Table of Contents. 1.0 Introduction Existing Site Conditions Proposed Site Statistics Sanitary Servicing Review...

Transcription

1 Table of Contents 1.0 Introduction Existing Site Conditions Proposed Site Statistics Sanitary Servicing Review Potential Sanitary Sewage Outlets Internal Sanitary Drainage Areas Northwest Drainage Area Southeast Drainage Area South central Drainage Area Existing Downstream Sanitary Infrastructure Parkhill Road Pumping Station Trunk Sewer from Parkhill Road to Wastewater Treatment Plant Peterborough Wastewater Treatment Plant (WWTP) External Flows Dry Weather Flow Total Flow Available Capacity Pre Development System Conditions Post Development System Conditions Peterborough Wastewater Treatment Plant Water Distribution Review Existing Water Distribution Network Proposed Water Connection Storm Drainage Review Minor System Conveyance Major System Conveyance Preliminary Road Grading Cost Sharing Guidelines Cost Sharing Principles Conclusions and Recommendations...17 L (September 2012) Page i

2 LIST OF TABLES Table 2 1 Pre Development System Conditions Sewer Hydraulic Analysis Preliminary Results...6 Table 2 2 Post development System Conditions Sewer Hydraulic Analysis Preliminary Results...9 Table 3 1 Design Water Supply Flow rates...12 LIST OF DRAWINGS Drawing No. SAN 1 Preliminary Sanitary Servicing Plan...End of Report Drawing No. WTR 1 Preliminary Water Distribution Plan...End of Report Drawing No. STM 1 Preliminary Storm Servicing Plan...End of Report Drawing No. GR 1 Preliminary Road Grading Plan...End of Report APPENDICES Appendix A Figures Figure 1 Site Location Plan Figure 2 Preliminary Concept Plan Figure 3 Existing Downstream Sanitary Sewer System Figure 4 Dry Weather Flow Pattern Figure 5 Total Hydrograph Flow Generation Figure 6 Pre Development Downstream Sanitary Trunk Sewer Conditions Figure 7 Existing Condition Trunk Sewer HGL Profile at bottleneck MH Figure 8 Post Development Downstream Sanitary Trunk Sewer Conditions Figure 9 Proposed Condition Trunk Sewer HGL Profile at bottleneck MH Appendix B Water Distribution Design and Background Data Appendix C Statement of Limiting Conditions & Assumptions L (September 2012) Page ii

3 1.0 Introduction Cole Engineering Group Ltd. (Cole Engineering) was retained by to prepare a Municipal Servicing Assessment Report in support of the Lily Lake Functional Planning Area for future residential development. This Report focuses on a review of the location and capacity of existing municipal services surrounding the site, i.e. sanitary sewers, pumping stations, watermains and water storage/supply. In addition, a preliminary design is presented for the internal site development in terms of sanitary and storm sewers, watermain network and road grading design Existing Site Conditions The site is located in the northwest corner of the, adjacent to Jackson Creek and encompasses a total area of approximately 189 ha and 156 ha of Gross Developable Area once Open Space Blocks have been subtracted. Refer to Figure 1 for the site location plan. The developable area contains a drumlin in the center with a high point of about m. It slopes down on all sides to the edges of the developable area at an average of 6% slope (maximum 12 %) to m. The developable portion of the site is mostly used for agricultural purposes and has some buildings on site to support this operation Proposed Site Statistics Based on the preliminary statistics prepared by, the proposed site development consists of the following residential land uses: Low & Medium Density Townhouses: 892 units x2.4 ppl/unit High Density: 431 units x2.0 ppl/unit Low Density: 1557 units x3.5 ppl/unit TOTAL UNITS: 2880 units 8452 ppl Refer to Figure 2 for the proposed development concept plan. 2.0 Sanitary Servicing Review Based on the preliminary site statistics and housing/population projections prepared by, the Lily Lake Functional Planning Area will contain approximately 2880 units and a total population of 8452 persons. The residential land uses varies from low to high density. While the gross site area is 189 ha, the sanitary drainage area utilized for inflow and infiltration is ha. Based on the City s sewage generation design criteria of 450 L/person/day, the following sanitary flow generation rates apply to the Lily Lake Functional Planning Area: Average Daily Flow = 450 L/person/day x 8452 persons = 44 L/sec L (September 2012) Page 1 of 18

4 Harmon Peaking Factor = 3.03 Peak Flow = 44 L/sec x 3.03 = L/sec Inflow and Infiltration = 0.25 L/sec/ha x ha = 36.4 L/sec Total Peak Flow = L/sec L/sec = L/sec (or cu.m/day) 2.1. Potential Sanitary Sewage Outlets Three potential sanitary sewage outlets were examined as part of this Assessment Report. The three outlets and corresponding analysis of the options are listed below: 1) Outlet at the southwest corner of the site, crossing under Jackson Creek and connecting to the existing Parkhill Road pumping station; Assessment: The Parkhill Road pumping station directs flow easterly to the nearby Lily Lake sanitary trunk sewer located on Wallis Drive. Based on the Parkhill Road Sewage Pumping Station Capacity Upgrades Design Brief, dated July 2005 and prepared by KMK Consultants, the has identified the intention to significantly increase the capacity of the Parkhill Road pumping station as development in the area proceeds. Currently, the wet well inlet invert at the existing Parkhill Road pumping station is m. In order to direct sewage from the Lily Lake Functional Planning Area to the existing Parkhill Road pumping station, a crossing under Jackson Creek will be required. The Creek invert in the vicinity of the sanitary sewer crossing is approximately 232.0m, which is below the existing wet well invert. To promote a gravity sewer connection from the site to the Parkhill Road pumping station requires a deepening of the wet well to accommodate flows. Alternatively, should the pumping station expansion not consider a deepening of the existing wet well, a new wet well may be constructed adjacent the existing at the appropriate depth or a siphon may be considered under Jackson Creek to convey sanitary flows from the site. The crossing distance for a sewer outlet under Jackson Creek is approximately 180m at this location. 2) Outlet at the southeastern corner of the site, crossing under Jackson Creek and connecting to the existing Valleyview pumping station; Assessment: The existing Valleyview pumping station is a relatively small station designed to service a localized area and outlets to a nominal sized gravity sewer, which ultimately coveys flow to the existing Lily Lake sanitary trunk sewer. There does not appear to be any considerations by the City to expand this pumping station to service future growth. Currently the Valleyview pumping station is operating at approximately 25% of its rated design capacity; therefore it may present an opportunity to accept sanitary drainage from a small portion of the site. However, the spare capacity within the Valleyview pumping station is reserved to receive emergency sewage overflow from the Lily Lake sanitary trunk sewer at the intersection of Parkhill Road and Wallis Drive. The financial feasibility should be examined to assess the construction costs associated with a sanitary sewer crossing Jackson Creek to service a relatively limited portion of the site. In particular, the width of Jackson Creek is approximately 380m from top of bank to top of bank at this crossing location, which significantly increases the trenchless sewer installation costs compared to Option 1. L (September 2012) Page 2 of 18

5 3) Outlet to the east of the site to a section of existing local sewer located on Fairbairn Street at Hillside St. Assessment: The existing sanitary sewer located on Fairbairn Street is a local sewer at 5m depth (invert = m) at the intersection with Hillside Street and could be extended northerly along Fairbairn Street to service the proposed lots along its frontage. In addition, a limited area of site drainage from the O Grady subdivision could be directed to the existing terminus of the sewer (from an invert elevation perspective), which ultimately conveys flows to the Park Street trunk sanitary sewer rather than the Lily Lake sanitary trunk sewer on Wallis Drive. This Assessment Report has not reviewed the downstream capacity constraints of the existing Park Street trunk sewer. Based on the assessment of the above three options, the recommended alternative for further review is Option 1 considering that Options 2 & 3 could potentially service only relatively small portions of the site. In addition, due to the City s consideration for improvements to the existing Parkhill Road pumping station, its close proximity to the Wallis Drive trunk sewer and the relatively short crossing distance of Jackson Creek, this option appears most feasible to outlet the sanitary flows from the Lily Lake Functional Planning Area. Refer to Drawing No. SAN 1 for locations of the three preliminary sanitary sewage outlet options Internal Sanitary Drainage Areas Gravity sanitary sewers have been designed according to the existing topography. Proposed sanitary drainage generated within the site will be directed to all four boundaries of the property, generally following the preliminary road grade design. As a result, the site is generally divided into three distinct sanitary drainage areas, labelled Northwest, Southeast and South central. There are significant lands within the Township which could potentially be serviced through the Lily Lake Secondary Plan Area in the future, but for the purposes of this report sanitary servicing was limited to the current City boundary. Based on utilizing the existing Parkhill Road pumping station as the preferred sanitary outlet for the site, the following assessment describes the preliminary internal sanitary conveyance strategy for the site Northwest Drainage Area This is the largest of the three drainage sheds with a contributing area totalling ha. Sanitary flow generated within the Northwest third of the site will be directed by gravity westerly towards the proposed lower elevation within the drainage shed. Flows will pass south of the 2.1 hectare park block then cross the City boundary into the Township of Smith Ennismore Lakefield and run along the western boundary of the study area. An outlet connection is proposed at the sanitary sewer constructed by others which runs through the Jackson Creek valley and is directed back into the city along the ORCA biking trail Southeast Drainage Area The southeast drainage shed is approximately ha in size and directs flows south westerly by gravity towards the south central area. This drainage area will conveyed mainly by two lines, one L (September 2012) Page 3 of 18

6 running along the proposed arterial road and the second running beneath the top of bank of the Jackson Creek valley, with both lines converging in the southwest corner on the site South-central Drainage Area The final drainage area is approximately ha in size and is entirely serviced by gravity sewers. The South central drainage area accepts sewage from the balance of the site and conveys flows to the preferred outlet (the Parkhill Road pumping station) via a proposed crossing of Jackson Creek. Refer to Drawing No. SAN 1 for a depiction of the preliminary internal sanitary sewer network and drainage area boundaries Existing Downstream Sanitary Infrastructure This section describes the external sanitary servicing opportunities and constraints for the Lily Lake Functional Planning Area. The external sanitary capacity has been determined after defining the existing system using design flows and completing preliminary hydrodynamic modelling of the system from the connection point at the Parkhill Road Pumping Station to the Peterborough Wastewater Treatment Plant (WWTP). The existing system information external to the Lily Lake area was used to determine potential sanitary servicing opportunities through the existing sewer system. The sanitary system is comprised of separate sanitary sewers and manholes, pumping stations and the WWTP as discussed below Parkhill Road Pumping Station The existing capacity of Parkhill Road Pumping Station is 76 l/s with a future expansion planned to accommodate a flow of 237 l/s. As will be discussed in Section 2.5, Parkhill Road Pumping station at it s current capacity cannot handle the additional flows generated by the proposed Lily Lake development and will need to be upgraded Trunk Sewer from Parkhill Road to Wastewater Treatment Plant The trunk sewer leading to the Wastewater Treatment Plant has pipe diameters ranging from 600 mm at Parkhill Road (Upstream) to 1372 mm at the inlet to the Wastewater Treatment Plant (Downstream). There is a bottleneck location near the intersection of Clonsilla Ave. and The Parkway, where the diameter of the trunk sewer drops from 825 mm to 533 mm and then back up to 762 mm. The consequences of this bottleneck will be discussed further in Section 2.5, Available Capacity Peterborough Wastewater Treatment Plant (WWTP) The Peterborough Wastewater Treatment Plant is an integrated fixed film activated sludge (IFAS) process that provides secondary level treatment for the sanitary flows from the. The Plant has an average day flow (ADF) rated capacity of 68,200 m3/d and a peak flow capacity of 190,900 m3/d. L (September 2012) Page 4 of 18

7 In relation to the WWTP and in response to past raw wastewater bypasses at the plant, the City of Peterborough has initiated a Municipal Class Environmental Assessment study for the Mitigation and Management of Extraneous Flows into the Sanitary Sewer System and makes recommendations regarding preferred remedial measures. Specific deliverables of that study include recommendations on measures to eliminate or reduce the frequency of raw bypasses at the Wastewater treatment plant and to recommend an ongoing work program for the continuous monitoring of the sanitary sewer system. In 2009, the WWTP was operating at an ADF of 51,712 cu.m/d and a peak flow of 157,547 cu.m/d. From January to June 2010, the WWTP was operating at an ADF of 43,045 cu.m/d and a peak flow of 81,281 cu.m/d. Based on the rated average and peak flows of the plant, there is capacity at the plant for additional flows from the proposed Lily Lake development area. Refer to Figure 3 depicting the sanitary sewer tributary area as defined from property boundaries along the sanitary sewer collection system. Note that sanitary trunk sewers refer to all sanitary sewer pipes that are equal to or greater than 375 mm in diameter External Flows The total sanitary flows entering the sanitary system includes wastewater from residential areas as well as industrial, commercial and institutional (ICI) areas, plus clean Infiltration and Inflow (I&I) from groundwater, foundation drains, and illegal storm drainage connections to the sanitary sewers. During rainfall events and soon after, the total flow in the system at any point is comprised of dry and wetweather contributions. Dry weather is wastewater plus groundwater infiltration. Wet weather contributions are typically connections from foundation drains and fast responding illegal connections from roofs or other storm drainage inlets. The method used to determine the capacity in the existing system first generates the design flow from existing developed areas. Unlike steady state (or static) analysis, the hydrodynamic modelling method accounts for time varying inflows into the system and the routing and storage effects in the sewers, manholes, pumping stations, and other sewer components in the system. Both peak flows and volumes were used to create a total design flow hydrograph matching the s Engineering and Construction Standards as per section A.1 Sanitary Sewers Dry-Weather Flow The dry weather hydrograph uses the City s criteria which includes the Harmon Peaking factor to establish the time varying flow pattern shown in Figure 4. This hydrograph matches the peak flow from a small contributing population and produces a daily design dry weather flow volume of 450 L/day/capita. This volume also includes ground water infiltration at a rate approximately equal to 15% of the total dry weather flow peak. Census data from 2006 has been used to estimate the population in each catchment area. The census data was analyzed and distributed over the census blocks covering the system downstream. Population within each sanitary area is based on the average population in the census blocks covering each area as determined from a detailed GIS analysis. L (September 2012) Page 5 of 18

8 Total Flow The total flow in the sanitary system is determined by superimposing the dry and wet weather contributions to as to match the peaks in each area as shown in Figure 5. As shown in Figure 5, the total inflow is the sum of the individual hydrograph contributions. For safety, the peak flow of the dry weather and wet weather hydrographs are assumed to coincide. Note that additional wastewater flow from potential infill developments has not been considered within the existing urban area but infiltration and inflow has been considered based on the tributary areas delineated and shown in the attached Dwg. No. SAN Available Capacity The flows entering the system within each catchment area have been modelled from the connection point at the Parkhill Road Pumping Station to the Peterborough Wastewater Treatment Plant (WWTP). Figure 6 and Figure 8 illustrate the capacity in the system downstream of the Lily Lake Planning area before and after development Pre-Development System Conditions As shown in Figure 6, the existing system can convey the flows without major surcharge to the Wastewater Treatment Plant. There is a slight bottleneck point located at MH shown in Figure 7. The ratio of flow to free flow capacity along the truck is summarized in Table 2 1. The maximum ratio other than the bottleneck location is at MH located near the intersection of Lansdowne St. West and The Pkwy and provides a free flow capacity margin of 29.1%. Table 2 1 Pre Development System Conditions Sewer Hydraulic Analysis Preliminary Results US MH ID DS MH ID Length (m) Pipe Full Capacity (m3/s) Existing Max. Flow (m3/s) % Full L (September 2012) Page 6 of 18

9 US MH ID DS MH ID Length (m) Pipe Full Capacity (m3/s) Existing Max. Flow (m3/s) % Full L (September 2012) Page 7 of 18

10 US MH ID DS MH ID Length (m) Pipe Full Capacity (m3/s) Existing Max. Flow (m3/s) % Full Post-Development System Conditions From the preliminary analysis, a peak flow of L/sec (14,657 cu.m/day) would be generated under ultimate conditions from the Lily Lake Functional Planning Area. These results are based on a net sanitary drainage area of ha, population of 8452, assuming an average DWF of 450 L/cap/day, Inflow and Infiltration rate of 0.25 L/s/ha and a small population Harmon peaking factor of As shown in Figure 8, with the ultimate development of the Lily Lake Functional Planning Area, the system surcharges at the same bottleneck location. The ratio of flow to free flow capacity along the trunk is summarized in Table 2 2. Comparing the hydraulic grade line with the ground elevation reveals a minimum free board of 0.9 m which can be seen the section profile in Figure 9. This free board estimate would be within the projected basement elevations and may result in potential basement flooding. L (September 2012) Page 8 of 18

11 Table 2 2 Post development System Conditions Sewer Hydraulic Analysis Preliminary Results US MH ID DS MH ID Length (m) Pipe Full Capacity (m3/s) Proposed Max. Flow (m3/s) % Full L (September 2012) Page 9 of 18

12 US MH ID DS MH ID Length (m) Pipe Full Capacity (m3/s) Proposed Max. Flow (m3/s) % Full L (September 2012) Page 10 of 18

13 US MH ID DS MH ID Length (m) Pipe Full Capacity (m3/s) Proposed Max. Flow (m3/s) % Full Potential solutions to elevated hydraulic grade lines include: 1. Flow monitoring and model calibration to increase the accuracy of the model. 2. Twinning bottleneck location to reduce hydraulic grade line elevation. 3. Flow Control: Flow attenuation upstream through storage control Flow reduction through I&I identification and reduction. 4. Basement isolation. Furthermore, as presented previously, the Parkhill Road pumping station located southwest of the development has an existing capacity of 76 L/s. This is not sufficient to handle the ultimate flows from the Lily Lake Functional Planning Area and the station along with the existing forcemain will have to be upgraded to handle the ultimate flow. However, in the interim, a station assessment should be completed to clearly define the current operating parameters with respect to the actual inflows and to determine the phasing plan for expanding the station s capacity Peterborough Wastewater Treatment Plant As indicated previously, the has initiated a Municipal Class Environmental Assessment study for the Mitigation and Management of Extraneous Flows into the Sanitary Sewer System and to make recommendations regarding measures to eliminate or reduce the frequency of bypasses at the Wastewater treatment plant. Therefore, alternatives to either reduce flows or store and treat wet weather flows at the WWTP will be forthcoming. However, since the EA study by the City would only reflect current developments, the reductions should either provide sufficient capacity to accommodate future developments or future development studies must extend the recommendations to accommodate and reduce future additional flows. 3.0 Water Distribution Review Domestic water usage calculations were prepared based on the preliminary site statistics and housing/population projections prepared by The 189 ha Functional Planning Area will contain approximately 2880 units and a total population of 8452 persons. Based on the City s water distribution system design criteria of 450 L/person/day, the total average water demand generated from the site is 44.0 L/s. The City s design peaking factors (Appendix B.5) of 0.7, 1.65 and 3.0 was used for the demand calculations. The estimate design flow rates are 31, 73 and 132 L/s for the min hour, max day and peak hours, respectively. Based on the previous design in other areas and the Fire Underwriters Survey (FUS, 1999) guideline, the required fire flow can be 17,000 L/min (283 L/s) for an industrial site. L (September 2012) Page 11 of 18

14 The required fire flow depends on the type and the floor areas of the industrial site and it needs to be revisited during detail design stage. Table 3 1 summarizes the estimated water demand from the site. Table 3 1 Design Water Supply Flow rates Av. day Min Hour Max day Peak Hour Peaking Factor Flow Rate (L/s) Fire Flow (L/s) 283 Max Day Plus fire (L/s) Existing Water Distribution Network Design information and water system GIS files supplied by the City were reviewed and the existing adjacent municipal water systems are shown on Drawing WTR 1 at the end of the report. Appendix B.2 shows the schematic watermain layout in the WaterCad model. The existing water system in the vicinity of the site is as follows: Water Supply Reservoir: Towerhill Reservoir in Zone 2 located at Hillview Drive and Towerhill Road. It is to supply water to the subject site development. o Capacity = 22.7 ML; o Operating range: Low Water Level (LWL)= 282.2m to High Water Level (HWL)=287.7m; Water storage facility: Sherbrooke Street Elevated Tank (ET) in Zone 3W located at Sherbrooke Street and Hywood Road. o Capacity=2.7 ML; o Operating range: LWL = 307.4m to 317.0m; Ground Elevation: 282m Watermains o A 200mm diameter watermain along Parkhill Road W, south of the site. o A 600mm/500mm diameter watermain from Parkhill Road W. to the existing Sherbrooke St. ET. It starts from the intersection of Ravenwood Dr. and Parkhill Road W., goes south along Ravenwood Dr., west along Glenforest Blvd., south along Woodglade Blvd., west along Sherbrooke Street and finally north to the existing Sherbrooke ET. Pumping station (PS) to supply water to Zone 3W o Fairmount PS: Design Capacity =21.8 MLD; Design head =38m. o Greenhill Ps: Design Capacity =8.6 MLD ; Design head = 44m. o Landowne PS: Design Capacity =3.7 MLD ; Design head = 61 to 66m L (September 2012) Page 12 of 18

15 The City provided approximately ten (10) pressure tests (Appendix B.3) at hydrants in the vicinity of the site from 1987 to 2005 (i.e Parkhill Road and 1730 Ravenwood Dr. at Zone 3W system, 940 Towerhill Road at Zone 2 to suction off Towerhill reservoir and 615 Towerhill Road at Zone 3N system). The static pressure measured at the above locations during the test days were as follows: Zones 3W and 3N between 70 and 84 psi; Zone 2 to suction off Towerhill reservoir between 29 and 35 psi. The current pressure tests were used to check the system head/pressure along the watermains at the proposed connection locations (see Appendix B.4 for the hydrant flow interpolated test results). As shown in Appendix B.4, a total of four current tests were analysed and plotted. Two of them were conducted at the Zone 3W system located southeast of the subject site near Parkhill Road W and Ravenwood Drive. The static system heads were between 304 and 310m. The third one was performed at Zone 3N system located northeast of the subject site near Towerhill Road and Chemong Road. The static system head was approximately 311m. The fourth one was conducted at the suction off the Towerhill reservoir (Zone 2 system) located northeast of the subject site near Towerhill Road and Hillview Drive. The static system head was approximately 284m, which corresponded to the 50% full level at Towerhill Reservoir Proposed Water Connection Based on the City s conceptual Watermain Plan, revised on June (shown in Appendix B.1), the following proposed trunk main and watermain extension near the subject site can be seen: Trunk main extension from the Towerhill reservoir to the existing Sherbrooke St. ET: Starting from the Towerhill reservoir, turns west along Lily Lake Road, south along the property boundary between the subject site and Jackson Land, west along Parkhill Road West, south along Brealey Drive, east along Sherbrooke Street and finally turns north to the existing Sherbrooke ET. The proposed trunk extension will link to the existing trunk system and create a trunk looping system to Zone 3W. Watermain Extension from the Towerhill reservoir to Brealey Drive: Starting from the Towerhill reservoir, turns west along Lily Lake Road, south along Fainbairn Street, west across the middle of the subject site, south along the property boundary between the subject site and Jackson Land, west along Parkhill Road West and finally turns south along Brealey Drive. CEG has incorporated the City s trunk or watermain extension strategy (above) into the design concept for the subject site. After review the grading and development limit in the vicinity of the subject site, more than half of the land along the property boundary between the subject site and the Jackson Secondary Plan are designated as undevelopable land (within the watercourse of Jackson Creek). CEG suggests moving the trunk main along a proposed internal street within the Lily Lake Planning Area, as shown on Drawing WTR 1 and Appendix B.2. This section of trunk relocation may result in less environmental impact as well as increased cost savings. A detailed EA process is required to review the alternatives and select the preferred route for the future trunk main extension. As discussed with the City, the water supply for the subject site will be from the Towerhill reservoir. The proposed trunk main and watermain in the vicinity of the subject site and the watermain with the subject site are shown on Drawing WTR 1. The alternative for other system upgrades (e.g. pumping station and storage) is discussed below: Alternative #1: Subject site incorporated into Zone 3W system (Storage Tank outside subject site), L (September 2012) Page 13 of 18

16 New pumping station to supply water to future 3W development including subject site (Potential site is near Lily Lake Road and Fairbairn Street as shown on Drawing WTR 1). Storage facility size upgrade for future zone 3W development including subject site (Potential site is at the existing Sherbrooke St. ET site). Pressure reduction will be required for a small area (e.g. elevation lower than 247 m). Alternatively, higher pressure rating pipelines and mechanical systems shall be installed in these areas. Alternative #2: Subject Site separated from Zone 3W system (Storage tank inside subject site) New pumping station to supply water to future 3W development including subject site [Potential site is near Lily Lake Road and Fairbairn Street (same as Alternative #1)]. New Storage facility (e.g. Tank HWL = 310m) at a high point of within subject site. Storage facility size upgrade for other future zone 3W development may still be required (Potential site is at the existing Sherbrooke St. ET site). Two (2) Pressure Reduction Valves (PRV) will be required: Due to higher system head outside the subject site, two PRVs would be required. One on the proposed 300mm watermain near Lily Lake Road and Fairbairn Street and another one along the proposed 300 mm watermain before the connection to the existing 200 mm at Parkhill Road (see Appendix B.2 and Drawing WTR 1 for potential PRV locations). 4.0 Storm Drainage Review The post development storm drainage pattern will closely follow the pre development drainage conditions as discussed in the Stormwater Management Assessment section of this Report. In the post development condition, storm drainage will generally be directed to the south and west towards four proposed stormwater management facilities Minor System Conveyance The minor system storm conveyance will consist of a network of storm sewers aligned within the proposed right of ways, outletting to a proposed stormwater management facility for water quantity and quality control, prior to outletting to Jackson Creek. The storm sewers will generally be installed at nominal depth to obvert of 3.0m below road surface, however in some instances may need to be deepened to accept drainage from development at lower elevations Major System Conveyance The major system storm drainage will be conveyed overland via the proposed right of ways within the Functional Planning Area and shall be directed to the proposed stormwater management facilities. Cross sections at the critical sections of overland flow routes will require analysis at the Draft Plan stage to assess their capacity to contain the 100 year storm without impacting private property. Refer to Drawing No. STM 1 for details of the preliminary storm sewer network, overland flow route and stormwater management facility locations. L (September 2012) Page 14 of 18

17 4.3. Preliminary Road Grading The objective of the preliminary grading design is to establish road grades in the range of 0.7% to 3% and direct major system storm drainage towards the proposed stormwater management facilities. Due to the significant elevation differences in existing site topography (20m difference from the center of the site to the perimeter), certain road sections will require steeper grades up to 5%. All site boundary grade conditions will be matched, however allowance should be considered for 3:1 sloping encroachments into the Open Space Blocks to support the site development in certain locations, i.e. window streets adjacent the Open Space. The secondary objective of the preliminary road grading design is to provide a balance between cut and fill earthworks operations to minimize the importing or exporting of soil. An earthworks analysis (cut/fill calculation) has not been completed for the site based on the preliminary road grading. Refer to Drawing No. GR 1 for the preliminary road grading design details. 5.0 Cost Sharing Guidelines Due to the nature of development planning on a larger scale such as the Lily Lake Functional Planning Area, frequently more than one landowner will be situated within the development area. As a result of multiple landowners relying on a network of spine services and roads located throughout the neighbourhood, spanning several different landowner properties, a fair and equitable solution must be established for all benefiting landowners to share the costs of such community spine services and roads. The principles of cost sharing community items such as spine services, roads and land has been well documented within numerous cost sharing agreements within Ontario s development industry. The purpose of the following section is to summarize the anticipated community items within the Lily Lake Functional Planning Area and provide a general outline of established cost sharing principles Cost Sharing Principles Typically, community cost sharable items can be divided into two categories: a) Community Servicing and b) Community Land. Each category has a defined set of principles that governs the fair and equitable distribution of costs among all benefiting landowners. Community Land Definition: Lands located within an Owner s Developable Area which are for the use by the Community and designated for the following uses: i. Schools ii. iii. Parks and neighbourhood parkettes Storm Water Management and Flood Control Facility sites L (September 2012) Page 15 of 18

18 iv. Sanitary Pumping Station sites v. Water Storage or Pumping Station Facility sites vi. vii. Hydro Transformer Station or Bell Canada Facility site(s) Oversized Right Of Ways (portion greater than the local r.o.w. width) Developable Area is the portion of an Owner s lands exclusive of valleylands or lands encumbered by easements which prevent the development of the lands or which prevent their use for park dedication or for which a landowner receives no compensation. Cost Sharing Principle Lands designated for Community purposes are commonly cost shared between several benefiting landowners within the defined Community on a proportionate share basis determined by the landowner s Developable Area. Land designated for Storm water Management Facilities or Sanitary Pumping Station sites may also be shared on a contributing flow basis. The monetary value for Community Land is typically determined and fixed at the onset of development within the Community and agreed to by the participating landowners. Community Services Definition: Construction costs incurred for items deemed to benefit more than one landowner. The following items may be considered Community Services: i. Oversized and/or deepened sanitary or storm sewers ii. iii. iv. Oversized watermains and valve chambers Oversized road and boulevard construction Stormwater management facilities, including earthworks structures and landscaping v. 50% of nominal road and servicing construction for roads adjacent to Community Lands vi. vii. viii. Bridges, culverts and creek crossings Sanitary pumping stations and/or downstream sanitary sewer upgrades Water Storage or Pumping Station Facilities and/or external watermain extensions/upgrades Cost Sharing Principle: Generally, the sharing of construction costs for Community Services is based on a landowner s proportionate share of Developable Area as it bears on the overall Developable Area within the Community. There are a couple exceptions, such as for items (i) Oversized/deepened sewers (iv) Stormwater Management Facilities and (vii) Sanitary pumping stations, which may be shared based on a flow contribution basis. L (September 2012) Page 16 of 18

19 6.0 Conclusions and Recommendations Based on the analysis completed in the preceding sections, the Lily Lake Functional Planning Area can be serviced via an extension of existing municipal services located near the site and the following conclusions/recommendations are summarized below. Sanitary Servicing Assessment: Under full build out of the proposed development, the site will generate an average daily sewage flow rate of approximately 44L/s. All proposed sanitary sewers will direct flow by gravity. Internal conveyance of sewage will be via a network of sanitary sewers directing flows towards an approved outlet. Several sanitary flow outlets were investigated and the recommended outlet option is located at the southwest corner of the site connecting to the existing Parkhill Road pumping station. The outlet sewer will require a crossing of Jackson Creek prior to connecting to the pumping station. Presently, the Parkhill Road pumping station does not have the wet well depth or capacity to accept flows from the site, however, the City has considered an expansion program for this pumping station to accommodate additional flows. It is recommended that as part of the pumping station expansion, the wet well be deepened to allow for a gravity connection from the site to the Parkhill Road pumping station. Pre development system conditions show the existing sanitary trunk sewer leading from the Parkhill Rd. pumping station to the Peterborough Wastewater Treatment Plant has sufficient capacity to convey flows without surcharging (with the exception of one leg) in the sanitary system. Post development system conditions show that the additional flow contributed by the Lily Lake Functional Planning Area leads to sections of localized surcharging in the existing sanitary trunk sewer system and may lead to basement flooding. The City s Wastewater Treatment Plant exhibits sufficient capacity to treat the additional flows from the development area. Water Supply/Distribution Assessment: Both water supply alternatives to supply water from Towerhill reservoir to the subject site seem feasible. The entire site meets the City s pressure requirements (e.g. between 275 and 700 kpa) as shown in Appendix B.5. Alternative #1 (subject site integrated into the Zone 3W system) is preferred. The subject site is operated at a relatively higher pressure range. Fewer valve chambers (e.g PRV) are required and it has relatively less risk involved in providing water to the subject site. A detailed hydraulic analysis of the water supply system shall be performed to investigate the existing and future system demand, system storage, pump operational ranges and the pumping capacity requirement to include the subject development. Storm Drainage Assessment: Minor system storm drainage will be conveyed by sewers towards one of four proposed stormwater management facilities (for facility details and pre to post development stormwater calculations, refer to the Stormwater Management Assessment Report). L (September 2012) Page 17 of 18

20 Major system storm drainage will be conveyed overland via proposed right of ways or approved overland flow easements towards the proposed SWM facilities. Preliminary grading has been designed to achieve a road gradient between 0.7% and 3%; however steeper grades will be necessary in certain areas due to the site topography. L (September 2012) Page 18 of 18

21 APPENDIX A Figures

22 Lily Lake Functional Planning Area N.T.S Ref. #: L (October 2010) Site Location Figure 1 Site Location

23 N.T.S Ref. #: L (October 2010) Lily Lake Functional Planning Area Figure 2 Preliminary Concept Plan

24 Lily Lake Functional Planning Area Ref. #: L (October 2010) Figure 4 Dry Weather Flow Pattern

25 Lily Lake Functional Planning Area Dry-weather inflow into the sanitary sewer. Direct inflow into the sanitary sewer. Groundwater Infiltration into the sanitary sewer. F l o w Day 1 Day 2 Day 3 Day 4 Ref. #: L (October 2010) Figure 5 Total Hydrograph Flow Generation

26 Lily Lake Functional Planning Area Ref. #: L (October 2010) Figure 7 Existing Condition Trunk Sewer HGL at Bottleneck MH

27 Lily Lake Functional Planning Area Hydraulic Grade Line Ref. #: L (October 2010) Figure 9 Proposed Condition Trunk Sewer HGL at Bottleneck MH

28 APPENDIX B Water Distribution Design And Background Data

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34 APPENDIX C Statement of Limiting Conditions & Assumptions

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