R.J. Burnside & Associates Limited 16775 Yonge Street Suite 200 Newmarket ON L3Y 8J4 Canada telephone (905) 953-8967 fax (905) 953-8945 web www.rjburnside.com Class Environmental Assessment Schedule B Project File Report Date: March 19, 2012 File No.: 300030647.0000 Project: To: From: Middletown Sewage Pumping Station and Forcemain Class Environmental Assessment Schedule B projects Project File Material Mr. Jon Morton, P. Eng., MBA, PMP Manager of Capital Projects Town of Bradford West Gwillimbury Stephen Walker, C.E.T. Introduction The following information is provided in support of a revised Notice of Completion for the proposed Middletown Sewage Pumping Station (SPS) and related forcemain to be constructed to service new development lands in the Town of Bradford West Gwillimbury. Both the SPS and the forcemain were recommended for implementation in the Town s Master Servicing Study (MSS), dated January 2003. The projects were identified as SWB-PS2 and SWB-FM2 respectively in Table 8.1 of the MSS. Since the MSS was completed, more than 5 years have passed without the start of construction of the projects. Therefore the Class Environmental Assessment (EA) guidelines under which the MSS was approved, require a review of the planning and design process to confirm the projects are still appropriate. The following sections summarize background information, provide a review of current conditions, conceptual design and preliminary cost estimates and include confirmation of the recommended projects. Background The Middletown SPS was planned to service new development in the south half of Lot 11, Concession 6 in the Town of Bradford West Gwillimibury. The development in this area falls within the boundary of Community Area 2 (CPA2) as defined in the Town s Official Plan (see Attachment A ). The service area is located generally north of the 6 th Line and east of Sideroad 10. The SPS was recommended in the MSS due to the topographic limitations in servicing this area with gravity sewers. The pumping station was planned to service approximately 43 ha and 1,800 persons based on available contour information and conceptual servicing designs in 2003.
Memorandum to Mr. Jon Morton, P. Eng., MBA, PMP Page 2 of 5 March 19, 2012 The Middeltown SPS was planned to consist of a pumping station structure meeting the Town and Ministry of the Environment design requirements. A forcemain from the station was planned to extend from the SPS site to the closest gravity sewer manhole which was in turn connected to the main Holland Street West SPS (now identified as the Ritchie Stong Sewage Pumping Station). Review of Planning and Physical Environment Servicing of development has proceeded in general conformity with the MSS and as reflected in the Functional Servicing Report (FSR) prepared for CPA2 (refer to Attachment B ). The Ritchie Stong SPS has been constructed and is operational. Gravity sewers have been constructed to the Ritchie Stong SPS and due to topographical and grading constraints, these sewers cannot be extended to service lands as far south as 6 th Line or west to Sideroad 10 (which was anticipated in the MSS). Therefore, the Middletown SPS is necessary to provide sanitary servicing to these lands within CPA2. The existing gravity sewer system will serve as the outlet for the discharge from the Middletown SPS via the proposed forcemain. Sanitary Service Area and Population From review of the submitted development-related servicing plans, it is noted that the grading design and sewer design have allowed for the gravity pipe system to extend further southwest than was originally proposed in the MSS. Therefore it is possible to shorten the original length of the proposed forcemain and connect to a new sanitary manhole proposed closer to the Middletown SPS site. In addition, the approved draft plan has set aside a block for future development purposes (see Attachment C ), which is beyond the population and servicing limits approved in the Official Plan and the MSS. Therefore the service area and related residential population to the Middletown SPS have decreased as noted below (also see Attachment D ). Area north of watercourse: Add area south of watercourse: Less future development block 746: Less future development block 747: Current approved service area to SPS: 1.76 ha +16.37 ha -0.51 ha -3.84 ha 13.78 ha Population: (based on 3.36 persons/single family unit from the 2009 Development Charge Background Study). The number of units identified in approved draft plan and the Middletown SPS sanitary drainage area was determined to be 212 single family units. Therefore, the design service population is 212 units x 3.36 persons/unit = 713 persons. Design Criteria and Sanitary Pumping Station and Forcemain Design Flows The Town of Bradford West Gwillimbury and the Ministry of the Environment design criteria were consulted to determine appropriate design flows for the pumping station and the forcemain outlet. The calculations are provided in Attachment E and are summarized below:
Memorandum to Mr. Jon Morton, P. Eng., MBA, PMP Page 3 of 5 March 19, 2012 Average day flow: Peak flow: 300 m 3 /day (3.5 L/s) 1,000 m 3 /day (11.6 L/s) Conceptual Pumping Station Location, Design and Cost Estimate The Middletown SPS site is proposed within a block to be deeded to the Town, adjacent to a watercourse and floodplain area above the Regional Storm floodline and adjacent to proposed residential lots (see Attachment F ). The detailed design of the station will be required to address setbacks, odour control and noise control issues and meeting the Town and Ministry s requirements for pumping stations and structures. Additional consultation will be undertaken, as appropriate, with relevant departments/agencies during detailed design with the aim of securing all appropriate permits/approvals. The proposed flows for the Middletown SPS are in a range that would be well suited for a submersible sewage pumping station. This type of facility is widely used in Ontario and can be constructed as a combined single structure or as modular components depending on the available site. A submersible pumping station is generally a more economical alternative to a pumping station with pumps located in a drywell. The submersible pumping station facility will be comprised of two equally sized submersible sewage pumps. The pumps will be located in a wet well. Based on the available topographical information the existing grade at the proposed SPS site is approximately 245.00 m. The lowest gravity sewer invert elevation entering the pumping station is estimated to be 239.00 m. Allowing for appropriate wet well design this will result in a station with a bottom of wet well elevation approximately 8 m below grade. A service platform will be provided at approximately the midway depth of the wet well. One or more pumps will be equipped with a hydraulic flush valve to ensure solids do not build up within the wet well. The pumps selected will be capable of pumping the peak design flow with one pump out of service while not exceeding 6 starts per hour. Pumps will be controlled based on liquid level in the wet well as measured by an ultrasonic level transducer. Back up floats will also be provided. Pump isolation valves, pressure gauge, emergency cleanout, station by-pass connection, flow meter and other appurtenances will be located in an external drywell chamber. A fully insulated and temperature controlled building will contain the electrical control panels for the station, a standby generator and associated appurtenances. General interior and exterior lighting, power receptacles and basic plumbing will be provided. Based on the information noted above and recent construction projects for similar submersible stations a capital cost estimate (excluding HST) is provided below:
Memorandum to Mr. Jon Morton, P. Eng., MBA, PMP Page 4 of 5 March 19, 2012 Middletown SPS (project SWB-PS2): Capital Cost Estimate based on Conceptual Design Mobilization, demobilization, bonding, insurance, miscellaneous. $50,000 Dewatering and environmental protection $25,000 Wet well and submersible pumps $285,000 Piping, Valves, Meter and Chamber $135,000 Odour control $50,000 Noise control $20,000 Control Building (structure and building mechanical only) $160,000 Yard Piping $10,000 Site Works $50,000 Electrical including stand-by power $230,000 Instrumentation and Controls $120,000 Site restoration and landscaping $10,000 Sub-total: $1,145,000 Contingency Allowance (15%) $172,000 Engineering, Approvals, Permits Allowance (15%) $172,000 Total (excluding HST): $1,489,000 Conceptual Forcemain Location, Design and Cost Estimate The forcemain from the Middletown SPS is planned to follow a proposed municipal road allowance from the SPS site to the closest proposed sanitary sewer manhole which will be connected by gravity sewer to the Ritchie Stong SPS collection system. This manhole is anticipated to be built approximately 170 m east of the Middletown SPS on Langford Boulevard (see Attachment F ). The proposed forcemain routing is to avoid the duplication of services involving parallel forcemain and gravity sewers flowing in the same direction. Ministry of the Environment Design Guidelines recommend flow velocity in a forcemain be maintained between 0.6 m/s and 3 m/s. Based on the peak design flow of 11.6 L/s and a design velocity of 1.5 m/s the forcemain diameter has been preliminarily sized at 100 mm diameter. It should be noted that the proposed forcemain diameter was originally sized at 150 mm. However based on the design flows discussed above the velocity in a 150 mm forcemain would be approximately 0.66 m/s which is only marginally above the minimum recommended scouring velocity as per MOE Design Guidelines. The available topographical information indicates that the grade elevation rises steadily from the proposed SPS site to the proposed receiving manhole on Langford Boulevard. As such it is unlikely that there will be any significant intermediate high or low points along the forcemain route that would require an air release chamber.
Memorandum to Mr. Jon Morton, P. Eng., MBA, PMP Page 5 of 5 March 19, 2012 The following cost estimate is provided for the forcemain construction and engineering: Middletown Forcemain (project SWB-FM2): Capital Cost Estimate based on Conceptual Design Bonding, insurance, construction layout $5,000 Environmental protection $2,000 100 mm diameter sanitary forcemain (170 m x $300/m) $51,000 Sub-total: $58,000 Contingency Allowance (15%) $8,700 Engineering, Approvals, Permits Allowance (15%) $8,700 Total (excluding HST): $75,400 (Rounded) $76,000 Environmental Mitigation Measures The environmental impacts and mitigation measures were reviewed and remain unchanged from those noted in the MSS. The measures to avoid or minimize impacts were noted as design-related and construction-related measures. Monitoring and reassessment strategies also remain unchanged. Specific mitigation measures are to be discussed with relevant departments and/or agencies during the detailed design of the pumping station and forcemain projects. Summary, Recommendation and Class EA Schedule Confirmation This memorandum has confirmed the need for the Middletown SPS and related forcemain projects identified in Class EA MSS. The projects have been updated based on recent planning and servicing documents and the Town and MOE design criteria. It is recommended that the peak design flow based on this information is 1,000 m 3 /day (11.6 L/s). A review of the Class EA project schedules confirmed that the Middletown SPS and related forcemain outlet are described as Schedule B activities. Following the publication and circulation of a Revised Notice of Completion and a minimum 30 day public and agency review and comment period, the Town may proceed to implement these projects if there are no outstanding comments. Respectfully submitted, R. J. Burnside & Associates Limited Stephen Walker, C.E.T. SW:ja Enc. 120319 EA Update Memorandum_030647 3/19/2012 11:49 AM
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ATTACHMENT E Middletown Sewage Pumping Station Class Environmental Assessment Notice of Completion Update Town of Bradford West Gwillimbury Population and Drainage Area: Area (ha) No. of Res. Units Persons/unit** Population Persons/net ha North of Watercourse 1.76 21 3.36 71 40 South of Watercourse* 12.02 191 3.36 642 53 Total: 13.78 212-713 *excludes two future development areas identified on draft plan south of watercourse (total of 4.35 ha) Therefore, drainage area = 16.37 ha -0.51 ha - 3.84 ha = 12.02 ha ** persons/single family unit based on data included in 2009 Development Charges Background Study Design Criteria: Per capita wastewater flow rate = 250 L/cap.day peaking factor = Harmon equation collection system peak extraneous flow design rate = 0.2 L/s/ha MOE average day extraneous flow design rate = MOE peak extraneous flow design rate 90 L/cap.day 227 L/cap.day Design Calculations: Peak flow based on collection system design criteria: Average day wastewater flow = 2.06 L/s Harmon peak factor = 3.89 Peak wastewater flow = 8.03 L/s Peak extraneous flow = 2.76 L/s Therefore, total peak design flow = 10.78 LIs OR 931 m3/day (ROUNDED) 1,000 m3/day Based on MOE design criteria: Average day wastewater flow = Average day extraneous flow = Total average day flow OR (ROUNDED) 2.06 LIs 0.74 LIs 2.81 LIs 242 m3/day 300 m3/day Average day wastewater flow 2.06 L/s Harmon peak factor = 3.89 Peak wastewater flow = 8.03 LIs Peak extraneous flow= 1.87 LIs Therefore, total neak design flow = 9.90 LIs OR 855 m3/day (ROUNDED) 900 m3/day R. J. Burnside & Associates Limited 3/5/2012 Population design flows_030647.xls
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