Pioneer Park Stormwater Management Rehabilitation Project Town of Richmond Hill Engineering and Public Works Department Design, Construction and

Transcription

1 Pioneer Park Stormwater Management Rehabilitation Project Town of Richmond Hill Engineering and Public Works Department Design, Construction and Water Resources Division

2 Presentation Outline Background Stormwater Management (SWM) Capital Planning SWM Priority Rating System Evaluation Criteria SWM 10 Year Capital Plan Introduction Location History of Pioneer Park SWM Pioneer Park Stormwater Management Facility Rehabilitation Project Benefits Project Funding Facility Design Don River Instream Rehabilitation Works TRCA Partnership Construction Challenges Facility Construction Monitoring Programs Operation of Facility

3 Background SWM Capital Planning 2006 SWM Priority Rating System developed Evaluation Criteria Council Approved (SRW.06.09) 2008 SWM Facility Evaluation Study completed Stormwater Management Ten Year Capital Plan established Council approved (SREPW ) SWM Financing for project established Pioneer Rehabilitation EA, Design and Approvals Project Tendered No Contract Awarded 2009 Project Value Engineering Exercise Completed Project Contract Awarded 2009/2010 Project Constructed

4 Background 10 Year Capital Plan SWM Priority Rating System Evaluation Criteria (SRW.06.09) Note: First Four factors count for 75% of the total score

5 Town of Richmond Hill - SWM Ten Year Capital Plan Year of Year of Design Build SWM Facility Name Cost Estimate Type of Work Available Reserve Funding Balance $17,030, Pioneer Park Pond $4,500,000 Rehabiliation - Critical to FDA - 2 $12,530, Don Head West Pond $1,808,000 Rehabiliation - Critical to FDA - 1 $10,722, Rumble Pond $2,815,000 Rehabiliation - Sediment Removal $7,907, Harding Park East Pond $449,000 Sediment Removal $7,458, Lake Wilcox Baif West Pond (5AB-FS $490,000 Sediment Removal $6,968, Beaver Creek Pond B $619,000 Rehabiliation - Sediment Removal $6,349, Orchard Pond (Minto West) (Pond 405 $203,000 Sediment Removal $6,146, Elgin West Pond D2 $1,179,000 Rehabiliation - Sediment Removal $4,967, Beaver Creek Pond A $2,787,000 Rehabiliation $2,180, Minto Southeast Pond (Pond 406) $410,000 Sediment Removal $1,770, Twickenham Pond D1 $935,000 Sediment Removal $835,000 Ten Year Program - Total Amount $16,195,000 Reserve Fund Balance after Ten Years $835, Snow Storage Facility $80,000 Sediment Removal 2-4 Beaufort Hills Pond $1,044,000 Rehabiliation - Sediment Removal 24-2 Don Head East Pond $2,652,000 On line Facility - Needs Study 19-6 Felgi Pond (Pond 408) $433,000 Sediment Removal 8-3 Mitchell Pond DF4 A/B $321,000 Sediment Removal 16-8 Elgin West Pond GM4W $227,000 Sediment Removal 8-2 Patrician Homes Pond $174,000 Sediment Removal 11-1 Summit Trail Pond $379,000 Sediment Removal 2-9 Casa Pond (3ABC) $223,000 Sediment Removal 23-1 Harding Park West Pond $34,000 Needs Study 17-3 Heritage Estates Pond $1,350,000 Needs Study 11-2 Country Heights $45,000 Needs Study 15-4 Elgin East Pond C $1,426,000 Needs Study 16-7 Elgin West Pond GM3 $1,000,000 Needs Study 19-1 Beaver Creek Pond (Pond 400) $1,000,000 Sediment Removal - Regular maintenance 27-1 Doncrest Pond $724,000 Development Activity in Area 28-2 Beaver Creek Pond C $1,000,000 Development Activity in Area $12,112,000

6 Pioneer Park Stormwater Management Facility Ranked 1 st in Priority Flood Vulnerable Area Statutory and Regulation Compliance 3.6% to 20.0%/20.0% Operations and Maintenance 3.6% to 14.7%/15% Critical Emergency Services Access

7 Introduction Location Watershed Little Don River watershed Headwaters of Don River draining to Lake Ontario Located on southern boundary of Oak Ridges Moraine Tributary area for SWM facility increased from 26 ha to 740 ha

8 History of Pioneer Park SWM Originally built in 1980 s. Accepted as Parkland dedication under the Ontario Planning Act. Dry, on-line stormwater quantity control facility for 26 ha of residential development. Original Structure was an online dam, with inappropriate volume control being provided. Built prior to the introduction of the Ontario Water Resources Act requirement for a Certificate of Approval. Over time, failure of the dam outlet structure (blockages) created a backwater condition. Backwater condition resulted in the creation of wetland conditions including the collection of sediment and increased water temperature.

9 Major Project Benefits Reduction in Identified Flood Vulnerable Areas. Provides a SWM Master Plan for the Watershed Increase in serviced tributary area form 26 Ha to 740 Ha. (infill - e.g. site plans, severances, small subdivisions) Provides Water Quantity, Quality and Erosion protection for the whole service area. Creation of Watercourse and Wetland habitat new stream channel constructed to restore fish passage for an endangered fish species (redside dace).

10 Major Project Benefits continued Optimization of hydraulic and environmental operations Facility operations optimized by several control structures which allows water level adjustment, baseflow fine tuning, etc. Protection of critical transportation route Major Mackenzie Drive protected in catastrophic storm. Emergency access route to York Central Hospital Police and Fire emergency routes Serves the Downtown Village Core of Richmond Hill Provide access to trunk (525mm dia.) sanitary sewer. Permits access by flusher trucks to undertake maintenance

11 Project Benefits continued Protection of Large Tract of Carolinian Forest Enhanced plantings of diverse native plant species, vegetation, trees and shrubs will all provide and improve the habitat for amphibians and other wildlife. Improved community accessibility to valley land trails promoting healthy active living. Improved access to York Central Hospital and local high school. Use of innovative stormwater technologies, such as the elimination of sediment forebay and the use of oil-grit separator to pre-treat sediment and reduce its entry into the system.

12 Project Funding Total Cost million Municipal Town of Richmond Hill SWM 10 Year Capital Plan $2.925 million Provincial Municipal Infrastructure Investment Initiative (MIII) Ontario $2.25 million Federal The Gas Tax Fund (GTF) $1.125 million Conservation Authority TRCA In-kind and partnership MOU funding First major stormwater management facility rehabilitation in Canada.

13 Design Stormwater Management Facility Catchment area 740 hectares Off-line wet pond for water quality and quantity control Provide (Level 2) water quality protection Flood protection up to 100-year return storm Discharging to East Don River

14 Design WET POND Design permanent pool of 8,200 m 3 Control of frequent runoff events with a volume of 12,000 m 3 (25mm 5 year) Discharge flow release rate on 1.9m 3 /s DRY POND On-line dry pond for water quantity Control from 5 year to 100 year return storm events. Retention volume of 30,000 m 3 with a discharge flow release rate of 15m 3 /s, above which a 2-stage spillway is designed to convey twice the Regional storm (Hurricane Hazel) flow rate of 140 m 3 /s

15 Design Facility will have pond by-pass to channel baseflow between the wet pond and the existing culvert under Major Mackenzie Drive, designed to accommodate fish passage around the wet pond during dry weather. Oil grit separator structure will provide pre-treatment. Stormceptor Model STC 3000 on the storm sewer outfall from the Don Head Estates subdivision (1200mm diameter sewer) to pre-treat the runoff from the existing 26 hectare subdivision.

16 Toronto and Region Conservation Authority (TRCA) Partnership Don River Instream Rehabilitation Works Section A - Bank Stabilization Section B - Erosion Control and Stream Protection Section C - Watercourse Realignment for the Protection of the Trunk Sanitary Sewer

17 Section A - Bank Stabilization BEFORE AFTER

18 Section B - Erosion Control and Stream Protection Before During Construction

19 Section C Watercourse Realignment for the Protection of the Trunk Sanitary Sewer Exposed Sewer Delineates where stream flowed previous to rehabilitation AFTER

20 Construction Timing Fisheries Window Department of Fisheries and Oceans (DFO) authorization for works of undertakings affecting fish habitat. No work shall occur from April 1 to June 30 to protect local fish populations during spawning and nursery periods. Wet / Dry Conditions

21 Construction Challenges Sediment Removal Sediment testing indicated disposal at hazardous landfill was not necessary. Sediment that needed to be removed mainly consisted of alluvium and clay. R&M Construction planned to use the alluvium to fill voids between the 800mm rip rap stone used for berms. A large majority of the material was used onsite for berm construction. Online Watercourse and Fish Passage

22 Construction December 2, 2010

23 Construction - March 10, 2010

24 Structure #5

25 Control Structure #4

26 Structure #4 and #5 Control structure 5 large concrete box culvert to convey flow under north berm. Benching in culvert embedding with river run to mimic stream channel. Control Structure 4 will divert baseflow into by-pass baseflow channel and rain events into wet pond. Stop logs in Control Structure 4 will allow for control of water levels in both the wet pond and baseflow channel.

27 Control Structure #3

28 Operation of Facility Dry Weather Baseflow rate of approximately ~30L/s will pass through the by-pass channel and go through the existing culvert under Major Mackenzie. Wet Weather The orifice in structure 4 will cause the water levels to increase with flow rate thereby causing the river to spill into the pond. Flows in the by-pass channel will increase slightly, the orifice in Structure 3 will prevent high flow rates to discharge. Storms larger that ~25mm will cause the wet pond to fill and discharge across the spillway to the culvert under Major Mackenzie. The outlet (Structure 1) has stop logs which enable the Town to raise or lower the NWL by 15cm.

29 Operation of Facility Wet Weather During 5 year to 100 year return storm events Structure 5 has metals beams installed across the inlet that act like large orifices. Runoff will back up into the river valley and be detained (release rate ~15m 3 /s). Storm events larger than 100 year will spill over the berm of the upper detention facility and spill over the wet pond spillway to the culvert under Major Mackenzie. Regional storm events (Hurricane Hazel) designed to flood the entire Pioneer Park Facility.

30 Monitoring Programs Department of Fisheries and Oceans (DFO) - Authorization for Works or Undertakings Affecting Fish Habitat Monitoring program from Water quality monitoring (Temperature and TSS); Determine the nature of flows and velocities in the low-flow bypass channel; Confirm that fish passage is indeed achieved, particularly for at least medium-sized forage fish under low-flow conditions; Identify the species, sizes and life stages of fish that are achieving upstream passage through the low-flow channel; Verify the stability of all rehabilitation and re-constructed stream channels. Town partnership with TRCA to complete study that will go beyond requirements to determine if water quality in wet pond is suitable fish habitat during times of entrapment and other fisheries concerns. Baseflow Monitoring 2009

31 Monitoring Programs Ministry of the Environment (MOE) Certificate of Approval Monitoring Program from Quarterly; at least once being from the snowmelt freshets and another being 72 hours after the fall of precipitation. Water quality parameters to be tested include: CBOD5, TSS, Total Phosphorus, E.Coli, ph, Metals and Temperature. Town to complete MOE C of A monitoring requirements. Water Quality Profiles Temp, DO, ph, Conductivity

32 Monitoring Programs Town of Richmond Hill Stormwater Management Monitoring Programs Town of Richmond Hill established a watershed monitoring program over 10 years ago to assess impacts to watercourses and ensure stormwater management facilities are functioning in accordance with design. The watershed monitoring program includes: Water Level Monitoring Continuous water level monitoring to assess if SWM facility is functioning in accordance with approved design. Sediment Surveys to assess sediment accumulation rates. Inspections Quarterly facility inspections to note any deficiencies that might negatively impact function of facility. Stream Flow Monitoring continuous flow measurements to identify changes in stream hydraulics. Facility 7-3 May 9-12, mm Rainfall (25mm Event) Water Elevation (masl) Hours Rainfall (mm) Facility Elevation PP Elevation 25mm Elevation Rain (Operations)

33 Pioneer Park Stormwater Management Rehabilitation Project Town of Richmond Hill Engineering and Public Works Department Design, Construction and Water Resources Division QUESTIONS? Contact: John Nemeth Manager of Water Resources (905)