Dunpar Developments Inc.

Transcription

1 Dunpar Developments Inc. Proposed Townhouse Development 2158, 2168, 2180 and 2192 Trafalgar Road Oakville, Ontario Functional Servicing and Stormwater Management Report (in Support of a Re-Zoning and Site Plan Application) Prepared by: Engineers, Planners and Landscape Architects Johnson Sustronk Weinstein + Associates 20 Mural Street, Unit 10 August 2012 Richmond Hill, Ontario L5B 1K3 Project No

2 Dunpar Developments Inc. Proposed Townhouse Development 2158, 2168, 2180 and 2192 Trafalgar Road Oakville, Ontario Functional Servicing and Stormwater Management Report (in Support of Re-Zoning and Site Plan Application) Johnson Sustronk Weinstein + Associates 20 Mural Street, Unit 10 August 2012 Richmond Hill, Ontario L5B 1K3 Project No

3 TABLE OF CONTENTS Page 1.0 Introduction Objectives Scope of Report Study Area Development Concept Development Sanitary Sewers Existing Sanitary Sewers Proposed Sanitary Design Parameters 3 a) Sanitary Population Density 3 b) Sanitary Demand Sanitary Sewer Design Summary and Conclusions Water Distribution Existing Watermains Design Parameters Layout of Proposed Watermain Summary and Conclusion Storm Drainage and Stormwater Management Existing Site Drainage and Storm Sewer System Storm Sewer Design Stormwater Management Summary and Conclusion 8

4 APPENDIES Appendix A Appendix B - Sanitary Sewer Design Sheet - Storm Sewer Design Sheet LIST OF TABLES AND CHARTS Table Year Storm Modified Rational Method LIST OF DRAWINGS DWG. NO. TITLE G-1 Grading Plan S-1 Servicing Plan GS-1 SD-1 STM-1 SAN-1 CM-1 Grading Sections and Details Servicing Details Storm Drainage Area Plan Sanitary Drainage Area Plan Construction Management and Siltation Control Plan

5 1.0 INTRODUCTION 1.1 Objectives This report has been prepared as supporting documentation for a Re-Zoning and Site Plan application for the property at 2158, 2168, 2180 and 2192 Trafalgar Road. The development consists of the construction of stacked townhouse units as indicated on the Architectural Site Plan prepared by O.P. Design Inc. 1.2 Scope of Report The servicing of the development is addressed with respect to storm and sanitary drainage. Water demand for domestic and fire flow requirements are presented. Stormwater management requirements are based on the Town of Oakville s criteria for stormwater management In more detail the Municipal Servicing sections of this report will address: anticipated domestic water consumption based on the Halton of Region s criteria anticipated fire flow demand based on the nature of the development and the requirements of the Fire Underwriter s Survey, 1999 (FUS). review of existing watermains servicing the area. pressure and flow test of existing watermain(s). determine if upgrades are required to the existing watermain infrastructure. anticipated sanitary discharge from the development. current capacity of existing sanitary sewer to which the development will connect. impact to the existing sanitary sewer as a result of the new demand will be assessed. determine if upgrades are required to the existing sanitary sewer infrastructure. storm drainage from the development will be controlled to 5 year predevelopment run-off levels for storm event up to and including the 1:100 year event as per the Town s criteria. 2158, 2168, 2180 and 2192 Trafalgar Road August 2012 Functional Servicing and Stormwater Management 1 JSW

6 the existing storm sewer capacity will be determined. impact to the existing storm sewer as a result of the new controlled flow from the development will be assessed. determine if upgrades are required to the existing storm sewer infrastructure. With regards to stormwater management the following is address: the Grading Plan enclosed with the report indicates the direction of surface drainage. emergency overland flow route is indicated on the Grading Plan. storage volumes are provided for detention storage of return period storms up to and including the 1:100 year event. water quality calculation indicating 80% TSS removal. 1.3 Study Area The ha. (4.02 ac.) site is bound by Trafalgar Road to the east, existing single family housing to the north and south, and a proposed future residential street to the west (see Figure No. 1 Key Plan). Presently on the site are no existing buildings. The grade of the site slopes gently from west to east at approximately 0.8%. The site also slopes from north to south at approximately 0.5% slope. Along Trafalgar Road approximately 7.0m to the west of the west curb line is a ditch with four (4) culverts providing access to the land to the west. Aligned with the culverts are existing curb cuts in the west curb. An asphalt sidewalk also exists just 3.0m west of the curb , 2168, 2180 and 2192 Trafalgar Road August 2012 Functional Servicing and Stormwater Management 2 JSW

7 2.0 DEVELOPMENT CONCEPT 2.1 Development The proposed development consists of 114 townhouses in 11 Blocks. The largest block of townhouses has 12 units which are the proposed 3 block to front on to Trafalgar Road. Each Townhouse unit provides parking for two(2) vehicles. In addition to the 228 parking space noted above 27 visitor spaces are provided around the site. 2158, 2168, 2180 and 2192 Trafalgar Road August 2012 Functional Servicing and Stormwater Management 3 JSW

8 3.0 SANITARY SEWERS 3.1 Existing Sanitary Sewers No sanitary sewer exists in the Trafalgar Road right of way that fronts the development. A future sanitary sewer is proposed in the future street to the west of the site. At the time of writing this report no information has been released by the neighboring developer or their consultants. It is anticipated that the proposed future sewer will be sized to accommodate the 114 unit townhouse development. 3.2 Proposed Sanitary Sewer Design.1 Sanitary Population Density: The Town of Oakville sanitary sewers are under the jurisdiction of Halton Region. The Region does not have a population count on a per unit bases, instead the population density is based on 135 persons per hectare. The cumulative population for the 114 unit development is 147 persons. This results in an average population of 1.29 persons per unit which seems low. JSW did contact the Region for further clarification regarding population criteria but received no further information from the Region in this regard. Based on the above the above the total population for the proposed development is 147 persons..2 Sanitary Demand: The sanitary demand using 275 l/capita/day including infiltration and a peaking factor is 2.29 l/s. 3.3 Sanitary Sewer Design A 200 mm minimum sewer size is used throughout the development. Minimum slope on the first leg is 1.00%. The intent is to have one (1) outlet to the proposed new street as indicated on the Servicing Plan Drawing No. S-1. The layout of the proposed sanitary sewer system for the development is illustrated on the Servicing Plan. In Appendix A is the sanitary sewer design sheet. 2158, 2168, 2180 and 2192 Trafalgar Road August 2012 Functional Servicing and Stormwater Management 4 JSW

9 3.4 Summary and Conclusion The anticipated flow from the development is 2.29 l/s. It is anticipated that the proposed development to the west will provide a sanitary sewer sized to accommodate the proposed flow from this development. 2158, 2168, 2180 and 2192 Trafalgar Road August 2012 Functional Servicing and Stormwater Management 5 JSW

10 4.0 WATER DISTRIBUTION 4.1 Existing Watermains A 300mm watermain exists in Trafalgar Road, which is located approximately 5.0 m west of the east curb line. It is anticipated that a watermain will be constructed in the proposed future road allowance along the west side of the development and will be sized to accommodate domestic and fire demand. 4.2 Design Parameters The watermain design must accommodate the demand for two conditions, which are domestic and fire supply. The Region of Halton s standard for domestic supply is 275 l/person/day, which is the average daily demand. The maximum daily demand will be based on a factor of 2.25 times the average daily demand and the maximum hourly demand or peak hour, will be based on a factor of 4.0 times the average daily demand. Based on the above the domestic demand requirements are the following: l/min. Average Daily Maximum Daily Maximum Hourly Fire demand for the development is based on the type of building construction and the requirements of Water Supply for Public Fire Protection 1999 Fire Underwriters Survey. A review of the townhouse units and the fire separation between each unit will need to be review with the architect to determine the required fire flow. 2158, 2168, 2180 and 2192 Trafalgar Road August 2012 Functional Servicing and Stormwater Management 6 JSW

11 4.3 Layout of Proposed Watermain The watermain service connection is proposed off of the proposed street to the west (see the Servicing Plan Drawing No. S-1). 4.4 Summary and Conclusions A pressure and flow test will be carried out once the watermain is constructed in the proposed street to the west. In the interim the modeled pressure and flows for the proposed development to the west will be used which will be taken from their functional servicing report for their development. There are no existing fire hydrants along the Trafalgar Road frontage. 2158, 2168, 2180 and 2192 Trafalgar Road August 2012 Functional Servicing and Stormwater Management 7 JSW

12 5.0 STORM DRAINAGE AND STORMWATER MANAGEMENT 5.1 Existing Site Drainage and Storm Sewer System Trafalgar Road does have an existing storm sewer however the proposed townhouse development is no proposing to make a connection to the Trafalgar Road storm sewer. The intent is to make a storm connection to the proposed storm sewer which is to be located in the proposed street to the west of the site. 5.2 Storm Sewer Design The proposed storm sewer design and layout is indicated on the Servicing Plan Drawing No. S-1. In Appendix B is the storm sewer design sheet. 5.3 Stormwater Management The stormwater management criteria used to assess and design the system provided at the site, is to the Town of Oakville s criteria. The 100 year postdevelopment flow is controlled to the 5 year post-development flow. Based on this criteria a detention stormwater management tank was sized to accommodate the required detention storage volume of m 3 (see Table 5.1 modified rational method analysis). 5.4 Summary and Conclusions The allowable outflow from the site is l/s based on the 5-year post development criteria. Under the 1:100 year event m 3 of storage is required. Storage of m 3 is provided. 2158, 2168, 2180 and 2192 Trafalgar Road August 2012 Functional Servicing and Stormwater Management 8 JSW

13 TRAFALGAR ROAD TOWNHOUSE DEVELOPMENT Table No , 2168, 2180, 2192 Trafalgar Rd. Modified Rational Method - 5 yr Post to 100 yr Post 100yr based on IDF curve defined by the following equation I = 2150/(T+5.7) mm/hr 5 yr based on IDF curve defined by the following equation I = 1170/(T+5.8) mm/hr 5 yr Post Development Condition Contributing Site Area = 1.48 ha Site runoff coefficient - C = 0.80 Time of concentration = min. Peak runoff rate for 5 year storm event = l/s Inflows = Q = A x C x I/360 THEREFORE : Design peak outflow rate for = l/s Time Intensity Inflows Inflow Volumes Outflows Outflow Volumes Storage Required (min.) (mm/hr) (cu.m/s) (cu.m.) (cu.m/s) (cu.m.) (cu.m.) THEREFORE : Required storage is = m³ ORIFICE PLATE SIZING CHECK C = 0.6 (constant) G = 9.81 m/s H = 2.86 m (based on an elevation of m and orific plate centre of m) Q = 341 l/s A = Q / 2GH x C m 2 A = m 2 r = m THEREFORE : orifice diameter = 311mm

14 Johnson Sustronk Weinstein + Associates Prepared By Reviewed By Lawrence Rutledge, C.E.T. Brent Schuknecht, P.Eng. 2158, 2168, 2180 and 2192 Trafalgar Road August 2012 Functional Servicing and Stormwater Management 9 JSW

15 APPENDIX A Sanitary Sewer Design Sheet

16 Sanitary Drainage Design Sheet Population Equivalents: Townhouse = 135 persons/hectare Pipe Comment Up Stream Down Stream Increment Cumulative M Pop./ Flow A Road A Gross Infilt. Q Total L Size Grade Cap. Vel. Act. Vel. % MH Invert MH Invert Units A Site ha P p Areas Ha. l/s (ha) (ha) l/s l/s (m) (mm) (%) (l/s) (m/s) (m/s) Full Block C,G 100A A Blocks B-A 101A A Blocks A,D 102A A Road 103A A Block K 104A A Blocks E-F 106A A Block J 105A A A A Blocks H-I 108A A A A A Ex. MH TRAFALGAR ROAD TOWNHOUSE DEVELOPMENT A= area in ha. q= 275 l / person / day (Townhouse) 2158, 2168, 2180, 2192 Trafalgar Rd. P= 135p/ha x Area in Hectares P flow = M * q * P / = Population flow (l/s) Town of Oakville, Ontario I = * A gross (l/s) Design: R.N. Job No: M= / {4+(p/1000)½} Q Total = P flow + I (l/s) Check: L.R. Date: July 2012 Sheet 1 of 1

17 APPENDIX B Storm Sewer Design Sheet

18 Storm Drainage Design Sheet Cont. Total Pipe Data Street Up Stream Down Stream No. of Hectares Total AxC I-5 Flow Design Flow L Size Grade Cap. Vel. Time % Pipe MH Invert MH Invert In Area Total In Area Cum T c (mm/hr) (m³/s) (m³/s) (m) (mm) (%) (m³/s) (m/s) (min.) Full Blocks C&G CBMH Blocks C&G CBMH CBMH Block B CBMH Blocks A&D CBMH Blocks A&D CBMH CBMH Blocks A CBMH Road Court Yard Clean out Block E Block E Block K CBMH CBMH CBMH CBMH Block J CBMH Block J CBMH Block E&F CBMH Block E&F CBMH Block J CBMH Block J CBMH Block H&I CBMH CBMH CBMH CBMH TRAFALGAR ROAD TOWNHOUSE DEVELOPMENT Q = 2.78 x A x C x I/1000 A = Area (Hectares) 2158, 2168, 2180, 2192 Trafalgar Rd. C = Runoff Coefficient n = Pipe Roughness = Town of Oakville, Ontario 5 Year Rainfall Intensity =1170/(t+5.8)0.843 Designed: R.N. Job No: Checked: L.R. Date: July 2012 Sheet 1 of 1