Madawaska Subdivision Arnprior, Ontario Serviceability Report
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Madawaska Subdivision Arnprior, Ontario Serviceability Report MADAWASKA SUBDIVISION ARNPRIOR , ONTARIO SERVICEABILITY REPORT Prepared For: T. Anas Holdings Ltd. 394 Madawaska Boulevard Arnprior, Ontario K7S 3H2 Prepared By: NOVATECH ENGINEERING CONSULTANTS LTD. Suite 200, 240 Michael Cowpland Drive Ottawa, Ontario K2M 1P6 January 2014 Ref: R-2013-225 Novatech File: 113186 Madawaska Subdivision Serviceability Report TABLE OF CONTENTS 1.0. INTRODUCTION ........................................................................................................................ 1 2.0. Proposed Development ................................................................................... 1 3.0. WATER SERVICING ................................................................................................................. 1 4.0. SANITARY SERVICING............................................................................................................ 2 5.0. STORM SERVICING .................................................................................................................. 2 6.0. STORMWATER MANAGEMENT ........................................................................................... 3 6.1. Stormwater Management Criteria .................................................................... 3 6.2. Stormwater Quantity Control ........................................................................... 3 6.3. Proposed Site Quality Control ......................................................................... 3 6.4. Overland Flow Route ....................................................................................... 4 7.0. EROSION AND SEDIMENT CONTROL MEASURES.......................................................... 4 7.1. Temporary Measures ...................................................................................... 4 8.0. CONCLUSIONS AND RECOMMENDATIONS ..................................................................... 5 List of Figures Figure 1 Key Plan Figure 2 Concept Plan Figure 3 Proposed Site Plan List of Appendices Appendix A Water Servicing Information Appendix B Sanitary Servicing Information Appendix C Stormwater Management Calculations Appendix D Oil-Grit Separator Information Novatech Engineering Consultants Ltd. i Madawaska Subdivision Serviceability Report 1.0. INTRODUCTION Novatech Engineering Consultants Ltd. has been retained by T. Anas Holdings Ltd. to prepare a Serviceability Report in support of a Draft Plan of Subdivision Application. The site is located on the north side of Madawaska Boulevard between Herrick Drive and Decosta Street (Part Lot 1, Concession C and D) within the Town of Arnprior. Figure 1 is a Key Plan showing the site location. 2.0. PROPOSED DEVELOPMENT The property is approximately 23.4 hectares in size and is currently undeveloped consisting of grass, brush and trees. The topography of the site slopes from south to north with an elevation difference of approximately 14.0m across the site. The site is bounded by Madawaska Boulevard to the south, an existing rail line to the north and a small area of existing commercial development by the southwest corner. It is proposed to construct a subdivision consisting of approximately 111 single family homes, 10 semi-detached homes (20 units), 31 townhouse/attached bungalow blocks (149 units) 1.33 hectares of multi-residential, and 4.42 hectares of commercial/retail development. The development will include an internal road network and can be accessed by two proposed entrances from Madawaska Boulevard. Figure 2 Preliminary Lotting Plan shows the proposed development concept as well as the phases of the proposed development. 3.0. WATER SERVICING There is an existing 300mm diameter municipal watermain located at the intersection of Madawaska Boulevard and Decosta Street. It is proposed to extend this existing municipal infrastructure to service the proposed development. A 300mm diameter watermain is proposed to service the commercial portion of the development, with 200mm watermain servicing the residential portion. The system will be looped with two connections to the existing municipal system. A Water and Wasterwater Master Plan (WWMP) has been prepared by Stantec (dated June 14, 2013) for the Town of Arnprior. This Master Plan shows the subject site as future development labeled as subarea #4. The Town of Arnprior also provided boundary conditions for the municipal watermain system. A preliminary analysis has been completed for the proposed development and the existing municipal watermain system can provide adequate domestic flow and fire protection for the development. A hydraulic analysis and model would be completed as part of the detailed design process. A fire flow of 125L/s is available throughout the site. This will meet the needs of the requirements for residential development, and most sprinklered commercial buildings. During the detailed design stage, criteria for the commercial sites may need to be established to ensure adequate fire protection. Novatech Engineering Consultants Ltd. Pg. 1 OTTAWA RIVER ELGIN STREET W DIVISION STREET S MCNAB STREET REID AVE. CANADIAN RAILWAY BASKIN DRIVE W SITE CANADIAN RAILWAY DANIEL STREET MADAWASKA BOULEVARD DECOSTA STREET CONNIFER LN. 29 HENRICK DR. TRANS-CANADA HYW 417 TRANS-CANADA HYW 417 MADAWASKA RIVER 29 MADAWASKA BLVD ARNPRIOR KEY PLAN OCT 2013 113186 FIGURE 1 M:\2013\113186\CAD\Design\Figures\Figure1.dwg, Sheet 8x11 portrait, Dec 23, 2013 - 4:17pm, iandric Madawaska Subdivision Serviceability Report Figure 3 shows the proposed servicing concept for the watermain system. Relevant figures from the WWMP are provided in Appendix A for reference and supporting preliminary calculations. 4.0. SANITARY SERVICING There is an existing 600mm diameter municipal sanitary sewer located at the intersection of Madawaska Boulevard and Decosta Street. The WWMP indicates that a 375mm diameter sanitary sewer can be extended to service the proposed development off the existing 600mm diameter sanitary sewer. A 250mm diameter sanitary sewer is proposed to service the development. The proposed development is labeled as Subarea #8 in the WWMP. The WWMP estimates a total sanitary flow of 27.1 L/s from Subarea #8. Sanitary flows for the proposed development are calculated to be 26.5/s. Therefore, the existing municipal infrastructure can adequately service the proposed development with excess capacity in the downstream sewers. Phase 1 and 4A will be serviced via gravity connections to the proposed 250mm sanitary sewer. Phase 2, 3 and 4B will drain via gravity to a proposed pump station. The proposed pump station will require a capacity of approximately13 L/s, with standby power and twin forcemains. The pump station forcemains will outlet to the gravity sewer at the limit of Phase 1. Figure 4 Sanitary Concept Plan shows a proposed sanitary sewer layout for the proposed development and preliminary drainage areas. Relevant figures from the Master Plan are provided in Appendix B for reference and supporting preliminary calculations. 5.0. STORM SERVICING As indicated previously, the site is currently undeveloped. Stormwater currently sheet drains across the property from south to north. There is also an elevation drop of approximately 14.0m across the site. Stormwater currently drains towards the existing ditch along the rail line. There are three culverts crossing the existing rail line that allows stormwater to drain from the subject property to the property to the north of the tracks. Stormwater sheet drains a short distance within the property to the north and then enters a wetland area. It is proposed to service the development with a storm sewer system with sewers ranging in size from 300mm diameter to 900 mm diameter. The culverts crossing the rail line and the existing wetland area will remain as the storm outlet for the site per existing conditions. Figure 6 Storm Concept Plan shows the proposed storm sewer layout for the proposed development and preliminary drainage areas. Novatech Engineering Consultants Ltd. Pg. 2 Madawaska Subdivision Serviceability Report 6.0. STORMWATER MANAGEMENT 6.1. Stormwater Management Criteria The following is the Stormwater Management criteria as established by the Town of Arnprior. • Quantity control is required to pre-development levels unless it can be shown that there are no adverse effects on the downstream wetlands. • Quality control is also required to a normal level of treatment or 70% removal of total suspended solids. 6.2. Stormwater Quantity Control Existing topographic information was reviewed to determine the pre-development drainage areas and calculate pre-development flows from the site and these areas are shown on Figure 5. The three existing culverts were also reviewed to determine their capacities in relation to the existing drainage from the property. It was determined that the capacities of the existing downstream culverts do not constrain the storm drainage from the site. These capacities are determined by the MTO Drainage Manual Design Chart 2.31, and are shown in the table below. Therefore, the allowable release rate from the development is the pre-development flow to each of the existing culverts crossing the rail line. Culvert 100 Year Allowable Flow Capacity (m 3/s) Culvert #1 0.45 0.75 Culvert #2 0.58 2.6 Culvert #3 0.72 1.9 There are two existing areas to the south of the site, south of Madawaska Boulevard and to the east of the site that currently drain across the site to one of the three culverts. The drainage from