CVC Head Office Stormwater Report

STORMWATER MANAGEMENT CREDIT APPLICATION REPORT CREDIT VALLEY CONSERVATION

December 2016 TABLE OF CONTENTS

CONTENTS 1.0. INTRODUCTION ...... 4 1.1. SITE DESCRIPTION ...... 6 1.1.1. General ...... 6 1.1.1.1. Meadowvale Conservation Area: ...... 7 1.2. PRE-DEVELOPMENT CONDITIONS ...... 11 2.0. INTEGRATED WATER MANAGEMENT (IWM) ...... 12 2.1. BUSINESS OBJECTIVES ...... 12 2.1.1. Integrated Water Management (IWM) ...... 13 2.2. MISSISSAUGA STORMWATER CRITERIA ...... 15 2.3. EXISTING CONDITIONS ...... 15 2.3.1. Geotechnical Investigation ...... 18 2.4. STORMWATER DRAINAGE SYSTEM ...... 19 2.4.1. Minor System ...... 19 Parking Lot 2 ...... 20 Parking Lot 3 ...... 20 Roof Drainage - Buildings A & B ...... 21 2.5. Stormwater Best Management Practices ...... 25 2.5.1. Rainwater Harvesting System (RWH) for Building A ...... 25 2.5.2. Permeable Pavement Parking Lots ...... 29 2.5.2.1. Paver Type and Thickness ...... 30 2.5.2.2. Bedding Layer and Thickness ...... 30 2.5.2.3. Granular Base Material and Thickness ...... 31 2.5.2.4. Underdrain System ...... 33 3. Vegetated Swales ...... 36 3.1.1.1. Wet Weather Drainage Patterns ...... 38 3.2. Major System ...... 39 3.0. HYDROLOGIC MODELLING ...... 40 3.1. STORMWATER CRITERIA ...... 46 3.2. Peak Flow Reduction ...... 46 3.3. WATER QUALITY TREATMENT ...... 47 3.3.1. Permeable Pavement ...... 48 3.3.2. Vegetated Swales ...... 49

3.4. RUNOFF VOLUME REDUCTION ...... 51 4.0. CREDIT REQUEST ...... 53 5.0. SYSTEM OPTIMIZATION ...... 55 Figure 28 : Stylized ADS enhanced swale design (Source: Advanced Drainage Systems (ADA) Canada) ...... 55 5.1. CREDITS FOR OVER CONTROL ...... 56 6.0. OPERATION & MAINTENANCE PLANS ...... 56 6.1. RAINWATER HARVESTING SYSTEM OPERATIONS AND MAINTENANCE MANUAL ...... 56 6.1.1. Introduction ...... 56 6.1.2. Rainwater Harvesting System Description ...... 56 6.1.3. RWH System Components ...... 57 6.2. CVC PERMEABLE PAVEMENT OPERATIONS AND MAINTENANCE PLAN ...... 83 Results ...... 83 7.0. ENGINEER’S CERTIFICATION & OPERATION ...... Error! Bookmark not defined. 7.1. CERTIFICATION THAT ALL BMPS HAVE BEEN CONSTRUCTED IN ACCORDANCE WITH THE SUBMITTED DRAWINGS AND THAT THEY ARE OPERATIONAL...... Error! Bookmark not defined. 7.2. CONFIRMATION OF THE DATE(S) THAT ALL THE BMPS WERE IMPLEMENTED INTO SERVICE ...... Error! Bookmark not defined. 8.0. APPENDICES ...... Error! Bookmark not defined.

1.0. INTRODUCTION

CVC has implemented a variety of innovative stormwater management best management practices on their property to reduce impacts to municipal stormwater infrastructure by controlling the quantity and quality of stormwater leaving the site.

The purpose of this report is to support an application for a stormwater credit for the Credit Valley Conservation (CVC)-owned property located at 1255 Old Derry Road in Mississauga. In 2016, CVC will have been assessed with a stormwater charge of $9,180.00 based on an impervious area of 24,506.2 m 2, which constitutes 91.8 billing units (Figure 1).

Figure 1 Annual Charge for CVC property (04439200)

Figure 2 shows the CVC-owned lands identified within the stormwater fee calculator tool. The area hatched in red represents lands that the City of Mississauga is currently leasing from CVC. While the area without hatching represents the lands associated with CVC’s administration office.

Figure 2 Total impervious cover across the CVC property

CVC has also measured the surface area of existing impervious surfaces which was found to be 23,810 m2. Table 1 provides a breakdown of the impervious cover for the entire CVC property.

Table 1 Breakdown of Impervious Cover

Land Use Area (m 2) Type Buildings 2,291 Gravel 8,206 Parking Lot 1,989 Paved Trail 80 Pervious Parking 3,866 Road 3,066 Sidewalk 1,204 Trail 3,108 Total 23,810

1.1. SITE DESCRIPTION

1.1.1. General

Located on the north side of Old Derry Road and west of the Credit River in Mississauga, the CVC property is located close to the heritage conservation district known as the Village of Meadowvale. The site is bounded by existing residential developments and centered within the Credit River valley. The property lies within the limits of Credit River Subwatershed No. 9.

CVC’s Administration Office is located on the west side of the Credit River while the property on the east side of the river is managed by the City of Mississauga. The east side of the property is the Meadowvale Conservation Area and includes the Glassford and Culham Trails which traverse the property and connect it to surrounding parks and neighbourhoods.

Figure 3 illustrates the parcel boundaries for the entire CVC property.

Figure 3 Meadowvale Conservation Area 1.1.1.1. Meadowvale Conservation Area:

The entrance to this section of the property is at 7250 2nd Line W. The main facilities for the conservation area include a washroom structure, a gravel parking lot, and gravel trail (Glassford Trail). A small section of the Glassford Trail is paved. The site is completely openly drained with no storm sewers or catchbasins.

Figure 4 Boundary of Meadowvale Conservation Area

The entrance to this portion of the property is at 1255 Old Derry Road. The CVC Administrative Office was opened in 1987. By 2006, CVC staff completed a feasibility study and report recommending that the existing head office site be expanded to include a new 3-storey addition as a solution to space shortage and to accommodate staff growth over the following ten (10) years. The Board of Directors accepted the recommendation and approved the design and development of the proposed building in January 2007.

The CVC Administrative Office is described as :

Part of Lot 11, Concession 3, West of Hurontario Street Part 12, Plan 43R-17252 1255 Old Derry Road, Mississauga

Figure 5 is the overall site plan for CVC Administrative Building. Table 2 provides a breakdown of the building coverage for the 9.0 ha site.

Table 2 Building Lot Coverage for CVC Administrative Building

Building Lot Coverage (m 2) 2 Story Office Building (Building B) 1,051 3 Story Office Building (Building A) 645 Portable Building 207 Outdoor Storage Building 33 Total Existing Building Area 1,936

Table 3 provides a breakdown of the different paved and parking areas.

Table 3 Paved Area and parking area breakdown

Paved Area Surface Type Area (m 2) Parking Spaces Handicapped Spaces Parking Lot 1 Asphalt 1,989 67 3 Parking Lot 2 Permeable Pavers 1,539 60 Parking Lot 3 Permeable Pavers 2,327 75 Driveway Asphalt 3,066 2 Sidewalk Concrete 1,204 Totals 10 ,125 202 5

Figure 5 Overall Site Plan for the CVC Administrative Building

Table 4 provides a comparison of the impervious surface areas for the two areas of the property.

Table 4 Breakdown of surface areas per hard surface features

Hard Surface Feature Total Area Meadowvale CVC (m 2) Conservation Administrative Area (m 2) Office (m 2)

Buildings 2,291 355 1,936 Parking Lot (Gravel) 8,206 8,206 - Parking Lot (Asphalt) 1,989 - 1,989 Paved Trail (Asphalt) 80 80 - Pervious Parking 3,866 - 3,866 Road (Asphalt) 3,066 - 3,066 Sidewalk (Concrete) 1,204 - 1,204 Trail (Gravel) 3,108 3,108 - Total Area (m 2) 23,810 11,749 12,061

1.2. PRE-DEVELOPMENT CONDITIONS

The City of Mississauga’s e-Maps tool was used to estimate pre-development conditions based on 1954 air photography. The site was predominately under cultivation with scattered woodlots and meadows. The pre-development runoff coefficient was assumed to be 0.25 .

Figure 6 is an aerial photo of the site in 1954.

Pre-development conditions:

The intent of characterizing the pre-development site conditions is to: • Provide input into the pre-development hydrologic parameters used for modelling • Estimate the pre-development peak flow rates for the 100 year design storm for the critical storm distributions and durations (i.e., 4 hour Chicago distribution) for each sub catchment.

Figure 6 Aerial View of the CVC Site in 1954

2.0. INTEGRATED WATER MANAGEMENT (IWM)

2.1. BUSINESS OBJECTIVES

As the CVC Administrative Office site was expanded to accommodate growth, several key objectives were established to ensure innovative environmental management solutions in building and land use were considered:

• Design a new office expansion that demonstrates environmentally sound principles of construction, operation and equipment use by finding effective models to promote innovative solutions and design. • Apply Leadership in Energy and Environmental Design (LEED) to elements of the building and site to optimize the use of land, energy and materials in a cost efficient and effective manner.

Building A is registered with the Canada Green Building Council, and is certified LEED Gold. It includes many green features, including a rainwater harvesting system, where rainwater that falls on the roof is routed to a basement rainwater storage tank.

2.1.1. Integrated Water Management (IWM)

An IWM approach was adopted for the site which is intended to mimic the natural hydrologic cycle. It looked at drinking water, wastewater and stormwater holistically, rather than as separate systems. The following objectives were adopted for the site:

• Harvest stormwater for water supply, irrigation, and/or infiltration benefits – Look at stormwater as a resource rather than as a waste product to be managed, and find ways to harvest and reuse it on site.

• Apply the “right water for right use” – Treat water to a level of quality suitable for its intended use. Water for irrigation and toilet flushing does not need to be treated to potable standards.

• Implement cost-effective, demand-side controls and green infrastructure before increasing grey infrastructure - Green Infrastructure are stormwater management systems and features that emphasize drainage and conveyance characteristics that mimic pre-development conditions.

The site design incorporated a variety of innovative stormwater features that promote infiltration and reduce stormwater runoff generated by frequent storm events. By storing and infiltrating frequent storm events, a large percentage of the annually-generated runoff can be managed close to where it falls and reduce the burden on pre-existing and aging municipal infrastructure.

The IWM theme is also an embedded concept within the LEED certification requirements. Building A received the Gold certification and the following are some of the principles that were adopted into the site design:

• Sediment & Erosion control; • Reduced site disturbance; • Stormwater management (rate, quantity, treatment); • Water efficient landscaping; • A declaration that the site will not be irrigated using potable water; • Innovative wastewater technologies (50.64% reduction in wastewater generation); • Water use reduction; • Reduced Heat Island Effect (Non- Roof) - A minimum of 30% of non-roof impervious surface area was constructed with high albedo materials. Product data for the Eco-Stone unit paving indicates that the product has a reflectance of 30% and a solar reflective index (SRI) of 32. • Reduced Heat Island Effect (Roof) - 91% of the roof area is covered with high-albedo roofing product.

Table 5 provides a high level overview of design considerations for different green infrastructure/stormwater management practices.

Table 5 Design Considerations

Design Considerations Comments Risk of Groundwater Contamination The runoff that will be directed to the LID features included roof, parking lot and landscaped areas. De-icers are applied to trafficked areas during the winter months. Risk of Soil Contamination None Performance in Winter Conditions All practices will be operational and Spring Snowmelt throughout the winter months. Standing Water and Mosquitoes The facilities have been designed to have no surface ponding. Wellhead Protection Area (WHPA) The site is not located in a WHPA Site Topography Average slopes of contributing drainage areas are 1-5%. Available Head The permeable pavement facilities are designed to connect to a storm sewer which limits the available head to 200mm . Water Table The water table is 1.2m below the bottom of all infiltration facilities. Soils The native soil infiltration rate is estimated to be 15 mm/hr . An underdrain has been included in all infiltration and filtration designs to account for this. I:P Ratio Impervious to Pervious ratio Pollution Hot Spot Runoff The site is not a pollution hot spot. Runoff will not be contaminated. Proximity to Underground Utilities Utilities are identified on base plan. Overhead Wires No overhead wires.

Please refer to the CVC Head Office Case study (http://www.creditvalleyca.ca/wp- content/uploads/2016/06/CaseStudy_CVC_Final.pdf ) and Infrastructure Performance and Risk Assessment (IPRA) report (http://www.creditvalleyca.ca/wp- content/uploads/2016/06/TechReport_CVC_Final.pdf ) for additional information about the CVC head office.

2.2. MISSISSAUGA STORMWATER CRITERIA

The stormwater management system for CVC’s head office will be evaluated based on how well it is achieving the following City of Mississauga Stormwater Credit Criteria:

1. Peak Flow Reduction (40%) 2. Runoff Volume Reduction (15%) 3. Water Quality Treatment (10%) 4. Pollution Prevention (5%)

Per the credit program guidance manual, credits are performance-based and not technology-based. Therefore, credits are awarded based on how well the stormwater BMPs will achieve the performance criteria listed above.

It is recognized that many of the BMPs could be eligible for more than one type of credit such as permeable pavement which can provide a combination of peak flow, water quality treatment and runoff volume reduction. For this example credits could be applied to multiple categories.

Further, credit eligibility will be contingent on proof of functionality and on-going maintenance through self-certification reports and periodic City inspections.

2.3. EXISTING CONDITIONS

The following section describes the existing conditions for the site. Appendix A provides a detailed site plan of the CVC Administrative office that identifies all structures, including buildings, parking, driveways and other impervious area. Figure 7 below is a schematic representation of the site plan that describes the hydrologic and hydraulic components.

Figure 7 Flow Chart of CVC Administrative Office - Catchments and Infrastructures (Grey and Green)

2.3.1. Geotechnical Investigation

The geotechnical investigation is necessary for most LID practices with the exceptions of green roofs, rainwater harvesting, pollution prevention, and landscape alternatives. The scope of work required varies depending on the practice selected. Refer to Table 5.2.1 provided in CVC’s Grey to Green Business & Multi-Residential Retrofits Guide (http://www.creditvalleyca.ca/wp-content/uploads/2013/10/SWI-Grey-to-Green- Business-Multires-Retrofits-Complete1.pdf ) for a summary of the necessary geotechnical investigation activities for the detailed design of LID practices.

For the CVC Administration Building site, two (2) geotechnical investigations and reports were prepared by Terraprobe Limited: o Geotechnical Investigation Report, December 15, 2006 o Supplemental Geotechnical Investigation Report, November 30, 2007

As an addendum to the November 30, 2007 report, a proposed addition was submitted on January 14, 2008 recommending the Unilock Eco-Stone permeable pavement structure.

The geotechnical reports note that glacial till was encountered to the vertical limit of investigation for all boreholes except borehole 13. The reports note that the glacial till found beneath the site has a low permeability and that there is a ‘perched water table’ above the low permeable glacial till soils that would impede the downward movement of water. The report goes on to note that water levels in the perched zone can be expected to fluctuate from season to season with the highest levels in the spring. The geotechnical investigations were completed in November 2006 and September 2007. No long term groundwater level monitoring exists for the site.

Boreholes 10, 12, 13 & 14 all represent the surficial conditions in the immediate vicinity of Parking Lot #2 and were characterized as follows:

• All of these boreholes were observed to have no groundwater based on a vertical investigation limit of 2.8m; • The upper soil layers consisted of topsoil and fill material with glacial till further down (except borehole 13);

The permeable pavement lots were excavated to a minimum depth of 555mm. Given that borehole 14 intercepted the glacial till layer at the shallowest depth of 800mm, the bottom of the permeable pavement base layer would be above the glacial till layer within the fill zone. The fill zone is described as sand and gravel with traces of silt, trace clay, dense to very dense brown to brownish-grey, damp to moist soils.

The type of soil dictates the infiltration rates that can be used to characterize the infiltration performance of the facilities. Table 6 summarizes surficial characteristics within the vicinity of Parking Lot #2, as identified in the November 30 th , 2007 report.

Table 6 Geotechnical investigation results for boreholes 12 and 14.

Borehole No. 12 14 Depth (m) 0.8 to 1.2 0.8 to 1.2 Soil Type Sand and Gravel, some Sand Silt, some clay, silt, trace clay (GM) some gravel (ML) Soil Composition Gravel (%) 49 12 Sand (%) 36 25 Silt (%) 12 47 Clay (%) 3 16 D10 (mm) 0.03 0.0004 Estimated Coefficient of Permeability 0.009 0.0000002 (cm/s) (Hydraulic Conductivity) Estimated Coefficient of Permeability 324 0.0072 (mm/hr) Percolation Time, T (min/cm) 6 - 8 Greater than 50 General Comments Permeable to medium Low permeability permeability

For the design of Parking Lot #3, no additional geotechnical investigations were conducted. The engineer’s report noted that the design was based on existing geotechnical information from the building expansion work from 2009/2010.

An infiltration rate of 15mm/hr was selected for this site.

2.4. STORMWATER DRAINAGE SYSTEM

The original stormwater servicing reports and plans were prepared in accordance with design criteria and requirements of the City of Mississauga and CVC. The following section describes the stormwater drainage system in detail. 2.4.1. Minor System

According to the existing design briefs, the minor system for the site has been designed to accommodate the 2 year peak flow and includes storm sewers, catchbasins, gutters, grass swales and roof leaders. The minor system will convey the frequent events off of the driveway surface, parking lots and landscaped areas. None of the features on this site have been designed to pond water for any period of time. For further details on the minor system (engineering drawings for stormwater pipes, catchbasins, culverts), please refer to Appendix B .

Parking Lot 2 The minor system for parking lot #2 was designed to convey the 2-year peak flow from the parking and open space areas and the 100-year peak flow from the roof of Building A.

Tables 7 and 8 summarize the characteristics of the closed minor system for parking lot 2.

Table 7 Summary of catchbasin characteristics for Parking Lot #2

Catchbasin Size OPSD Top of Invert(s) Invert Depth to Sump I.D. (mm) Grate Elev. IN OUT Surface Depth (m) (mm) CB.1 600x600 705.01 170.44 169.03 1.41 600 CB.MH.2 1200 701.01 170.30 168.755 168.705 1.55 300 CB.MH.3 1200 701.01 170.18 168.465 168.415 1.72 300 CB.MH.4 1200 701.01 169.40 168.195 168.145 1.26 300

Table 8 Summary of pipe characteristics for Parking Lot #2

Pipe ID From To Pipe Material Length Slop Invert Invert Dia. (m) e (%) U/S D/S (mm) MD 1 CB.1 CB.MH.2 200 PVC 27.5 1 169.03 168.75 MD 2 CB.MH.2 CB.MH.3 250 PVC 24 1 168.705 168.46 MD 3 CB.MH.3 CB.MH.4 250 PVC 22 1 168.415 168.14 MD 4 CB.MH.4 Outfall #7 300 PVC 9 1 168.145 168.05 Br 1 RWH CB.MH.2 200 PVC 16.5 2 169.085 168.75 Total Length 99

Parking Lot 3

The minor system for parking lot 3 is comprised of a number of grass swales that lead to a ditch inlet catchbasin (DICB 5) and 600mm corrugated steel pipe (CSP; Culvert 1). There is also a 600x600mm catchbasin (CB 6) within the entrance lane to the parking lot that is connected to a second 600mm CSP (Culvert 2). Tables 9 and 10 describe the different components of the minor system for parking lot 3.

Table 9 Summary of catchbasin characteristics for Parking Lot 3

Catchbasin Size (mm) OPSD Top of Grate Invert OUT Depth to Sump I.D. Surface Depth (m) (mm) DICB 5 1200x1200 702.05 170.15 169.278 0.872 300 CB.6 600x600 701.01 170.25 169.427 0.82 600

Table 10 Summary of culvert and pipe characteristics for Parking Lot 3

Pipe ID From To Pipe Dia . Material Length Slope Invert Invert (mm) (m) (%) U/S D/S Culvert 1 DICB 5 Outfall 600 CSP 26 0.5 169.278 169.15 #8 Culvert 2 S3-3 Outfall 600 CSP 9 1 169.65 169.56 #9 CB Lead CB.6 600mm 250 PVC 5 1 169.427 169.377 CSP

Due to the low infiltration capacity of the sub soils, an underdrain was specified to facilitate the conveyance of excess water from beneath both permeable pavement lots. Table 11 summarizes the sub-drain characteristics within both parking lots 2 and 3.

Table 11 Summary of sub-drain characteristics for Parking Lots 2 & 3

Sub -drains Diameter Material Length (mm) Parking Lot #2 100 Perforated Corrugated PVC 46 Parking Lot #3 100 Perforated Corrugated PVC 100

Roof Drainage - Buildings A & B

Buildings A & B were not designed to include roof top storage for the larger storm events. Both buildings have a series of internal roof drains that then convey the water via 100mm pipes. Figures 8 contain photos of roof drain inlets. Table 12 summarizes information about the roof drain infrastructure.

Building A - 100mm roof drain inlets Building A - 450mm lip around perimeter of roof

Building B – 100mm roof drain inlets Building B – 100mm lip around perimeter of roof Figure 8 Roof Drainage Characteristics of Buildings A and B

Table 12 Roof drainage infrastructure details

Depth of Volume of Diameter of Roof Area #of Roof storage storage Building Roof Drain (m2) Drains above drain above drain (mm) (m) (m3) Building A 1,051.35 8 100 0 0 Building B 644.63 7 100 0 0

Vegetated Swale

The most common form of minor drainage conveyance is through a series of low gradient vegetated swales. Table 13 summarizes the characteristics of these swales.

Table 13 Swale Characterization for CVC Administration Building

Swale ID Swale Swale Upstream Downstream Manning's Length Slope Max Bottom Left Right Type Lining Invert (m) Invert (m) n (m) Depth Width (m) Side side (m) Slope Slope Swale 1 Saucer Forest 170.8 170.4 0.03 80 0.5% 0.34 4 0.08 0.025 Swale 3-1 Saucer Turf 170.4 170 0.03 30 1.3% 0.13 0.93 0.06 0.072 Swale 3-2 Saucer Turf 170 169.8 0.03 26 0.8% 0.13 0.93 0.06 0.03 Swale 3-3 Saucer Turf 169.8 169.65 0.03 28 0.5% 0.13 0.93 0.06 0.03 Swale 4 V Turf 170.76 170.15 0.024 58 1.1% 0.14 0 0.15 0.06 shaped Swale 5 V Turf 170.5 170.08 0.024 27 1.6% 0.09 0 0.10 0.014 shaped Swale 6 V Turf 170.08 169.4 0.024 19 3.6% 0.05 0 0.06 0.16 shaped Swale 7 V Turf 170.28 170.18 0.024 23 0.4% 0.02 0 0.02 0.03 shaped Swale 8 V Turf 170.36 170.3 0.024 12 0.5% 0.05 0 0.05 0.06 shaped Swale 9 V Turf 170.58 170.44 0.024 40 0.4% 0.05 0 0.05 0.06 shaped Swale 10 Saucer Forest 170.9 170.45 0.03 55 0.8% 0.18 3.97 0.09 0.03 Swale 11-2 Saucer Turf 171.2 170.45 0.03 42 1.8% 0.16 1.98 0.16 0.04 Swale 11-3 Saucer Turf 171.3 170.5 0.024 33 2.4% 0.07 0.96 0.07 0.02 Swale 14 Saucer Turf 170.85 170.45 0.03 40 1.50% 0.16 1.98 0.16 0.04

2.5. Stormwater Best Management Practices

A number of stormwater best management practices were incorporated into the site design such as rainwater harvesting system, permeable pavement parking lots and vegetated swales. 2.5.1. Rainwater Harvesting System (RWH) for Building A

Rainwater harvesting is the process of intercepting, conveying and storing rainfall for future use and provides the combined benefits of conserving potable water and reducing stormwater runoff. With minimal pre-treatment, harvested rainwater from Building A is used:

• Outside to irrigate landscaped areas and the water is either evapotranspired by vegetation or infiltrated into the soil, thereby helping to maintain predevelopment water balance; • Inside to flush toilets or urinals.

By providing a reliable and renewable source of water at the site, the rainwater harvesting system can also help reduce demand on drinking water supplies. By reducing demand on water resources, rainwater harvesting can result in significant cost savings due to:

• delayed expansion of municipal water treatment and distribution systems; • lowered energy use for pumping and treating water; and • lowered consumer water bills

The RWH system uses a 5,000 litre rainwater storage tank located in the basement of Building A. Rainwater from the roof is directed through interior 100mm drains to a central mechanical room. The drains then combine into a 150mm pipe and roof water enters the storage tank via a 75 mm diameter pipe. The same size pipe (75mm) is used to convey excess rainwater from the tank when there is too much volume in the storage tank.

All excess rainwater is discharged through the building’s 200mm PVC storm drain that then connects to catchbasin 2 (CB.2). The tank is also periodically filled with water from the building’s sump pump.

The rainwater and groundwater collected via the sump pump is used to supply non- potable water to toilets and urinals in Building A and also supplies water to outdoor hose taps. Figure 9 is a schematic diagram of the RWH system. Figure 10 is a plan view of the RWH. Please refer to Section 6.1 for a detailed description of the RWH system and operation & maintenance plan. Table 14 provides a summary of the RWH characteristics

Table 14 Summary of RWH system characteristics

Design Parameters Value Total Storage of Tank * 4,487 litres Total Roof Area 644 m2 Maximum Active 4,337 litres Storage** Available Active Storage 967 litres * Volume below 75mm overflow ** Lowest recorded tank volume

Water Balance: A simple water balance equation for the RWH tanks can be expressed as follows:

QIN1 + Q IN2 = QOUT1 + QOUT2 + QOUT3

Where: QIN1 = Roof drainage flowing into the tank (m3/s) QIN2 = Sump pump water discharged into the tank (m3/s) QOUT1 = Water pumped from tank for non-potable uses (m3/s) QOUT2 = Water by-pass (m3/s) QOUT3 = Water overflow (m3/s)

Table 15 below summarizes which inflows and outflows have been monitored for the RWH system.

Table 15 Water Balance Components of RWH System

Flow Description Measurement QIN1 Flow from roof drainage Level logger* QIN2 Flow from sump pump Level logger* QOUT1 Flow harvested for non- Probe potable use QOUT2 Water by-passing the Not measured RWH tank QOUT3 Water Overflow Level Logger *Inflow measurements are not able to distinguish rainwater inflow versus sump pump inflow.

It is not possible at this time to accurately perform a water balance for the RWH system. Based on existing monitoring work CVC is unable to estimate the total inflow to the tank during wet weather events due to sump-pump water inputs and bypass. However, the monitoring data does allow CVC to estimate the available active storage to be approximately 967 litres.

Figures 9 &10 provide a detailed schematic and plan view of the RWH system.

QIN1 QIN2 QOUT2 (Roof) (Sump Pump) (By-Pass)

QOUT3 (Overflow)

QOUT1 (Non-Potable)

Figure 9 Schematic of Rainwater Harvesting System

Figure 10 Plan View of Rainwater Harvesting System

2.5.2. Permeable Pavement Parking Lots

Permeable pavement is an innovative stormwater management approach that promotes the infiltration of stormwater between paving stones and into a stone reservoir where it is infiltrated into the underlying native soil and/or temporarily detained. This technique has been successfully implemented across the CVC watershed within low traffic roads, parking lots, driveways, and walkways.

The permeable pavement parking lots were designed for filtration, storage, and infiltration of runoff. Given the lower permeability of the native subsoil, underdrains were installed above the stone reservoirs to ensure drainage of the sub-base and prevent winter freeze/thaw damage.

Table 16 provides a detailed summary of the physical characteristics used to model the performance of the two permeable parking lots.

Table 16 Physical characteristics of Parking Lots 2 and 3

Parameter Value Parking Lot #2 Parking Lot #3 Paver Type & Thickness Standard Unilock Eco-Stone Standard Unilock Eco-Stone Natural Charcoal Grey 80mm 80mm Note: The pavers have nubs around them which leave a consistent 1 cm space between each paver that allows water to drain through.

Bedding Layer Material ASTM D 448 Aggregated Size No. 8 & Thickness 25mm Note: The same chip stone also fills the spaces between the pavers.

Granular Base Material 19.0mm clear open recycled 19.0mm clear open recycled & Thickness concrete, OPSS 1010 concrete, OPSS 1010 Gradation Requirements Gradation Requirements 450mm (250mm) 19.0mm clear stone (200mm) 450mm Geotextile Yes – Woven No Surface Area (m 2) 1,704 2,096 Total Excavation Depth 555mm Total Storage Depth 200mm (below underdrains) Total Storage (m 3) 136 168 Under -drain System 100mm Perforated Corrugated PVC subdrain with geotextile and granular filter material placed 300mm below subgrade Construction August 2009 August 2012 Completion Date

Measured Infiltration 798 mm/hr 1952 mm/hr Rates Permeability of 15 mm/hr Subgrade

2.5.2.1. Paver Type and Thickness

Figure 11 illustrate the different paver types implemented at the CVC Administrative Office.

Parking Lot 2 – Standard Unilock Parking Lot 3 - Standard Unilock Eco-Stone Eco-Stone Natural Charcoal Grey

Parking Lot 2 during a rainfall event (Oct 2015) Parking Lot 3 during the a rainfall event (Oct 2015) Figure 11 Paver Types installed in Parking Lot 2 and 3

2.5.2.2. Bedding Layer and Thickness

Figure 12 includes photos of the bedding material for parking lots 2 and 3 during construction.

Parking Lot 2 (left) and Parking Lot 3 (right) placed on 25mm base layer

ASTM D 448 Aggregated Size No. 8 25mm (Same materials is used to fill in joints between paving stones). Figure 12 Installation of bedding Materials for parking Lot 2 and 3

2.5.2.3. Granular Base Material and Thickness

Figure 13 shows images of the two (2) different types of granular base materials installed at Parking Lot 3.

Parking Lot 3 – First 250mm of Granular base Parking Lot 3 – Remaining 200mm of Granular layer was crushed concrete. base layer was clear stone.

Parking Lot 3 – Photo showing granular base profile with both crushed stone and clear stone. Figure 13 Installation of granular base layer

Figures 14 are photos of parking lots 2 and 3, taken during construction. Geotextile was installed in parking lot 2 at the interface between bedding and granular base layer but not in parking lot 3.

Geotextile used at Parking Lot #2 between Geotextile not placed at interface between gravel bedding and granular base layers layers in Parking Lot 3 Figure 14 Further details of permeable pavement 2.5.2.4. Underdrain System

A 100mm perforated corrugated PVC sub-drain with geotextile and granular filter material was placed 300mm below the subgrade of both parking lots. As water begins to pond in the subsurface granular base to a depth of over 200mm, excess water will be conveyed through the sub-drains and towards an outlet. All water below the 100mm sub-drain will infiltrate into the ground.

Figure 15 shows the sub-drain detail and photos of the sub-drains being installed during construction. Figure 16 illustrates a cross section of the permeable pavement lots representing as-built conditions.

Sub-drain detail Sub-drain layout for Parking Lot 3

Sub-drain installation Parking Lot 3 Sub-drain depth Parking Lot 3 Figure 15 Sub-drain details and installation photos

Figure 16 Cross Section of Permeable Pavement in Parking Lot 2 and 3

3. Vegetated Swales

Vegetated swales are designed to convey, treat and attenuate stormwater runoff. The swales have shallow longitudinal slopes to promote sedimentation, filtration, evapotranspiration, and infiltration into the underlying native soil.

These swales do not have engineered soil media and an underdrain to promote filtration and therefore have lower performance compared to bioretention facilities. However, vegetated grass swales are a preferred alternative to both curb and gutter and storm drains as a stormwater collection and conveyance system. The vegetated swales located on the CVC property are vegetated with both grass and forest.

Evaluating Vegetated Swale Performance

The following criteria were used for assessing water quality treatment performance:

• The velocity is 0.5 m/s or less for a 4 hour, 25 mm Chicago storm (CVC 2010); • Typical ratios of impervious drainage area to swale area range from 5:1 to 10:1 . The conveyance capacity should match the drainage area and sheet flow to the grass swale is preferable. High discharge through the swale may not allow for filtering and infiltration, and may create erosive conditions.

Figure 17 shows examples of vegetated swales around the perimeter of the parking areas and driveway.

Swale 9 (drains to CB1) Swale 4 (drains to CB 5)

Swale 8 (drains to CB 2) Swale 7 (drains to CB 3) Figure 17 Examples of vegetated Swales around the perimeter of the parking areas and the driveway

Note that the swale leading to the DICB 5 has 100mm of topsoil and No. 1 nursery sod. Figure 18 below is a photo of landscaping work taking place in June of 2012.

Figure 18 Landscaping and swale grading around Parking Lot # 2 (June 2011)

3.1.1.1. Wet Weather Drainage Patterns

The following images capture a number of different rainfall events at the CVC administration building site and the resulting flow paths. During heavy rainfall events, drainage from the impermeable surfaces sheet flows into the vegetated swales. The swales allow the water to spread out and gently flow towards the catchbasin inlets.

External drainage from catchment 11 flowing Parking lot #3 - overflow spillway into the top of onto parking lot 2 and flowing towards CBMH.4. Swale 3-3.

Parking lot #1 – sheet flow drainage into Swale 9. Swale 9 - low gradient swale conveying drainage towards catchbasin 1 during heavy rainfall event. Figure 19 Wet Weather Drainage Patterns

3.2. Major System

Flows exceeding the capacity of the minor system will be conveyed overland generally following the direction of the minor system.

For parking lot 2, the major system flows easterly towards the parking lot entrance and then spills down the asphalt laneway towards the Credit River.

For parking lot 3, the two (2) 600mm CSP culverts will direct flow to the existing swale and have the capacity to convey the 100-year peak flow.

Appendix C illustrates the drainage path and direction of flow for the major system/overland flow routes.

3.0. HYDROLOGIC MODELLING

The EPA Storm Water Management Model (SWMM) version 5.1 was used to develop a physical representation of the CVC administration building site for quantifying the stormwater benefits of the existing stormwater management system. Hydrologic modelling using the RUNOFF module was undertaken to help assess peak flow control, water quality treatment and runoff volume reduction from the stormwater features in the CVC administrative property. A hydraulic component of the model is currently under development and will be completed in 2017.

The following three scenarios were modelled:

1. Scenario 1: Pre-Conditions

o Pre-development condition means the 100-year flow from a theoretical “raw” land condition of the site, with an assumed runoff coefficient of 0.25. o All land is assumed to be pervious with a Curve number of 71 based on soil types (Silt-loam)

2. Scenario 2: Post Conditions without Stormwater Control

o Post development without LID refers to the site without any stormwater control (i.e. permeable pavers, rain water harvesting, vegetated swales) o The permeable paver parking lot is assumed to have smooth asphalt surfaces with a Manning’s n of 0.011 o The vegetated swales, S1 and S10 are assumed to be grass lined (short, prairie) with a Manning’s n of 0.15.

3. Scenario 3: Post Conditions with Stormwater Controls (LID Treatment Train)

o Permeable Pavement (Parking lots 2 and 3); o Vegetated Swales; o Rain Water Harvesting Tank (967 L of available active storage). o The vegetated swales, S1 and S10 have dense vegetation (woods with light underbrush) with a Manning’s n of 0.4. o Permeable Pavement Parking Lot 1 and 2 have an infiltration rate of 798 mm/hr and 1952 mm/hr respectively.

Figure 20 is a site plan showing the various subcatchment areas, drainage features and land use types.

Figure 20 Catchments Area Delineation for Hydrologic Modelling (Refer to Appendix D) It is important to note that, the hydraulic features of the minor system (catch basins, culverts and storm sewers) have not been modelled in the three scenarios. The hydrologic model assumes that the minor system does not function during the 100 year event. The major flow paths within the CVC site are illustrated in Figure 21 . The major flow route indicates that the north east catchments of the site (C1, C2, C4 and C5) drains towards the ravine, modelled in SWMM with Outfalls 1, 2, 5 and 6). The rest of the site is drained through the parking lots and perimeter swales onto the driveway. Further details of model parameters can be found in Appendix E .

Figure 21 Major Flow System of the CVC Office Site (Refer to Appendix C)

Figure 22 is a flow diagram showing the layout of the various catchments. The schematic describes the drainage pattern and the routing that occurs from:

• catchment to swale; • catchment to permeable paver; • catchment to outfall; • swale to outfall, and • swale to permeable pavers.

Figure 23 is a schematic diagram in the EPA SWMM model. Table 17 is a detailed summary of the SWMM Model parameters for Scenario 3. Detailed Model Output can be found in Appendix F .

43 Figure 22 Flow Chart of Hydrologic Model Set up

Figure 23 Schematic of Hydrology Model in SWMM. (Refer to Appendix F for detailed Model Outputs)

Table 17 SWMM Model Parameters with Catchment Area with LID Features (Scenario 3)

Directly Directly Depression Depression Connected Connected Manning's N Storage - Storage - Total Area Total Area Imp. Area Imp. Area Pervious Pervious Outlet Catchment Catchment Manning's N for Pervious imperv area perv area Weighted Contributes Drainage Catchment (m2) (ha) Soil Type (m2) (ha) Area Area (ha) (Catchment/Outfall) % Imperv Width Slope (%) for Imp Area Area (mm) (mm) Curve # to LID Features C1 2423 0.2423 Silt Loam 39 0.00390 2384 0.23840 S10 1.1 60 111 0.0 0.15 1.27 2.54 71 no Swale C2 2000 0.2000 Silt Loam 839 0.08387 1161 0.1161 S11-2 41.9 300.011 1 0.15 1.27 2.54 82 no Swale C5 1008 0.1008 Silt Loam 954 0.09540 55 0.0055 Outfall 5 94.60 2 1 0.011 0.15 1.27 2.54 82 no mone C6 894 0.0894 Silt Loam 90 0.00900 804 0.0804 Outfall 6 10.1 121 0.011 0.15 1.27 2.54 82 no none C7 671 0.0671 Silt Loam 597 0.05970 74 0.0074 Rain Water Tank 89 14 0 0.011 0.15 1.27 2.54 82 yes RWT C8 265 0.0265 Silt Loam 207 0.02070 58 0.0058 S8 78.1 12 2 0.011.15 1.27 0 2.54 82 Yes Swale C9 645 0.0645 Silt Loam 424 0.04240 221 0.0221 S7 65.8 20 2 0.0110.15 1.27 2.54 82 Yes Swale C10 2688 0.2688 Silt Loam 1745 0.17450 943 0.0943 S9 64.9 27 111 0.0 0.15 1.27 2.54 82 Yes Swale C11 372 0.0372 Silt Loam 173 0.01730 199 0.0199 PP1 46.5 18 11 0.01 0.15 1.27 2.54 82 yes Permeable Paver C13 2957 0.2957 Silt Loam 509 0.05086 2448 0.245 S1 33 30 1 0.011.4 1.27 0 7.62 71 Yes Swale C14A 101 0.0101 Silt Loam 0 0.00000 101 0.0101 PP2A 0 0.5 1 0 0.15.54 0 0 2 Yes Permeable Paver C14B 161 0.0161 Silt Loam 29 0.00290 132 0.0132 PP2B 18 18 2 0.011.15 1.27 0 2.54 82 yes Permeable Paver C14C 43 0.0043 Silt Loam 0 0.00000 43 0.0043 PP2C 0 0.5 1 0 0.154 0 82 2.5 yes Permeable Paver C18 10 0.0010 Silt Loam 10 0.00100 0 0 PP3 100 4 1 0.011 0 1.27 0 0Permeable yes Paver C19 32 0.0032 Silt Loam 16 0.00160 16 0.0016 PP4 50 0.5 1 0.0115 1.27 0.1 2.54 82 Yes Permeable Paver C20 263 0.0263 Silt Loam 79 0.00790 184 0.0184 PP5 30 4 1 0.0115 1.27 0.1 2.54 82 Yes Permeable Paver PP1 817 0.0817 Silt Loam 817 0.00000 0 0 CB4/Outfall 7 100 18 0.7 0 0 1.27 0 0 yesPaver Permeable PP2A 643 0.0643 Silt Loam 643 0.06430 0 0 S3-2 100 18 2 0.011 0 1.27 0 0 yes Swale PP2B 1025 0.1025 Silt Loam 1025 0.10250 0 0 Culvert/Outfall9 100 18 2 0.011 0 1.27 0 0 yesable Paver Perme PP2C 428 0.0428 Silt Loam 428 0.04280 0 0 S3-3 100 18 2 0.011 0 1.27 0 0 yes Swale PP3 469 0.0469 Silt Loam 469 0.04690 0 0 CB4 100 4 0.7 0.011 0 1.27 0 0 yes Permeable Paver PP4 174 0.0174 Silt Loam 174 0.01740 0 0 PP5 100 4 0.7 0.011 0 1.27 0 0 yes Permeable Paver PP5 244 0.0244 Silt Loam 244 0.02440 0 0 CB6 100 4 1 0.011 0 1.27 0 0 Yes Permeable Paver SW 1 1050 0.1050 Silt Loam 0 0.00000 1050 0.105 Outfall 10 0 45 0. 0 0.4 0 7.62 71 no none SW 3-2 150 0.0150 Silt Loam 0 0.00000 150 0.015 S3-3 0 1 0.8 0 0.1554 0 82 2. no none SW 3-3 120 0.0120 Silt Loam 0 0.00000 120 0.012 Culvert/Outfall 09 1 0.5 0 0.15 0 2.54 82 no none SW 4 558 0.0558 Silt Loam 0 0.00000 558 0.0558 Outfall 8 0 1 1.1.15 0 0 0 2.54 82 no none SW 7 70 0.0070 Silt Loam 0 0.00000 70 0.007 CB3 0 1 0.5 0 0.15 02 2.54 no 8 none SW8 40 0.0040 Silt Loam 0 0.00000 40 0.004 CB2 0 1 0.5 0 0.15 02 2.54 no 8 none SW 9 165 0.0165 Silt Loam 0 0.00000 165 0.0165 CB2 0 1 0.4 0 0.1554 0 82 2. no none SW 10 800 0.0800 Silt Loam 0 0.00000 800 0.08 CB1 0 4 0.8 0 0.4 02 7.62 no 8 none SW 11-2 215 0.0215 Silt Loam 0 0.00000 215 0.0215 Outfall 2 0 2 1.8.15 0 0 0 2.54 82 no none Total Area 21501 2.15 9510 0.87 11991.39 1.20

3.1. STORMWATER CRITERIA

The following section describes how the site was evaluated based on the applicable SWM criteria.

3.2. Peak Flow Reduction

Using the City of Mississauga intensity-duration frequency curves, the rainfall intensity for the 100yr storm was calculated using the following equation:

= + Where:

I = Rainfall Intensity (mm/hr) A = 1450 B = 4.9 C = 0.78 Tc = Time of Concentration (mins)

Based on an estimated Tc of 10mins, the maximum rainfall intensity for the 100yr storm is 176.3mm/hr. The 100yr peak flow intensity was also modelled using a 100yr - 4 hour Chicago Design storm with a depth of 72 mm and the peak rainfall intensity was 370.68 mm/hr.

The measured infiltration rates for parking lots 2 and 3 were approximately 700mm/hr and 1900mm/hr respectively. Since the maximum rainfall intensity for the 100yr storm is lower than the measured infiltration capacity of the permeable pavement lots, all of the rainfall will enter the subsurface granular storage layers.

Parking lots 2 & 3 provide a combined storage volume of 304m3. This is the total volume of water that can be stored below the 100mm perforated sub drains. Dividing this volume over the available surface area of the permeable lots is equivalent to 80mm of storage depth which exceeds the 100yr rainfall depth of 72mm.

The modelling identified that some additional peak flow control was achieved through:

• the routing of the 100yr storm runoff through existing swales; • the major system from catchment areas such as C10 spilling onto parking lot 2 and a portion of this major flow getting absorbed into the permeable pavement;

• external drainage running onto parking lot #2 from catchment C11.

This additional peak flow control storage was not accounted for in this credit application . However, the modelling work has provided valuable insight into how the site could be further optimized to receive additional credit.

Table 18 summarizes the peak flow runoff amounts for the three scenarios described above.

Table 18: Modelled Peak Flows for the three (3) scenarios

Catchments Modelled Peak Flow (m3/s) Peak Flow Control Scenario 1 Scenario Scenario 3 Pre- 2 Permeable Development Asphalt Pavement PP1 0.004 0.1 0.0002 100% PP2A 0.004 0.1 0 100% PP2B 0.006 0.10 0 100% PP2C 0.004 0.04 0 100% PP3 0.001 0.04 0 100% PP4 0.001 0.02 0 100% PP5 0.002 0.03 0.0002 100%

3.3. WATER QUALITY TREATMENT

The LEED designation required that the stormwater best management practices remove 80% of TSS and 40% of TP from stormwater. The stormwater credit requires a treatment performance consistent with Provincial criteria for enhanced treatment.

The IPRA report indicates the existing stormwater management controls are achieving an 81% TSS reduction based on real-time monitoring data from 2014- 2015. This achieves the provincial standards for enhanced water quality treatment of 80% TSS removal. Table 19 is a summary of the results from the monitoring period recorded for the CVC Head Office.

Table 19 CVC Head Office water quality treatment performance summary for zero-effluent and samples events between 2015-2015

The monitoring station is located in catchbasin 4 and captures the combined flow of the minor system drainage from roof tops, driveways, walkways, parking lot 1 and permeable parking lot 2. The estimated total TSS load reduction of 81% represents the combined treatment performance of the RWH, vegetated swales and permeable pavement lot.

3.3.1. Permeable Pavement

Parking Lot 2 and 3 are estimated to provide enhanced water quality treatment performance based on the existing design and current monitoring results from the IPRA program.

3.3.2. Vegetated Swales

The water quality treatment performance for the vegetated swale features were estimated using two approaches.

Approach 1 – Comparison to CVC/TRCA LID Planning and Design Guidelines

The Low impact Development SWMM Manual (201, Version 1) identifies factors that impact the swale’s ability to provide water quality treatment performance. (Section 4.8 of LID SWM Guideline, pg. 4-141).

Table 20 below summarizes the factors or physical characteristics that impact the treatment efficiency of vegetated swales. The swales at the CVC site were evaluated based on these factors in order to estimate their potential water quality treatment performance.

Table 20 Factors that impact water quality performance of vegetated swales

Swale ID Longitudinal Infiltration 4 hr Pre Side Bottom Impervious to Water Slope <1% (15mm/h) Chicago treatment Slopes width Pervious Ratio Quality 25mm (H:V) 3:1 0.75 to 5:1 to 10:1 Treatment Max. 3.0 m velocity <0.5m/s

Swale 1 yes yes yes no yes no 0.48 1 yes

Swale 7 yes yes yes no yes yes 6.1 1 yes

Swale 8 yes yes yes no yes yes 5.2 1 yes

Swale 9 yes yes yes no yes yes 10.6 1 yes

Swale 10 yes yes yes no yes no 0.05 1 yes

Swale 11 -2 no yes yes no yes no 3.9 1 yes

Given that the swales satisfy most of the criteria/factors identified in Table 20 , they are assumed to provide water quality treatment performance.

Approach 2 – Utilizing the monitoring data

The IPRA monitoring data shows that the overall site is providing 80% TSS removal which further substantiates that the swales are supporting the enhanced water quality objective.

3.4. RUNOFF VOLUME REDUCTION

The SWM Credit application evaluates runoff reduction based on the percent capture of the first 15mm of rainfall during a single rainfall event. For this scenario, a 4 hour Chicago design storm with 25 mm depth was run through the SWMM Model.

Table 21 summarizes the modelled infiltration amounts for the various subcatchment areas.

Table 21 Existing infiltration amounts for existing conditions

Subcatchment ID Runoff Volume Reduction 4hr Chicago Infiltration Depth 25 mm "capture of first 15 Infiltration (mm) mm" (mm)

C14B 17.4 15 Cat1 22 15 Cat10 6.8 6.8

Cat11 10.1 10.1 Cat13 15 15 Cat14A 20.9 15 Cat14C 20.1 15 Cat19 9.7 15

Cat2 11.3 11.3 Cat20 13.7 15 Cat7 2.1 1.5 1 Cat8 4.1 4.1 Cat9 6.5 6.5

1 The calculation for Catchment 7 can be found in Appendix I

PP1 31.3 15

PP2A 25.46 15 PP2B 26.04 15 PP2C 25.39 15 PP3 25.53 15 PP4 27.69 15 PP5 36.07 15

The above table shows the results generated from the modelling output of a 25 mm, 4 hr Chicago storm as indicated in the second column. Some areas receive greater than 25 mm, and this is resulted by upstream catchment runoff being routed to the permeable pavers. The third column represents the first 15 mm capture within each catchment.

The hard surfaces associated with the catchments in Table 21 were assigned an infiltration credit that was pro-rated based on the percentage of that hard surface receiving the credit. The detail of the calculation can be found in Appendix I.

For example, to determine the runoff reduction in Parking Lot 1, the impervious area of the parking lot is broken down for each catchment (as each catchment generates an infiltration depth) and weighted as a fraction to apply a credit. In this example, Parking lot 1 has a total impervious area of 1989 m2 which includes 39 m 2 of parking lot in Catchment 1; 509 m 2 in Catchment 13; 326 m 2 in Catchment 2; and 1116 m 2 in Catchment 10. Each of these catchments is treated by swales as represented in the flow chart in Figure 22 or Appendix A. The following are the treatment swales for these catchments in Parking Lot 1:

- Catchment 1: Swale 10 (15 mm infiltration) - Catchment 2: Swale 11-2 (11.3 mm infiltration) - Catchment 13: Swale 1 (15 mm infiltration) - Catchment 10: Swale 9 (6.8 mm infiltration)

Following the determination of infiltration for each segments of parking lot 1, the area draining to each catchment are fractioned against the total area of the parking lot and a weighted credit is applied as seen in Table below.

Table 22 Parking Lot 1 Runoff Reduction Credit

Parking Lot 1 Fraction Credit Weighted Credit 39 0.02 15.00 0.29

1116 0.56 6.82 3.83 509 0.26 15.00 3.84 326 0.16 11.31 1.85 1989 1 9.81

4.0. CREDIT REQUEST

Table 23 provides a detailed breakdown of the land use types, associated areas and percentage of overall impervious surfaces. Credits were assigned to the individual land use types based on the information provided above and then weighted per the credit weighting provided in the stormwater charge credit application guidance manual dated September 23, 2015. Finally, the credits were then pro-rated based on the total impervious area.

Table 23 Aggregated Credit for the entire CVC property (Refer to Appendix J)

Peak Flow Water Quality Volume Percent of Total Meadowvale CVC Control Peak Flow Treatment Water Quality Reduction Runoff Volume Total Total Area Runoff Volume Landuse Type Impervious Conservation Area Administration Credit Treatment Credit Reduction Credit Aggregated (m2) Reduction (mm) Area (m2) Office (m2) 0.4(Weighted) 0.1 (Weighted) 0.15 (Weighted) Credit Score

Buildings 2,291 10% 355 1,936 0 0 0.00 0.000 0.01 0.00 1 0.001

Building B 1,051 46% 1,051 0 0 0 Building A 645 28% 645 0 0 1.5 0.10

Portable Building 207 9% 207 0 0 0.1 0.009 8.8 0.59 0.053 0.06 Outdoor Storage 33 1.4% 33 0 1.0 0 Building Meadowvale 355 15.5% 355 0 0 0 Bathroom

Parking Lot (Gravel) 8,206 34% 8,206 - 0 0 0 0 0 0 0 Treated 0 0% 0 0 0 Untreated 8,206 100% 0 0 0 Parking Lot 1 1,989 8% - 1,989 0 0 0.1 0.01 0.10 0.008 0.017 (Asphalt) Treated 1,989 100% 0 1.0 9.81 0.65 Untreated 0 0% 0 0 0 Paved Trail 80 0.3% 80 - 0 0 0 0 0 0 0 (asphalt) Treated 0 0% 0 0 0 Untreated 80 100% 0 0 0 Pervious Parking 3,866 16% - 3,866 0.4 0.06 0.1 0.02 0.2 0.024 0.106 Parking Lot 2 1,539 40% 1,539 1.0 1.0 15.0 1.0 Parking Lot 3 2,327 60% 2,327 1.0 1.0 15.0 1.0 Road (Asphalt) 3,066 13% - 3,066 0 0 0 0 0.03 0.0041 0.0041 Treated 1,215 40% - 1,215 0 0 8.1 0.5 Untreated 1,850 60% - 1,850 0 0 0 Sidewalk (concrete) 1,204 5% - 1,204 0.2 0.01 0.04 0 .002 0.04 0.002 0.012 Treated 467 39% 467 1.0 1.0 9.0 0.6 Untreated 737 61% 737 0 0 0 Trail (gravel) 3,108 13% 3,108 - 0 0.0 0 0 0 0 0 Treated 0 0% 0 0 0 Untreated 3,108 100% 0 0 0

Total 23,810 100% 11,749 12,061 Totals 0.073 Totals 0.036 Totals 0.093 20.1%

5.0. SYSTEM OPTIMIZATION

A detailed hydrologic and hydraulic model will be used to help optimize the site in an effort to earn additional stormwater credits. Types of site optimization techniques could include the following: 1. Vegetated Swale Enhancements • Retrofit existing swales with underground storage vaults to reduce the 100yr peak flow rate from the site (i.e. stormwater chambers by ADS Canada).

Figure 28 : Stylized ADS enhanced swale design (Source: Advanced Drainage Systems (ADA) Canada)

2. Rainwater Harvesting System Based on the current configuration, it is difficult to ensure that the RWH system is achieving measurable, effective and reliable stormwater management of roof drainage. The following optimization techniques will be explored:

• Forecast precipitation events so that the tank can be drawn down and the active storage increased before a rainfall event to capture a larger volume. • Explore the use of a drawdown valve that drains the tank before a precipitation event. • Install a second rainwater tank for stormwater capture and reuse. • Estimate the additional peak flow, volume and water quality reductions credits

3. Roof Leader Retrofit of Building B

• Direct existing 150mm outlet pipe into soak away pit or underground storage vault to promote infiltration and peak flow control of the 100yr storm event.

5.1. CREDITS FOR OVER CONTROL

Through site optimization, there may be potential to provide over control to retain more than the required stormwater volume in one area and less in another depending on site constraints. Through over control, landowners would be able to balance the amount of water retained in multiple areas. If landowners were able to demonstrate ‘over control’, could they qualify for additional credits?

6.0. OPERATION & MAINTENANCE PLANS

6.1. RAINWATER HARVESTING SYSTEM OPERATIONS AND MAINTENANCE MANUAL 6.1.1. Introduction This document provides guidance on how to maintain Credit Valley Conservation’s rainwater harvesting (RWH) system. This guide provides an overview of the system and its components describes the maintenance tasks that should be performed for each of the various components of the system (including the maintenance frequency) and provides a summary maintenance task sheet and log. The maintenance guidance provided in this document is organized using the following categories:

1. Catchment Area (Roof) 2. Storage Tank 3. Treatment System 4. Pumps & Pressure System 5. Top-up and Bypass System 6. Backflow Prevention Devices 7. Control Panel 8. Decommissioning the RWH System

6.1.2. Rainwater Harvesting System Description Credit Valley Conservation’s RWH system uses a 5,000 Litre rainwater storage tank located in the basement of Building A. Rainwater from the roof is directed through interior rain leaders to a central mechanical room. The roof runoff is conveyed through 75 mm diameter ABS piping to the tank. The same size pipe is used to convey excess rainwater from the tank when there is too much volume in the storage tank. All excess rainwater is discharged through the building’s 150 mm diameter storm drain, connected to an on-site wetland. The tank is also periodically filled with water that was collected in the building’s groundwater sump.

The rainwater and groundwater collected via the sump pump is used to supply non-potable water to toilets and urinals in the building addition as well as supply water to outdoor hose bibs. To supply this water to the connected fixtures, the system uses a standard constant-speed style pump and pressure tank. The pump provides a flow rate of 40 Litre per minute (LPM), while the pressure tank stores 100 Litres.

Rainwater is treated by a 100-micron particle filter (model JUDO JFXL-T). The filter includes an automatic timer-based self-cleaning backwash system.

The RWH system features a “top-up” system, where municipal water is supplied to the tank during times it is nearly empty. The RWH system uses a rod-style mechanical float to determine a low level, at which time a normally-closed solenoid valve opens to permit potable water to enter the tank. The building’s potable water system is protected from contamination by the non-potable rainwater by using a backflow prevention device.

NOTE: As the RWH system is currently monitored frequently, this “top-up” system is not being used. Instead, the RWH system is manually turned offline during times where the level is low, and municipal water is connected directly to the toilets, urinals, and outdoor hose bibs. This allows the tank to slowly re-fill with roof runoff or groundwater.

6.1.3. RWH System Components This section provides a summary of the RWH system components.

Component Photograph Conveyance Conveyance pipes piping and (large pipes rainwater storage conveying water tank to/from tank)

Rainwater storage tank

Component Photograph Inlet shut-off valve

Inlet shut -off valve in OPEN position

Top-up rod style Municipal water mechanical float topping up tank

Top -up level switch in DOWN position (initiating top-up)

Component Photograph Top-up system components: • piping • backflow prevention Solenoid device valve • solenoid valve Municipal top-up • water meter water piping

Water meter Backflow prevention device

Pump and pressure tank Non -potable water to toilets and hose bibs

Pressure tank

Pump

Component Photograph System control panel and pressure gauges Control panel

Pressure gauges

Post-storage filter (Model no. JUDO JFXL-T)

Tank drain pipe and valve

Component Photograph Groundwater collection sump Groundwater pumped up to conveyance pipes (then into rainwater storage tank)

Rainwater harvesting system bypass system

Catchment Area (Roof)

Overview The catchment area for CVC’s RWH system is the roof of the expansion. Rainwater is collected from this surface and conveyed to the RWH system through internal rain leaders in the building.

Inspection and Maintenance Tasks Task Frequency Tasks Frequent 1. Inspect the catchment surface to identify sources of (every 3 months) contamination (i.e., bird/animal droppings, dead birds, leaves or other debris). If contaminants are

Task Frequency Tasks present: a. Remove debris mechanically (clean surface by sweeping). Do not use hose to wash contaminants down roof drains, as this will contaminate the tank. Debris should be disposed of appropriately. 2. Inspect the roof drain(s) to identify sources of contamination or blockage (i.e., dead birds, leaves or other debris). If items blocking drain are present: a. Remove debris mechanically (do not use hose to wash contaminants down roof drains) and dispose of debris appropriately.

There are seven (7) roof drains (see figure below)

Bi -Annual 1. Inspect storm water sump pit (once every 6 months) Annually 1. Visually inspect the catchment surface for the (once a year) presence of overhanging tree branches. If present, trim tree branches/foliage overhanging roof to minimize opportunities for animals to access and contaminate the roof.

Task Frequency Tasks Health and Safety All activities on the roof should only be undertaken by qualified staff, and all precautions, such as fall arrest training and equipment should be used as required.

Maintenance Tips

Inspect the catchment surface and roof drains for debris late in the fall after leaves have fallen to prevent debris clogging drains in the winter.

Figure 33: Roof Drainage Scheme

Storage Tank

Overview CVC’s RWH system uses a 5,000 Litre tank to store rainwater. This tank is located in the mechanical room in the basement of Building A. CVC’s RWH system does not have a filter to screen out debris from the roof prior to storage, and because of this, debris may accumulate in the tank. A number of systems and components connect to the tank and/or are located inside the tank. This means that care must be taken when inspecting and performing maintenance activities on the tank.

NOTE: As CVC’s electrical system is located in the same room as the RWH, great care should be taken that water never reaches the components of the electrical system.

Inspection and Maintenance Tasks Task Frequency Tasks Frequent 1. Inspect the tank for any signs of leaks. Look for wet (every 3 months) spots on concrete flooring surrounding tank or wet spots at or near tank inlets or outlets. If leaks are observed: a. If the leak is rapid or if it requires that work be undertaken in water pooled on the floor, the rainwater harvesting system should be immediately taken offline and municipal water sent to fixtures to permit inspection and maintenance work. Refer to the Decommissioning the RWH System section for instructions on how take the system offline. The tank should then be drained by turning the drain valve to the OPEN position (in line with the pipe). b. Identify the source of leak. Most likely leaks will come from tank inlets or outlets. c. If a leak is coming from an inlet or outlet, tighten the bulkhead fitting on the tank and/or the fittings connected to the tank. d. If not successful, contact a plumber to repair faulty plumbing connections.

Bi -Annual 1. Inspect the interior of the storage tank for the (once every 6 accumulation of debris in the bottom of the tank and months) along the tank walls. Accumulation of too much debris within the tank may also be evident from

Task Frequency Tasks observation of the filter (excess debris on filter screen) or by debris being visible in toilets. If debris is observed a tank cleaning procedure should be initiated. 2. If tank odour, algae growth and/or the growth of a biofilm that clogs equipment (filter and/or the pump) is encountered, it may be necessary to both clean and disinfect the tank. Disinfection is only recommended to address these issues and it is not considered necessary each time the tank is cleaned. 3. Tank cleaning procedure: a. Make sure that you are prepared to undertake the work safely. Refer to the Health and Safety section at the end of this chapter and consult with CVC Health and Safety staff for further guidance. b. Have equipment on-hand to assist with mechanically removing debris. Examples include a brush with long handle and power washer. A hose should also be available to supply water for rinsing the tank and/or connecting to the power washer. A wet vacuum should be used to assist with removing debris that remains below the bottom of the tank drain outlet pipe. c. Take the RWH system offline and ensure that municipal water is sent to fixtures to allow maintenance work to take place without affecting water supply to connected fixtures. Refer to the Decommissioning the RWH System section for instructions on how take the system offline. d. Drain the tank by turning the drain valve to the OPEN position (in line with the pipe). Ensure that all water drains to the floor drain. e. Connect a hose to an available hose bib in the mechanical room and either directly or as connected to a power washer, rinse any accumulated debris from the bottom of the tank. f. If debris remains on the bottom of the tank,

Task Frequency Tasks use a wet vac to remove water containing debris. g. A brush and/or power washer can be used to remove fine debris from the sides and bottom of the tank. Care should be taken to avoid contacting the rod-style mechanical float. Damage to this item will require costly repair work by a specialist contractor. h. Once the mechanical cleaning procedure is complete, and all possible debris has been removed, the tank should be filled to capacity with municipal water. i. Municipal water should be allowed to sit within the tank for a minimum of 6 hours, 24 hours maximum. Chlorine residual in municipal water may provide some minor disinfection benefit. j. Stored water is considered suitable for use when re-commissioning the RWH system, or can be discharged to the floor drain. k. All water used during the cleaning procedure should be discharged to the floor drain, for treatment by the municipal wastewater treatment system. 4. Tank disinfection procedure: a. Warning: Disinfection typically uses chlorine or other chemicals. Extreme caution should be exercised when using disinfection chemicals, particularly in areas with reduced ventilation. b. Before disinfecting the tank, ensure that the tank has first been cleaned using the instructions above. c. The number and type of PPE should be modified to be appropriate for the use of disinfection chemicals. Additional ventilation should be provided, and staff should take frequent breaks outside of the room where the storage tank is located. Refer to the Health and Safety instructions below for further details. d. There are numerous methods used for

Task Frequency Tasks disinfecting water cisterns. The method below describes shock chlorination which is the most common practice. e. Shock chlorination should be conducted according to the following instructions 2: i. Fill the tank with municipal water just below the overflow. ii. Add chlorine and blend it to mix with the stored water to obtain a free chlorine concentration of 50 mg/L (50 ppm). Note: The 50 mg/L concentration is achieved by adding 1 L of new unscented household bleach (e.g., 5% liquid sodium hypochlorite) for each 1,000 L of water (1 gal of bleach for each 1,000 gal of water). For CVC’s 5,000 L tank, 5 L of new unscented household bleach would be required. iii. Blending of chlorine can be done using a paddle or other suitable tool. Care should be taken to ensure that chemical-laden water does not splash. iv. Leave the mixed chlorinated water in the cistern for a contact time of at least 6 hours, 24 hours maximum. v. Chemical-laden water should be discharged to the floor drain so that it can be treated by the municipal wastewater treatment system. f. Water containing disinfection chemicals should not be allowed to overflow from the tank. All chemical-laden water should be discharged to the floor drain so that it can be treated by the municipal wastewater treatment system. 5. During the tank cleaning procedure the groundwater sump pit should also be inspected, and if necessary, cleaned to remove accumulated dirt and debris. The groundwater sump pit should be inspected and cleaned using the instructions provided above.

2 Adapted from CSA B126 Series-13 Water Cisterns.

Task Frequency Tasks Annually 1. Visually inspect the catchment surface for the (once a year) presence of overhanging tree branches. If present, trim tree branches/foliage overhanging roof to minimize opportunities for animals to access and contaminate the roof.

Health and Safety All inspection and maintenance work should be carried out outside of the tank – staff should never enter the tank. If it is necessary to enter the tank, follow all requirements of Ontario Confined Spaces Regulations (O. Reg. 632/05).

If using chemicals to clean and/or disinfect the tank, appropriate personal protective equipment must be worn at all times. Consult the Health and Safety guidance provided below and consult CVC Health and Safety staff for further guidance.

Product labels and material safety data sheets (MSDS) should be read and all statements of caution should be observed when handling or using chlorine and/or other chemical products.

While using chlorine and/or other chemicals, proper ventilation must be provided at all times. Exhaust fans should be set up to bring in fresh air. Staff should take frequent breaks outside of the cleaning area.

Ensure that all electrical devices/equipment are disconnected, where possible. If not possible, polyethylene sheeting should be used to shield electric equipment and/or to shield the work area, as required.

Ensure that all electric devices used for cleaning the tank (pressure washer and any other electric equipment) are used in accordance with the manufacturer’s instructions).

Maintenance Tips

Care should be taken to avoid contacting the rod-style mechanical float inside the tank during cleaning. Damage to this item will require costly repair work by a specialist contractor.

Treatment System

Overview The treatment system for CVC’s RWH system is a 100-micron particle filter (model JUDO JFXL-T). The system is equipped with an automatic backwash system which should keep the filter clean and minimize maintenance requirements. The filter’s automatic backwashing procedure has been set for one week by the factory.

Inspection and Maintenance Tasks Task Tasks Frequency Frequent 1. Inspect the filter for signs of debris building up on the filter screen. (every 3 2. If the filter appears clogged with dirt, a manual filter backwash can months) be initiated by pushing the ‘Manual release button’ on the filter control panel. Bi -Annual 1. Check the filter’s control panel for signs of a fault with the unit. A (once every list of typical faults and ways to address them are reproduced 6 months) from the manufacturer’s operation & maintenance manual below:

If there is a fault with the filter.

Task Tasks Frequency

Annually 1. If the filter and/or filter housing appears clogged with debris and (once a backwashing does not remove the debris, the unit can be cleaned year) manually. 2. It is recommended that the unit be serviced by a qualified person. Contact the manufacturer for a list of qualified contractors to service the unit. 3. Alternatively, the manufacturer’s operation and maintenance instructions can be used. 4. Before performing any maintenance activities on the filter unit disconnect the electricity supply to the unit and decommission the RWH system and send municipal water to connected fixtures before starting cleaning of the filter. 5. Remove the housing, and manually clean the filter and housing only using water and light mechanical cleaning – do not use chemical cleaners as these can damage the filter screen or the plastic seals. 6. Refer to the manufacturer’s instructions for further details.

Health and Safety

Be sure to follow the manufacturer’s operation and maintenance protocols when performing any work on the filter.

Maintenance Tips If the pressure or flow to toilets is low, you can try increasing the frequency of filter backwashing cycles – this will remove debris from the filter, making it easier for the pump to push water through it to the connected fixtures. See the manufacturer’s operating manual for instructions on how to adjust the backwash frequency.

Pump and Pressure Tank

Inspection and Maintenance Tasks Task Frequency Tasks Frequent 1. Inspect the pump, pressure tank, pipes and fittings to (every 3 months) look for signs of leaks. If leaks are found, these should be repaired by CVC staff if possible. If not possible for CVC staff to fix the leak, a qualified plumber should undertake the work. 2. Check the flow and pressure of the system to ensure that it is performing properly. 3. To check system pressure, check the pressure gauges below the system’s control panel. a. The pressure gauge on the left (vacuum of pump) should be between: 0 – -10 PSI b. The pressure gauge on the right (system pressure) should be between: 60 – 80 PSI 4. To check the system’s flow, flush a toilet and observe the rate at which it refills the toilet bowl. 5. If system flow or pressure is reduced, inspect the filter for signs of debris. If debris is present, initiate a manual filter backwashing by pressing the ‘Manual release’ button on the filter control panel. 6. If cleaning the filter does not improve flow or

Task Frequency Tasks pressure, see instructions below Bi -Annual N/A (once every 6 months)

If there is a fault with 1. If you are having problems with the pump and the pump and pressure system (reduced or no pressure or flow) pressure system directions are provided below to help identify and resolve the issue.

Note: pump and pressure systems are complicated, and it is sometimes difficult to identify and fix issues with these systems. If the information below does not help troubleshoot the problem, contact a qualified plumber with experience with pumps.

2. If the pump is “off” and not functioning. Visually examine the volume of rainwater in the storage tank: a. If the rainwater tank is empty, the pump and pressure system should not operate, and the fact that it is “off” may indicate that a water level sensor connected to the pump, or the pump’s internal dry run protection, is acting as intended and preventing the system from operating, b. If there is sufficient rainwater in the tank, and the pump and pressure are not operating, examine the electrical supply for the pump and pressure system. Verify that all necessary components are connected to the electricity supply, and that all components are supplied electricity (i.e., all on/off switches are in the ‘on’ position and any electrical panel breakers are also in the ‘on’ position on the RWH system control panel), 3. Most often a problem with the pump and pressurized distribution system is not due to the pump itself but the associated components and equipment. The following steps are recommended for examining each of these components: a. Top-up water system and water level sensors: i. During the visual inspection of the rainwater storage tank, if the tank appeared empty, this may indicate that

Task Frequency Tasks there are problems with the top-up system. Refer to the Top-up System section for instructions on how to troubleshoot this system, ii. It is possible that the bypass system has been activated and municipal water is being sent to the connected fixtures instead of rainwater. The RWH system will need to be re-commissioned to send rainwater to fixtures using the pump and pressure system. Refer to the Decommission the RWH System section for further details. b. Pressure tank: i. If the pump cycles on and off repeatedly, and/or the system never comes up to the desired pressure, there may be a problem with the pressure tank, ii. The static pressure of the pressure tank (the pressure of the tank when there is no water inside of it) must be 14 kPa [2 psi] less than the desired cut-in pressure. iii. Adjust the static pressure of the pressure tank by adding/removing air pressure inside the tank using the bicycle-style air valve on the tank. c. Pressure sensor/switch: i. Pump cycling and/or an inability to come up to the desired pressure may also be a problem with the pressure switch, ii. For constant speed pumps utilizing a pressure switch, consult the pump, and/or pressure switch manufacturers’ instructions for instructions on adjusting the pressure switch. d. Pipes and shut-off valves: i. If the pump appears to be dry running for a period of time but does not discharge any water, there may be a blockage in the rainwater pressure piping, ii. A blockage can also be created by a

Task Frequency Tasks shut-off valve, located in the rainwater pressure piping that is in the ‘closed’ position. Inspect all shut-off valves to ensure they are open. e. Foot valves, check valves and leaks in the system: i. If the pump cycles on during times when there is no rainwater demand or if the pressure gauge shows that the system pressure slowly decreases over time, there may be a problem with the foot valve or check valve or there may be a leak in the system, ii. Inspect all foot valves and check valves to ensure that they are installed in the correct orientation (as indicated on the device) and that the valve is not clogged by dirt and debris, iii. If the foot valves and check valves appear to be operating properly, then there may be a leak in the rainwater pressure piping. Inspect all piping to ensure that there are no leaks from the pipelines or leaks from the fixtures connected to the pump and pressurized distribution system. 4. If the above steps do not resolve the issues with the pump and pressure system, the problem may lie directly with the pump. Refer to the pump manufacturer’s operation instructions for troubleshooting recommendations, and if these actions are unsuccessful at resolving the problem, consult a licensed plumber, electrician and/or pump service technician.

Health and Safety Be sure to follow the manufacturer’s operation and maintenance protocols when performing any work on the pump and/or pressure tank.

Maintenance Tips

Issues with the pump and pressure system may be caused by a number of different components that make up the RWH system. Take a step-by-step approach to rule out what components aren’t causing issues to determine the likely cause of a pump and pressure system fault.

Top-up and Bypass System

Overview CVC’s RWH system has both a top-up system, to top up the tank when it runs dry and a bypass system, which can be used to send municipal water directly to connected fixtures – bypassing the RWH’s pump and pressure system. The components of the top-up system should be inspected regularly, and if required, maintained to minimize system downtime.

Inspection and Maintenance Tasks Task Frequency Tasks Frequent N/A (every 3 months) Bi -Annual 1. To inspect the performance of the top-up system, the (once every 6 tank level can be modified manually, by opening up months) the tank drain valve, to drain a portion of the tank volume. 2. As the tank drains, open the hatch on the top of the tank and observe the rod-style mechanical float inside the tank. 3. A large metal ball should be seen floating on the surface of the water, and should fall along with the falling water level. 4. When the ball reaches its low set point (a metal contact on the rod) it should initiate a top-up, which is evident by municipal water being discharged into the tank via the copper pipe entering through the top of the tank. 5. If the ball appears fixed at a particular spot on the rod, or does not move freely, it may be necessary to clean the rod or ball float to allow it to move freely. 6. Before performing work on the ball float, decommission the RWH system following the instructions provided in the Decommissioning the RWH System section. Once the RWH system has been decommissioned, drain the tank, and ensure that the electricity supply to the RWH is switched OFF.

Task Frequency Tasks 7. It is recommended that if performing maintenance on the top-up system that the interior of the tank be inspected, and if a large amount of debris is seen within the tank then the tank be cleaned first. Refer to the Storage Tank section for instructions on how to clean the tank. 8. Make sure that you are prepared to undertake the work safely. Refer to the Health and Safety section at the end of this chapter and consult with CVC Health and Safety staff for further guidance. 9. Once the tank has been cleaned (or if cleaning was not necessary), carefully remove debris from the rod and float by using a soft cloth or a soft brush. Do not use any chemicals or other cleaning agents as this may damage the rod float switch. 10. Continue the cleaning process, trying to carefully move the float if it is stuck in a particular position. Try using a hose or a pressure washer on a very low setting to carefully loosen debris from the rod and the float. 11. If this cleaning procedure does not work, it is recommended that you contact a plumber or mechanical contractor who is experienced with repairing rod-style float switches. 12. If the cleaning procedure is successful, ensure that the rod is in a vertical position and fill the rainwater storage tank with water and decommission the tank. Annually N/A (once a year)

Appropriate personal protective equipment must be worn at all times. Consult the Health and Safety guidance provided below and consult CVC Health and Safety staff for further guidance.

(pressure washer and any other electric equipment) are used in accordance with the manufacturer’s instructions).

Maintenance Tips

Care should be taken when contacting the rod-style float switch inside the tank during cleaning. Damage to this item will require costly repair work by a specialist contractor.

Backflow Prevention Devices

Overview CVC’s RWH system has two backflow prevention devices that protect CVC’s water supply and the municipal water system from contamination from rainwater. These devices should be inspected (and if required, repaired) on a regular basis to ensure they are working properly.

Inspection and Maintenance Tasks Task Frequency Tasks Frequent N/A (every 3 months) Bi -Annual N/A (once every 6 months) Annually 1. The City of Mississauga does not currently require (once a year) that prevention devices be inspected and tested to verify that they are performing adequately and protecting the municipal water supply. 2. Despite the lack of requirement, it is recommended that CVC have the devices inspected on an annual basis and records kept of inspection and repairs undertaken on the valves.

Heal th and Safety

Backflow preventers should be inspected, tested and repaired by qualified personnel.

Control Panel

Overview CVC’s RWH system has a control panel that can be used to supply power to the components of the RWH system, provide information on the performance of the system (and any faults) and must be adjusted to switch between rainwater and municipal water supply.

Inspection and Maintenance Tasks Task Frequency Tasks Frequent 1. Inspect the control panel for signs of issues or a fault (every 3 months) with the RWH system. When the RWH system is operating normally, the following should be observed on the panel: 1. Power On – Check that the power on indicator lamp is lit (ON), and that the power switch is at the ‘ø’ position. 2. Fault gauges: No flow shutdown, low level and no flow. All of these indicator lamps should be OFF. 3. Run indicator lamp should be ON 4. The Handoff Auto switch should be pointing to the RIGHT. 5. Pressure gauges below the control panel – the pressure gauge on the left should be between -10 - 0 PSI and the pressure gauge on the right should be 60 – 80 PSI. 2. If any of the fault indicators are lit or if any other settings of the RWH system are changed, then the system may not be operating properly and/or municipal water is being sent to the connected fixtures. Bi -Annual N/A (once every 6 months) Annually N/A (once a year)

Decommissioning the RWH System

Overview From time to time it will be necessary to take CVC’s RWH system offline for inspection or repair, and to then bring the system back online. This section provides step-by-step instructions on how to decommission the system.

Inspection and Maintenance Tasks Task Instructions Decommissioning 1. Prior to decommissioning, attempt to let the rainwater harvesting tank drain through use. 2. Shut off the tank intake valve. 3. On the Control Panel, turn the ‘Hand Off / Auto’ switch to ‘Hand Off’. 4. Turn the ‘Emergency Water’ shut-off valve on the wall opposite to the control panel to the OPEN position (valve handle in line with pipe). 5. Disconnect power to RWH system by turning Power ON switch from ‘ø’ to ‘ O’. 6. Drain the remaining water in the rainwater harvesting tank by opening the drain valve. 7. Close the drain valve.

Routine Inspection Checklist

Site: CVC Head Office Rainwater Harvesting Tank Inspector: Date:

Notes: Catchment Area (Building “A” rooftop):

Are the rooftop inlets Yes or No clear and able to accept incoming flow?

Is the rooftop clear of Yes or No possible sources of contaminants? (e.g. bird droppings, dead animals)

Rainwater Storage Tank:

Are there any signs of Yes or No leaks from the storage tank?

Sediment Accumulation None --- Light--- Moderate --- Severe in the tank (needs cleaning)

Is algae observed? Yes or No

Pump and Treatment System: Is the RHW system Yes or No currently online? Is the filter clogged? Yes or No Left pressure gauge reading: (Should be -10 ______to 0) Right pressure gauge reading: ______(Should be 60 to 80) Are any of the fault Yes or No indicator lights on? Maintenance:

Is maintenance required? Yes or No

What needs to be done?

Photos:

Number of Photo Description/Notes

Site Comments:

6.2. CVC PERMEABLE PAVEMENT OPERATIONS AND MAINTENANCE PLAN

In June and July of 2017, CVC, City of Mississauga, University of Toronto and Interlocking Concrete Pavement Institute (ICPI) partnered to test a variety of technologies and methods for restorative maintenance of the permeable pavement lots at the CVC Administrative Building.

In early June of 2016, The City of Mississauga provided the use of their contractor’s Tyco DST6 truck to clean CVC’s permeable parking lot. Jennifer Drake from the University of Toronto (Out) provided grad students who tested different pre-treatment technologies that could help loosen dirt between the paving stones making it easier for the vacuum truck to remove dirt and dust particles. Pre-treatment included power washing and sweeping. The truck was a regenerative air vacuum truck and did not use water in the process. The truck has wire brushes that scour out the dirt particles which are then vacuumed up and collected in a chamber.

CVC staff and students from performed infiltration testing before and after the vacuuming to evaluate the effectiveness of the maintenance work at restoring the infiltration performance of the parking lot.

Results From the prediction maps of Pre- Maintenance Infiltration Rate, Post- Maintenance Infiltration Rate and Change Ratio below (see below), the vacuuming truck helped improve the infiltration rate significantly on Parking lot #2, especially the area right in front of our office. The average Pre-Maintenance infiltration rate of Parking Lot #2 is 381.6 mm/hr with 6 failures, and the average Post-M infiltration rate is 797.8 mm/hr with only 4 failures. Nine (9) of fourteen (14) test spots benefited from the maintenance (6 of 9 infiltration rates improved by more than 100%!), 4 of 14 still failed, and 1 spot slightly decreased after the maintenance by 12%. Overall, the average change ratio on the old parking lot is 143%, quite improved!

However, only 5 of 17 test spots on the new parking lot benefited from the maintenance. But most area on the new parking lot still performs well on infiltrating, with average Pre-M Infiltration Rate of 2441 mm/hr to Post-M Infiltration Rate of 1952 mm/hr (range 158mm/hr - 5556 mm/hr). 7 of 14 test locations have infiltration rates decreased less than 50%, and the rest 5 locations have infiltration rates decreased by 51% - 71%. The overall infiltration rate change ratio of the new parking lot is -6%.

*Change ratio = (Post-Maintenance Infiltration Rate – Pre-Maintenance Infiltration Rate)/Pre-Maintenance Infiltration Rate.

a. Proposed Inspection and Documentation Plan

1) Proposed/On-going Inspection Plan o Frequency: Once per month; o Inspect the Inlets, observe and record the percentage of trash/debris, sediment accumulation, erosion, structural damage, etc.; o Inspect the Grass Swale, observe and record the percentage of trash/debris, area ponding, exposed Soil, sediment accumulation, erosion; o Inspect the Permeable Pavement, observe and record the percentage of trash/debris, structural damage, sediment accumulation, evidence of clogging; o Inspect the Outlet, observe and record the percentage of trash/debris, structural damage, sediment accumulation, erosion, etc.; o Determine if maintenance is needed; o Photo log of LID features

2) Proposed/On-going Storm Events Inspection o Check drain outfalls for free flow of water and outflow from observation well after a major storm; o Water ponding on surface immediately after a storm (paver joints or openings severely loaded with sediment): if needed test surface infiltration rate (ASTM C1781/C1781 M)

3) Inspection Documentation Plan o For each inspection, LID Inspection Checklist is required to be completed (Appendix G ), take pictures or/and videos and record the pictures’ number; Document the Inspection checklist, pictures or/and videos in electronic file and/or hard copy. o If any maintenance is required, details and procedures must be documented separately under maintenance

b. Proposed Maintenance and Documentation Plan 1) Smaller Areas – As needed: Prevent contamination from routine landscape maintenance such as grass clippings from mowing, hedge trimming, etc. by implementing the following cleaning procedures immediately after contamination occurs: o Hand broom debris from the paver surface; o Blow debris from the paver surface with backpack blower type device;

Observe any collection areas of debris, dirt, topsoil, mulch, etc. after events such as snowfall, rain storms, etc. and investigate if clogging is occurring. Immediately restore infiltration using the following cleaning options: o Break up any crust covering the joint aggregate material with hand broom for smaller areas. Remove debris material;

If clogging observed for larger areas, and requires mechanical equipment to restore the infiltration, please follow the maintenance procedures in below section ‘Larger Areas – Yearly’. If the monthly inspection checklists indicate that maintenance on a small or large scale is required, complete as necessary.

2) Larger Area – Yearly Once per year: o Sweep/Vacuum entire permeable paving surface with appropriate preventative sweeping devices; o Apply pre-treatment approaches, such as power wash or brush, to permeable paving surface depending on its condition (i.e. clogged); o Replenish joint aggregate material to ‘lip’ of paver;

3) Larger Area – Every ten or more years Plan long term maintenance to rejuvenate infiltration rates: o Complete restoration of the joint aggregate material; o Replenish joint with cleaned or new aggregate material to ‘lip’ of paver.

4) Maintenance Documentation Plan For each maintenance action taken for Smaller Areas, Maintenance Record (Appendix G ) for Smaller Area must be filled or memorandum must be documented in electronic version and/or hard copy. Pictures or/and videos for pre- and post- conditions are proposed to be taken and documented in electronic version and/or hard copy. For annual maintenance, detailed Annual Maintenance Record ( Appendix G) must be filled or memorandum must be documented with the information of operator’s information, equipment type and brand, rental cost, aggregate material cost, and observed effectiveness, etc. Pictures or/and videos for pre- and post- conditions are proposed to be taken and documented in electronic version and/or hard copy.

Additionally, if infiltration test is processed before and after the maintenance, infiltration test results and infiltration improvement is supposed to be documented.