Edgehill Properties Limited c/o Wrighthaven Homes Ltd.

Transcription

1 Prepared By: Edgehill Properties Limited c/o Wrighthaven Homes Ltd. FUNCTIONAL SERVICING AND STORMWATER MANAGEMENT REPORT Granwood Gate Subdivision, Phase III Township of Centre Wellington (Elora) GMBP File No Revised February 2018 Guelph Owen Sound Listowel Kitchener London Hamilton GTA 650 Woodlawn Rd. W., Block C, Unit 2, Guelph ON N1K 1B8 P:

2 FUNCTIONAL SERVICING AND SWM REPORT EDGEHILL PROPERTIES LIMITED C/O WRIGHTHAVEN HOMES LTD. GRANWOOD GATE SUBDIVISION, PHASE III GMBP FILE NO REVISED FEBRUARY 2018 TABLE OF CONTENTS 1. INTRODUCTION SITE INFORMATION PROPOSED DEVELOPMENT Sanitary System Storm System Water System STORMWATER MANAGEMENT Design Criteria Pre-Development Conditions Post-Development Conditions Routing WATER QUALITY ROADWAYS AND GRADING CONCLUSIONS... 8 LIST OF FIGURES Figure No. 1 Figure No. 2 Figure No. 3 Figure No. 4 Figure No. 5 Figure No. 6 Site Location Map Site Layout Typical Road Cross Section Granwood Subdivision Pond Outlet Pre-Development Drainage Area Plan Post-Development Drainage Area Plan LIST OF APPENDICES Appendix A Appendix B Appendix C Appendix D Appendix E Appendix F LIST OF DRAWINGS Drawing No. 1 Drawing No. 2 Drawing No. 3 Preliminary Geotechnical Investigation, prepared by Trow Consulting Engineers Ltd., revised August 27, 1999 Township of Centre Wellington Preliminary Outlet Storm Sewer Design MIDUSS IDF Curve Fit Modeling Pre-Development MIDUSS Computer Model Output for the 2-, 5- and 100-Year Design Storms Post-Development MIDUSS Computer Model Output for the 2-, 5- and 100-Year Design Storms and Stage-Storage Discharge Calculation Tables Wetland Sizing Details Preliminary General Servicing Proposed Grading Stormwater Management Facility Sections I

3 FUNCTIONAL SERVICING AND SWM REPORT EDGEHILL PROPERTIES LIMITED C/O WRIGHTHAVEN HOMES LTD. GRANWOOD GATE SUBDIVISION, PHASE III GMBP FILE NO REVISED FEBRUARY 2018 FUNCTIONAL SERVICING AND STORMWATER MANAGEMENT REPORT WRIGHTHAVEN HOMES LIMITED GRANWOOD GATE SUBDIVISION, PHASE III TOWNSHIP OF CENTRE WELLINGTON (ELORA) FEBRUARY 2018 GMBP FILE NO INTRODUCTION In support of the Draft Plan of Subdivision Application, this Functional Servicing and Stormwater Management Report documents the proposed site servicing and stormwater management design for the proposed Phase III of the Granwood Subdivision located in the Village of Elora within the Township of Centre Wellington (Town), as shown on Figure No. 1. The Granwood Gate Subdivision was originally designed by K.J. Behm & Associates Inc. and approved in approximately The subdivision was proposed to be constructed in three (3) phases. Phase I and II have since been fully serviced and residents have been living within Phase I and II for several years. Phase III was rough graded, but was never serviced. This current Draft Plan of Subdivision Application and Functional Servicing and Stormwater Management Report are being submitted due to the lapse of the previous Draft Plan and conditions. This Functional Servicing and Stormwater Management Report was revised as per Township comments and supersedes all previous Functional Servicing and Stormwater Management Reports. The existing and proposed site details are shown on the Preliminary Site Grading and Servicing Plans (attached). 2. SITE INFORMATION Phase III covers an area of approximately 8.76 hectares and consists of a total of 54 single family residential lots, 12 semi-detached lots, 20 on-street townhouses, 66 stacked townhouses, a walkway block and a stormwater management block, as shown on Figure No. 2. The site is currently vacant with grass and shrubbery cover. The subject property is irregular in shape with a frontage of approximately 335 metres along Waterloo Street. For the purposes of this report, the Waterloo Street right-of-way adjacent to the site is assumed to run northsouth and is assumed to be west of the site. The site is bound to the north by residential lots located along the south side of McNab Street East, Clarke Street and York Street (Granwood Gate Subdivision Phase I and II) to the east, Waterloo Street to the west, and bound to the south by the Trestle Bridge Trail followed by the Jefferson Elora Corporation property. 1 OF 5

4 GRANWOOD GATE SUBDIVISION, PHASE 3 TOWNSHIP OF CENTRE WELLINGTON (ELORA) N MELVILLE ST. CHALMERS ST. EAST MILL ST. BRIDGE ST. CUTTING DR. DICKSON CRT. PRINCESS ST. WALKING BRIDGE TRAIL YORK ST. E RONALD ST. FILE:W:\Guelph\ \ Granwood SWM Review\5 Work In Progress\Drafting\ FIGURES.dwg LAYOUT:SITE MAP LAST SAVED BY:Fcrew, 3/1/2018 1:28:00 PM PLOTTED BY:Field Crew - GM BluePlan 3/1/2018 3:56:42 PM METCALF ST. CARLTON PL. WELLINGTON RD. 7 McNAB ST. GEDDES ST. EAST MILL ST. METCALF ST. VICTORIA ST. CLYDE ST. HIGH ST. Not To Scale GRAND RIVER WATER ST. WELLINGTON ST. McNAB ST. PARK RD. WATERLOO ST. NICHOL ST. YORK ST. W WATER ST. ELGIN ST. CLARK ST. McNAB ST. SUBJECT PROPERTY YORK ST. E FISHER ST. TRESTLE BRIDGE TRAIL HALLS DR. CLARKE ST. BRIDGE ST. MURRAY DR. SITE LOCATION MAP Figure No. 1 BluePlan ENGINEERING FEBRUARY 2018 Scale: N.T.S. NAD 1983 UTM Zone 17N

5 FILE:W:\Guelph\ \ Granwood SWM Review\5 Work In Progress\Drafting\ FIGURES.dwg LAYOUT:SITE LAYOUT LAST SAVED BY:Fcrew, 3/1/2018 1:28:00 PM PLOTTED BY:Field Crew - GM BluePlan 3/1/2018 3:56:42 PM DRAFT PLAN PREPARED BY BLACK, SHOWMAKER, ROBINSON AND DONALDSON LTD. DATED FEBUARY 2, GRANWOOD GATE SUBDIVISION, PHASE 3 TOWNSHIP OF CENTRE WELLINGTON (ELORA) LEGEND MUNICIPAL RIGHT OF WAY PROPOSED LOTLINES EXISTING LOT LINES SUBDIVISION BOUNDARY :2000 (m) SITE LAYOUT Figure No. 2 BluePlan ENGINEERING FEBRUARY 2018 Scale: 1:2000 NAD 1983 UTM Zone 17N N

6 FUNCTIONAL SERVICING AND SWM REPORT EDGEHILL PROPERTIES LIMITED C/O WRIGHTHAVEN HOMES LTD. GRANWOOD GATE SUBDIVISION, PHASE III GMBP FILE NO REVISED FEBRUARY 2018 The Wellington County Soils Map (Ontario Soil Survey Report No. 35), prepared by the Department of Agriculture, describe soils at the site as smooth, gently sloping, Grey-Brown Podzolic, stone free loam till, with good drainage characteristics. A Preliminary Geotechnical Investigation was completed by Trow Consulting Engineers Ltd., revised August 27, 1999 for the site and is included as Appendix A. A total of four (4) test pits were completed on-site which found surficial topsoil which was underlain by fill which was underlain by sandy silt till. The Geotechnical Investigation estimates the groundwater on-site to be 1.8m to 4.1m below grade. The hydraulic conductivity of the underlying soils is estimated at 1x10-6 cm/sec. Under existing conditions the subject property generally slopes from the east to the west. 3. PROPOSED DEVELOPMENT The proposed development includes 54 single family residential lots, 12 semi-detached lots, 20 on-street townhouses, 66 stacked townhouses, walkway blocks, a stormwater management block and roadways throughout. A typical on-site roadway section is shown on Figure No Sanitary System The sanitary sewer system throughout the entire subdivision was originally designed by K.J. Behm & Associates Inc. in approximately Phase I and II have since been fully serviced and residents have been living within Phase I and II for several years. During the detailed design stage for Phase III, the sanitary sewer design will be peer reviewed in more; detail however at this time, it is anticipated that no capacity issues will exist with the current sanitary sewer system or downstream outlet sewers. A portion of the Phase III sanitary sewer was constructed during the development of Phase II along the proposed York street right-of-way in order to service the westerly portion of Phase II. The existing 200mm diameter sanitary sewer continues north along Waterloo Street to Nichol Street and then turns west on Nichol Street. Sanitary service connections to the proposed lots in Phase III were also constructed; however the lot fabric of the development has been revised since the time of construction. The existing service connections will therefore be relocated and/or abandoned as necessary to service the proposed Phase III lots and the existing sanitary sewer will be maintained. As part of Phase III, the sanitary sewer will be extended along Waterloo Street from York Street to the south for approximately 170 metres. This extension will serve as an outlet for the sanitary flows from Halls Drive within Phase III. Individual lateral service connections will be provided for each lot as per current municipal and provincial standards. 3.2 Storm System As per current practice and guidelines, the stormwater management approach for this development is a treatment train designed to remove sediment prior to discharge to the existing municipal storm sewer system. The treatment train will include lot level and end-of-pipe management practices. Lot level controls will consist of directing roof leaders to grassed surfaces to promote infiltration. End-ofpipe controls will be provided by a wetland type stormwater management (SWM) facility located along the west property limit of the Phase III development, adjacent to the Waterloo Street right-of-way. Oil/grit 2 OF 8

7 FILE:W:\Guelph\ \ Granwood SWM Review\5 Work In Progress\Drafting\ FIGURES.dwg LAYOUT:TYP. X-SEC LAST SAVED BY:Fcrew, 3/1/2018 1:28:00 PM PLOTTED BY:Field Crew - GM BluePlan 3/1/2018 3:56:43 PM TYPICAL CROSS SECTION FOR 8.0m ROAD ON 20.0m R.O.W. N.T.S. GRANWOOD GATE SUBDIVISION, PHASE 3 TOWNSHIP OF CENTRE WELLINGTON (ELORA) Not To Scale TYPICAL ROAD CROSS SECTION Figure No. 3 BluePlan ENGINEERING FEBRUARY 2018 Scale: N.T.S.

8 FUNCTIONAL SERVICING AND SWM REPORT EDGEHILL PROPERTIES LIMITED C/O WRIGHTHAVEN HOMES LTD. GRANWOOD GATE SUBDIVISION, PHASE III GMBP FILE NO REVISED FEBRUARY 2018 separators will also be utilized as part of the treatment train approach to stormwater quality control. These units will be placed within the storm sewer network prior to discharging to the stormwater management pond. The specific design of these oil/grit separators will be considered at the time of detailed design. Minor storm runoff from the development will discharge to the SWM facility via the proposed municipal storm sewer system. Major storm runoff exceeding the capacity of the storm sewer system will be conveyed overland via the municipal right-of-way to the SWM facility. There is currently no outlet for the proposed SWM facility. As part of the Phase III development, a storm sewer outlet is proposed from the outlet pipe of the SWM facility, along Waterloo Street, York Street West, and High Street north to McNab Street, for a distance of approximately 550 metres, where a connection is proposed to the existing 975mm diameter storm sewer that ultimately discharges to the Grand River. The existing 975mm storm sewer outlet to the Grand River was installed by the municipality in anticipation of the proposed Phase III development. The location of the proposed storm sewer is shown in Figure No. 4. Preliminary design of the proposed storm sewer outlet was prepared by the Township of Centre Wellington, and is provided in Appendix B. The design of the proposed storm sewer outlet will be finalized the time of detailed design. A portion of the Phase III development is proposed to outlet eastward to the existing Phase I & II SWM Pond. The Phase I & II pond was designed to accommodate this portion of the Phase III development. A portion of the Phase III development will drain uncontrolled off-site to the existing Trestle Bridge Trail ditch south of the site. The Phase III SWM facility will be designed with a sediment forebay to provide energy dissipation and promote sediment settlement. The facility will also be designed with an outlet structure to attenuate flows to the proposed storm sewer outlet. As per Township standards, storm services will be provided to each lot which will be provided on the Plans during the detailed design. Further details regarding the SWM facility are provided in Section 4.0 below. 3.3 Water System A 200mm diameter municipal watermain currently exists along Waterloo Street from approximately South Queen Street to Nichol Street and within the York Street East right-of-way through Phase III. A watermain also currently exists along Fisher Street and Halls Drive within the Phase II portion of the subdivision and is currently stubbed at the boundary of Phase III. A portion of the Phase III watermain was constructed during the development of Phase II along the proposed York street right-of-way. The existing 200mm diameter watermain continues north along Waterloo Street to Nichol Street and then turns west on Nichol Street. As part of the Phase III development, the existing watermain on Waterloo Street will be extended southerly for approximately 50 metres and will connect to Halls Drive with a 90 degree bend. The existing watermain on Halls Drive will be extended from the existing stub and connect to the proposed watermain extension on Waterloo Street. A watermain is also proposed on Carter Place which will tee off of the existing watermain located within the York Street East right-of-way within Phase III and be installed to the end of the cul-de-sac, terminating at a hydrant to provide flushing and maintenance capabilities. 3 OF 8

9 FILE:W:\Guelph\ \ Granwood SWM Review\5 Work In Progress\Drafting\ FIGURES.dwg LAYOUT:OUTLET FIG LAST SAVED BY:Fcrew, 3/1/2018 1:28:00 PM PLOTTED BY:Field Crew - GM BluePlan 3/1/2018 3:56:43 PM THIS DATA IS FOR ILLUSTRATIVE PURPOSES ONLY. INFORMATION CONTAINED HEREON IS NOT A SUBSTITUTE FOR PROFESSIONAL REVIEW OR A SITE SURVEY AND IS SUBJECT TO CHANGE WITHOUT NOTICE. WELLINGTON COUNTY, AND GM BLUEPLAN TAKE NO RESPONSIBILITY FOR, NOR GUARANTEES, THE ACCURACY OF THE INFORMATION CONTAINED ON THIS MAP. ANY INTERPRETATIONS OR CONCLUSIONS DRAWN FROM THIS MAP ARE THE SOLE RESPONSIBILITY OF THE USER PARK RD. WELLINGTON RD. 7 VICTORIA ST. McNAB ST. HIGH ST. WELLINGTON ST. NICHOL ST. WATERLOO ST. METCALF ST. McNAB ST. CARLTON PL. CLYDE ST. WATER ST. GRAND RIVER EAST YORK ST. W ELGIN ST. SUBJECT PROPERTY TRESTLE FISHE 30 GRANWOOD GATE SUBDIVISION, PHASE 3 TOWNSHIP OF CENTRE WELLINGTON (ELORA) N LEGEND EXISTING 975Ø STORM SEWER PROPOSED STORM SEWER :2000 (m) PROPOSED STM SEWER GRANWOOD SUBDIVISION POND OUTLET Figure No. 4 BluePlan ENGINEERING FEBUARY 2018 Scale: 1:2500 NAD 1983 UTM Zone 17N

10 FUNCTIONAL SERVICING AND SWM REPORT EDGEHILL PROPERTIES LIMITED C/O WRIGHTHAVEN HOMES LTD. GRANWOOD GATE SUBDIVISION, PHASE III GMBP FILE NO REVISED FEBRUARY 2018 Individual lateral service connections will be provided for each lot as per current municipal and provincial standards. 4. STORMWATER MANAGEMENT 4.1 Design Criteria The stormwater management criteria used for the analysis of the site is as follows: 1. The 100-year allowable outlet rate to the proposed storm sewer outlet in the Waterloo Street right-of-way shall be the lesser of the 100-year pre-development peak flow rate and the design capacity of the outlet storm sewer. Preliminary design of the outlet storm sewer provided by the Township of Centre Wellington indicates that the design capacity of the outlet sewer is approximately 0.840m 3 /s. A copy of the Township s preliminary design is provided in Appendix B. 2. The post-development peak runoff rates to the proposed storm sewer outlet shall be less than the pre-development peak runoff rates to the Waterloo Street right-of-way. 3. The minimum acceptable water quality level of discharge from the site is 80% TSS removal. The Chicago Storm rainfall distributions were used to generate rainfall for the 2-, 5-, and 100-year design storms. Rainfall data was obtained from the Environment Canada Short Duration Rainfall IDF Data for the Fergus Shand Dam station. This data was converted to Chicago Storm parameters using the IDF Curve Fit tool in the MIDUSS modeling software. The Chicago Storm parameters are provided in Table No. 1 below. The MIDUSS Curve Fit modeling is provided in Appendix C. Table No. 1: Chicago Storm Parameters Coefficient 2-Year 5-Year 100-Year A B C R Duration (min) Total Depth (mm) The SCS Curve Number infiltration method was used in the MIDUSS model. The parameters summarized in the following Table No. 2 were used according to the MTO Drainage Management Manual for a Group BC Soil Classification (Design Chart 1.09). Table No. 2: MIDUSS SCS Curve Number Parameters Group B Group BC Group C Impervious Areas Long Grass Areas (Meadow) Lawns (Farmstead) Pre-Development Conditions For pre-development analysis purposes, the site and the external drainage area west of the right-of-way were modelled as four (4) drainage catchments. The pre-development drainage catchments are shown on Figure No. 5 and described below. The pre-development MIDUSS computer modeling is attached in Appendix D. 4 OF 8

11 FILE:W:\Guelph\ \ Granwood SWM Review\5 Work In Progress\Drafting\ GRADING.dwg LAYOUT:STM FIG PRE DEVL LAST SAVED BY:Fcrew, 3/2/2018 1:27:44 PM PLOTTED BY:Field Crew - GM BluePlan 3/2/2018 1:30:46 PM WATERLOO STREET McNAB STREET HALLS DRIVE CLARKE STREET LEGEND 102 CATCHMENT NUMBER 10.13ha. 90% % IMPERVIOUS AREA IN HECTARES CATCHMENT BOUNDARY SUBDIVISION BOUNDARY EXISTING MAJOR OVERLAND FLOW EXISTING CONTOURS :2000 (m) PRE-DEVELOPMENT DRAINAGE AREA PLAN Figure No. 5 BluePlan ENGINEERING FEBRUARY 2018 Scale: 1:2000 NAD 1983 UTM Zone 17N N GRANWOOD GATE SUBDIVISION, PHASE 3 TOWNSHIP OF CENTRE WELLINGTON (ELORA) STORMWATER MANAGEMENT

12 FUNCTIONAL SERVICING AND SWM REPORT EDGEHILL PROPERTIES LIMITED C/O WRIGHTHAVEN HOMES LTD. GRANWOOD GATE SUBDIVISION, PHASE III GMBP FILE NO REVISED FEBRUARY 2018 Catchment 100 (10.25 hectares) represents the existing on-site drainage area which currently drains overland to Waterloo Street. Catchment 100 is comprised of the vacant portion of the site and ground cover consists primarily of grass and shrubbery. Catchment 300 (2.53 hectares) represents the external drainage area west of Waterloo Street. Catchment 300 encompasses portions of the industrial and residential lands west of the site and drains to the Waterloo Street right-of-way. Catchment 400 (0.65 hectares) represents the portion of the site which currently drains to the existing Trestle Bridge Trail ditch south of the site. Catchment 400 is comprised of vacant land and ground cover is primarily grass and shrubbery. Catchment 401 (0.14 hectares) represents the portion of the site which drains to the existing SWM Pond that was constructed as part of Phase I & II of the Granwood development. Ground cover is primarily grass and shrubbery. Note that this catchment area was accounted for in the design of the Phase I & II SWM Pond. 4.3 Post-Development Conditions For post-development analysis purposes, the site was modelled as six (6) drainage catchments. The post-development drainage catchments are shown on Figure No. 6 and described below. The postdevelopment MIDUSS computer modeling is attached in Appendix E. Catchment 200 (5.04 hectares) represents the northerly portion of the Phase III development which includes the proposed park block. Stormwater runoff from Catchment 200 will be conveyed to the proposed stormwater management facility via the proposed storm sewer system and overland flow routes. Catchment 201 (3.99 hectares) consists of the southerly portion of the Phase III development. Stormwater runoff from Catchment 201 will be conveyed to the proposed stormwater management facility via the proposed storm sewer system and overland flow routes. Catchment 202 (1.22 hectares) consists of the proposed stormwater management facility and surrounding areas. Runoff from Catchment 202 will drain overland to the stormwater management facility. Catchment 300 (2.53 hectares) represents the external drainage area west of Waterloo Street. Catchment 300 will remain unchanged from the pre-development condition and is proposed to drain via the proposed storm sewer and overland to the proposed stormwater management facility. Catchment 500 (0.65 hectares) represents the rear yards of the proposed lots along the south side of Halls Drive. Runoff from Catchment 500 will continue to drain uncontrolled to the existing Trestle Bridge Trail ditch south of the site. Catchment 501 (0.14 hectares) represents a portion of Halls Drive. Catchment 501 will continue to drain to the existing Phase I & II SWM Pond. This catchment area was accounted for in the design of the Phase I & II SWM Pond. The on-site stormwater management facility is proposed to be a wetland which will provide quantity control for all storms up to, and including, the 100-year design storm. The stormwater management facility is expected to provide runoff quality control quality for all storms up to, and including, the 2-year design storm. 5 OF 8

13 FILE:W:\Guelph\ \ Granwood SWM Review\5 Work In Progress\Drafting\ GRADING.dwg LAYOUT:STM FIG POST DEVL LAST SAVED BY:Fcrew, 3/2/2018 1:27:44 PM PLOTTED BY:Field Crew - GM BluePlan 3/2/2018 1:30:44 PM WATERLOO STREET PART 1, PLAN McNAB STREET PARK 61R HALLS DRIVE CLARKE STREET LEGEND 102 CATCHMENT NUMBER 10.13ha. 90% % IMPERVIOUS AREA IN HECTARES CATCHMENT BOUNDARY SUBDIVISION BOUNDARY PROPOSED MAJOR OVERLAND FLOW EXISTING MAJOR OVERLAND FLOW EXISTING CONTOURS :2000 (m) POST-DEVELOPMENT DRAINAGE AREA PLAN Figure No. 6 BluePlan ENGINEERING FEBRUARY 2018 Scale: 1:2000 NAD 1983 UTM Zone 17N N GRANWOOD GATE SUBDIVISION, PHASE 3 TOWNSHIP OF CENTRE WELLINGTON (ELORA) STORMWATER MANAGEMENT

14 FUNCTIONAL SERVICING AND SWM REPORT EDGEHILL PROPERTIES LIMITED C/O WRIGHTHAVEN HOMES LTD. GRANWOOD GATE SUBDIVISION, PHASE III GMBP FILE NO REVISED FEBRUARY 2018 The wetland was designed to meet the Ministry of the Environment (MOE) Stormwater Management Planning and Design Manual design guidelines. 4.3 Routing The hydrologic model MIDUSS was used to create the runoff hydrographs and to route the flows through the storage structure. The routing results for the proposed on-site stormwater management facility are summarized in Table No. 3 below. The output hydrographs are provided in Appendix E. Table No. 3: Proposed Stormwater Management Facility - Stage-Storage-Discharge Capacity Storage and Control Bottom of Active Storage/ Orifice Peak Flow m³/s Available Capacity Storage Volume m³ Storage Elevation m Peak Flow m³/s Actual Capacity Used Storage Volume m³ Storage Elevation m Year Year Year , Weir , Top of Pond , A summary of the pre- and post-development peak flow rates to the Waterloo Street stormwater outlet for the 2-, 5- and 100-year design storm events are provided in Table No. 4 below. Table No. 4: Summary of Peak Flow Rates to Waterloo Street Outlet (m 3 /s) 2 Year 5 Year 100 Year Pre- Development Peak Flow Rate (m 3 /s) Preliminary Design Capacity of Outlet Storm Sewer (m 3 /s) Post-Development Un-attenuated Peak Flow Rate (m 3 /s) Post- Development Controlled Peak Flow Rate from SWM Facility (m 3 /s) As shown in the above Table No. 4, the post-development peak flow rates to the Waterloo Street outlet are less than the pre-development peak flow rates for the 2-, 5- and 100-year design storm events. The 100-year post-development peak flow rate is also less than the preliminary design capacity of the outlet storm sewer (0.840m 3 /s). A summary of the pre- and post-development peak flow rates to the existing Trestle Bridge Trail ditch south of the site and Phase I & II SWM Pond outlets for the 2-, 5- and 100-year design storm events are provided in Table No. 5 below. 6 OF 8

15 FUNCTIONAL SERVICING AND SWM REPORT EDGEHILL PROPERTIES LIMITED C/O WRIGHTHAVEN HOMES LTD. GRANWOOD GATE SUBDIVISION, PHASE III GMBP FILE NO REVISED FEBRUARY 2018 Table No. 5: Summary of Peak Flow Rates to the Ditch South of the Site and to the Existing Phase I & II SWM Pond (m 3 /s) Peak Flow Rates to Existing Trestle Bridge Trail Ditch Peak Flow Rates to Existing Phase I & II SWM Pond 2-Year 5-Year 100-Year 2-Year 5-Year 100-Year Pre- Development Peak Flow Rate (m 3 /s) Post-Development Unattenuated Peak Flow Rate (m 3 /s) As shown in Table No. 5, the increase in peak flow rates to the existing Trestle Bridge Trail ditch south of the site are minor (0.104m 3 /s during the 100-year storm event) and does not require quantity control measures, as runoff to the ditch will be exclusively from grassed areas and rooftop, and is therefore considered clean. As discussed above, the existing Phase I & II SWM was designed to accommodate runoff from Catchment 501, therefore no additional SWM control measures are required for this catchment. 5. WATER QUALITY Initial water quality treatment on individual lots will begin with roof leader runoff discharging to the surface and allowing the grass cover to provide initial quality treatment. Oil/grit separators will also be utilized as part of the treatment train approach to stormwater quality control. These units will be placed within the storm sewer network prior to discharging to the stormwater management pond. The specific design of these oil/grit separators will be considered at the time of detailed design. Final water quality will be achieved through the proposed on-site stormwater management facility (wetland). The 2-year design storm event was used to size the quality control component of the stormwater management facility. As shown in the wetland sizing details provided in Appendix F, the wetland is capable of removing 80% of the TSS. 6. ROADWAYS AND GRADING All proposed roadways are to be developed to full urban standards, with storm sewers, sanitary sewers, watermain, curb and gutter, and street lighting. Sidewalks are proposed on one side of Halls Drive, and both sides of York Street. No sidewalks are proposed for Carter Place. Due to the natural easy slope of the lands from east to west, appropriate road grades can be achieved to provide positive drainage towards the SWM facility. Proposed road grades will typically be within the range of 0.5% to 2.0%. Typical proposed lot grades will be within the range of 2.0% to 5.0% in accordance with Township standards. 7 OF 8

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17 Appendix A Preliminary Geotechnical Investigation

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48 Appendix B Township of Centre Wellington Preliminary Outlet Storm Sewer Design

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50 FOR REFERENCE M6430A

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52 Appendix C MIDUSS IDF Curve Fit Modeling

53 Rainfall Distribution Calc " MIDUSS Output >" " MIDUSS version Version 2.25 rev. 473" " MIDUSS created Sunday, February 07, 2010" " 10 Units used: ie METRIC" " Job folder: W:\Guelph\ \" " Granwood SWM Review\5 Work in Progress\Design Calcs\Modeling Files" " 85 IDF CURVE FIT" " 6 Number of Storms" " 1 Storm no." " 2 Return interval" " 12 Data Pairs" " " " " " minutes" " " " " " mm" " " " " " mm/hr" " mm/hr 'A' coeff." " minutes 'B' coeff." " 'C' exponent" " Std.error of estimate" " 2 Storm no." " 5 Return interval" " 12 Data Pairs" " " " " " minutes" " " " " " mm" " " " " " mm/hr" " mm/hr 'A' coeff." " minutes 'B' coeff." " 'C' exponent" " Std.error of estimate" " 3 Storm no." " 10 Return interval" " 12 Data Pairs" " " " " " minutes" " " " " " mm" " " " " " mm/hr" " mm/hr 'A' coeff." " minutes 'B' coeff." " 'C' exponent" " Std.error of estimate" " 4 Storm no." " 25 Return interval" " 12 Data Pairs" " " " " " minutes" Page 1

54 Rainfall Distribution Calc " " " " " mm" " " " " " mm/hr" " mm/hr 'A' coeff." " minutes 'B' coeff." " 'C' exponent" " Std.error of estimate" " 5 Storm no." " 50 Return interval" " 12 Data Pairs" " " " " " minutes" " " " " " mm" " " " " " mm/hr" " mm/hr 'A' coeff." " minutes 'B' coeff." " 'C' exponent" " Std.error of estimate" " 6 Storm no." " 100 Return interval" " 12 Data Pairs" " " " " " minutes" " " " " " mm" " " " " " mm/hr" " mm/hr 'A' coeff." " minutes 'B' coeff." " 'C' exponent" " Std.error of estimate" " 38 START/RE-START TOTALS " " 3 Runoff Totals on EXIT" " Total Catchment area hectare" " Total Impervious area hectare" " Total % impervious 0.000" " 19 EXIT" Page 2

55 Appendix D Pre-Development MIDUSS Computer Model Output for the 2-, 5- and 100-Year Design Storms

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62 Appendix E Post-Development MIDUSS Computer Model Output for the 2-, 5- and 100-Year Design Storms and Stage-Storage Discharge Calculation Tables

63 Granwood Subdivision Township of Centre Wellington GMBP File: Stormwater Management Pond Storage Volume Calculations Surface Perm. Pool Accum. P.P. Surface Active Accum. Active Elevation Depth Area Volume Volume Area Volume Volume (m) (m) (m 2 ) (m 3 ) (m 3 ) (m 2 ) (m 3 ) (m 3 ) Bottom of Pond Permanent Pool/Top of Forebay , , , , , Catchbasin Inlet Lip , , , , , , , , , , , , , , , , , , Weir , Top of Pond Orifice (Quality) Orifice (Quantity) Overflow Weir ( m) ( m) ( m) Q = m 3 /s Q = m 3 /s d1 = 2.50 m Cd = Cd = h = 2.30 m H = m H = m H = 0.20 m 2g = g = g = L = 7.00 m A = m 2 A = m 2 D = m D = m Q = 0.87 m 3 /s

64 Stormwater Management Pond Stage-Storage-Discharge Table Elevation Stage Storage 300 mm Orifice Catchbasin Inlet Lip Overflow Weir Total Discharge m m m (m) (m) (m 3 ) (m 3 /s) (m 3 /s) (m 3 /s) (m 3 /s) Permanent Pool/Top of Forebay , , Catchbasin Inlet Lip , , , , , , , , , , , , , , , , , , Weir , , Top of Pond

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77 Appendix F Wetland Facility Sizing Details

78 Project No Project: Granwood Gate Subdivision, Phase III Date: February 22, 2018 Designer: Peter Soligo Stormwater Management Facility Quality Sizing: The stormwater management facility has been designed to function as a wetland. From Table 3.2 of the MOE Stormwater Management Planning and Design Manual, 2003, in order to provide Enhanced water quality treatment (80% TSS Removal), a wetland facility requires: 105m³/ha of quality storage volume for a contributing drainage area that is approximately 55% impervious. 40m³/ha of the required quality storage volume is extended detention volume, while the remaining is permanent pool. Calculating the total required quality volume: Total contributing drainage area = 12.82ha Combined imperviousness of contributing area = 53% (assume 55% for quality sizing purposes) Quality Storage Requirement = 105m 3 /ha = 1,346m 3 Calculating Extended Detention Volume: Extended Detention Requirement = 40m 3 /ha for site and external areas Required Extended Detention Volume = 513m 3 Calculating Permanent Pool Volume: Required Permanent Pool Volume = Total Quality Volume Extended Detention Volume Required Permanent Pool Volume = 833m 3 Alternative Extended Detention Sizing: Given that the 2 year storm has been used as the quality sizing event for this facility, the extended detention volume is required to store at a minimum the full capacity of the 2-year design storm. From the MIDUSS modeling, the 2-year design storm requires a maximum storage volume of approximately m 3, which correspond to an elevation of m. As such, the inlet of the catchbasin outlet structure has been set at an elevation of m. A summary of the quality sizing volumes are provided in Table No. E-1 below:

79 Table No. E-1: Quality Sizing Volumes Summary Required Provided Extended Detention Volume m m 3 Permanent Pool Volume 833m 3 1,158.6m 3 Total Quality Volume 1,346m m 3 Sediment Forebay Design The Sediment forebay has been designed to meet the MOE Stormwater Management Planning and Design Manual requirements for wetland facilities. The design of the forebay is summarized in Table No. E-2 below: Table No. E-2: Forebay Design Details Forebay Settling Length (m) 13.8 Dispersion Length (m) 29.0 Required Flow Velocity (m/s) 0.15 Length to Width Ratio 2:1 Settling Velocity (m/s) Forebay Length (m) 56 Provided Flow Velocity (m/s) 0.05 Length to Width Ratio 2:1