBS at Bluffers Park, Toronto The following is a short summary of findings from a monitoring study of the DFBS, which has been implemented at Bluffers Park, City of Toronto. This review is based on the document Performance Assessment of a Flow Balancing and Wetland Treatment System Toronto, Ontario, produced by the SWAMP program in April Initial reactions are reported regarding the efficiency of the system and its potential for implementation as a retrofit option for specific outfalls along the Ottawa River. The objective of the Dunkers Flow Balancing system is to reduce contaminant discharge effectively and efficiently through flow recirculation while promoting aquatic habitat creation. The implemented system at Bluffers Park is comprised of 5 storage cells, divided by both permeable and impermeable pontoons as shown in Figure 4.1. Influent flows into cell 1 and is transferred to cell 2, followed by cell 3. The pontoon placed between cell 3 and 4 is impermeable, forcing flow to discharge to the lake via an outlet structure. Additionally, a pumping system pumps lake water into cell 3, promoting the recirculation of flow back into cell 2 and subsequently cell 1, where a second pump re-routes flow to cell 4. Cell 4 is a small sedimentation cell that discharges into cell 5, which operates as a wetland. A second outfall from cell 5 permits flow to discharge from the wetland and into the lake. A s s e s s m e n t o f t h e R e l a t i v e I m p a c t o f S W M R e t r o f i t P a g e 1 4

45 Figure 4.1 Schematic of Bluffers Park DFBS (from SWAMP 2005) The design of the Bluffers Park DFBS is based on the assumption of plug flow (the water moves together in a mass, rather than having localized flow paths, or excessive mixing) during peak rainfall events. The monitoring study (completed between 2000 and 2002) revealed that the treatment facility did not behave as intended, and that the effluent flow traveled primarily near the surface through the respective detention cells. Poor vertical integration of effluent was observed. Flow monitoring throughout 110 rain and snowmelt events (combined sewer overflow contributing to 32 events) revealed that 75% of the flow was being discharged from cell 3 and the remaining 25% was being diverted through the wetland prior to being discharged. Sixty percent of total suspended solids (herein referred to as TSS) were found to be removed in cell 1, with an additional 15-25% removed in cells 2 and 3. Water quality parameters were similar at both outfalls. Although the overall performance of the DFBS located at Bluffers Park was deemed effective in improving the water quality of the effluent being discharge into the lake, the efficiency of some of the system components is highly questionable. For a large portion of the monitoring study, the pump, which pumped lake water into cell 3 thus promoting recirculation, was non-operational. The resulting flow through cells 1, 2 and 3 were therefore not re-circulated as was originally designed. The monitoring study revealed that this change in operation did not reduce the quality of the discharge, therefore raising the question of whether the intake pump is necessary at all. A s s e s s m e n t o f t h e R e l a t i v e I m p a c t o f S W M R e t r o f i t P a g e 1 5

46 Furthermore, sediment accumulation resulted in complete blockage of the cell 5 (wetland) outfall for much of the study period. This effectively eliminated any flow through cells 4 and 5 during this time period, rendering the pump which transfers effluent from cell 1 into cell 4 ineffective. No significant change in the efficiency of the system was noted during this period. A principal conclusion of the monitoring study was that the pumping system may be dispensable. This, coupled with the fact that only 25% of flow was being routed through cells 4 and 5 and that water quality was consistent downstream from both outfalls suggests that such a complex, expensive and maintenance demanding system may not be necessary. Additionally, 75% to 85% of TSS was removed in cells 1, 2 and 3 alone, with the majority being removed in the first cell. Due to these conclusions, a simple storage pond configuration with a single outfall may generate similar results with respect to water quality while being much more efficient and cost effective over both the short and long-term. Additionally, the integration of a wetland could prove effective in promoting aquatic habitat and reducing surface isolated flows. However, the benefit of implementing an expensive pumping system is highly questionable. The system that was tested at Bluffers Park was not functioning as intended for much of the time due to tears in the baffles, pump problems and other issues. This example is therefore not a true test of the intended layout of the Dunkers Flow Balancing System. However, this test may also provide insight into how the Dunkers Flow Balancing system performs in real world conditions, where maintenance challenges exist. The Bluffers Park example provides no evidence that the capital and maintenance costs of this system are warranted compared to using a more conventional retention pond or wetland approach. 4.2 Proposed System for the Westboro Area The information that was reviewed in the Toronto region, specifically at Bluffers Park, suggested that the DFBS improved the condition of the stormwater that reached Lake Ontario. However, there were a number of problems with the system that related to pump maintenance, a beach berm clogging one of the outlets, and damage to the internal membranes that separated the cells. During these challenges, the discharge from the system continued to be improved, suggesting that some of the more complex features of this system provided marginal benefit. The overall conclusion from this review was that there was no information that suggests that the cost associated with many of the more complex components was warranted. The proposed system for the Westboro area would be located in the shallow nearshore regions of the river, approximately 1.4 km upriver of Westboro Beach. The system is laid out in a manner that would allow for the addition of some of the DFBS components in the future, should these elements be desired. Figure 4.2 shows the general location of the proposed system. A s s e s s m e n t o f t h e R e l a t i v e I m p a c t o f S W M R e t r o f i t P a g e 1 6

47 4.3 Design Conditions This region of the Ottawa River will be subject to a number of forces that must be considered in the design, including the following. Outfall Discharge: The flow rate in the outfalls is an important consideration, since it will affect the overall space requirement of the system. This will control how far offshore and how far along the shoreline the system will span. Water Levels: There is a range in water levels that must be considered in the functioning of the structures. During very high water levels, it is reasonable to assume that the system would be inundated and would not function in the same manner. Since this would be a very high flow period and very rare (and outside the swimming season) this inundation was deemed to be acceptable. Waves: Waves in this part of the Ottawa River will be very small as a result of the limited fetch for wave growth. Other factors will control the armouring of the structure. Currents: Currents will play a role in the protection of the outer face of the structure, the inside of the structure, and possibly scour protection in front of the structure. Ice: Ice in this region of the river could be a significant factor, both when it is fast to the shore, and when it is moving in the currents. Bottom Conditions: The bottom conditions, and the ease with which excavation can take place, will be an important factor in the overall sizing of the facility. A facility that is limited in depth will require more surface area in order to provide the volume that is required. A s s e s s m e n t o f t h e R e l a t i v e I m p a c t o f S W M R e t r o f i t P a g e 1 7

48 Figure 4.2 Location of Potential SWM Facility A s s e s s m e n t o f t h e R e l a t i v e I m p a c t o f S W M R e t r o f i t P a g e 1 8

49 4.3.1 Outfall Discharge There are two outfalls in the area that are being considered for treatment in the proposed facility: Wavell and Ardmore. These two outfalls drain a combined catchment area of 338 ha; design conditions were based on a rainfall event of approximately 29 mm, which corresponds to a total discharge of about 45,000 m3. This value has been selected as the target volume that would be contained within the facility Water Levels Water levels in this section of the Ottawa River are not gauged, and it is therefore necessary to make assumptions about the range in water levels based on available information such as physical characteristics of the river and some period spot elevations in the river. Water levels are measured at Britannia; this dataset was used as the primary indicator of probable water levels in the Westboro reach of the river. Water levels at Britannia are controlled by the natural weir of the Deschenes Rapids, which is approximately 600 m in width. Similarly, the Westboro reach has water levels that are controlled by flow into the Champlain Rapids, which have a similar width to the Deschenes Rapids. Both of these rapids have bathymetric variability across their width; however, since these features could not be surveyed, it assumed that there is similar variability. This leads to the assumption that the range of water level fluctuation at Westboro is similar in magnitude to that at Britannia. A comparison of water levels at Britannia and at the water treatment plant during the time of the hydrographic survey indicates that the water level difference between the two pools of the river are about 2.8 m. Therefore, water level values that are determined for the Britannia reach must be reduced by 2.8 m to be valid in the Westboro region. Based on a review of the monthly mean water levels at Britannia, a level of 58.8 m (56.0 m at Westboro) was selected as the high water during which the system should be operational. Above this level, the structures would be overtopped and the system would not be effective. This selected water level is higher than all but two of the June monthly means from 1950 to 2006, and it would be higher than all of the monthly means for July to September (except for July 1957). Typical summer water levels are important to determine since these will likely affect construction, which would probably take place during July to October. During this time period, a water level of 58.2 m (55.4 m at Westboro) was exceeded by about 15 per cent of the monthly means. A construction access elevation of about 55.4 m would be have some risk of being overtopped during construction, although only about a 15 per cent chance. This value is important since it will be a determining factor in the overall width of the structures. A s s e s s m e n t o f t h e R e l a t i v e I m p a c t o f S W M R e t r o f i t P a g e 1 9

50 4.3.3 Currents Currents in the area were available from the numerical modeling efforts previously completed by Baird, in addition to measurements that were completed with an Acoustic Doppler Current Profiler (ADCP) current meter. The current measurements were conducted during a period of relatively low water levels and is not representative of the more extreme conditions that would occur during the higher flow conditions. To assess the approximate range of speeds that would occur at the site, the highest recorded flow at Britannia over the last 90 years (i.e. 5,800 m3) was simulated using the 2D model MIKE21, which had been previously developed by Baird for previous Ottawa River studies in the area. Proposed Site The results of the simulation, shown in Figure 4.3, indicate that current speeds in the area are very low, with an eddy that forms downstream of the headland to the west. This will result in lesser current forces and scour on the structure, and will also minimize any possible concerns about constricting the river and causing additional flooding. Figure 4.3 Current Speeds Approx 100 year Flow Conditions Based on the simulated currents, it appears that the proposed location in the river for the stormwater facility is ideal from a hydraulic perspective Ice Protection Ice protection will be an important consideration for this site. The shoreline along this reach is exposed to ice forces, but due to the gentle slope of the shoreline and the forgiving nature of much of the shore, there is little concern or issues along the shore. Conversely, a structure in the river would not be as gently sloping due to cost implications, and returning to repair the structure could be costly since access will be difficult once the structure is complete. For this reason, the face of the structure must have a higher level of ice resistance than the nearby shoreline. The location of the proposed structure limits the type of ice forces that may be experienced. Any large sheets of moving ice in the area would typically be moved downstream by the current and would not, for example, be blown in from the north. Ice sheets moving downstream from the A s s e s s m e n t o f t h e R e l a t i v e I m p a c t o f S W M R e t r o f i t P a g e 2 0

51 Britannia reach are coming from an area with lesser currents, so they would likely be moving once the ice was weaker (e.g. during spring deterioration of the ice), and would also be broken up in the rapids. Therefore moving ice in the area would be of limited size and strength. The greatest threat from ice would be an in-situ sheet that changes its position/elevation through expansion or shifts in the water levels. This is very similar to the processes that would be experienced by the Britannia breakwaters, and therefore these will be used to guide the required stone size for ice protection Toe Scour Protection The need for toe scour protection will be dependent on the bottom conditions in the area. If rocky conditions are found, then protection may not be necessary. If the bottom is sand, mud or clay, then some scour protection would be required. Toe protection could be required on both the inside and outside of the structure to withstand the river currents, and the currents from the stormwater respectively. In most areas of the facility, the currents on the inside will be minimal and limited scour protection will be required Structure Cross Section The design of the structure cross section is controlled by a number of factors: Adequate width to provide access during construction; A crest elevation that is high enough to keep the facility operable during the summer months; Adequate armouring to withstand the ice forces, and other lesser forces that will affect the structure. Figure 4.4 shows the proposed structure cross section for the exposed perimeter of the system. On the inside of the crest and on the inner slope of the structure, the system would be armoured with a mixture of soil and riprap, which would provide the protection from any extreme events, but also provide a surface for planting of native species. A membrane is also proposed in order to better isolate the water within the system from the river. This would also allow the system to be filled somewhat, if additional storage capacity were required. Figure 4.4 Typical Structure Cross Section in Shallow Water A s s e s s m e n t o f t h e R e l a t i v e I m p a c t o f S W M R e t r o f i t P a g e 2 1

52 An example of the structure cross section in deeper water is provided in Figure 4.5. Due to the mild current and wave conditions, it is not necessary to extend the armour to the toe of the structure. The armour is primarily for ice protection and therefore is needed near the water level, but not significantly below the water level. Figure 4.5 Typical Structure Cross Section in Deeper Water The volume of material required for this structure is dependent on the elevation of the riverbed, and whether soft sediments exist that could result in some settlement. Assuming that no significant settlement will occur, Table 4.1 provides a summary of the volume of material that is required at different depths, for each metre of structure. Table 4.1 Materials Required for Structures -1.0 m depth -2.5 m depth Armour Stone 84 t 84 t Core 19 t 41 t RipRap 2.4 t 4.0 t Stone/Soil Mixture 4.4 t 4.4 t Geotextile 8 m 2 8 m 2 Membrane 8 m 2 8 m 2 The total costs for these cross sections are discussed in Section 4.5, based on the layout suggested in the following section 4.4 Position and Layout of Proposed Facility The proposed facility would be a single retention area that was located between the Wavell and Ardmore outfalls. Given the required size of the facility for each outfall, it makes sense to combine them rather than have two similar facilities very close together. This would reduce the overall cost for the capital works, as well as maintenance costs. An example layout for the proposed facility is shown in Figure 4.6. This facility has the required volume of about 45,000 m3, and is located in relatively shallow water (less than 2.5 m deep). A s s e s s m e n t o f t h e R e l a t i v e I m p a c t o f S W M R e t r o f i t P a g e 2 2

53 Figure 4.6 Example Layout of Proposed System The system features a central location where the two outfalls would discharge. This would be the primary settling area where solids are removed. This part of the facility could be raised above the remainder of the system so that in flood events, the solids are less likely to be transported into the river. Raising this primary retention area may also reduce the excavation costs. However, raising this area will be contingent on the elevation of the outfalls, since some grade will be required to move the stormwater from the outfalls to the facility. Flow from the primary cell would go towards the west (up-river) in the section closer to the shore. The central structure is used to lengthen the flow path and prevent short circuiting of the effluent towards the outlet, which is located at the downstream (east end). We are recommending that allowances for a pumping system be included so that water can be circulated from the river, into the facility. One option may be to have the flow into the facility driven by the current in the river; however, this may not be possible given the low flows in this area. This could be investigated further in subsequent design stages. There are different options for the outlet of this structure. To maximize the flow path, the outlet could be at the downstream end of the structure; however, this would result in the outlet being closer to Westboro Beach and the rest of the shoreline area. Other options would be to have the outlet further upstream, or to use a submerged pipe to discharge the water further offshore. A s s e s s m e n t o f t h e R e l a t i v e I m p a c t o f S W M R e t r o f i t P a g e 2 3

54 4.5 Facility Cost Very preliminary costs have been estimated based on the volume of material that would be needed and the proposed cross section. The cost of core material, riprap, armour stone, and membrane/geotextile is estimated to be in the range of $6,000,000 for the facility outlined in the previous section. Note that this cost is for the installation of the materials, and does not include a range of other items that must be considered when assessing the total cost. Additional cost items would include: Engineering; Environmental Assessments; Final design; Permitting; Tendering; Construction administration; Mobilization; Pump Systems; Internal baffles; Sediment control during construction; Reinforced concrete structures such as weirs, etc; Planting and landscaping; and Operating and maintenance costs Fish habitat loss/compensation requirements Costs for these items have not been assessed to date, but it would be reasonable to estimate that these could cost 1 to 5 million dollars, depending on the complexity of the system and a number of other factors. A s s e s s m e n t o f t h e R e l a t i v e I m p a c t o f S W M R e t r o f i t P a g e 2 4

55 5.0 CONCLUSIONS A numerical assessment was carried out to evaluate the performance of various storm water management (SWM) retrofit alternatives, for Pinecrest Creek and contributing outfalls, on Ottawa River water quality. The development of the SWM objectives, targets and scenarios as well as the hydrological and fluvial geomorphological analyses were undertaken by J.F. Sabourin & Associates Inc. (JFSA) and JTBES Environmental Systems. The following SWM scenarios were considered in this study: 1. Existing Conditions 2. Highest Practical Implementation 3. Highest Practical Implementation without End-of-Pipe (EOP) Facilities. 4. Moderate Implementation 5. Public Property Only Implementation For each retrofit alternative, predicted hydrographs and E.coli pollutographs were developed at all outlets in order to support the in-river analysis that was undertaken in this study. The hydrological assessment of SWM alternatives was conducted using three rainfall events from 1980, which is considered to be an average year in terms of rainfall. These events represent a cross-section of storms that range from a moderate rainfall, which would occur every two to three weeks, to more significant, less frequent rainfall events (Event 20), which would occur every two to three months (Stantec, 2005). The hydrographs and pollutographs generated from these events were used to define the wet weather inflows and loadings in the three-dimensional hydrodynamic and transport model of the Ottawa River that was developed as part of the Westboro Beach water quality study (Baird, 2008). This model was then used to conduct an assessment of the relative impact of various retrofit options on river water quality at Westboro Beach. The following observations were made based on the findings from the study: Of the eight point sources considered in this study, the four most significant contributors of E.coli loading to the Ottawa River were Pinecrest Creek, Wavell outfall (OUT4307), Ardmore outfall (OUT4300), and Highland Park outfall (OUT4313). A s s e s s m e n t o f t h e R e l a t i v e I m p a c t o f S W M R e t r o f i t P a g e 2 5

56 Pinecrest Creek, Wavell, Ardmore, and Highland Park also had the largest impacts on E.coli concentrations at Westboro Beach; however the priority of the sources changed. Although Pinecrest Creek represented approximately 75% of the total E.coli load to the river, outfalls such as Wavell (OUT4307), Highland Park (OUT4313) and Ardmore (OUT4300) had more significant impacts at Westboro Beach due to proximity; all three outfalls are situated within 1.5 km of the beach, as compared with Pinecrest Creek which is approximately 3 km upstream of the beach area in a sheltered bay. All retrofit alternatives that were considered in this study resulted in a reduction in E.coli concentrations at Westboro Beach ranging from 22% to 42%. The most notable reductions occurred for those options that included end-of-pipe facilities. The prioritization of key outfalls also changed with the implementation of end-of-pipe facilities as Highland Park (OUT4313) became the most significant contributor at the beach. The Highest Practical scenario generated the largest reduction in E.coli loads to the river (38%) and in E.coli concentrations at Westboro Beach (42%). The most noticeable reductions were observed in the Wavell (OUT4307) and Ardmore (OUT4300) catchments, where endof-pipe facilities such as storm ponds are proposed for this alternative. The Moderate and Public Property scenarios are comprised of the same types of measures and end-of-pipe facilities proposed for the Highest Practical scenario; as such, these two scenarios represent the second and third most effective stormwater management alternatives. A general assessment of the feasibility of implementing a Dunker's flow balancing type solution for some of the larger outfalls upstream of Westboro Beach was also conducted. This included a review of the performance of the existing Dunker's Flow Balancing System at Bluffers Park in Toronto. The conclusion from this review was that although the overall performance of the DFBS located at Bluffers Park was deemed effective at improving the water quality of the effluent being discharge into the lake, the efficiency of some of the system components is highly questionable, given that they were not functioning as intended for much of the time due to tears in the baffles, pump problems and other issues. The overall conclusion from this review was that there was no information to suggest that the cost associated with many of the more complex components was warranted. The development of a conceptual treatment system in the Westboro area was carried out in a shallow embayment near the Wavell (OUT4307) and Ardmore (OUT4300) outfalls. The proposed facility is a single retention area located between the two outfalls. The system is laid out in a manner that would allow for the addition of some of the DFBS components in the future, should these elements be desired. However, based on a review of the DFBS at Bluffers Park, there was no evidence to suggest that the capital and maintenance costs of this system are warranted compared to using a more conventional retention pond or wetland approach. A s s e s s m e n t o f t h e R e l a t i v e I m p a c t o f S W M R e t r o f i t P a g e 2 6

57 6.0 REFERENCES Baird & Associates. (2008). Bacterial Assessment at Westboro Beach. Report Prepared for the City of Ottawa. Stantec Consulting Ltd. (2005). Real Time Control Feasibility Study. Prepared for the City of Ottawa Infrastructure Services Division. A s s e s s m e n t o f t h e R e l a t i v e I m p a c t o f S W M R e t r o f i t P a g e 2 7

58 APPENDIX A STORMWATER VOLUMES AND E.COLI CONCENTRATIONS TO RIVER A s s e s s m e n t o f t h e R e l a t i v e I m p a c t o f S W M R e t r o f i t A p p e n d i x A

59 Table A1. Stormwater Volume and E.coli Concentrations for June 20, 1980 Event June 20, 1980 Storm Volume to River (m 3 ) Highest Highest Practical Practical SWM No SWM with Moderate EOP EOP SWM Public Property Only June 20, 1980 E.coli Concentration to River (counts/100ml) Highest Highest Practical Practical Public Existing SWM No SWM with Moderate Property Conditions EOP EOP SWM Only ID Description Existing Conditions ID Description 4490 Workman Outfall Workman Outfall Highland Park Outfall Highland Park Outfall Mansfield Outfall Mansfield Outfall Wavell Outfall Wavell Outfall Ardmore Outfall Ardmore Outfall Pooler Outfall Pooler Outfall Orchard Outfall Orchard Outfall Pinecrest Pinecrest Creek Pinecrest Pinecrest Creek Total Storm Volume 93,514 68,627 68,627 82,005 92,016 June 20, 1980 Percent Reduction in Storm Volume to River Highest Highest Practical Practical Public Existing SWM No SWM with Moderate Property ID Description Conditions EOP EOP SWM Only 4490 Workman Outfall 46% 46% 30% 4% 4313 Highland Park Outfall 37% 37% 23% 11% 4301 Mansfield Outfall 35% 35% 22% 6% 4307 Wavell Outfall 35% 35% 20% 8% 4300 Ardmore Outfall 31% 31% 19% 8% 4299 Pooler Outfall 41% 41% 25% 4% 4298 Orchard Outfall 26% 26% 16% 3% Pinecrest Pinecrest Creek 24% 24% 10% 0% Total Storm Volume 27% 27% 12% 2% A s s e s s m e n t o f t h e R e l a t i v e I m p a c t o f S W M R e t r o f i t A p p e n d i x A

60 Table A2. Stormwater Volume and E.coli Concentrations for July 7, 1980 Event July 7, 1980 Storm Volume to River (m 3 ) Highest Practical Highest Practical SWM No SWM with Moderate EOP EOP SWM Public Property Only July 7, 1980 E.coli Concentration to River (counts/100ml) Highest Highest Practical Practical Public Existing SWM No SWM with Moderate Property Conditions EOP EOP SWM Only ID Description Existing Conditions ID Description 4490 Workman Outfall Workman Outfall Highland Park Outfall Highland Park Outfall Mansfield Outfall Mansfield Outfall Wavell Outfall Wavell Outfall Ardmore Outfall Ardmore Outfall Pooler Outfall Pooler Outfall Orchard Outfall Orchard Outfall Pinecrest Pinecrest Creek Pinecrest Pinecrest Creek Total Storm Volume 248, , , , ,099 July 7, 1980 Percent Reduction in Storm Volume to River Highest Practical Highest Practical Public Existing SWM No SWM with Moderate Property ID Description Conditions EOP EOP SWM Only 4490 Workman Outfall 41% 41% 25% 4% 4313 Highland Park Outfall 35% 35% 20% 9% 4301 Mansfield Outfall 33% 33% 19% 5% 4307 Wavell Outfall 32% 32% 17% 6% 4300 Ardmore Outfall 29% 29% 16% 7% 4299 Pooler Outfall 38% 38% 21% 4% 4298 Orchard Outfall 22% 22% 13% 2% Pinecrest Pinecrest Creek 21% 21% 7% -1% Total Storm Volume 23% 23% 10% 1% A s s e s s m e n t o f t h e R e l a t i v e I m p a c t o f S W M R e t r o f i t A p p e n d i x A

61 Table A3. Stormwater Volume and E.coli Concentrations for July 15, 1980 Event July 15, 1980 Storm Volume to River (m 3 ) Highest Practical Highest Practical SWM No SWM with Moderate EOP EOP SWM Public Property Only July 15, 1980 E.coli Concentration to River (counts/100ml) Highest Practical Highest Practical Public Existing SWM No SWM with Moderate Property Conditions EOP EOP SWM Only ID Description Existing Conditions ID Description 4490 Workman Outfall Workman Outfall Highland Park Outfall Highland Park Outfall Mansfield Outfall Mansfield Outfall Wavell Outfall Wavell Outfall Ardmore Outfall Ardmore Outfall Pooler Outfall Pooler Outfall Orchard Outfall Orchard Outfall Pinecrest Pinecrest Creek Pinecrest Pinecrest Creek Total Storm Volume 171, , , , ,533 July 15, 1980 Percent Reduction in Storm Volume to River Highest Practical Highest Practical Public Existing SWM No SWM with Moderate Property ID Description Conditions EOP EOP SWM Only 4490 Workman Outfall 41% 41% 24% 4% 4313 Highland Park Outfall 35% 35% 20% 9% 4301 Mansfield Outfall 34% 34% 19% 5% 4307 Wavell Outfall 32% 32% 17% 7% 4300 Ardmore Outfall 29% 29% 16% 7% 4299 Pooler Outfall 39% 39% 21% 4% 4298 Orchard Outfall 23% 23% 13% 2% Pinecrest Pinecrest Creek 22% 22% 7% -1% Total Storm Volume 24% 24% 10% 1% A s s e s s m e n t o f t h e R e l a t i v e I m p a c t o f S W M R e t r o f i t A p p e n d i x A

62 APPENDIX B MIKE3 MODEL RESULTS A s s e s s m e n t o f t h e R e l a t i v e I m p a c t o f S W M R e t r o f i t A p p e n d i x B

63 E.coli Loading to River Table B1. Impact of Retrofit Scenarios on River Water Quality for the June 20, 1980 Event June 20, 1980 E.coli Load to River (colonies) Highest Practical Highest Practical SWM No SWM with Moderate EOP EOP SWM Public Property Only E.coli Concentrations at Westboro Beach Background Concentration for June = 30 counts/100l Highest Practical SWM No EOP Highest Practical SWM with EOP Moderate SWM ID Description Existing Conditions ID Description Existing Conditions 4490 Workman Outfall 1.48E E E E E Workman Outfall Highland Park Outfall 1.88E E E E E Highland Park Outfall Mansfield Outfall 8.04E E E E E Mansfield Outfall Wavell Outfall 3.27E E E E E Wavell Outfall Ardmore Outfall 2.49E E E E E Ardmore Outfall Pooler Outfall 1.98E E E E E Pooler Outfall Orchard Outfall 1.50E E E E E Orchard Outfall Pinecrest Pinecrest Creek 2.57E E E E E+12 Pinecrest Pinecrest Creek Total Loading to River June 20, 1980 Peak E.coli Conc at Westboro Beach (counts/100ml) 3.39E E E E E+12 Combined Concentration Peaks occur at different times Public Property Only June 20, 1980: % Reduction in EC Loads Highest Practical Highest Practical SWM No SWM with Moderate EOP EOP SWM Public Property Only June 20, 1980: % Reduction in E.coli Concentration Highest Practical SWM No EOP Highest Practical SWM with EOP Moderate SWM ID Description Existing Conditions ID Description Existing Conditions 4490 Workman Outfall 32% 32% 20% 11% 4490 Workman Outfall 4% 4% 2% 1% 4313 Highland Park Outfall 31% 31% 20% 14% 4313 Highland Park Outfall 17% 17% 11% 7% 4301 Mansfield Outfall 29% 29% 17% 10% 4301 Mansfield Outfall 1% 1% 1% 1% 4307 Wavell Outfall 29% 65% 59% 56% 4307 Wavell Outfall 16% 38% 35% 33% 4300 Ardmore Outfall 29% 65% 59% 56% 4300 Ardmore Outfall 12% 28% 26% 25% 4299 Pooler Outfall 32% 32% 20% 8% 4299 Pooler Outfall 0% 0% 0% 0% 4298 Orchard Outfall 23% 23% 15% 6% 4298 Orchard Outfall 0% 0% 0% 0% Pinecrest Pinecrest Creek 21% 33% 21% 17% Pinecrest Pinecrest Creek 7% 11% 7% 5% Total Loading to River 23% 38% 28% 24% Combined Concentration 20% 38% 33% 30% Public Property Only A s s e s s m e n t o f t h e R e l a t i v e I m p a c t o f S W M R e t r o f i t A p p e n d i x B

64 E.coli Loading to River Table B2. Impact of Retrofit Scenarios on River Water Quality for the July 7, 1980 Event July 7, 1980 E.coli Load to River (colonies) Highest Practical Highest Practical SWM No SWM with Moderate EOP EOP SWM Public Property Only E.coli Concentrations at Westboro Beach Background Concentration for July = 25 counts/100ml Highest Practical SWM No EOP Highest Practical SWM with EOP Moderate SWM ID Description Existing Conditions ID Description Existing Conditions 4490 Workman Outfall 3.90E E E E E Workman Outfall Highland Park Outfall 4.95E E E E E Highland Park Outfall Mansfield Outfall 2.13E E E E E Mansfield Outfall Wavell Outfall 8.61E E E E E Wavell Outfall Ardmore Outfall 6.48E E E E E Ardmore Outfall Pooler Outfall 5.25E E E E E Pooler Outfall Orchard Outfall 3.85E E E E E Orchard Outfall Pinecrest Pinecrest Creek 6.86E E E E E+12 Pinecrest Pinecrest Creek Total Loading to River July 7, 1980 E.coli Conc at Westboro Beach (counts/100ml) 9.02E E E E E+12 Combined Concentration Peaks occur at different times Public Property Only July 7, 1980: % Reduction in EC Loads Highest Practical Highest Practical Existing SWM No SWM with Moderate Conditions EOP EOP SWM Public Property Only July 7, 1980: % Reduction in E.coli Concentration Highest Practical SWM No EOP Highest Practical SWM with EOP Moderate SWM ID Description ID Description Existing Conditions 4490 Workman Outfall 31% 31% 19% 11% 4490 Workman Outfall 6% 6% 3% 2% 4313 Highland Park Outfall 31% 31% 19% 13% 4313 Highland Park Outfall 22% 22% 14% 10% 4301 Mansfield Outfall 28% 28% 16% 7% 4301 Mansfield Outfall 3% 3% 2% 1% 4307 Wavell Outfall 28% 64% 58% 55% 4307 Wavell Outfall 19% 47% 44% 42% 4300 Ardmore Outfall 28% 64% 59% 55% 4300 Ardmore Outfall 16% 39% 36% 35% 4299 Pooler Outfall 32% 32% 19% 7% 4299 Pooler Outfall 1% 1% 0% 0% 4298 Orchard Outfall 19% 19% 12% 4% 4298 Orchard Outfall 0% 0% 0% 0% Pinecrest Pinecrest Creek 19% 32% 21% 17% Pinecrest Pinecrest Creek 11% 18% 12% 9% Total Loading to River Public Property Only 22% 37% 27% 23% Combined Concentration 23% 45% 38% 35% A s s e s s m e n t o f t h e R e l a t i v e I m p a c t o f S W M R e t r o f i t A p p e n d i x B

65 E.coli Loading to River Table B3. Impact of Retrofit Scenarios on River Water Quality for the July 15, 1980 Event July 15, 1980 E.coli Load to River (colonies) Highest Practical Highest Practical SWM No SWM with Moderate EOP EOP SWM Public Property Only E.coli Concentrations at Westboro Beach July 15, 1980 E.coli Conc at Westboro Beach (counts/100ml) Background Concentration for July = 25 counts/100ml Highest Practical SWM No EOP Highest Practical SWM with EOP Moderate SWM ID Description Existing Conditions ID Description Existing Conditions 4490 Workman Outfall 2.66E E E E E Workman Outfall Highland Park Outfall 3.38E E E E E Highland Park Outfall Mansfield Outfall 1.45E E E E E Mansfield Outfall Wavell Outfall 5.89E E E E E Wavell Outfall Ardmore Outfall 4.45E E E E E Ardmore Outfall Pooler Outfall 3.58E E E E E Pooler Outfall Orchard Outfall 2.67E E E E E Orchard Outfall Pinecrest Pinecrest Creek 4.70E E E E E+12 Pinecrest Pinecrest Creek Total Loading to River 6.18E E E E E+12 Combined Concentration Peaks occur at different times Public Property Only July 15, 1980: % Reduction in EC Loads Highest Practical Highest Practical SWM No SWM with Moderate EOP EOP SWM Public Property Only July 15, 1980: % Reduction in E.coli Concentration Highest Practical SWM No EOP Highest Practical SWM with EOP Moderate SWM ID Description Existing Conditions ID Description Existing Conditions 4490 Workman Outfall 31% 31% 19% 11% 4490 Workman Outfall 7% 7% 4% 2% 4313 Highland Park Outfall 31% 31% 19% 14% 4313 Highland Park Outfall 22% 22% 13% 10% 4301 Mansfield Outfall 29% 29% 16% 8% 4301 Mansfield Outfall 3% 3% 2% 1% 4307 Wavell Outfall 28% 64% 58% 56% 4307 Wavell Outfall 19% 47% 44% 42% 4300 Ardmore Outfall 29% 64% 59% 56% 4300 Ardmore Outfall 16% 39% 36% 35% 4299 Pooler Outfall 32% 32% 19% 8% 4299 Pooler Outfall 1% 1% 1% 0% 4298 Orchard Outfall 20% 20% 13% 4% 4298 Orchard Outfall 0% 0% 0% 0% Pinecrest Pinecrest Creek 20% 33% 21% 18% Pinecrest Pinecrest Creek 13% 19% 13% 9% Total Loading to River Public Property Only 22% 38% 27% 24% Combined Concentration 24% 44% 38% 34% A s s e s s m e n t o f t h e R e l a t i v e I m p a c t o f S W M R e t r o f i t A p p e n d i x B

66

67 Note: Background concentrations included Figure B1. Timeseries of Predicted E.coli Concentrations at Westboro Beach under Existing Conditions (June 20, 1980 Event) A s s e s s m e n t o f t h e R e l a t i v e I m p a c t o f S W M R e t r o f i t A p p e n d i x B

68 Note: Background concentrations included Figure B2. Timeseries of Predicted E.coli Concentrations at Westboro Beach under Existing Conditions (July 7, 1980 Event) A s s e s s m e n t o f t h e R e l a t i v e I m p a c t o f S W M R e t r o f i t A p p e n d i x B

69 Note: Background concentrations included Figure B3. Timeseries of Predicted E.coli Concentrations at Westboro Beach under Existing Conditions (July 15, 1980 Event) A s s e s s m e n t o f t h e R e l a t i v e I m p a c t o f S W M R e t r o f i t A p p e n d i x B

70 Note: Background concentrations included Figure B4. Timeseries of Predicted E.coli Concentrations at Westboro Beach under Highest Practical Implementation (June 20, 1980 Event) A s s e s s m e n t o f t h e R e l a t i v e I m p a c t o f S W M R e t r o f i t A p p e n d i x B

71 Note: Background concentrations included Figure B5. Timeseries of Predicted E.coli Concentrations at Westboro Beach under Highest Practical Implementation (July 7, 1980 Event) A s s e s s m e n t o f t h e R e l a t i v e I m p a c t o f S W M R e t r o f i t A p p e n d i x B

72 Note: Background concentrations included Figure B6. Timeseries of Predicted E.coli Concentrations at Westboro Beach under Highest Practical Implementation (July 15, 1980 Event) A s s e s s m e n t o f t h e R e l a t i v e I m p a c t o f S W M R e t r o f i t A p p e n d i x B

73 Note: Background concentrations included Figure B7. Timeseries of Predicted E.coli Concentrations at Westboro Beach under Highest Practical Implementation with no EOP (June 20, 1980 Event) A s s e s s m e n t o f t h e R e l a t i v e I m p a c t o f S W M R e t r o f i t A p p e n d i x B

74 Note: Background concentrations included Figure B8. Timeseries of Predicted E.coli Concentrations at Westboro Beach under Highest Practical Implementation with no EOP (July 7, 1980 Event) A s s e s s m e n t o f t h e R e l a t i v e I m p a c t o f S W M R e t r o f i t A p p e n d i x B

75 Note: Background concentrations included Figure B9. Timeseries of Predicted E.coli Concentrations at Westboro Beach under Highest Practical Implementation with no EOP (July 15, 1980 Event) A s s e s s m e n t o f t h e R e l a t i v e I m p a c t o f S W M R e t r o f i t A p p e n d i x B

76 Note: Background concentrations included Figure B10. Timeseries of Predicted E.coli Concentrations at Westboro Beach under Moderate Implementation (June 20, 1980 Event) A s s e s s m e n t o f t h e R e l a t i v e I m p a c t o f S W M R e t r o f i t A p p e n d i x B

77 Note: Background concentrations included Figure B11. Timeseries of Predicted E.coli Concentrations at Westboro Beach under Moderate Implementation (July 7, 1980 Event) A s s e s s m e n t o f t h e R e l a t i v e I m p a c t o f S W M R e t r o f i t A p p e n d i x B

78 Note: Background concentrations included Figure B12. Timeseries of Predicted E.coli Concentrations at Westboro Beach under Moderate Implementation (July 15, 1980 Event) A s s e s s m e n t o f t h e R e l a t i v e I m p a c t o f S W M R e t r o f i t A p p e n d i x B

79 Note: Background concentrations included Figure B13. Timeseries of Predicted E.coli Concentrations at Westboro Beach under Public Property Implementation Only (June 20, 1980 Event) A s s e s s m e n t o f t h e R e l a t i v e I m p a c t o f S W M R e t r o f i t A p p e n d i x B

80 Note: Background concentrations included Figure B14. Timeseries of Predicted E.coli Concentrations at Westboro Beach under Public Property Implementation Only (July 7, 1980 Event) A s s e s s m e n t o f t h e R e l a t i v e I m p a c t o f S W M R e t r o f i t A p p e n d i x B

81 Note: Background concentrations included Figure B14. Timeseries of Predicted E.coli Concentrations at Westboro Beach under Public Property Implementation Only (July 15, 1980 Event) A s s e s s m e n t o f t h e R e l a t i v e I m p a c t o f S W M R e t r o f i t A p p e n d i x B

82 City of Ottawa - Wastewater & Drainage Services Stormwater Facility Annual Performance Summary Effluent Targets E.coli Bacteria (E.coli) Sediments (TSS) Phosphorous (TP) Control Quality Monitoring E.coli TSS TSS (% Ave. Influent Ave. Effluent % # Ave. Influent Ave. Effluent % # Ave. Influent Ave. Effluent % Stormwater Facility Pond Type Mechanism Year By (#/100mL) (mg/l) removal) Conc. (#/100mL) Conc. (#/100mL) Removal Exceedances Conc. (mg/l) Conc. (mg/l) Removal Exceedances Conc. (mg/l) Conc. (mg/l) Removal Clarke Bellinger 1 Wet, 2-cells, UV Active 2001 City (Delcan) Clarke Bellinger 1 Wet, 2-cells, UV Active 2002 City (Delcan) Clarke Bellinger 1 Wet, 2-cells, UV Active 2003 City (Delcan) Clarke Bellinger 1 Wet, 2-cells, UV Active 2004 City (Delcan) Riverside South Pond-1 Wet, 5-cells Active 1997 City (Glouc.) & CG&S Riverside South Pond-1 Wet, 5-cells Active 1998 City (Glouc.) & CG&S Riverside South Pond-1 Wet, 5-cells Active 1999 City (Glouc.) & CG&S Riverside South Pond-1 Wet, 5-cells Active 2001 City & CH2MHill Riverside South Pond-1 Wet, 5-cells Active 2002 City & CH2MHill INSUFF. DATA 117 INSUFF. DATA 2 INSUFF. DATA 11.5 INSUFF. DATA 0 INSUFF. DATA INSUFF. DATA Riverside South Pond-1 Wet, 5-cells Active 2003 City (CH2MHill) Riverside South Pond-1 Wet, 5-cells Active 2004 City (CH2MHill) Strandherd 3 Wet, 3-cells Active 2001 City (CH2MHill) Strandherd 3 Wet, 3-cells Active 2002 City (CH2MHill) Strandherd 3 Wet, 3-cells Active 2003 City (CH2MHill) Strandherd 3 Wet, 3-cells Active 2004 City (CH2MHill) Stonebridge Wet, 2-cells Active 2001 City (CH2MHill) (-) Stonebridge Wet, 2-cells Active 2002 City (CH2MHill) Stonebridge Wet, 2-cells Active 2003 City (CH2MHill) Stonebridge Wet, 2-cells Active 2004 City (CH2MHill) Nepean Creek Wet, 3+ cells Passive 2002 City (CH2MHill) (-) Nepean Creek Wet, 3+ cells Passive 2003 City (Delcan) Nepean Creek Wet, 3+ cells Passive 2004 City (Delcan) Hunt Club - Rideau Bridge Dry, filtration Passive 2000 City (WEPP) Hunt Club - Rideau Bridge Dry, filtration Passive 2001 City (WEPP) < Hunt Club - Rideau Bridge Dry, filtration Passive 2003 City (Delcan) Hunt Club - Rideau Bridge Dry, filtration Passive 2004 City (Delcan) Monahan Wetlands 4 Wet, 5-cells Passive 1996 City (Kanata) - TSH Monahan Wetlands 4 Wet, 5-cells Passive 1997 City (Kanata) - TSH Monahan Wetlands 4 Wet, 5-cells Passive 1998 City (Kanata) - TSH Monahan Wetlands 4 Wet, 5-cells Passive 1999 City (Kanata) - TSH Monahan Wetlands 4 Wet, 5-cells Passive 2000 City (Kanata) Monahan Wetlands 4 Wet, 5-cells Passive 2001 City (WEPP) Monahan Wetlands 4 Wet, 5-cells Passive 2002 City (WEPP) Monahan Wetlands 4 INSUFF. DATA INSUFF. DATA INSUFF. DATA Wet, 5-cells Passive 2003 City (CH2MHill) n/a (-) 5 Monahan Wetlands 4 Wet, 5-cells Passive 2004 City (CH2MHill) Riddell Duck Pond 6 Wet, 1-cell Passive 2000 City (Kanata) n/a n/a n/a n/a n/a No samples 4.2 n/a --- n/a n/a n/a Riddell Duck Pond 6 Wet, 1-cell Passive 2001 City (WEPP) n/a n/a n/a n/a n/a No samples 3 n/a --- n/a n/a n/a Riddell Duck Pond 6 Wet, 1-cell Passive 2002 City (WEPP) n/a n/a n/a n/a n/a n/a n/a n/a Riddell Duck Pond 6 Wet, 1-cell Passive 2003 City (CH2MHill) n/a n/a n/a n/a n/a (-) --- n/a n/a n/a Riddell Duck Pond 6 Wet, 1-cell Passive 2004 City (CH2MHill) n/a n/a n/a n/a n/a n/a n/a n/a Central Park Wet, 2-cells, offline Passive 2003 Developer (TROW) n/a n/a --- n/a n/a n/a n/a n/a n/a n/a Central Park Wet, 2-cells, offline Passive 2004 Developer (TROW) n/a n/a --- n/a n/a n/a n/a n/a n/a n/a Amberlakes 9 Wet, 1-cell Passive 2003 Developer (PSR Group) n/a n/a --- n/a n/a n/a n/a n/a n/a n/a n/a Amberlakes 9 Wet, 1-cell Passive 2004 Developer (PSR Group) n/a n/a --- n/a n/a n/a n/a n/a Kennedy-Burnett 10 Wet, 2-cells Manual 1996 City (Nepean) - TSH No data (-) No data (-) Kennedy-Burnett 10 Wet, 2-cells Manual 1997 City (Nepean) - TSH No data (-) No data (-) Kennedy-Burnett 10 Wet, 2-cells Manual 1998 City (Nepean) - TSH No data No data Kennedy-Burnett 10 Wet, 2-cells Manual 1999 City (Nepean) - TSH No data No data Riverside-Hackett 11 Wet, 1-cell, offline Passive 1998 City (Ottawa) - TSH ,884 1, Riverside-Hackett 11 Wet, 1-cell, offline Passive 1999 City (Ottawa) - TSH Riverside-Hackett 11 Wet, 1-cell, offline Passive 2000 City (Ottawa) - TSH Bellinger 1 : Use 201/202 as outlet for TSS and TP for Bellinger because UV does not reduce these parameters, so outflow is based on the influent to the UV system and won't change with UV treatment. Influent is an average of 101/102/103 Bellinger 2 : These were not included in report. Strandherd 3 : Average of South Forebay Inlet and North Forebay Inlet used for 2001 & 2004 data. Note that table in 2002 report has an 'inlet average' that is not equal to the avg. of the N & S values unclear as to derivation. Monahan 4 : Data based on 'wetland cell' monitoring since other cells are not actively monitored. Monahan 5 : According to p.9 in 2003 Monahan report, %removal for Phosphorus was -110% (High algae concentrations present in effluent are likely cause) Riddell 6 : Pond data goes as far back as '94, but samples only taken at effluent (control structure No.3) Central Park 7 : Inflow TSS values not averaged in report done by hand. Central Park 8 : Report reads "outflow TSS concentration had an average range of." Amberlakes 9 : Avg. values calculated by hand from p report. Note: "[TSS at both inflow and outflow was] quite low and the effectiveness of the pond in TSS removal was not readily measurable in the 2004 season". Kennedy-Burnett 10 : Data from City of Nepean Stormwater Management Facilities, 1999 Performance Monitoring Program (TSH), Table 3, p. 15. Riverside-Hackett 11 : Data based on wet-weather sampling only. SWM Facility Monitoring Performance Summary, Ver1.xls

83 Water Quality Summary Table Pollutant NURP (1) Rideau River SWM Study (2) 1998 Ottawa River Input Monitoring (3) City of Toronto (4) Pinecrest Creek Wavell Avenue Outfall Kent Street Outfall Ogilvie Road Outfall Median Maximum Average Maximum Average Maximum Average Maximum Average Maximum Average Average TSS, mg/l TP, mg/l EC, counts/100ml n/a n/a n/a 8,400 3, ,000 8,132 64,000 8,821 49,000 5, ,000 FC, counts/100ml 21,000 35,000 16,900 n/a n/a n/a n/a n/a n/a n/a n/a n/a Notes 1. Median value for all sites studied by NURP, i.e., no distinction for different land uses (results of Nationwide Urban Runoff Program, Executive Summary, United States Environmental Protection Agency, December 1983). 2. Maximum and average values for "Suburban Developed" as per Table 10-3, Rideau River SWM Study, RMOC, Maximum and average values for creek and storm outfalls from River Input Monitoring Program - Ottawa River (RMOC, 1998). 4. Average value from all storm outfalls as per Table , City of Toronto WWFMMP, Etobicoke and Mimico Watersheds, TSH, All of the above is wet weather data. Source: City of Ottawa, 2011

84 Source: Center for Watershed Protection (2007), Urban Subwatershed Restoration Manual 3, B 3.