D.M. Wills Associates Limited PARTNERS IN ENGINEERING. Stormwater Management Report. City of Peterborough

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1 Stormwater Management Report City of Peterborough P Parkway Corridor Class Environmental Assessment Jackson Park Parkhill Road West to Chemong Road D.M. Wills Project No D.M. Wills Associates Limited PARTNERS IN ENGINEERING Peterborough North Bay Revised January 2014 December 2013 Prepared for: City of Peterborough Otonabee Region Conservation Authority

2 Table of Contents 1.0 Purpose Site Description Methodology Stormwater Management Stormwater Quality Control Stormwater Management Wet Pond Facility Stormwater Management Oil / Grit Separator Stormwater Quantity Control Jackson Creek Wet Pond Facility Jackson Creek Parkhill Road West Hydraulic Elements Overland Flow Route Regulatory Floodplain HEC-RAS Model Development Flood Line and Velocity Impacts Conclusion List of Figures and Tablets Figure 1 Location Plan... 4 Figure 2 Pre-Development Drainage Area Plan... 8 Figure 3 Post-Development Drainage Area Plan... 9 Figure 4 Preliminary Pond Layout Figure 5 Post-Development Floodplain Assessment Table 1 Post-Development Hydrologic Parameters... 7 Table 2 Extended Detention, Wet Pond Features Table 3 Stage-Storage-Discharge Wet Pond Facility Table 4 Existing & Proposed Controlled Peak Flows Table 5 Existing & Proposed Uncontrolled Peak Flows Parkhill Road West Table 6 Jackson Creek Flood Line Elevations Timmins Storm Table 7 Jessie Creek Velocities Timmins Storm... 23

3 List of Appendices Appendix A Appendix B Appendix C Appendix D Appendix E Hydrologic Parameters Quality and Quantity Controls VO2 Model Hydraulic Elements HEC-RAS

4 Parkway Environmental Assessment SWM Report Parkway Corridor Jackson Park, Parkhill Road to Chemong Road 1.0 Purpose D.M. Wills Associates Limited (Wills) has been retained by AECOM to provide Drainage and Stormwater Management expertise as part of the project engineering team for The Parkway Corridor Environmental Assessment, in the City of Peterborough. The consultant team is led by AECOM (Engineering Consultant), with the assistance of Wills in the field of Stormwater Management, Drainage and Structural Engineering. The study has proceeded as a Schedule C under the Municipal Class Environmental Assessment (Class EA) process according to the guidelines set out in the Municipal Class EA document (as amended in 2007 and 2011). The purpose for the process is to ensure that municipal infrastructure projects are planned, designed and constructed such that proper consideration is given to the full range of environmental impacts. By adhering to the approved Municipal Class EA guidelines, municipal infrastructure projects will comply with the requirements of the Province s Environmental Assessment Act. The Municipal Class Environmental Assessment process consists of five (5) phases, which include: Phase 1 Problems and Opportunity Phase 2 Alternative Solutions Phase 3 Alternative Design Concepts for Preferred Solution Phase 4 Environmental Study Reports Phase 5 Implementation Through the first three (3) phases of the Class EA process, which included discussions with the City of Peterborough, ORCA, stakeholders and the public through four (4) Public Information Sessions (PIC), a preferred solution for The Parkway has been identified. As part of the fourth phase of the Class EA, Drainage and SWM Reports are to be prepared to demonstrate how the implementation of the preferred alternative may proceed without negatively impacting the upstream and downstream lands and watercourses in terms of both water quantity and water quality. Consideration was given to flood potential, erosion, thermal impacts, current and future drainage patterns, infrastructure improvement opportunities, social economic value and aesthetics. This report has been prepared specifically for the City of Peterborough and the Otonabee Region Conservation Authority (ORCA) to address stormwater management issues as part of The Parkway Class EA process. D.M. Wills Associates Limited Page 1 Project No

5 Parkway Environmental Assessment SWM Report Parkway Corridor Jackson Park, Parkhill Road to Chemong Road The following reports were used as reference to compile the Stormwater Management Reports for The Parkway Class EA: City of Peterborough Flood Reduction Master Plan, prepared by UMA / AECOM in April of City of Peterborough - Jackson Creek Flood Reduction Master Plan, prepared by AECOM in April of Jackson Diversion Project Hydrology and Hydraulic Model Updates, prepared by AECOM in 2013 (DRAFT). Byersville/Harper Creek Detailed Flood Reduction Study, prepared by XCG in April of Bears Creek Flood Reduction Master Plan, prepared by XCG in February of Riverview Creek Detailed Flood Reduction Study, Prepared by Greenland International Consulting Ltd., in March of Flood Risk Mapping Otonabee River Tributary Byersville Creek, prepared by Marshall Macklin Monaghan Limited and Totten Sims Hubicki Associates Limited in March of Stormwater Quality Management Master Plan Project Report prepared by XCG in May of 2013 (DRAFT). Peterborough Regional Health Centre (PRHC) Access Road Stormwater Management Report, prepared by D.M. Wills Limited, in March of The Stormwater Management component of The Parkway Class EA will be broken down into four (4) individual Stormwater Management Reports. Each of the four (4) reports will correspond to a different outlet location along The Parkway. The four (4) reports include: Parkway Corridor Clonsilla Avenue to Parkhill Road West Parkway Corridor Jackson Creek, Parkhill Road West to Chemong Road Parkway Corridor Sunset Park, Chemong Road to Hilliard Street Parkway Corridor Hilliard Street to Water Street This report will focus solely on The Parkway Corridor Jackson Park between Parkhill Road West and Chemong Road. D.M. Wills Associates Limited Page 2 Project No

6 Parkway Environmental Assessment SWM Report Parkway Corridor Jackson Park, Parkhill Road to Chemong Road 2.0 Site Description The Parkway Corridor Jackson Park, between Parkhill Road West and Chemong Road accepts drainage from Fairbairn Street, Highland Road and Hemlock Street. The primary focus of this report is The Parkway Corridor between Parkhill Road West and Highland Heights Public School, approximately 450 m west of Chemong Road. The location of the Site is shown on Figure 1. The surrounding land use includes mixed residential to the north, east, south and west of the site, with Jackson Park passing through the middle of the site. The existing Parkway Corridor through this area consists primarily of vegetated areas (grass areas) and impervious areas (existing building with asphalt parking areas external to The Parkway Corridor). The topography of the site to the north of Jackson Park is moderately flat, draining from east to west into Jackson Park. The topography within, and to the south of Jackson Park, fall steeply into Jackson Creek. The proposed change in land use includes the removal of vegetated areas to allow for the construction of a four (4) lane arterial road; a bridge to span Jackson Creek leaving the majority of existing vegetation within the Jackson Park intact, a sidewalk and a multi-use trail system. The proposed development will introduce new impervious surfaces and therefore alter the runoff rate leaving the site and impact downstream stormwater quantity and quality. The location and elevation of existing site features were determined based on 0.5 m contour information obtained from the City of Peterborough and were also used to determine drainage patterns and to establish the proposed grades. The Flood Reduction Master Plan (UMA / AECOM, 2005) and the Jackson Creek Flood Reduction Master Plan, (AECOM, 2010) were also used to help define catchment boundaries and drainage patterns. D.M. Wills Associates Limited Page 3 Project No

7 Parkway Environmental Assessment SWM Report Parkway Corridor Jackson Park, Parkhill Road to Chemong Road Figure 1 Location Plan 3.0 Methodology The present hierarchy of watershed planning in Ontario can be described by the following descending order: Watershed Plans, Sub-watershed Plans and individual Stormwater Management Plans. The Parkway Corridor between Parkhill Road West and Chemong Road is contained within the study area of the Jackson Creek Flood Reduction Master Plan, (AECOM, 2010). The flood reduction master plan was developed to assess the severe flooding that occurred adjacent to Jackson Creek in July of 2004 and to determine remedial measures to improve the operation of the drainage system. The Master Drainage Plan does not provide any significant recommendation for drainage works within or adjacent to The Parkway Corridor in this area. Due to the proximity to Jackson Creek, this area of the corridor was not investigated as a site specific stormwater management report, but instead provides recommendations that will mitigate the impact of the proposed development on a watershed basin. D.M. Wills Associates Limited Page 4 Project No

8 Parkway Environmental Assessment SWM Report Parkway Corridor Jackson Park, Parkhill Road to Chemong Road The proposed Parkway Corridor Jackson Creek, Parkhill Road West to Chemong Road stormwater management report was prepared based on the hydrologic modeling developed within the Jackson Creek Flood Reduction Master Plan, (AECOM, 2010), and the Jackson Diversion Project (AECOM, 2013). The following list summarizes the design strategy: Provide stormwater quantity control to maintain pre-development peak flows downstream of The Parkway Corridor at or below pre-development levels within Jackson Creek. Provide water quality control to Enhanced (Level 1) protection. For the pre-development condition, The Parkway Corridor will effect two (2) catchments within the Jackson Creek Flood Reduction Master Plan, (AECOM, 2010). The existing catchments are shown on Figure 2 and include: Catchment area 301 includes the lands draining directly to Jackson Creek. The catchment is comprised primarily of vegetated areas (grass) and impervious areas (buildings and asphalt). The catchment slopes moderately from north to south into Jackson Creek. Catchment area 302 includes the lands draining directly to Jackson Creek. The catchment is comprised primarily of vegetated areas (grass) and impervious areas (buildings and asphalt). The catchment slopes moderately from south to north into Jackson Creek. Catchment area Ex.WS3 is a sub-catchment of catchment 302. This catchment represents the area of The Parkway Corridor that discharges to Parkhill Road West. This catchment is comprised primarily vegetated areas (grass). For the post-development condition, the two (2) existing drainage areas will be redistributed based on the proposed grading of the new roadway. The proposed bridge over Jackson Creek will convey surface drainage from catchment 302 to be treated in catchment 301. The proposed catchment areas are shown on Figure 3 and include: Catchment area WS301 includes the lands draining to The Parkway Corridor, including the eastern limit of the proposed bridge and outleting to Jackson Creek. The catchment is comprised primarily of vegetated areas (grass) and impervious areas (buildings and asphalt). The catchment slopes moderately from east to west and into a proposed stormwater management facility before outleting to the Jackson Creek. Catchment area WS302 includes the existing subdivision on Hemlock Street that discharged into an existing Stormwater Management Dry Pond Facility. The catchment is comprised primarily of vegetated areas (grass) and impervious areas (buildings and asphalt). The catchment slopes moderately from east to D.M. Wills Associates Limited Page 5 Project No

9 Parkway Environmental Assessment SWM Report Parkway Corridor Jackson Park, Parkhill Road to Chemong Road west and into the proposed stormwater management facility before outleting to Jackson Creek. Catchment area WS303 includes the lands outleting to The Parkway Corridor, including the western limit of the proposed bridge. The catchment is comprised primarily of vegetated areas (grass) and impervious areas (asphalt). The catchment slopes moderately from west to east and into the proposed catchment area WS301. Catchment WS304 includes lands draining to Highland Road. The catchment is comprised primarily vegetated areas (grass) and impervious areas (building and asphalt). This catchment is derived from the existing residential neighborhood discharging to the intersection of Fairbairn and Highland Road. This catchment will drain uncontrolled as per existing conditions and is included for consideration in sizing Hydraulic Elements only. Catchment WS305 is a sub catchment 301. The catchment is comprised primarily vegetated areas (grass) and impervious areas (asphalt). This catchment is derived from the existing catchment Ex.WS3 and includes additional impervious areas from the four (4) lane roadway within The Parkway Corridor. Catchment area 301-NEW is comprised of the existing catchment 301 excluding the lands associated with the proposed catchments WS301 and WS302. Catchment area 302-NEW is comprised of the existing catchment 302 excluding the lands associated with the proposed catchments WS303. The hydrologic parameters are summarized in Table 1 and documented in Appendix A. D.M. Wills Associates Limited Page 6 Project No

10 Parkway Environmental Assessment SWM Report Parkway Corridor Jackson Park, Parkhill Road to Chemong Road Table 1 Post-Development Hydrologic Parameters Catchment Command Line 1 Area (ha) % Impervious CN 2 Ia StandHyd StandHyd Ex.WS3 NasHyd WS301 StandHyd WS302 StandHyd WS303 StandHyd WS304 StandHyd WS305 StandHyd NEW StandHyd NEW StandHyd Notes: 1. Command Line refers to the unit hydrograph used in the VO2 hydrologic model for the respective catchment area. 2. CN refers to the modified CN number adjusted to Antecedent Moisture Conditions II. Excludes Impervious Area (Standhyd). 3. Ia refers to Initial Abstraction values taken from the Environmental and Engineering Services Department, The Corporation of the City of London, Dec Excludes Impervious Area (Standhyd). 4. Tp refers to Time of Peak. Hydrologic parameters such as soil infiltration properties, land use and runoff response were determined based on a literature review of reference materials as well as City of Peterborough and ORCA design standards. Topographic mapping and AutoCAD Civil 3D 2012 software were used to establish sub-watershed area, land use and slope. Rainfall data for the site is taken from the City of Peterborough as well as the Jackson Creek Flood Reduction Master Plan, (AECOM, 2010) and is included in Appendix A. Hydrology within this report is preliminary only, and is meant to give a preliminary assessment of the flows in and around The Parkway Corridor consistent with a preliminary design level of detail. Final hydrology will be revised during the detailed design phase of the project and may be adjusted accordingly. D.M. Wills Associates Limited Page 7 Project No

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13 Parkway Environmental Assessment SWM Report Parkway Corridor Jackson Park, Parkhill Road to Chemong Road 4.0 Stormwater Management 4.1 Stormwater Quality Control The construction of a new four (4) lane arterial road including sidewalk and multi-use trail will result in increased stormwater runoff, which may cause additional pollutants to be conveyed off-site. To address this, a series of measures to improve stormwater quality will be required. The selection and sizing of the water quality measures will be based on the procedures set out in the Stormwater Management Planning and Design Manual (MOE, March 2003) for Enhanced (Level 1) protection. According to the Ministry of Environment (MOE) SWMP Planning and Design Manual, the goal of stormwater management is to preserve the natural hydrologic cycle. The manual also states that stormwater management measures should be assessed in the following order: Stormwater lot level controls Stormwater conveyance controls End-of-pipe stormwater management facilities Stormwater lot level controls represent measures which are implemented at the individual lot level (soak-a-way pits, flatter grading, etc.). Stormwater conveyance controls represent the conveyance systems used to transport stormwater runoff from the lots to the receiving waters (pervious pipes, grassed swales, etc.). End-of-pipe stormwater management facilities represent the common urban stormwater management measures used to service numerous lots or whole subdivisions (wet ponds, wetlands, infiltration basins, etc.). Through The Parkway Class EA process, end-of-pipe quality controls were determined to be the most reasonable measures to address stormwater quality treatment within The Parkway Corridor. A review of the various controls was completed including but not limited to: Wet ponds and wetlands Dry ponds Infiltration basins / infiltration trenches Bio-retention swales Filter strips Sand filters Underground storage Oil/grit separators D.M. Wills Associates Limited Page 10 Project No

14 Parkway Environmental Assessment SWM Report Parkway Corridor Jackson Park, Parkhill Road to Chemong Road The preferred solution was selected based on the size of the catchment being treated and land restrictions within the corridor, which indicates that a stormwater management wet pond facility, in conjunction with an Oil / Grit Separator (OGS), are the most feasible stormwater quality control measures for this portion of The Parkway Corridor. Surface runoff generated by catchment area WS301, WS302 and WS303 will discharge directly into, and be controlled within a stormwater management wet pond facility. The wet pond facility will discharge directly into Jackson Creek. Surface runoff generated by catchment area WS305 will be controlled prior to being discharged into an OGS. The OGS will outlet in the Parkhill Road West right-of-way. The wet pond facility will not only treat surface runoff from within The Parkway Corridor but also a portion of Fairbairn Street and a portion of the residential subdivision on Hemlock Street. Surface runoff from these additional lands were receiving basic quality treatment, but as a result of the proposed SWM strategy associated with The Parkway Corridor this additional surface runoff will be treated by an enhanced wet pond facility before outleting to Jackson Creek. As a result, the total level of treatment for runoff discharging into Jackson Creek will be improved as a result of The Parkway Corridor Stormwater Management Wet Pond Facility The proposed stormwater facility will incorporate several measures for quality treatment. The proposed stormwater pond will have a sediment forebay at the inlet end. The purpose of the sediment forebay is to improve pollutant removal by trapping larger particles near the inlet of the pond. In addition, the sediment forebay reduces the inflow velocities and minimizes the re-suspension of existing sediment in the forebay area. The second quality treatment measure consists of the permanent pool portion in the stormwater facility that never drains (except during maintenance). A 1.5 m deep permanent pool is located in the remaining portion of the pond, which provides two (2) functions. During a storm event, the pool acts as a buffer such that any water being released from the facility is either clean or diluted. After the storm, pollutants remain trapped in the permanent pool. The inter-event settling is one of the main reasons why wet ponds are more effective in pollutant removal than dry ponds. The runoff originating from catchment WS301, WS302 and WS303 will be collected by a storm sewer system within The Parkway right-of-way and discharge to the proposed wet pond facility. A total drainage area of 9.26 ha will discharge to the proposed extended detention, wet pond facility. The storage volumes required are based on Table 3.2, page 3-10, Stormwater Management Practices Planning and Design Manual (March 2003), Ministry of the Environment. Water quality objectives for the proposed Wet Pond Facility are presented in Table 2. D.M. Wills Associates Limited Page 11 Project No

15 Parkway Environmental Assessment SWM Report Parkway Corridor Jackson Park, Parkhill Road to Chemong Road Table 2 Extended Detention, Wet Pond Features Feature Remarks Level of Protection Enhanced (Level 1) Contributing Area 9.26 ha (WS101) Percent Impervious 54% Storage Volumes 188 m 3 /ha for 54% impervious 148 m 3 /ha for permanent pool Permanent Volume required is 1366 m 3 Pool Design Volume provided is 1405 m 3 Ponding depth is 1.5 metres and side slope is 5 to 1 and 3 to1 Forebay Design Required settling length (Ls) is 13 m Required dispersion length (Ld) is 7 m Forebay length provided is 53 m Extended Detention Design Outlet Design Volume required is 964 m 3 for quality control based on the 25 mm, 4 hour Chicago Distribution Volume provided is 1024 m 3 at a depth of 0.50 m for quality control 2 stage outlet system: 110 mm dia. orifice (236.9 to m) 1200 mm dia. Riser Pipe (237.4 to 237.7m) 25 mm drawdown time = 27 hours A review of Table 2 indicates that the proposed stormwater facility will achieve all of the water quality objectives. The supporting calculations for the wet pond are included in Appendix C. The pond locations and cross-sections are preliminary only, and are meant to give a representation of how the proposed stormwater management facilities will be constructed. Final configuration and design of the wet pond facility will be provided during the detailed design phase of the project and may be revised from the design provided within this report. During the detailed design phase of the project, the level of protection should not be reduced from what has been provided herein Stormwater Management Oil / Grit Separator A total drainage area of 0.74 ha at 50.0 % imperviousness (OGS305) will discharge into a proposed OGS via the proposed storm sewers within the right-of-way. The Ministry of Environment (MOE) guidelines for oil-grit separators for Normal (Level 1) protection are as follows: D.M. Wills Associates Limited Page 12 Project No

16 Parkway Environmental Assessment SWM Report Parkway Corridor Jackson Park, Parkhill Road to Chemong Road 80% total suspended solids (TSS) removal Treat 85% of the annual runoff volume The OGS analyzed is described below: Stormceptor modeling tools recommend the Stormceptor System model STC 300. The STC 300 will achieve 81% TSS removal and treat 96% of annual runoff. The proposed OGS exceeds the MOE requirements for Enhanced (Level 1) treatment for the proposed development. The sizing calculations for the oil-grit separators are included in Appendix D. The OGS unit will require periodic maintenance. The manufacturer will provide maintenance requirements for the selected system. During the detailed design phase of the project, a bio retention swale could be incorporated into the design to provide additional quality control measures. 4.2 Stormwater Quantity Control The alteration of the existing area from open space into a roadway corridor will increase the imperviousness and the corresponding stormwater runoff leaving the site. In order to ensure that the new roadway does not increase downstream flooding, stormwater management facilities are typically required to maintain post-development flows to existing development levels, unless the receiving body of water will not be adversely effected by the increase in surface runoff Jackson Creek Wet Pond Facility Peak flows were estimated using the VO2 hydrologic model. Peak flows were calculated for each of the 2, 5, 10, 25, 50 and 100 year design storms. These calculations consider calibrated 1 hour and 12 hour AES storm distributions, as described in the Jackson Creek Flood Reduction Master Plan, (AECOM, 2010). The analysis also considered the 100 year design storm for the 1 hour, 4 hour and 6 hour Chicago storm distributions, the 1 hour, 6 hour and 12 hour AES storm distribution and the 12 hour and 24 hour SCS Type II storm duration to ensure the wet pond facility does not overtop during a major storm event. The 25 mm 4 hour Chicago storm distributions were also included as part of the analysis. A total of twenty two (22) design storms were analyzed for this development. The flow chart and the VO2 model are presented in Appendix C. D.M. Wills Associates Limited Page 13 Project No

17 Parkway Environmental Assessment SWM Report Parkway Corridor Jackson Park, Parkhill Road to Chemong Road For the post-development conditions, catchment WS301, WS302 and WS303 will discharge directly into the Wet Pond Facility adjacent to the intersection of The Parkway and Fairbairn Drive. The stage-storage-discharge values for the proposed wet pond facility are summarized in Table 3. Table 3 Stage-Storage-Discharge Wet Pond Facility Elevation (m) Ponding Depth (m) Discharge (m 3 /s) Storage Volume (m 3 ) Remarks Stage 1 - Permanent Pool 110 mm Orifice Invert m , mm 964 m ,024 Stage 2 - Top of Weir 1200 mm dia ,790 Top of Extended Detention 100 Year 6 hour SCS ,658 Top of pond Centerline / Low Point in Road Notes: 1. Design storms noted in the remarks column are for the 6 hour SCS Type II design storm mm, refers to the 25 mm 4 hour Chicago storm distribution. The pond will provide 1790 m 3 in the extended detention portion of the pond at an elevation of m. 868 m 3 of additional storage is provided within the 0.3 m zone of freeboard to an elevation of m. The pond discharge is controlled by a two stage outlet system. The first stage from elevation m to m is controlled by a 110 mm diameter orifice plate within the outlet structure. At elevation m, water will discharge over the 1200 mm diameter riser pipe activating the second stage that is controlled by a 900 mm diameter outlet pipe within the outlet structure. The first and second stages will both outlet through the 900 mm diameter concrete storm sewer with a slope of 2.0 %. No emergency outlet has been provided within the wet pond facility. Due to the configuration of the road and the location of the pond, an emergency overflow is not a feasible option. The flow into the wet pond facility will be restricted to 0.61 m 3 /sec expressed as the 5 year post development flows derived from the Rational Method. Major overland flow will be directed from the low point in the road to a channel, described in greater detailed in section 4.2.2, that will direct flows directly into Jackson Creek. D.M. Wills Associates Limited Page 14 Project No

18 Parkway Environmental Assessment SWM Report Parkway Corridor Jackson Park, Parkhill Road to Chemong Road Supporting calculations are included in Appendix B and Appendix C. A preliminary pond layout in presented on Figure 4. The results of the controlled post-development peak flows are presented in Table 4. A review of Table 4 indicates that for the 1 hour storm distribution, the peak flows downstream of The Parkway development will be reduced where the 1 hour AES storm distribution is the controlling storm (greater than the 12 hour storm). For the 12 hour storm distribution, peak flows downstream of The Parkway development will increase slightly when compared to the existing condition. A maximum percent increase of 0.05% will occur within the Jackson Creek, during the 100 year 12 hour storm, as a direct result of the proposed development. Due to the physical size of the hydrologic model, including a significant number of catchments and routing elements the longer duration (12 hour) storm, the max peak occurs after the peak for the proposed stormwater management facility, located at the midpoint of the model. In order to reduce the peaks during the 12 hour storm downstream of the proposed stormwater management facility, a substantial amount of additional storage will be required to hold back runoff leaving the facility. Additional property acquisition would be required to expand the facility to maintain peak flows at pre-development conditions. Given the overall improvement to the system during shorter, extreme events, it is our recommendation that the proposed solution, along with a negligible increase in peak flows downstream, be deemed acceptable. D.M. Wills Associates Limited Page 15 Project No

19 Parkway Environmental Assessment SWM Report Parkway Corridor Jackson Park, Parkhill Road to Chemong Road Jackso n Weir Parkhill Road Downie Street Bethun e Street Brock Street Hunter Street Little Lake Outlet Storm Distribution Reservo ir 33 AddHy d 49 AddHy d 70 AddHy d 74 AddHy d 75 AddHy d 77 AddHy d 85 Table 4 Existing & Proposed Controlled Peak Flows Peak Flows (m 3 /sec) Pre Post Diff 1 Hr 12 Hr 1 Hr 12 Hr 1 Hr 12 Hr % 2 Yr % 5 Yr % 25 Yr % 100 Yr % 2 Yr % 5 Yr % 25 Yr % 100 Yr % 2 Yr % 5 Yr % 25 Yr % 100 Yr % 2 Yr % 5 Yr % 25 Yr % 100 Yr % 2 Yr % 5 Yr % 25 Yr % 100 Yr % 2 Yr % 5 Yr % 25 Yr % 100 Yr % 2 Yr % 5 Yr % 25 Yr % 100 Yr % Notes: 1. Pre refers to the pre-development condition model provided by AECOM revised in 2013 as part of the Jackson Diversion Project. 2. Post refers to the post-development uncontrolled condition discharging into AddHyd 49 of the existing AECOM revised model. 3. Diff refers to the difference in peak flow between the existing condition and the post development condition. D.M. Wills Associates Limited Page 16 Project No

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21 Parkway Environmental Assessment SWM Report Parkway Corridor Jackson Park, Parkhill Road to Chemong Road Jackson Creek Parkhill Road West Peak flows discharging to Parkhill Road West were estimated using the Rational Method. Peak flows were calculated for each of the 2, 5, 10, 25, 50 and 100 year design storms. For the post-development conditions, catchment WS305 will discharge directly into an underground facility within The Parkway Corridor before discharging onto Parkhill Road West right-of-way. The peak flows discharging to the Jackson Creek for the postdevelopment uncontrolled and pre-development conditions are summarized in Table 5. Table 5 Existing & Proposed Uncontrolled Peak Flows Parkhill Road West Design Storm Peak Flows (m 3 /sec) (yr) Pre Post Diff Notes: 1. Pre refers to the pre-development condition (Ex.WS3). 2. Post refers to the post-development uncontrolled condition (WS305). 3. Diff refers to the difference in peak flow between the Attenuated condition and the post development uncontrolled condition. A review of Table 5 indicates that Parkhill Road West will see a maximum increase in peak flow of 0.15 m 3 /s during the 100 year design storm. A Modified Rational Method calculation was completed to estimate the storage volume required to control the post development peak flows to that of the existing condition for the 5, 25 and 100 year design storms. Based on the Modified Rational Method calculation, 64.7 m 3 of storage will be required to control the 5 year storm, 83.2 m 3 will be required to control the 25 year storm and 125 m 3 will be required to control the 100 year storm. These volumes can be achieved with oversized pipes or underground facilities. Supporting calculations are included in Appendix B. During the detailed design phase of the project, a bio retention swale could be incorporated into the design to provide additional quantity control measures. D.M. Wills Associates Limited Page 18 Project No

22 Parkway Environmental Assessment SWM Report Parkway Corridor Jackson Park, Parkhill Road to Chemong Road 4.3 Hydraulic Elements Overland Flow Route Hydraulic calculations were completed to ensure that the proposed ditches and culverts within the right-of-way will have the capacity to convey the proposed design flows. The major overland flow from WS301, WS302 and WS303 was used to size the channel from the low point in The Parkway to the proposed crossing under Fairbairn Street. The maximum 100 year design flow was estimated at m 3 /s for the 1 hour AES Storm Distribution (DivertHyd 3332). The overland flow route into the pond starts at the road right-of-way and parallels the access road. The overland flow route is a 0.6 m deep trapezoidal channel with 3:1 side slopes, a 2.0 m flat bottom and a longitudinal slope of 1.0%. The maximum depth of flow within the channel was estimated at 0.30 m, with a maximum velocity of 1.05 m/s, which satisfies a threshold value of 1.5 m/s for grass lined channels. The proposed pedestrian underpass or a separate hydraulic crossing under Fairbairn Street will require a major conveyance route under the road. The final configuration for the underpass will be established during detailed design. During the detailed design phase of the project overland flow from major overland flow form WS301, WS302, WS303 and WS304 should be used to size the conveyance of the 100 year flow under Fairbairn Street. The 100 year design flow was estimated at m 3 /s for the 1 hour AES Storm Distribution (AddHyd 3339). The stormwater management facility and the major conveyance route under Fairbairn Street will both outlet to an existing overland flow route draining into Jackson Park. A detailed analysis of the overland flow route should be performed during the detailed design phase of the project, considering capacity, velocities and erosion. The hydraulic elements presented in this report are preliminary only, and meant to give a representation of how the water will be conveyed through the study area. Final configuration and design of the overland flow routes will be provided during the detailed design phase of the project and may be revised from the preliminary design provided within this report. D.M. Wills Associates Limited Page 19 Project No

23 Parkway Environmental Assessment SWM Report Parkway Corridor Jackson Park, Parkhill Road to Chemong Road 4.4 Regulatory Floodplain HEC-RAS Model Development The one dimensional, steady-state HEC-RAS Version 4.0 model, developed by the U.S. Army Corps of Engineers, was used for the hydraulic analysis of the existing condition to determine the location of the existing Regulatory Floodline. The primary model input parameters include the existing topography upstream and downstream of The Parkway Corridor, inserted as cross-sections, and are based on detailed topographic information. Roughness coefficients for the channel and overbank areas were estimated from field inspection and literature review and are reflective of a clean, winding channel (0.035), mature and medium to dense brush with trees (0.060). An existing HEC-RAS model of Jackson Creek was prepared as part of the Jackson Creek Flood Reduction Master Plan (AECOM, 2010). The existing model begins just downstream of Little Lake (Section 3.90) and extends upstream to distance of m to just downstream of Lily Lake (Section ). The existing model includes eighty (80) cross sections as well as twenty three (23) structures within the limits of the channel. To properly assess the impact of a proposed bridge within Jackson Park, two (2) additional cross sections were added to the hydraulic model upstream and downstream of the proposed bridge. These two sections, located at Section and Section , were interpolated from upstream and downstream sections. The two (2) additional sections are shown on Figure 5. For the purpose of the analysis, the proposed Jackson Creek Bridge was analyzed as a ten (10) span precast concrete box girder bridge with a concrete cast in place deck and sub structure. The proposed bridge has a span of 370 m, a total width of 28 m and a roadway width of 14 m. Each span of the bridge will be 40 m in length and be held in place by a 1.5 m wide piers. Hydrology within the HEC-RAS model will remain unchanged from the original model. The results of the hydraulic modeling are discussed below and presented in full in Appendix E Flood Line and Velocity Impacts The flood line analysis considered the impact to the water surface elevations and channel velocities on both sides of the proposed bridge crossing. The flood line elevations and channel velocities for the existing and proposed bridges are summarized in Table 6 and Table 7 respectively. D.M. Wills Associates Limited Page 20 Project No

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25 Parkway Environmental Assessment SWM Report Parkway Corridor Jackson Park, Parkhill Road to Chemong Road Table 6 Jackson Creek Flood Line Elevations Timmins Storm Station Water Surface Elevation (m) Existing Proposed Difference Existing Pedestrian Bridge < - New Section Proposed Parkway Bridge < - New Section Existing Pedestrian Bridge Parkhill Road Bridge Table 6 shows that there is an increase in water surface elevation immediately upstream of the proposed bridge during the design storm as a result of a pier in the bank of the section Minor fluctuation in the water surface is observed upstream of the proposed bridge until reaching a constant equilibrium at section D.M. Wills Associates Limited Page 22 Project No

26 Parkway Environmental Assessment SWM Report Parkway Corridor Jackson Park, Parkhill Road to Chemong Road Table 7 Jessie Creek Velocities Timmins Storm Station Water Velocities (m/s) Existing Proposed Difference Existing Pedestrian Bridge < - New Section Proposed Parkway Bridge < - New Section Existing Pedestrian Bridge Parkhill Road Bridge A review of Table 7 shows that there is a decrease in velocity immediately upstream of the proposed bridge during the design storm as a result of a pier in the creek bank of the section Minor fluctuations in channel velocity are observed upstream of the proposed bridge until reaching a constant equilibrium at section The detailed model output is included in Appendix D. The proposed Jackson Creek Bridge will have an impact on the Jackson Creek Regulatory Floodplain Water Surface Elevation immediately upstream of the proposed bridge. With Jackson Creek confined to a valley system at the bridge location, any change to the floodline will have little to no effect on neighboring properties or structure. D.M. Wills Associates Limited Page 23 Project No

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28 Parkway Environmental Assessment SWM Report Parkway Corridor Jackson Park, Parkhill Road to Chemong Road Statement of Limitations This report has been prepared by D.M. Wills Associates Limited on behalf of AECOM to prepare a Stormwater Management Report for The Parkway Environmental Assessment to address the requirements of the City of Peterborough. The conclusions and recommendations in this report are based on available background documentation and discussions with applicable agencies at the time of preparation. The report is intended to demonstrate the means whereby stormwater runoff originating from the site will be managed with respect to both quantity and quality control. The report is applicable only to the project described in the text, constructed substantially in accordance with the plans and details accompanying this report. Any use which a third party makes of this report, other than a stormwater management report for the proposed development, is the responsibility of such third parties. D.M. Wills Associates Limited accepts no responsibility for damages, if any, suffered by a third party as a result of decisions made or action taken based on using this report for purposes other than a stormwater management report for The Parkway Environmental Assessment. D.M. Wills Associates Limited is not responsible for any changes made to the stormwater management measures which are not in accordance with the design drawings. Any person(s) relying on the as-constructed stormwater measures should confirm that the field conditions are in accordance with the design drawings. D.M. Wills Associates Limited Page 25 Project No

29 Appendix A Hydrologic Parameters

30 Hydrologic Parameters for WS301 Sheet 1 of 1 Project No: Project Name: Parkway EA Designed/Checked By: MJH / KS Date: 17-Oct-13 Drainage Area 5.32 ha Rainfall Data Land Use 0.00 ha Agriculture Rainfall Gauging Station = Peterborough 0.00 ha Range 100 Yr, 12 Hour Rainfall depth = 90.4 mm 2.26 ha Grass 0.00 ha Woods 0.00 ha Wetland Soil Type Otonabee Loam 0.00 ha Bare Earth (>70% Rock) 3.06 ha Impervious Hydrologic Soil Group 1 B Percent Impervious 57.5 % US Elev.= m DS Elev. = m Length m Slope 1.0 % Flat Flat: 0-2% Slopes Rolling: 2-6% Slopes Hilly: >6% Slopes Land Use Composite Value Parameter Incl. Not Incl. Agriculture Range Grass Woods Wetland Bare Earth Imperv. Imperv. Imperv. >70% Rock Nashyd Standhyd Runoff Coefficient 2, C n.a. SCS Curve No. 3, CN Modified Curve No. 4, CN n.a. n.a. n.a. n.a n.a. n.a. n.a Initial Abstraction 5, mm min. Time of Concentration 6 Bransby - Method Airport Uplands 0.40 hr. Williams 16.2 min. Time to Peak 7 Tc (min) hr. Notes: 1. Hydrologic Soil Group obtained from Design Chart H2-6A, M.T.O. Drainage Manual, Runoff coefficient obtained from M.T.O. Design Chart 1.07, M.T.O. Drainage Management Manual, 1997, and Tables 4-5a to 4-5d, Maryland State Highway Administration. 3. SCS Curve No. obtained from M.T.O. Design Chart 1.09, M.T.O. Drainage Management Manual, 1997, and Table 2-2a, TR-55, page The modified curve number is adjusted as per Paul Wisner & Associates (1982) and represents anticedent moisture conditions Type II 5. Initial Abstraction values taken from the Environmental and Engineering Services Department, The Corporation of the City of London, Dec Use Airport Equation to calculate time of concentration for C <= 0.4, and Bransby-Williams for C > Minimum Time to Peak for use in the Rational Method and Hydrologic Model is 10 minutes Hydrology Calculations WS301

31 Hydrologic Parameters for WS302 Sheet 1 of 1 Project No: Project Name: Parkway EA Designed/Checked By: MJH / KS Date: 17-Oct-13 Drainage Area 2.82 ha Rainfall Data Land Use 0.00 ha Agriculture Rainfall Gauging Station = Peterborough 0.00 ha Range 100 Yr, 12 Hour Rainfall depth = 90.4 mm 1.55 ha Grass 0.00 ha Woods 0.00 ha Wetland Soil Type Otonabee Loam 0.00 ha Bare Earth (>70% Rock) 1.27 ha Impervious Hydrologic Soil Group 1 B Percent Impervious 45.0 % US Elev.= m DS Elev. = m Length m Slope 1.8 % Flat Flat: 0-2% Slopes Rolling: 2-6% Slopes Hilly: >6% Slopes Land Use Composite Value Parameter Incl. Not Incl. Agriculture Range Grass Woods Wetland Bare Earth Imperv. Imperv. Imperv. >70% Rock Nashyd Standhyd Runoff Coefficient 2, C n.a. SCS Curve No. 3, CN Modified Curve No. 4, CN n.a. n.a. n.a. n.a n.a. n.a. n.a Initial Abstraction 5, mm min. Time of Concentration 6 Bransby - Method Airport Uplands 0.27 hr. Williams 11.0 min. Time to Peak 7 Tc (min) hr. Notes: 1. Hydrologic Soil Group obtained from Design Chart H2-6A, M.T.O. Drainage Manual, Runoff coefficient obtained from M.T.O. Design Chart 1.07, M.T.O. Drainage Management Manual, 1997, and Tables 4-5a to 4-5d, Maryland State Highway Administration. 3. SCS Curve No. obtained from M.T.O. Design Chart 1.09, M.T.O. Drainage Management Manual, 1997, and Table 2-2a, TR-55, page The modified curve number is adjusted as per Paul Wisner & Associates (1982) and represents anticedent moisture conditions Type II 5. Initial Abstraction values taken from the Environmental and Engineering Services Department, The Corporation of the City of London, Dec Use Airport Equation to calculate time of concentration for C <= 0.4, and Bransby-Williams for C > Minimum Time to Peak for use in the Rational Method and Hydrologic Model is 10 minutes Hydrology Calculations WS302

32 Hydrologic Parameters for WS303 Sheet 1 of 1 Project No: Project Name: Parkway EA Designed/Checked By: MJH / KS Date: 17-Oct-13 Drainage Area 1.12 ha Rainfall Data Land Use 0.00 ha Agriculture Rainfall Gauging Station = Peterborough 0.00 ha Range 100 Yr, 12 Hour Rainfall depth = 90.4 mm 0.46 ha Grass 0.00 ha Woods 0.00 ha Wetland Soil Type Otonabee Loam 0.00 ha Bare Earth (>70% Rock) 0.66 ha Impervious Hydrologic Soil Group 1 B Percent Impervious 58.9 % US Elev.= m DS Elev. = m Length m Slope 0.7 % Flat Flat: 0-2% Slopes Rolling: 2-6% Slopes Hilly: >6% Slopes Land Use Composite Value Parameter Incl. Not Incl. Agriculture Range Grass Woods Wetland Bare Earth Imperv. Imperv. Imperv. >70% Rock Nashyd Standhyd Runoff Coefficient 2, C n.a. SCS Curve No. 3, CN Modified Curve No. 4, CN n.a. n.a. n.a. n.a n.a. n.a. n.a Initial Abstraction 5, mm min. Time of Concentration 6 Bransby - Method Airport Uplands 0.32 hr. Williams 13.0 min. Time to Peak 7 Tc (min) hr. Notes: 1. Hydrologic Soil Group obtained from Design Chart H2-6A, M.T.O. Drainage Manual, Runoff coefficient obtained from M.T.O. Design Chart 1.07, M.T.O. Drainage Management Manual, 1997, and Tables 4-5a to 4-5d, Maryland State Highway Administration. 3. SCS Curve No. obtained from M.T.O. Design Chart 1.09, M.T.O. Drainage Management Manual, 1997, and Table 2-2a, TR-55, page The modified curve number is adjusted as per Paul Wisner & Associates (1982) and represents anticedent moisture conditions Type II 5. Initial Abstraction values taken from the Environmental and Engineering Services Department, The Corporation of the City of London, Dec Use Airport Equation to calculate time of concentration for C <= 0.4, and Bransby-Williams for C > Minimum Time to Peak for use in the Rational Method and Hydrologic Model is 10 minutes Hydrology Calculations WS303

33 Hydrologic Parameters for WS304 Sheet 1 of 1 Project No: Project Name: Parkway EA Designed/Checked By: MJH / KS Date: 17-Oct-13 Drainage Area 4.10 ha Rainfall Data Land Use 0.00 ha Agriculture Rainfall Gauging Station = Peterborough 0.00 ha Range 100 Yr, 12 Hour Rainfall depth = 90.4 mm 2.53 ha Grass 0.00 ha Woods 0.00 ha Wetland Soil Type Otonabee Loam 0.00 ha Bare Earth (>70% Rock) 1.57 ha Impervious Hydrologic Soil Group 1 B Percent Impervious 38.3 % US Elev.= m DS Elev. = m Length m Slope 2.5 % Rolling Flat: 0-2% Slopes Rolling: 2-6% Slopes Hilly: >6% Slopes Land Use Composite Value Parameter Incl. Not Incl. Agriculture Range Grass Woods Wetland Bare Earth Imperv. Imperv. Imperv. >70% Rock Nashyd Standhyd Runoff Coefficient 2, C n.a. SCS Curve No. 3, CN Modified Curve No. 4, CN n.a. n.a. n.a. n.a n.a. n.a. n.a Initial Abstraction 5, mm min. Time of Concentration 6 Bransby - Method Airport Uplands 0.25 hr. Williams 10.1 min. Time to Peak 7 Tc (min) hr. Notes: 1. Hydrologic Soil Group obtained from Design Chart H2-6A, M.T.O. Drainage Manual, Runoff coefficient obtained from M.T.O. Design Chart 1.07, M.T.O. Drainage Management Manual, 1997, and Tables 4-5a to 4-5d, Maryland State Highway Administration. 3. SCS Curve No. obtained from M.T.O. Design Chart 1.09, M.T.O. Drainage Management Manual, 1997, and Table 2-2a, TR-55, page The modified curve number is adjusted as per Paul Wisner & Associates (1982) and represents anticedent moisture conditions Type II 5. Initial Abstraction values taken from the Environmental and Engineering Services Department, The Corporation of the City of London, Dec Use Airport Equation to calculate time of concentration for C <= 0.4, and Bransby-Williams for C > Minimum Time to Peak for use in the Rational Method and Hydrologic Model is 10 minutes Hydrology Calculations WS304

34 Hydrologic Parameters for WS305 Sheet 1 of 2 Project No: Project Name: Parkway EA Designed/Checked By: MJH / KS Date: 17-Oct-13 Drainage Area 0.74 ha Rainfall Data Land Use 0.00 ha Agriculture Rainfall Gauging Station = Peterborough 0.00 ha Range 100 Yr, 12 Hour Rainfall depth = 90.4 mm 0.37 ha Grass 0.00 ha Woods 0.00 ha Wetland Soil Type Otonabee Loam 0.00 ha Bare Earth (>70% Rock) 0.37 ha Impervious Hydrologic Soil Group 1 B Percent Impervious 50.0 % US Elev.= m DS Elev. = m Length m Slope 3.6 % Rolling Flat: 0-2% Slopes Rolling: 2-6% Slopes Hilly: >6% Slopes Land Use Composite Value Parameter Incl. Not Incl. Agriculture Range Grass Woods Wetland Bare Earth Imperv. Imperv. Imperv. >70% Rock Nashyd Standhyd Runoff Coefficient 2, C n.a. SCS Curve No. 3, CN Modified Curve No. 4, CN n.a. n.a. n.a. n.a n.a. n.a. n.a Initial Abstraction 5, mm min. Time of Concentration 6 Bransby - Method Airport Uplands 0.14 hr. Williams 5.5 min. Time to Peak 7 Tc (min) hr. Notes: 1. Hydrologic Soil Group obtained from Design Chart H2-6A, M.T.O. Drainage Manual, Runoff coefficient obtained from M.T.O. Design Chart 1.07, M.T.O. Drainage Management Manual, 1997, and Tables 4-5a to 4-5d, Maryland State Highway Administration. 3. SCS Curve No. obtained from M.T.O. Design Chart 1.09, M.T.O. Drainage Management Manual, 1997, and Table 2-2a, TR-55, page The modified curve number is adjusted as per Paul Wisner & Associates (1982) and represents anticedent moisture conditions Type II 5. Initial Abstraction values taken from the Environmental and Engineering Services Department, The Corporation of the City of London, Dec Use Airport Equation to calculate time of concentration for C <= 0.4, and Bransby-Williams for C > Minimum Time to Peak for use in the Rational Method and Hydrologic Model is 10 minutes Hydrology Calculations WS305

35 Rational Method for WS305 Sheet 2 of 2 Project No: Project Name: Parkway EA Designed/Checked By: MJH / KS Date: 17-Oct-13 Drainage Area A = 0.74 ha Percent Impervious % Imp = 50.0 % Slope S = 3.6 % Peterborough IDF Parameters 2 Year 5 Year 10 Year 25 Year 50 Year 100 Year a = b = c = Development Area C-value Tc Int. Flow Condition (ha) (min) (mm/hr) (m 3 /s) 25 mm Storm Year Year Year Year Year Year Notes : 1. Rainfall intensity rainfall data obtained for Peterborough 2. For storms having return period of more than 10 years the runoff coefficient was increased as follows to a maximum value of yr: add 10% 50 yr: add 20% 100 yr: add 25% 3. IDF parameters for the 25 mm storm: a: 405 b: 3.0 c: 0.76 Hydrology Calculations WS305

36 Hydrologic Parameters for Ex.WS3 Sheet 1 of 2 Project No: Project Name: Parkway EA Designed/Checked By: MJH / KS Date: 17-Oct-13 Drainage Area 0.74 ha Rainfall Data Land Use 0.00 ha Agriculture Rainfall Gauging Station = Peterborough 0.74 ha Range 100 Yr, 12 Hour Rainfall depth = 90.4 mm 0.00 ha Grass 0.00 ha Woods 0.00 ha Wetland Soil Type Otonabee Loam 0.00 ha Bare Earth (>70% Rock) 0.00 ha Impervious Hydrologic Soil Group 1 B Percent Impervious 0.0 % US Elev.= m DS Elev. = m Length m Slope 3.6 % Rolling Flat: 0-2% Slopes Rolling: 2-6% Slopes Hilly: >6% Slopes Land Use Composite Value Parameter Incl. Not Incl. Agriculture Range Grass Woods Wetland Bare Earth Imperv. Imperv. Imperv. >70% Rock Nashyd Standhyd Runoff Coefficient 2, C n.a. SCS Curve No. 3, CN Modified Curve No. 4, CN n.a. n.a. n.a. n.a n.a. n.a. n.a Initial Abstraction 5, mm min. Time of Concentration 6 Bransby - Method Airport Uplands 0.43 hr. Williams 17.3 min. Time to Peak 7 Tc (min) hr. Notes: 1. Hydrologic Soil Group obtained from Design Chart H2-6A, M.T.O. Drainage Manual, Runoff coefficient obtained from M.T.O. Design Chart 1.07, M.T.O. Drainage Management Manual, 1997, and Tables 4-5a to 4-5d, Maryland State Highway Administration. 3. SCS Curve No. obtained from M.T.O. Design Chart 1.09, M.T.O. Drainage Management Manual, 1997, and Table 2-2a, TR-55, page The modified curve number is adjusted as per Paul Wisner & Associates (1982) and represents anticedent moisture conditions Type II 5. Initial Abstraction values taken from the Environmental and Engineering Services Department, The Corporation of the City of London, Dec Use Airport Equation to calculate time of concentration for C <= 0.4, and Bransby-Williams for C > Minimum Time to Peak for use in the Rational Method and Hydrologic Model is 10 minutes Hydrology Calculations Ex.WS3

37 Rational Method for Ex.WS3 Sheet 2 of 2 Project No: Project Name: Parkway EA Designed/Checked By: MJH / KS Date: 17-Oct-13 Drainage Area A = 0.74 ha Percent Impervious % Imp = 0.0 % Slope S = 3.6 % Peterborough IDF Parameters 2 Year 5 Year 10 Year 25 Year 50 Year 100 Year a = b = c = Development Area C-value Tc Int. Flow Condition (ha) (min) (mm/hr) (m 3 /s) 25 mm Storm Year Year Year Year Year Year Notes : 1. Rainfall intensity rainfall data obtained for Peterborough 2. For storms having return period of more than 10 years the runoff coefficient was increased as follows to a maximum value of yr: add 10% 50 yr: add 20% 100 yr: add 25% 3. IDF parameters for the 25 mm storm: a: 405 b: 3.0 c: 0.76 Hydrology Calculations Ex.WS3

38 Hydrologic Parameters for 301-NEW Sheet 1 of 1 Project No: Project Name: Parkway EA Designed/Checked By: MJH / KS Date: 17-Oct-13 Drainage Area ha Rainfall Data Land Use 0.00 ha Agriculture Rainfall Gauging Station = Peterborough 0.00 ha Range 100 Yr, 12 Hour Rainfall depth = 90.4 mm ha Grass 0.00 ha Woods 0.00 ha Wetland Soil Type Otonabee Loam 0.00 ha Bare Earth (>70% Rock) ha Impervious Hydrologic Soil Group 1 B Percent Impervious 18.5 % US Elev.= m DS Elev. = m Length m Slope 0.2 % Flat Flat: 0-2% Slopes Rolling: 2-6% Slopes Hilly: >6% Slopes Hydrology Calculations 301-NEW

39 Hydrologic Parameters for 302-NEW Sheet 1 of 1 Project No: Project Name: Parkway EA Designed/Checked By: MJH / KS Date: 17-Oct-13 Drainage Area ha Rainfall Data Land Use 0.00 ha Agriculture Rainfall Gauging Station = Peterborough 0.00 ha Range 100 Yr, 12 Hour Rainfall depth = 90.4 mm ha Grass 0.00 ha Woods 0.00 ha Wetland Soil Type Otonabee Loam 0.00 ha Bare Earth (>70% Rock) ha Impervious Hydrologic Soil Group 1 B Percent Impervious 25.0 % US Elev.= m DS Elev. = m Length m Slope 2.0 % Flat Flat: 0-2% Slopes Rolling: 2-6% Slopes Hilly: >6% Slopes Hydrology Calculations 302-NEW

40 Intensity Duration Frequency Statistics for Peterborough Parameters as supplied by City of Peterborough on Nov. 8, 2006 Parameters values based on data analyis for Peterborough Airport Rainfall Intensity (mm/hr) = a/(tc+b)^c where Tc is the Time of concentration in minutes 2 Year Return Interval Duration (min) Intensity (mm/hr) Fitted Measured a b c Year Return Interval (Interpolated) Duration (min) Intensity (mm/hr) Fitted Measured a b c Year Return Interval Duration (min) Intensity (mm/hr) Fitted Measured a b c

41 10 Year Return Interval Duration (min) Intensity (mm/hr) Fitted Measured a b c Year Return Interval Duration (min) Intensity (mm/hr) Fitted Measured a b c Year Return Interval Duration (min) Intensity (mm/hr) Fitted Measured a b c Year Return Interval Duration (min) Intensity (mm/hr) Fitted Measured a b c

42 Appendix B Quality and Quantity Controls

43 Wet Pond Facility

44 Quality Control Requirements - MOE Table 3.2 Sheet 1 of 3 Project No: Project Name: Parkway EA - South End Designed/Checked By: MJH / KS Date: October 22, Site Data Area = 9.26 ha % Imp Calculated = 54.0 % Imp Area = 5.00 ha 2. Storage Requirements Facility Type: Level of Protection: Wet Pond Enhanced 3. Req'd Storage Volume 4. Req'd Extended Detention Volume 5. Req'd Perm. Pool Volume Vs = 188 m 3 /ha (Table 3.2, p. 3 10, SWMP Manual) Vs = 1736 m 3 Ved = 40 m 3 /ha (Table 3.2, p. 3 10, SWMP Manual) Ved = 370 m 3 Ved 25mm = 964 m 3 Ved Provided = 1024 m 3 Vpp = 148 m 3 /ha (Table 3.2, p. 3 10, SWMP Manual) Vpp = 1366 m 3 Vpp Provided = 1405 m 3 1 From Table 3.2 of the SWMPD Manual Enhanced - Wet Pond Impervious Level Storage Volume (m³/ha) 35% % % % Table 3.2, SWMP Manual Volume Per Ha (m3/ha) Percent Impervious (%) 5061_2 Pond Quality V1.01.xlsx MOE Table 3.2

45 Quality Control Requirements - Forebay Sheet 2 of 3 Project No: Project Name: Parkway EA - South End Designed/Checked By: MJH / KS Date: October 17, Settling Length, Lf (min.) r = 3.0 : 1 (length to width ratio) Minimum = 2.0 : 1 Contributing Area = 9.3 ha Q= m 3 /s (25 mm storm pond outflow) Q= m 3 /s (Eq'n 4.8 & 4.9, p. 4-57) Vs = m/s (settling velocity for 150 micron particles see page 4-55 in SWMP Manual) Lf = 13 m Equation 4.5, p. 4-55, SWMP Manual Provided = 53 m 2 Dispersion Length, Ld (min.) Qi = 0.61 m 3 /s (10 year storm or inlet pipe capacity) Inlet Pipe d = 1.50 m (perm. pool depth) Vf = 0.50 m/s (desired velocity prior to erosion see page 4-56 in SWMP Manual) Ld = 7 m Equation 4.6, p. 4-56, SWMP Manual Provided = 53 m 3 Bottom Width, Wb (min.) Dist. = 53 m (Length at surface) Wb = 7 m Equation 4.7, p. 4-56, SWMP Manual Provided = 7 m 4 Surface Area, As (max.) At = 1750 m 2 (total perm. pool surface area) As = 685 m 2 (Sediment Forebay Area) Maximum = 33% (Maximum surface Area of Forebay) Provided = 39% Vt = 1405 m 3 (Total perm. pool Volume) Vs = 573 m 3 (Forebay perm. pool Volume) Maximum = 20% (Maximum Volume of Forebay) Provided = 41% 5061_2 Pond Quality V1.01.xlsx Forebay

46 Quality Control Requirements - Clean Out Frequency Sheet 3 of 3 Project No: Project Name: Parkway EA - South End Designed/Checked By: MJH / KS Date: October 17, TSS Removal Efficiency 2 Target Maintenance Removal Level of Protection = Enhanced TSS Removal is = 80 % Target Rate = Level 1 5% Target Rate = 75 % 3 Annual Sediment Production Avg. Removal Rate = ( Level 2 + Target Rate ) / 2 Avg. = 77.5 % From Table 6.3 in SWMP Manual, the annual sediment loading for 35% imperviousness is: Imp. % Loading m 3 /ha m 3 /ha m 3 /ha m 3 /ha % Imp Calculated = 54 % Facility Type = Wet Pond Sl = 1.84 m 3 /ha Annual Sediment Production is: Sa = Area x Sl x Avg. Removal Rate Contributing Area = 9.26 ha Sa = m 3 4 Permissible Accumulated Sediment Volume Permitted = Total Permanent Pool Target Volume Permanent Pool Provided = 1405 m 3 Storage Volume per Hectare = 152 Target Volume for 75% Removal = m 3 /ha Target Volume = 1002 m 3 (Interpolated from Table 3.2 SWMP) Sediment Vol. Permitted = 403 m 3 5a 5b Cleanout Frequency by Sediment Production Calculations Removal Frequency = 31 years Cleanout Frequency by Storage Volume vs. Removal Frequency Curves Sediment Removal Frequency = 26.9 years Interpolated from Figures and 6.3, pages 6-11, 6-12 Operation, Maintenance and Monitoring Sediment Accumulated B/W Cleanout = 354 m 3 6 Drying Area Required Recommended Sediment Removal Frequency = 10.0 years Sediment Volume Accumulated Between Cleanout = 132 m 3 Depth of Sediment to be Dryed = 0.30 m Minimum Drying Area Required = 439 m _2 Pond Quality V1.01.xlsx Clean Out Frequency

47 110mm Orifice Plate 27 Hours

48 Stage - Storage - Discharge Sheet 1 of 1 Project No: Project Name: Parkway EA Designed/Checked By: MJH / KS Date: 17-Oct-13 Summary of Conceptual Rating Curve Elevation Stage Peak Flows Volume Notes m m m 3 /s m 3 ham Passive / Dead Storage-Retention Storage Bottom of Dead Storage , Top of Dead Storage Stage 1 Orifice Riser Control Stage 2 Orifice Weir Control Total Discharge Rate Elevation Stage < - Invert Elevation Notes - mm - mm - mm width - m Volume m m m 3 /s m 3 ham Active Storage-Extended Detention Zone+Attenuation Zone+Freeboard , < - 25 mm 4 hour m , , , < - Top of Active Storage , , , < Top of Pond Notes: The volumes are derived from AutoCAD - CIVIL 3D 2012 Cd for Orifice Plate = 0.6 Outlet Pipe 1 = 900mm diameter 2 % - Q = cms, V = 2.18 m/s Peak flow in Pipe = cms, therefore 91 % full 100 Year Uncontrolled Peak Flow into the Pond = 4.4 cms, conveyed by the 29.4 m Weir At a depth of 0.2 m (Elev m) assuming blockage of the outlet system

49 Stage-Storage Summation Table - Storage-SUM 1 of 2 Project No: Project Name: Parkway EA Designed/Checked By: MJH / KS Date: October 17, 2013 Contour Elevation Stage AC (1) AC (2) AC (3) SUM (m) (m) (m 3 ) (m 3 ) (m 3 ) (m 3 ) (m 3 ) (m 3 ) (m 3 ) (m 3 ) (m 3 ) (m 3 )

50 Contour Elevation Stage AC (1) AC (2) AC (3) of 2 SUM (m) (m) (m 3 ) (m 3 ) (m 3 ) (m 3 ) (m 3 ) (m 3 ) (m 3 ) (m 3 ) (m 3 ) (m 3 )

51 Stage-Storage - AC (1) 1 of 1 Project No: Parkway EA Project Name: Designed/Checked By: MJH / KS Date: Thursday, October 17, 2013 Elevation Stage Total Volume Total Volume (m) (m) (m 3 ) (ha.m) << Bottom of Ponding = << Top of Ponding =

52 Stage-Storage - AC (2) 1 of 1 Project No: Parkway EA Project Name: Designed/Checked By: MJH / KS Date: Thursday, October 17, 2013 Elevation Stage Total Volume Total Volume (m) (m) (m 3 ) (ha.m) << Bottom of Ponding = << Top of Ponding =

53 Stage-Storage - AC (3) 1 of 1 Project No: Parkway EA Project Name: Designed/Checked By: MJH / KS Date: Thursday, October 17, 2013 Elevation Stage Total Volume Total Volume (m) (m) (m 3 ) (ha.m) << Bottom of Ponding = << Top of Ponding =

54 Fairbairn Project: Basin Contour Contour Depth Incremental Cumulative Incremental Cumulative Elevation Area (m) Volume Volume Volume Volume (sq. m) Avg. End Avg. End Conic Conic (cu. m) (cu. m) (cu. m) (cu. m) N/A N/A 0.00 N/A , , , , , , , , , , , , , , file:///f /...on%20park/03%20-%20appendix/appendix%20b%20-%20quality%20and%20quantity/ws301/fairbairn%20wet%20pond.txt[10/17/2013 3:39:02 PM]

55 , , , , , , , , , , , , , , , , , , , , , , file:///f /...on%20park/03%20-%20appendix/appendix%20b%20-%20quality%20and%20quantity/ws301/fairbairn%20wet%20pond.txt[10/17/2013 3:39:02 PM]

56 Mechanics of Fluids, 3rd Edition Merle C. Potter & David C. Wiggert 2002 Wadsworth Group. Books/Cole ISBN Weir Calculations

57

58

59 Underground

60 Modified Rational Method for WS305 Project Name: Parkway EA - Jackson Creek Designed By: MJH Project No: Checked By: KS Date: October 18, 2013 Sheet 1 of 1 Drainage Area 0.74 ha Runoff Coefficient 0.53 Rainfall Data Extranious Flows 0.00 m 3 /s Rainfall Gauging Station : Peterborough Bottom of Tc Range 15.0 min 100 Yr, 12 Hour Rainfall depth = 90.4 mm Time Increment 1.0 min Discharge Rate m 3 /s Return Interval Storm 5 Year IDF Parameters a: 1098 Storage Required m 3 b: 10.1 c: 0.83 Inflow Volume T I (m 3 /s) (m 3 ) (min) (mm/hr) Catchment Extranious Incoming Released Runoff Flows Net Storage _02 - MRM.xls 5 Year Page 1

61 Modified Rational Method for WS305 Project Name: Parkway EA - Jackson Creek Designed By: MJH Project No: Checked By: KS Date: October 18, 2013 Sheet 1 of 1 Drainage Area 0.74 ha Runoff Coefficient 0.58 Rainfall Data Extranious Flows 0.00 m 3 /s Rainfall Gauging Station : Peterborough Bottom of Tc Range 15.0 min 100 Yr, 12 Hour Rainfall depth = 90.4 mm Time Increment 1.0 min Discharge Rate m 3 /s Return Interval Storm 25 Year IDF Parameters a: 2010 Storage Required m 3 b: 14 c: 0.88 Inflow Volume T I (m 3 /s) (m 3 ) (min) (mm/hr) Catchment Extranious Incoming Released Net Storage Runoff Flows _02 - MRM.xls 25 Year Page 2

62 Modified Rational Method for WS305 Project Name: Parkway EA - Jackson Creek Designed By: MJH Project No: Checked By: KS Date: October 18, 2013 Sheet 1 of 1 Drainage Area 0.74 ha Runoff Coefficient 0.66 Rainfall Data Extranious Flows 0.00 m 3 /s Rainfall Gauging Station : Peterborough Bottom of Tc Range 15.0 min 100 Yr, 12 Hour Rainfall depth = 90.4 mm Time Increment 1.0 min Discharge Rate m 3 /s Return Interval Storm 100 Year IDF Parameters a: 2507 Storage Required m 3 b: 14.8 c: 0.88 Inflow Volume T I (m 3 /s) (m 3 ) (min) (mm/hr) Catchment Extranious Incoming Released Net Storage Runoff Flows _02 - MRM.xls 100 Year Page 3

63 Stage-Storage-Discharge - 600mm 1 of 1 Project No: Parkway EA Project Name: Designed/Checked By: MJH / KS Date: Friday, October 18, 2013 Total Volume Total Volume Elevation Stage Length of Pipe = m (m) (m) (m 3 ) (ha.m) Diameter of Pipe = mm << Downstream Invert = 100 Slope of Pipe = 0.00 % Downstream Invert = m << Upstream Obvert =

64 City of Peterborough J a c k s on C r e e k F l o o d R e d u c t i o n M a s t e r P l a n Figure Jackson Urban Overland Flow 100-year storm

65 City of Peterborough J a c k s on C r e e k F l o o d R e d u c t i o n M a s t e r P l a n Figure 3.8. Estimated Storm Sewer Capacity Southwest Jackson

66 Stormceptor Sizing Detailed Report PCSWMM for Stormceptor Project Information Date 10/18/2013 Project Name Project Number 5061 Location Parkway EA Peterborough Stormwater Quality Objective This report outlines how Stormceptor System can achieve a defined water quality objective through the removal of total suspended solids (TSS). Attached to this report is the Stormceptor Sizing Summary. Stormceptor System Recommendation The Stormceptor System model STC 300 achieves the water quality objective removing 81% TSS for a Fine (organics, silts and sand) particle size distribution and 96% runoff volume. The Stormceptor System The Stormceptor oil and sediment separator is sized to treat stormwater runoff by removing pollutants through gravity separation and flotation. Stormceptor s patented design generates positive TSS removal for all rainfall events, including large storms. Significant levels of pollutants such as heavy metals, free oils and nutrients are prevented from entering natural water resources and the re-suspension of previously captured sediment (scour) does not occur. Stormceptor provides a high level of TSS removal for small frequent storm events that represent the majority of annual rainfall volume and pollutant load. Positive treatment continues for large infrequent events, however, such events have little impact on the average annual TSS removal as they represent a small percentage of the total runoff volume and pollutant load. Stormceptor is the only oil and sediment separator on the market sized to remove TSS for a wide range of particle sizes, including fine sediments (clays and silts), that are often overlooked in the design of other stormwater treatment devices. 1

67 Small storms dominate hydrologic activity, US EPA reports Early efforts in stormwater management focused on flood events ranging from the 2-yr to the 100-yr storm. Increasingly stormwater professionals have come to realize that small storms (i.e. < 1 in. rainfall) dominate watershed hydrologic parameters typically associated with water quality management issues and BMP design. These small storms are responsible for most annual urban runoff and groundwater recharge. Likewise, with the exception of eroded sediment, they are responsible for most pollutant washoff from urban surfaces. Therefore, the small storms are of most concern for the stormwater management objectives of ground water recharge, water quality resource protection and thermal impacts control. Most rainfall events are much smaller than design storms used for urban drainage models. In any given area, most frequently recurrent rainfall events are small (less than 1 in. of daily rainfall). Continuous simulation offers possibilities for designing and managing BMPs on an individual site-by-site basis that are not provided by other widely used simpler analysis methods. Therefore its application and use should be encouraged. US EPA Stormwater Best Management Practice Design Guide, Volume 1 General Considerations, 2004 Design Methodology Each Stormceptor system is sized using PCSWMM for Stormceptor, a continuous simulation model based on US EPA SWMM. The program calculates hydrology from up-to-date local historical rainfall data and specified site parameters. With US EPA SWMM s precision, every Stormceptor unit is designed to achieve a defined water quality objective. The TSS removal data presented follows US EPA guidelines to reduce the average annual TSS load. Stormceptor s unit process for TSS removal is settling. The settling model calculates TSS removal by analyzing (summary of analysis presented in Appendix 2): Site parameters Continuous historical rainfall, including duration, distribution, peaks (Figure 1) Interevent periods Particle size distribution Particle settling velocities (Stokes Law, corrected for drag) TSS load (Figure 2) Detention time of the system The Stormceptor System maintains continuous positive TSS removal for all influent flow rates. Figure 3 illustrates the continuous treatment by Stormceptor throughout the full range of storm events analyzed. It is clear that large events do not significantly impact the average annual TSS removal. There is no decline in cumulative TSS removal, indicating scour does not occur as the flow rate increases. 2

68 Figure 1. Runoff Volume by Flow Rate for PETERBOROUGH A ON 6418, 1971 to 2002 for 0.74 ha, 50% impervious. Small frequent storm events represent the majority of annual rainfall volume. Large infrequent events have little impact on the average annual TSS removal, as they represent a small percentage of the total annual volume of runoff. Figure 2. Long Term Pollutant Load by Flow Rate for PETERBOROUGH A 6418, 1971 to 2002 for 0.74 ha, 50% impervious. The majority of the annual pollutant load is transported by small frequent storm events. Conversely, large infrequent events carry an insignificant percentage of the total annual pollutant load. 3

69 Stormceptor Model TSS Removal (%) STC Drainage Area (ha) Impervious (%) Figure 3. Cumulative TSS Removal by Flow Rate for PETERBOROUGH A 6418, 1971 to Stormceptor continuously removes TSS throughout the full range of storm events analyzed. Note that large events do not significantly impact the average annual TSS removal. Therefore no decline in cumulative TSS removal indicates scour does not occur as the flow rate increases. 4

70 Appendix 1 Stormceptor Design Summary Project Information Date 10/18/2013 Project Name Parkway EA Project Number 5061 Location Designer Information Company Peterborough D.M. Wills Assoicates Limited Rainfall Name PETERBOROUGH A State ON ID 6418 Years of Records 1971 to 2002 Latitude 44 14'N Contact Mark Hoar, P.Eng. Longitude 78 22'W Notes N/A Drainage Area Total Area (ha) 0.74 Imperviousness (%) 50 The Stormceptor System model STC 300 achieves the water quality objective removing 81% TSS for a Fine (organics, silts and sand) particle size distribution and 96% runoff volume. Water Quality Objective TSS Removal (%) 80 Runoff Volume (%) 85 Upstream Storage Storage Discharge (ha-m) (L/s) Stormceptor Sizing Summary Stormceptor Model TSS Removal Runoff Volume % % STC STC STC STC STC STC STC STC STC STC STC STC

71 Particle Size Distribution Removing silt particles from runoff ensures that the majority of the pollutants, such as hydrocarbons and heavy metals that adhere to fine particles, are not discharged into our natural water courses. The table below lists the particle size distribution used to define the annual TSS removal. Fine (organics, silts and sand) Particle Size Distribution Specific Settling Specific Settling Particle Size Distribution Gravity Velocity Gravity Velocity µm % m/s µm % m/s Stormceptor Design Notes Stormceptor performance estimates are based on simulations using PCSWMM for Stormceptor version 1.0 Design estimates listed are only representative of specific project requirements based on total suspended solids (TSS) removal. Only the STC 300 is adaptable to function with a catch basin inlet and/or inline pipes. Only the Stormceptor models STC 750 to STC 6000 may accommodate multiple inlet pipes. Inlet and outlet invert elevation differences are as follows: Inlet and Outlet Pipe Invert Elevations Differences Inlet Pipe Configuration STC 300 STC 750 to STC 9000 to STC 6000 STC Single inlet pipe 75 mm 25 mm 75 mm Multiple inlet pipes 75 mm 75 mm Only one inlet pipe. Design estimates are based on stable site conditions only, after construction is completed. Design estimates assume that the storm drain is not submerged during zero flows. For submerged applications, please contact your local Stormceptor representative. Design estimates may be modified for specific spills controls. Please contact your local Stormceptor representative for further assistance. For pricing inquiries or assistance, please contact Imbrium Systems Inc.,

72 Appendix 2 Summary of Design Assumptions SITE DETAILS Site Drainage Area Total Area (ha) 0.74 Imperviousness (%) 50 Surface Characteristics Width (m) 172 Slope (%) 2 Impervious Depression Storage (mm) Pervious Depression Storage (mm) 5.08 Impervious Manning s n Pervious Manning's n 0.25 Maintenance Frequency Sediment build-up reduces the storage volume for sedimentation. Frequency of maintenance is assumed for TSS removal calculations. Maintenance Frequency (months) 12 Infiltration Parameters Horton s equation is used to estimate infiltration Max. Infiltration Rate (mm/h) Min. Infiltration Rate (mm/h) Decay Rate (s -1 ) Regeneration Rate (s -1 ) 0.01 Evaporation Daily Evaporation Rate (mm/day) 2.54 Dry Weather Flow Dry Weather Flow (L/s) No Upstream Attenuation Stage-storage and stage-discharge relationship used to model attenuation upstream of the Stormceptor System is identified in the table below. Storage Discharge ha-m L/s

73 PARTICLE SIZE DISTRIBUTION Particle Size Distribution Removing fine particles from runoff ensures the majority of pollutants, such as heavy metals, hydrocarbons, free oils and nutrients are not discharged into natural water resources. The table below identifies the particle size distribution selected to define TSS removal for the design of the Stormceptor System. Fine (organics, silts and sand) Distribution Specific Settling Specific Particle Size Distribution Gravity Velocity Gravity µm % m/s µm % m/s Particle Size Settling Velocity Figure 1. PCSWMM for Stormceptor standard design grain size distributions. 8