STORMWATER MANAGEMENT REPORT Southgate Solar Project DRAFT– December 2014

Southgate Solar Project DRAFT Stormwater Management Report

Table of Contents Page

Executive Summary ................................................................................................................................. 1 1. Introduction................................................................................................................................ 2

2.

3. 4.

1.1

Objectives and Regulatory Requirements ....................................................................... 4

1.2

Existing Conditions ......................................................................................................... 5

1.3

Proposed Development Conditions ................................................................................ 5

Analysis Methodology ................................................................................................................. 7 2.1

Hydrologic Parameters ................................................................................................... 7

2.2

Visual OTTHYMO Version 2 (VO2) ................................................................................... 9

2.3

Catchment Properties..................................................................................................... 9

2.4

Quantity Control Assessment ....................................................................................... 10

2.5

Floodplain Management Requirements ........................................................................ 13

2.6

Quality Control ............................................................................................................. 13

2.7

Enhanced Grass Swale Maintenance............................................................................. 16

2.8

Transformer Containment Area .................................................................................... 17

Erosion and Sediment Control Plan During Construction ........................................................... 18 Conclusions............................................................................................................................... 20

P age |i

Southgate Solar Project DRAFT Stormwater Management Report

List of Figures Figure 1: General Location of Southgate Solar Project ............................................................................. 3

List of Tables Table 1: Land Use Hydrologic Characteristics .......................................................................................... 8 Table 2: Existing Conditions Hydrologic Characteristics ............................................................................ 9 Table 3: Proposed Conditions Hydrologic Characteristics ........................................................................ 9 Table 4: VO2 Modelled Peak Flow Summary ......................................................................................... 12 Table 5: Enhanced Grass Swale Summary Table .................................................................................... 14 Table 6: Factors that Influence the Pollutant Removal Capacity of Grass Swales ................................... 15 Table 7: Typical Inspection and Maintenance Activities for Enhanced Grass Swales .............................. 16

List of Appendices Appendix A: SVCA Meeting Minutes Appendix B: Catchment Area and Soils Mapping Appendix C: Hydrologic Modelling Input & V02 Output Appendix D: Enhanced Grass Swale Sizing Calculations and Typical Details

P a g e | ii

Southgate Solar Project DRAFT Stormwater Management Report

EXECUTIVE SUMMARY This Draft Stormwater Management report outlines the proposed stormwater management (SWM) strategy and proposed erosion and sediment control (ESC) strategy for the development of the Southgate Solar Project. The proposed solar facility will be located primarily within lands currently zoned by the Township of Southgate as, Agricultural. Land use within the Project Location includes wetlands, woodland and some rural residential properties. The lands are generally drained by overland flow and outlet into existing roadside ditches within the project location or to watercourses adjacent to the project location. In general, the proposed development will not significantly alter the existing grades. The solar panels will be aligned in table rows between 8 to 12 m apart, and will be mounted on racking structures. Based on the results of a geotechnical assessment, it is anticipated that helical ground screws will be used to anchor the racking system into the ground. The use of a racking system with helical ground screws will have minimal effect on the imperviousness of the project location, both above and below ground, as the area of the ground screws compared to the area of the project location is small. The entire Project area, with the exception of new access roads is anticipated to be covered with low maintenance, densegrowing vegetation. A hydrologic assessment was completed using VO2 software. Precipitation data from the Mount Forest Climate Station (#6145504) was utilized with a 6-hour SCS Type II storm distribution for multiple return periods. The modelled results show a marginal reduction in peak flow from all outlets. It is expected that the change in land use from agricultural to open grassed area will reduce runoff potential from the drainage catchments through increased resistance to flow, infiltration and evapotranspiration, consequently reducing the amount of flow leaving the Project. The findings demonstrate that peak flow attenuation via on-site storage will not be required. With the reduction in peak flow at the outlets, it is not expected that lands downstream of the Project will suffer a loss of service from the change in flow regimes. No impacts to flooding and erosion are expected for watercourses downstream of the Project under proposed conditions. It is expected that peak flows from the Project site will be diverted around neighboring properties via the use of recommended stormwater conveyance controls, such as enhanced grass swales. Stormwater quality control is proposed following a treatment train approach with source and conveyance measures. The proposed source control system is a dense-growing vegetative surface cover and a transformer spill containment system. Conveyance control is to be provided by enhanced grass swales with rock check dams. To minimize the potential for water quality impairment to any receiving waters or sensitive environmental features during construction, an Erosion and Sediment Control (ESC) plan will be developed and implemented prior to and during construction. At this preliminary stage, ESC recommendations are made in this report and should be considered when the ESC plan is developed during detailed design.

P age |1

Southgate Solar Project DRAFT Stormwater Management Report

1.

INTRODUCTION

Southgate Solar LP proposes to develop a solar facility with a maximum nameplate capacity of 50 megawatts alternating current (MWac), located near Mount Forest, in the Township of Southgate, County of Grey, Ontario (Figure 1). The renewable energy facility will be known as the Southgate Solar Project (the "Project"). Southgate Solar LP has initiated the Project through a power purchase agreement (PPA) with the Ontario Power Authority. The Project will require approval under Ontario Regulation 359/09 (O. Reg. 359/09) - Renewable Energy Approval (REA) under Part V.0.1 of the Ontario Environmental Protection Act. This draft Stormwater Management Report outlines the proposed stormwater management (SWM) strategy and the proposed erosion and sediment control (ESC) strategy for the Project. Figure 1 shows the project location in Ontario.

P age |2

GEORGIAN BAY LAKE HURON OWEN SOUND

SOUTHGATE SOLAR PROJECT

BARRIE

FIGURE 1 GENERAL PROJECT LOCATION

'e '³

'` _Project Location ^

'd

SHELBURNE

'³ ORANGEVILLE

1:500,000

'`

0

5

10

20 km

²

MAP DRAWING INFORMATION: DATA PROVIDED BY MNR

BRAMPTON

MAP CREATED BY: GM MAP CHECKED BY: MB MAP PROJECTION: NAD 1983 UTM Zone 17N

FILE LOCATION: I:\GIS\149154 - Samsung Southgate\mxd\PDR\

PROJECT: 149154

GUELPH

STATUS: DRAFT DATE: 11/12/2014

Southgate Solar Project DRAFT Stormwater Management Report 1.1

Objectives and Regulatory Requirements This report has been prepared in order meet the requirements O. Reg. 359/03. Information pertaining to “any works for the collection, transmission, treatment and disposal of sewage, including details of any sediment control features and stormwater management facilities” must be discussed as part of the Design and Operations Report. The following work was undertaken to develop a preliminary SWM plan in co-ordination with the civil site plan development: ·

Assessment of existing conditions hydrology and runoff

·

Confirmation of SWM design criteria from correspondence with relevant agencies

·

Assessment of proposed hydrologic conditions to determine potential impact to peak flows and water quality

·

Preliminary sizing of proposed water quality measures

·

Provision of design criteria for the substation containment unit and preliminary volume sizing for the stormwater containment area

·

Recommendation for ESC practices during construction

·

Development of a preliminary stormwater management plan indicating the location of proposed water quality control measures and typical details of the proposed measures

Preliminary meetings were held with the Saugeen Valley Conservation Authority (SVCA) for the proposed solar development. A copy of the meeting minutes from July 4, 2014 and November 12, 2014 are included in Appendix A. This report is based on a preliminary level of design for the proposed mitigation measures, including the proposed stormwater conveyance, water quality treatment systems, transformer containment area, and ESC recommendations. The results from this report are intended to provide guidance for the detailed design of the Project, with consideration for meeting SVCA requirements.

P age |4

Southgate Solar Project DRAFT Stormwater Management Report

1.2

Existing Conditions

The proposed solar facility will be located primarily within lands currently zoned by the Township of Southgate as Agricultural. The Official Plan for the Township of Southgate designates the Project Location as Agricultural, with some Rural areas and Hazard Lands. The upper-tier municipality (County of Grey) designates the lands as Agricultural and Rural, with some Hazard Lands. Land use within the Project Location includes wetlands, woodland and some rural residential properties. The lands are generally drained by overland flow and outlet into existing roadside ditches within the project location or to watercourses adjacent to the project location (i.e. the Beatty Saugeen River and an unnamed headwater tributary to Camp Creek). The entire Project is within the Saugeen River Watershed. 1.3

Proposed Development Conditions

In general, the proposed development will not significantly alter the existing grades. The panels will be aligned in table rows between 8 to 12 m apart, and will be mounted on racking structures. The racking system will be in a fixed position and tilted to 28-42 degrees, subject to refined modeling during the detailed design stage to achieve optimal energy yields. Based on the results of a geotechnical assessment, it is anticipated that helical ground screws will be used to minimize potential negative environmental effects. Additional details on the racking and support system are provided in the Design and Operations Report. It is expected that the use of a racking system with helical ground screws will have little effect on the imperviousness of the project location, both above and below ground, as the area of the ground screws compared to the area of the project location is small. Native ground cover will be located in and around the base of the solar panel racking. The area of the Project Location is 235 ha however the approximate area of the lands to be covered by components is 166 ha. The lands proposed for development include the solar panels, gravel access roads, substation and fenced area. The study areas considered for this Stormwater Management Report are larger than the development area as they include upstream drainage areas to the project. Although the solar panels themselves are impervious, rain water will land on the solar collector panels and runoff directly onto the ground below the individual panels. Minimal erosion is anticipated beneath each solar panel, once the ground cover vegetation is re-established after construction. The overall effects of the runoff generated from the solar panels will be minimal, as the majority of the anticipated ground cover during the operations phase (i.e., a low-growing native grassland species) will improve hydrologic conditions relative to existing conditions (i.e. longer duration flow paths and reduced runoff potential).

P age |5

Southgate Solar Project DRAFT Stormwater Management Report

The facility will include panel areas, access roads, Medium Voltage (MV) Stations and one main high voltage (HV) substation transformer. Foundations for MV Stations and the main HV substation transformer are anticipated to be helical ground screws and concrete pads, respectively. Permanent gravel access roadways will be constructed using a suitable depth of granular material. Once completed, any foundation excavations will be backfilled and leveled to match the proposed grading. The entire Project, with the exception of new access roads is anticipated to be covered with low growing vegetation.

P age |6

Southgate Solar Project DRAFT Stormwater Management Report

2.

ANALYSIS METHODOLOGY

The study area was divided into catchments based on the land parcels to be developed in this phase. Due to the dispersed nature of the lands to be developed, drainage sub-catchments were delineated based on outlet points downstream of the Project Location. Six outlets, each at a downstream point of the receiving watercourses and roadside ditches have been identified as points of interest to compare pre and post development peak flows. Figure 2 in Appendix B shows the six outlet points. The existing conditions catchment areas were delineated using 0.5 m contour survey of the proposed development area. Additionally aerial photography, Ministry of Natural Resources and Forestry (MNRF) watercourses, and GIS data were also used to refine the catchment boundaries. At this preliminary design stage, it is expected that there will be minimal changes in the overall grading of the catchment areas. Consequently, the post-development drainage areas were kept the same as existing conditions. Please refer to Figure 2 and Figure 3 in Appendix B for the existing conditions and proposed conditions catchment areas. 2.1

Hydrologic Parameters

The soil type distribution was determined using Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA) agricultural soil database and Ontario Soil Survey of Grey County (Richards, Gillespie, 1954). The site is composed primarily of Pike Lake Loam (approximately 85%) with some areas of Gilford, Lily and Burford Loams and areas of Muck (total of approximately 15%). The characteristic hydrologic soil group (HSG) for the predominant soil type is loamy soils, HSG A, with a small proportion of silty loams (HSG C) and organic matter (HSG D). See Figure 4 in Appendix B for soils mapping information. Average existing catchments slopes range from approximately 0.7% to 1.5%. The major land uses considered in the hydrologic analysis were: 1. Agricultural lands – Row Crops 2. Paved Roads 3. Dirt Roads and Rural Residential Areas 4. Grass Covered Lands 5. Undeveloped lands – Woods or Woodlands 6. Wetlands 7. Gravel Roads 8. Other Paved or Impervious surfaces

P age |7

Southgate Solar Project DRAFT Stormwater Management Report

The hydrologic properties, both Soil Conservation Services Curve Number (SCS CN) and Rational Method runoff coefficient (C) for each land use was referenced from the MTO Drainage Management Manual (MTO, 1997) and TR-55: Urban Hydrology for Small Watershed (NRCS, 1986). This information is summarized in Table 1. The Rational Method C was only used for time of concentration calculations. Table 1: Land Use Hydrologic Characteristics HSG Group A

Land Use

SCS CN

Runoff Coefficient (C)

Additional Information

Agricultural – Row Crops

74

0.35

Row/small crop - good Hydrologic Condition (HC)

Dirt Roads and Rural Residential Areas

89

0.60

Dirt roads, includes rural residential properties

Undeveloped – Woods or Woodlands

58

0.25

Assumed to have good HC

Undeveloped – Pasture/Meadow

64

0.28

Assumed to have good HC

Wetlands

50

0.05

Wetland/swamp/marsh and open water areas

Gravel Roads

91

0.66

Proposed gravel access roads

Other Paved or Impervious Surfaces

98

0.90

Proposed paved pads or roofs

Precipitation data from Environment Canada was utilized to develop design storms for use in this study. The Mount Forest Climate Station (#6145504) was considered the most appropriate for the site, and recommended by the SVCA. Two storm distributions were assessed in the hydrologic modeling: a 4-hour Chicago storm and a 6-hour SCS Type II storm. The 6-hour SCS Type II storm distribution yielded higher peak flows for the various return periods and is presented in this report.

P age |8

Southgate Solar Project DRAFT Stormwater Management Report

2.2

Visual OTTHYMO Version 2 (VO2)

Stormwater peak flows were calculated using the Visual OTTHYMO Version 2 (VO2) model. OTTHYMO is a hydrologic management model that has been used for watershed studies, subwatershed studies, master drainage plans, functional stormwater management plans, site plans, and stormwater management pond design. VO2 has been accepted by the Ministry of the Environment and Climate Change (MOECC), the MNRF, the Ministry of Transportation (MTO), the Ministry of Municipal Affairs and Housing (MMAH), Conservation Ontario (CO), and most municipal governments as a valid hydrologic simulation program. 2.3

Catchment Properties

A summary of the hydrologic properties for the existing conditions catchments and the proposed conditions catchments are outlined in Table 2 and Table 3.

Table 2: Existing Conditions Hydrologic Characteristics

Catchment Label

Total Area (ha)

SCS CN

Runoff Coefficient (C)

Time to Peak (hr)

EX-OUT-A

73.1

60

0.33

1.43

EX-OUT-B

58.2

59

0.33

1.04

EX-OUT-C

35.4

51

0.24

1.80

EX-OUT-D

109.8

55

0.30

0.99

EX-OUT-E

120.6

59

0.29

0.98

EX-OUT-F

115.6

54

0.27

1.29

EX-OUT-G

49.1

56

0.27

0.87

Table 3: Proposed Conditions Hydrologic Characteristics

Total Area (ha)

SCS CN

Runoff Coefficient (C)

PROP-OUT-A

73.1

56

0.32

1.46

PROP-OUT-B

58.2

55

0.32

1.05

Catchment Label

Time to Peak (hr)

P age |9

Southgate Solar Project DRAFT Stormwater Management Report

Total Area (ha)

SCS CN

Runoff Coefficient (C)

PROP-OUT-C

35.4

49

0.24

1.82

PROP-OUT-D

109.8

54

0.30

0.99

PROP-OUT-E

120.6

57

0.29

0.98

PROP-OUT-F

115.6

51

0.26

1.31

PROP-OUT-G

49.1

55

0.27

0.86

Catchment Label

Time to Peak (hr)

For the existing and proposed condition catchments, the time of concentration was calculated using the Airport Formula method (Federal Aviation Administration, 1970). This method was considered the most appropriate as runoff coefficient (C) values are less than 0.40. Overland flow paths under proposed conditions may be slightly longer (i.e., via potential grass swales along interior roads) and would result in lower peak flow values. Hence, a conservative approach was used in the analysis based on the assumption that the times of concentration are similar for both existing and proposed conditions (refer to Figure 2 in Appendix B for flow paths, and Appendix C for time of concentration calculations). In general, there is a reduction of the C and SCS CN values under proposed conditions. The predominant land use under existing conditions is agricultural row crops with exposed soils. Under proposed conditions, the predominant land use is grassed open area with significantly less exposed soil. Once vegetation on the site has been fully established, it is expected that the land hydrologic conditions will provide additional resistance, promote infiltration and evapotranspiration (i.e. reducing runoff potential), and increase flow path travel times. Refer to Appendix B for additional details related to the existing and proposed land use. 2.4

Quantity Control Assessment

The VO2 model results for existing and proposed conditions peak flows are outlined in Table 4. For complete model outputs see Appendix C. The modelled results show a marginal reduction in peak flow from all outlets under proposed conditions. Soils within this area are predominantly loams which have high infiltration rates (HSG A). The increase in impervious area at the project location is minimal and does not have a large impact on peak flows. As mentioned, the change in land use from agricultural to open grassed area will reduce runoff potential from the catchments through increased resistance to flow, infiltration and evapotranspiration, consequently reducing the amount of flow leaving the site.

P a g e | 10

Southgate Solar Project DRAFT Stormwater Management Report With the reduction in peak flow at the outlets, it is not expected that lands downstream of the Project will suffer a loss of service from the change in flow regimes. No impacts to flooding and erosion are expected for watercourses downstream of the Project under proposed conditions. It is expected that peak flows from the Project will be diverted around neighboring properties via the use of recommended stormwater conveyance measures, such as enhanced grass swales. These findings demonstrate that peak flow attenuation via on-site storage will not be required. It is recommended that at locations where a direct outlet to drainage feature is not available onsite, that the outlet from the enhanced grass swale include a level spreader or similar device to dissipate the concentrated flow to a sheet flow.

P a g e | 11

Southgate Solar Project DRAFT Stormwater Management Report

Table 4: VO2 Modelled Peak Flow Summary 6HR SCS TYPE II STORM DISTRIBUTION

Return Period (Year)

Outlet A

Outlet B

Outlet C

Outlet D

Outlet E

Outlet F

Outlet G

(m3/s)

(m3/s)

(m3/s)

(m3/s)

(m3/s)

(m3/s)

(m3/s)

EX

PROP

EX

PROP

EX

PROP

EX

PROP

EX

PROP

EX

PROP

EX

PROP

2

0.31

0.26

0.30

0.25

0.09

0.08

0.50

0.48

0.64

0.60

0.42

0.37

0.25

0.25

5

0.51

0.43

0.49

0.43

0.15

0.14

0.84

0.81

1.07

1.00

0.70

0.63

0.43

0.41

10

0.66

0.57

0.64

0.56

0.20

0.19

1.10

1.07

1.39

1.31

0.92

0.82

0.56

0.54

25

0.87

0.76

0.86

0.75

0.27

0.25

1.48

1.43

1.86

1.74

1.23

1.10

0.75

0.73

50

1.05

0.91

1.03

0.90

0.32

0.30

1.78

1.72

2.23

2.10

1.49

1.33

0.91

0.88

100

1.24

1.08

1.21

1.06

0.38

0.36

2.11

2.04

2.64

2.48

1.76

1.58

1.07

1.04

P a g e | 12

Southgate Solar Project DRAFT Stormwater Management Report

2.5

Floodplain Management Requirements

Based on discussions with the SVCA, floodplain mapping is not available for the Project site however hazard lands mapping (i.e. areas subject to natural hazards, including flooding) can be utilized as a general guide. A 50 m buffer from designated hazard lands may be considered as a general regulated area therefore permits may need to be acquired if development is proposed to occur within the buffer area. Floodplain extents may also need to be established prior to construction to ensure the SVCA requirements are met, as noted in the meeting minutes from November 12, 2014 (refer to Appendix A). Given that detailed site grading is not being completed as part of the REA process, the determination and delineation of floodplain extents would be deferred to detailed design if necessary. Any further requirements related to floodplain management will need to be addressed during the detailed design phase. It is recommended that consultation with SVCA is re-established at that time to ensure all the requirements, including permitting are understood. 2.6

Quality Control

Stormwater quality control will be achieved during the operational phase of the Project following a treatment train approach of source controls and conveyance controls. The proposed source control treatment system is provided by dense-growing vegetative surface cover over the majority of the open space. The cover type will be determined during detailed design. After construction and the establishment of the new surface cover, the water quality to the receiving watercourses is expected to improve when compared to existing conditions. The proposed vegetative cover allows for removal of suspended solids during overland flow through the grassed areas. Although the majority of the project location poses no increased loading of total suspended solids (TSS), or other pollutants such as oil, spill containment design features for the substation and inverter transformers have been considered (refer to Section 2.8). In addition to the source controls, it is proposed that the conveyance system of enhanced grass swales with rock check dams provide water quality treatment. These swales are designed to promote infiltration of stormwater and the filtering and settling of pollutants by reducing the velocity along the swales. The proposed enhanced grassed swales were designed following the recommendations outlined in the MOE SWM Planning and Design Manual (MOECC, 2003) for enhanced grass swales. Design recommendations from the Low Impact Development SWM Planning and Design Guide (Credit Valley Conservation Authority [CVCA]) & Toronto Region Conservation Authority [TRCA], 2010) were also considered.

P a g e | 13

Southgate Solar Project DRAFT Stormwater Management Report

Under the proposed layout, the locations of the enhanced grass swales were generally established along the gravel access roads. The following preliminary design criteria and assumptions considered for the enhanced swales: · · · · · · ·

Water quality design storm is a 25 mm, 4-hour Chicago event Manning’s roughness coefficient of 0.045 (vegetated stream based on vegetation length of 150 mm) Constant longitudinal slopes of 1% 3:1 side slopes Minimum bottom width of 0.75 m Freeboard of 0.30 m (under water quality storm) Check dam height of 0.30 m

Refer to Figure D102 in Appendix D for typical details of the proposed enhanced grass swales. The detailed design of each enhanced grass swale and outlet has been deferred to the detailed design phase of this project. Refer to Table 5 for summary of the geometry and hydraulics of the proposed enhanced swales. Table 5: Enhanced Grass Swale Summary Table

Catchment ID

Quality Storm Peak Flow (m3/s)

Bottom Width (m)

Normal Depth (ND) in Swale (m)

ND Velocity in Swale (m/s)

Freeboard – ND to Top of Bank (m)

Depth just Upstream of Check Dam (m)

PROP-OUT-A

0.11

0.75

0.21

0.44

0.19

0.39

PROP-OUT-B

0.10

0.75

0.20

0.43

0.20

0.38

PROP-OUT-C

0.03

0.75

0.10

0.30

0.30

0.34

PROP-OUT-D

0.19

0.75

0.28

0.51

0.12

0.42

PROP-OUT-E

0.24

0.75

0.32

0.54

0.08

0.44

PROP-OUT-F

0.15

0.75

0.25

0.48

0.15

0.40

PROP-OUT-G

0.10

1.0

0.20

0.35

0.20

0.38

Refer to Appendix D for the hydraulic and hydrologic calculations for the proposed enhance grass swales. Hydraulic calculations were completed using Bentley FlowMaster software. The enhanced swales in each catchment area were conservatively sized using the quality storm peak flow rate for the entire catchment.

P a g e | 14

Southgate Solar Project DRAFT Stormwater Management Report

It is anticipated that the areas draining to each enhanced swale will be much smaller under proposed conditions and will therefore result in smaller peak flow rates. The geometry and hydraulics of the enhanced swales should be confirmed in detailed design. As previously noted, the proposed enhanced grassed swales geometry and hydraulic characteristics were designed following the recommendations outlined by the MOECC (2003). The velocity for all swales was found to be 0.5 m/s or less under the water quality design storm. Following Table 4.8.3 from CVCA and TRCA (2010), 4 of the 5 factors that enhance removal rates in enhanced swales are met with the proposed design. Refer to Table 6 for a comparison of pollutant removal enhanced factors included in the proposed design. Table 6: Factors that Influence the Pollutant Removal Capacity of Grass Swales Provided on-Site

Additional Comments

Longitudinal slope < 1%

Yes

All proposed enhanced swales have slopes lower than 1%

Measured soil infiltration rate is 15 mm/hr or greater

Yes

Infiltration rates to be confirmed but it is assumed the rates are higher than 15 mm/hr (Loamy soils)

Flow velocity within channel is 0.5 m/s or less during a 4 hour, 25 mm Chicago storm event

Yes

Refer to Table 5. It is assumed that flow velocities will be less than 0.5 m/s due to the smaller areas draining to each swale.

Pretreatment with vegetated filter strips, gravel diaphragms and/or sedimentation forebays

Yes

Pretreatment is provided by overland flow over the upstream grassed surfaces.

Side slopes 3:1 (H:V) or less

No

Due to space limitations; a 2:1 slope was provided for all swales.

Factors that Enhance Removal Rates

The treatment train approach of source and conveyance controls is considered adequate for the proposed development and will provide an improvement to the water quality of the runoff leaving the site when compared to existing conditions. Based on discussions with the SVCA (refer to November 12 meeting minutes in Appendix A), an “Enhanced” level of water quality treatment (i.e. 80% TSS removal) is required considering the location of the proposed Project and its proximity to receiving water bodies. The water quality treatment level of the enhanced swales should be confirmed during detailed design.

P a g e | 15

Southgate Solar Project DRAFT Stormwater Management Report

Erosion protection at the outlets of the enhanced grassed swales prior to discharge into the receiving watercourses/roadside ditching is recommended. The protection measures may include rip rap lined channels and energy/flow spreaders. The requirements for, and design of, erosion protection will be confirmed during the detailed design stage. 2.7

Enhanced Grass Swale Maintenance

The maintenance requirements for enhanced grassed swales under normal operations (i.e. after vegetation becomes established) are generally considered low intensity. The major maintenance requirement is mowing. Occasionally, sediment will need to be removed from the swales. Onsite upstream sediment erosion and transport will be minimized by ensuring these areas are stabilized, prior to commencing normal operations of the enhanced swales. Routine roadside swale maintenance practices such as scraping and re-grading should be avoided whenever possible. Similarly, less intensive sediment removal practices should be undertaken whenever possible (i.e. hand digging, etc.). Vehicles should not be parked or driven on the enhanced ditching. For routine mowing, the lightest possible mowing equipment should be used to prevent soil compaction. A summary of recommended maintenance activities and scheduling is outlined in Table 7 referenced from the TRCA and CVC (2010). Table 7: Typical Inspection and Maintenance Activities for Enhanced Grass Swales Activity

Frequency

·

Inspect for vegetation density (at least 80% coverage), damage by foot or vehicular traffic, channelization, accumulation of debris, trash and sediment, and structural damage to pretreatment devices.

After every major storm event (>25 mm), quarterly for the first two years, and twice annually thereafter.

·

Regular watering may be required during the first two years while vegetation is becoming established; Maintain vegetation height between 75 to 150 mm; Remove trash and debris from pretreatment devices, the swale surface and inlet and outlets.

At least twice annually. More frequently if desired for aesthetic reasons.

Remove accumulated sediment from pretreatment devices, inlets and outlets; Replace dead vegetation, remove invasive growth, dethatch, remove thatching and aerate; Repair eroded or sparsely vegetated areas; Remove accumulated sediment on the swale surface when dry and exceeds 25 mm depth; If gullies are observed along the swale, regrading and revegetating may be required.

Annually or as needed

· · · · · · ·

P a g e | 16

Southgate Solar Project DRAFT Stormwater Management Report

2.8

Transformer Containment Area

The Project substation is a component of the proposed development on Property #11 (refer to Figure 3). The substation would house the switchyard, control, protection, communication tower (33 M) and metering system required to support the operation of the substation. The substation would have a footprint of approximately 0.5 ha. The site would be largely covered with gravel, and underlain by a grounding grid. It is assumed that external drainage will be directed around the substation area and away from the transformer to minimize sizing of the proposed containment feature described below. The detailed grading and layout of the substation will be confirmed during detailed design. Within the substation yard, the substation will contain a power oil filled transformer, switch gear and monitoring equipment. The secondary containment for the substation transformer will be built to reduce potential negative environmental effects from an oil leak. The secondary containment will be confirmed in the detailed design stage. Based on preliminary design estimates, the substation will rest in a concrete basin designed to hold the liquid contents of the transformer and stormwater equivalent to that of a 24-hour, 25-year storm. Stormwater will be contained in the concrete basin with quenching stone and then drained through an oil/water separator, which will contain the oil detection system which will prohibit the sump pump from releasing the water back into the surrounding environment. Upon oil detection an alarm will notify the operator of oil in the containment facility. Any oil separated from the oil/water separator will be collected and disposed of at a registered facility. Additional details of the spill containment units and during the detailed design stage.

P a g e | 17

Southgate Solar Project DRAFT Stormwater Management Report

3.

EROSION AND SEDIMENT CONTROL PLAN DURING CONSTRUCTION

To minimize the potential for impairment of the quality of any receiving waters during construction, an erosion and sediment control (ESC) plan will be developed in detail and implemented prior to and during construction. At this preliminary stage, the following recommendations may be considered when developing the ESC plan: · Identifying and protecting all trees and plants not shown for removal that are contained within the construction area; · Installing silt fences (placed at the downslope side of proposed grading activities, proposed stockpile areas, and the site limits) and all necessary erosion control measures prior to commencing construction activities; · Installing an additional row of silt fence during grading and clearing activities to provide additional protection to adjacent watercourses and sensitive natural features; · Installing construction entrances (mud mats) at all vehicle access points adjacent to paved roads to limit the potential transport of materials off-site; · Phasing construction, where possible, to limit areas with and the duration of exposed soils; · Implementing proper dewatering techniques to ensure the site and excavations are free from water. These techniques include diverting water into a dewatering trap with a filter bag on the outlet hose or to a or well-vegetated area a minimum of 30 m from any waterbody/wetland; · Using appropriate grading techniques to prevent increased run-off potential and maintain positive drainage; · Utilizing sedimentation basins or sediment traps to treat relatively large drainage areas (i.e., greater than 2 ha); · Implementing temporary water passages techniques for proposed in-water works with appropriate approvals confirmed prior to construction; · Re-vegetation of disturbed areas after grading has been completed and prior to construction activities where feasible (either through natural re-growth or planting, as necessary); · Protecting stockpiled areas with silt fencing and locating the areas a safe distance from sensitive natural features; · Stabilizing with vegetation or other erosion and sediment control measures, all disturbed areas that are not under immediate construction (i.e. areas not under construction within 30 days).

P a g e | 18

Southgate Solar Project DRAFT Stormwater Management Report

All ESC measures should be designed and implemented in accordance with local guidelines and regulations. See also Ontario Provincial Standard Specification (OPSS) 577 “Construction Specifications for Temporary Erosion and Sediment Control Measures”. Throughout the construction phase of the Project, the ESC plan and individual ESC measures should be evaluated for efficacy and modified as required to meet changing site conditions. Proper maintenance and inspection of the temporary erosion and pollution control features is required throughout the duration of the construction phase of the Project. Inspection of all temporary erosion controls is recommended after rainfall events and at least daily during prolonged rainfall. Accumulated sediment should be cleared when 50% of capacity of the protection is reached. All ESC measures should be maintained until a vigorous growth of vegetation is established in the disturbed areas.

P a g e | 19

Southgate Solar Project DRAFT Stormwater Management Report

4.

CONCLUSIONS

Once the project location has been restored and the ground cover re-established, it is anticipated that the total runoff from the project location will decrease. With the reduction in peak flow to the outlets, it is not expected that lands downstream of the Project will suffer a loss of service from the change in flow regimes. No impacts to flooding and erosion are expected for watercourses downstream of the Project under proposed conditions. It is expected that peak flows from the Project location will be diverted around neighboring properties via the use of stormwater conveyance controls, such as enhanced grass swales, in order to prevent alterations to existing drainage characteristics. Stormwater quality control is proposed following a treatment train approach with source and conveyance measures. The proposed source control system is a dense-growing vegetative surface cover and transformer spill containment system. The vegetative cover will allow for removal of suspended solids during overland flow through the grassed areas. Conveyance control is to be provided by enhanced grass swales with rock check dams. To minimize the potential for water quality impairment to receiving waters or sensitive environmental features during construction, an ESC plan will be developed in-detail and implemented prior to and during construction. At this preliminary stage, a number of recommendations are made and may be considered when developing the ESC plan. The plan should include but not be limited to the following: · Installing silt fences (placed at the downslope side of proposed grading activities, proposed stockpile areas, and the site limits) and all necessary erosion control measures prior to commencing construction activities; · Phasing construction, where possible, to limit areas with and the duration of exposed soils; · Using appropriate grading techniques to prevent increased run-off potential and maintain positive drainage; · Stabilizing with vegetation or other erosion and sediment control measures, all disturbed areas that are not under immediate construction (i.e. areas not under construction within 30 days). Based on this preliminary stormwater management assessment, it is expected that the Southgate Solar Project can be constructed with minimal effects to the existing drainage characteristics, provided the recommended mitigation measures are implemented.

Respectfully submitted:

Yena Ahadzie, E.I.T Water Resources

Michael Thompson, P.Eng. Associate

P a g e | 20

Southgate Solar Project DRAFT Stormwater Management Report

APPENDIX A SVCA Meeting Minutes

Southgate Solar Project SVCA Introductory Meeting July 4, 2014

Minutes Southgate Solar LP Saugeen Valley Conservation Authority (SVCA) 1078 Bruce Road 12, South Bruce, ON 10:00am – 12:00pm Attendees: Name Jennifer Petruniak Megan Bellamy Grace Tesa A. Jose De Armas Erik Downing

Organization Dillon Consulting Dillon Consulting Dillon Consulting SSLP SVCA

Acronyms: EIS = Environmental Impact Study EPC = Equipment, Procurement and Construction Contractor PSW = Provincially Significant Wetland REA = Renewable Energy Approval SAR = Species at Risk SSLP = Southgate Solar LP

Position Natural Heritage and Water Lead Southgate Project Coordinator Stormwater Management Lead Manager Manager, Environmental Planning and Regulations

NHA = Natural Heritage Assessment NHIC = Natural Heritage Information Centre SSP = Southgate Solar Project SVCA = Saugeen Valley Conservation Authority SWM = Stormwater Management

1. Overview of the project  Megan provided an overview of the project. Erik indicated that SVCA has had experience with wind projects but that this would be the first solar project within their jurisdiction. The Southgate Solar Project is a proposed 50 MWac solar facility in Grey County and the Township of Southgate.  Erik explained that SVCA’s regulation is text based and that the regulation limit is not available on the website, nor is it mapped (with the exception of some of the urban areas). SVCA generally uses hazard mapping and restrictions related to development are discussed on a parcel by parcel basis. The hazard mapping is available digitally. If Dillon’s field work results in a drainage feature or wetland being mapped that is not shown on the hazard mapping, and SSLP intends to develop within 30 m of it, SVCA would likely visit the area to determine if the drainage feature or wetland would be regulated. Erik Page 1 of 4

Southgate Solar Project SVCA Introductory Meeting July 4, 2014

 







will check if Dillon will need to enter into a data sharing agreement and will provide Dillon with the digital hazard mapping. SVCA has experience with a wind project in the area (Armow). For that project, similar works were bundled into one permit. The stormwater component wasn’t of interest to SVCA for Armow. SVCA has a service agreement with the Township of Southgate to review planning applications. If the Township requests that SVCA review the REA application for SSP, the documents will be reviewed on a technical basis. SVCA is careful to remain neutral about renewable energy projects. SVCA’s technical review of documents would focus on the flooding and erosion components. Dillon explained that the environmental reports for wind and solar are similar, but solar facilities have no moving pieces once built, and SSP will be using fixed panel racking. The REA Regulation requires setback distances of 30 m from unevaluated wetlands and 120 m from PSWs. The REA Regulation identifies streams as permanent or intermittent watercourses. SVCA doesn’t have an approved policy where they regulate for certain features. Instead, SVCA regulates watercourses as a feature with a defined bed and bank that are confirmed on a site-by-site basis. Dillon/SSLP may need to confirm water bodies with SVCA, where SVCA would consider a feature a watercourse, but it is not defined as such under REA. If works are proposed in/adjacent to the regulated feature and a permit is required, the permit would be issued to the actual landowner, or the landowner would need to provide something to SVCA that indicates SSLP is allowed to undertake the works and file a permit on their behalf. The REA Regulation stipulates that no solar panel can be within 30 m of a REA water body (average annual high water mark – top of bank). The only possible exception would be fence or access road. SVCA does not consider fish habitat as part of their technical document review, however they still apply timing windows for water crossings and in-water works from an erosion and sediment control perspective. Timing windows would also be applicable for directional boring. Erik to verify if there are cold or cool water fish habitat areas within the project location.

2. Stormwater Management and Drainage  The SWM and drainage information at this stage in the REA process is high level and would speak to what would be required as the project moves toward detailed design. The exact dimensions/design of culverts and SWM measures would be determined by the EPC prior to construction.  Solar sites typically require only minimal grading and limited changes to land cover. Therefore, there is no impact to peak runoff rates. As part of the REA application, we will develop a stormwater management plan that addresses water quality. The SWM plan generally includes enhanced ditching to convey and treat drainage from less pervious surfaces (e.g. access roads) to an outlet (e.g., watercourse or roadside ditch). Page 2 of 4

Southgate Solar Project SVCA Introductory Meeting July 4, 2014

 





The access roads are typically constructed at grade, to provide a level of service as required by the developer (i.e., not to ensure safe access during extreme events) and are not usually an impediment to flow. Erik indicated that Dillon’s methods for SWM sound reasonable and that he would be interested in understanding the potential effects of runoff to neighbouring houses. Erik understands that design details for crossings would come later prior to construction. If it is demonstrated that a watercourse can be crossed without impacts, it should be easy for SVCA to issue a permit. The level of analysis and details required to secure a permit is dependent on the crossing location/size of the watercourse. Approval by SVCA requires detail design details and analysis. Potential impacts (i.e., erosion and sedimentation) during construction can be greater than during operations. Best management practices (including erosion and sediment controls) during construction and stormwater management during operations are recommended to mitigate any potential impacts. Erik indicated that document review time is variable, but 60 days should be enough to provide a comment letter. Dillon will try to get the draft REA documents to Erik greater than 60 days before the second public meeting. Dillon will let Erik know in advance when the reports are coming.

3. Required Reporting (NHA)  Jen explained the four components of the NHA – Records Review, Site Investigation, Evaluation of Significance and the Environmental Impact Study.  An EIS is done if a proponent wants to develop within 50 m of a significant feature. Similarly for water, an EIS is done if a proponent wants to develop between 30 and 120 m of a significant water body or watercourse. The NHA process doesn’t speak to hazard lands, so Dillon would like to understand what other policies may need to be considered by SVCA if there is anything above and beyond what is required by REA. Erik will follow up with Dillon to identify areas that experienced localized flooding this year.  Erik mentioned that at this stage based on the information provided he is unable to identify “red flag” areas. “Red flag” areas would include new buildings or structures in hazard areas (i.e., typically not permitted activities) and watercourse crossings. If SSLP tries to avoid hazard areas, this would be the best approach. Works within the hazard area, including watercourse crossings require permits and further studies to ensure no negative impacts through mitigation. Dillon to provide GIS files of access road layout and disturbance area as early as possible to facilitate SVCA review.  SVCA does not have designated staff to do NHA inventory, SAR surveys or water surveys. SVCA relies on information available from NHIC. Jen to send Erik the link to the NHIC mapping.  Permit applications could be approximately $1,200 for a project of this size. The Township of Southgate may require a fee for site plan review (up to $500 per property);

Page 3 of 4

Southgate Solar Project SVCA Introductory Meeting July 4, 2014

 

however no fee was charged for the Armow wind project. Erik will confirm if review fees will be bundled with the cost for permit applications. Dillon reminded SVCA that it won’t necessarily be SSLP applying for permits but could be the EPC. The permitting and construction processes for REA often have two separate teams. Erik indicated that the Saugeen Field Naturalist Club is quite active in the area and may have information that could be included as part of the NHA.

4. Action Items Category Action Item Verify if there is cold or cool water fish habitat within the project area. Provide any available information regarding localized flooding in the project area.

Information Requests

Provide digital hazard mapping for the Township of Southgate. Include digital data agreement (if necessary). Provide link to Natural Heritage Information Centre Mapping to SVCA. Confirm any fees related to permitting and/or document review. Update SVCA regarding water survey work if water features are found that may be of interest to SVCA but are not considered “water bodies” as part of the REA regulation.

Page 4 of 4

Responsibility SVCA

SVCA

SVCA

Dillon SVCA

Dillon

Deadline Week of July 14, 2014. Week of July 14, 2014. Week of July 14, 2014. Week of July 7, 2014. Prior to July 31, 2014. Ongoing

Southgate Solar Project SVCA Update Meeting November 12, 2014

Minutes Southgate Solar LP Saugeen Valley Conservation Authority (SVCA) 1078 Bruce Road 12, South Bruce, ON 11:00am – 12:00pm Attendees: Name Michael Enright Jennifer Petruniak Megan Bellamy Yena Ahadzie A. Jose De Armas Erik Downing

Organization Dillon Consulting Dillon Consulting Dillon Consulting Dillon Consulting SSLP SVCA

Position Southgate Project Manager Natural Heritage and Water Lead Southgate Project Coordinator Stormwater Management Support Manager Manager, Environmental Planning and Regulations

Acronyms: NHA = Natural Heritage Assessment SSLP = Southgate Solar LP SVCA = Saugeen Valley Conservation Authority SWM = Stormwater Management

REA = Renewable Energy Approval

1. Recap from last meeting  Dillon provided an overview of what had occurred since the last meeting with SVCA on July 4, 2014 (refinement of Project Location boundary and completion of field studies for the NHA, incorporation of 30 m buffer from water bodies and areas of operational flexibility). SVCA provided a letter that outlined SWM requirements. SVCA will provide a revised version of this letter with the correct address for SSLP. 2. Project Location and Hazard Land Mapping  SVCA will require a site visit for anything within 50 m of hazard lands. Dillon inquired if there were any potential issues from SVCA’s perspective related to the location of the main substation. SVCA indicated their primary concern would be to avoid alteration to the floodplain area and that this would require back up evidence (e.g., if the proponent does not believe the substation is in a flood plain area, hydrology reports would need to be produced to confirm this). A site visit was tentatively scheduled for November 28 to Page 1 of 3

Southgate Solar Project SVCA Update Meeting November 12, 2014



view the substation area and confirm no major issues. SSLP will send an invitation for this visit. Dillon will identify areas of priority for SVCA to visit but the main substation is the top priority. Dillon will send SVCA the water body map with a 50 m buffer applied around the hazard areas. Dillon will also include topography on the mapping as well as a more detailed substation drawing if possible.

3. Update: Stormwater Management  Based on a quick review of the letter SVCA provided, Dillon has already addressed most of their criteria in the preliminary Stormwater Management Report.  The methodology for the SWM Report includes considering outlets under existing conditions and comparing them with outlets under proposed conditions and ultimately comparing the peak flows. The model used analyzes the longest flow path to the prescribed outlet.  SVCA’s preferred approach is to verify the location of catchment areas on the ground but since Dillon has LiDAR data for the site, accuracy is not likely to be a concern. 4. Groundwater Monitoring Program  Dillon explained that a preliminary groundwater monitoring program will take place to establish baseline water quality conditions. Dillon inquired if there were any specific concerns or groundwater controls that they should be aware of. SVCA does not have any specific groundwater controls and confirmed there are no monitoring wells that have been installed in the area. There are groundwater source protection reports for the area that are available online. 5. Permitting Process  SVCA is interested in where the disturbance area is (e.g., where project activities will take place – inside Project Location boundary). SVCA tries to bundle permits wherever possible so only one permit is needed for both the construction and operational stages. SVCA understands that most of these fine details will not be available until the detailed design stage of the project.  Permits are issued to the landowner but SVCA would need indication from SSLP that SSLP can get the permits on behalf of the landowners.  SVCA confirmed that poles and electrical cables that are above ground don’t require permits. SVCA would require timing windows for directional drills (only allowed between June 15 –Sept 30). If cabling needs to be installed under a wetland, it should be installed through boring.

Page 2 of 3

Southgate Solar Project SVCA Update Meeting November 12, 2014

6. Next Steps  Dillon explained the next steps in the REA process (Draft Release of REA documents to municipalities before the end of the year, release to Aboriginal communities and public in the new year, second Public Meeting likely in March 2015).

7. Action Items Category Action Item Provide revised version of letter SWM with correct address for SSLP. Requirements

Site Visit

Mapping

Page 3 of 3

Send invitation for site visit on November 28, 2014. Identify areas of priority for site visit. Provide water body map with 50 m buffer applied around hazard areas. Include topography on this mapping as well. Provide more detailed drawing of substation.

Responsibility SVCA

SSLP Dillon

Deadline As soon as possible. This will need to be included in the project Consultation Report. Week of November 17, 2014. November 24, 2014. November 24, 2014.

Dillon

Dillon

November 24, 2014.

Southgate Solar Project DRAFT Stormwater Management Report

APPENDIX B Catchment Area and Soils Mapping

RD 24 435

41 0

40 5

GATE SOUTH

0 38

435 43 0

41 5

390

42 5

40 0

41 5

40 0

42 0

44 0

41 5

43 5

38 5

SOUTHGATE SOLAR PROJECT

405

385

42 0

16 0.29

435

EX-OUT-E

14

110

42 5

5 44

FIGURE 2 EXISTING CONDITIONS

5 43

44 0

41 5

RD 22

, & Outlet E 430

ATE SOUTHG

, &

Outlet Sub-Catchment Boundary

0 43

Longest Flow Path

415

5 m Contour Project Location

18

Parcel Boundary with Property #

40 5

RD 22

40 5

EX-OUT-G 0.27

0.30

110

49 41 5

, Outlet D & 41 5

41 0

Runoff Coeff.

EX-OUT-A 73 42 0

THGATE 47 SOU

0.33

42 0

EX-OUT-B 0.33

ea

n gee S au tty

er Ri v

43 0

58 43 0

41 5

3 SIDERD

EX-OUT-C 0.24

35

410

HGATE

AD GREY RO

41 5

13

9 SOUT 405

100

200

400

600 m

MAP DRAWING INFORMATION: DATA PROVIDED BY MNR

²

41 5

42 0

0

FILE LOCATION: I:\GIS\149154 - Samsung Southgate\mxd\SWM

, & Outlet C

, &

9

1:15,000

43 0

MAP CREATED BY: GM MAP CHECKED BY: DYA, MKT MAP PROJECTION: NAD 1983 UTM Zone 17N

0 42

40 5

PROJECT: 149154

Outlet B 420

41 0

41 5

0 40

STATUS: DRAFT DATE: 12/2/2014 5 42

40 5

0 39

39 0

425

B

39 0

420

400

40 0

Area (ha)

, Outlet F &

41 0

405

12

Catchment ID

SIDERD

, Outlet A &

EX-OUT-A 0.33 73

430

ed

, Outlet G &

116

42 5

am

0.27 EX-OUT-D

5 43

n Un

38 5

400

erc o W at

11

EX-OUT-F

THGATE 41 SOU

400

Hazard Lands SIDERD

urs e

ATE SOUTHG

41 0

5 40

Permanent Watercourse

19

41 5

41 5

43 0

RD 24 435

41 0

40 5

GATE SOUTH

0 38

435 43 0

41 5

390

42 5

40 0

41 5

40 0

42 0

44 0

41 5

43 5

38 5

SOUTHGATE SOLAR PROJECT

405

385

42 0

16 0.29

435

PROP-OUT-E

14

110

42 5

5 44

FIGURE 3 PROPOSED CONDITIONS

5 43

44 0

, &

Sub-Catchment Boundary

41 5

RD 22

, &

Swale Flow Direction

Outlet E

Fence

430

ATE SOUTHG

Access Road

0 43

Solar Panel Inverter

415

41 5

43 0

RD 22

19

Substation Transformer

41 5

Substation Yard (Point of Common Coupling, Communication Tower)

18

Permanent Watercourse Project Location

40 5

ATE SOUTHG

41 0

5 40

Outlet

40 5

PROP-OUT-G 0.27

110

49

41 5

41 5

41 0

, Outlet D &

Runoff Coeff.

, Outlet F &

41 0

405

12

PROP-OUT-A 73

42 0

THGATE 47 SOU

0.32

42 0

ea

n gee S au tty

er Ri v

43 0

43 0

41 5

3 SIDERD

PROP-OUT-C 0.24

13

35

58

AD GREY RO

41 5

0.32

405

100

200

400

600 m

MAP DRAWING INFORMATION: DATA PROVIDED BY MNR

²

41 5

42 0

0

FILE LOCATION: I:\GIS\149154 - Samsung Southgate\mxd\SWM

, & Outlet C

, &

9

1:15,000

43 0

MAP CREATED BY: GM MAP CHECKED BY: DYA, MKT MAP PROJECTION: NAD 1983 UTM Zone 17N

0 42

40 5

HGATE

PROP-OUT-B

410

9 SOUT

PROJECT: 149154

Outlet B 420

41 0

41 5

0 40

STATUS: DRAFT DATE: 12/2/2014 5 42

40 5

0 39

39 0

425

B

39 0

420

400

40 0

Area (ha)

SIDERD

, Outlet A &

Catchment ID

PROP-OUT-A 0.33 73

430

ed

PROP-OUT-D 0.30

42 5

am

, Outlet G &

Hazard Lands

116

5 43

n Un

38 5

400

erc o W at

11

0.26

THGATE 41 SOU

400

SIDERD

urs e

Parcel Boundary with Property # PROP-OUT-F

D 24 GATE R SOUTH

P.L.I. ZZ

B.L.

Gil

Dos

Dos

16 Bg

SOUTHGATE SOLAR PROJECT

P.L.I.

14 M 2 ATE RD SOUTHG

Bg

FIGURE 4 SOILS

2

Fence Access Road Solar Panel Permanent Watercourse

19

Project Location Project Location 50 m Setback

Hs

Project Location 120 m Setback Project Location 300 m Setback ATE SOUTHG

RD 22

Inverter

M

Dos

Substation Transformer

Parcel Boundary with Property # B.L., BOTTOM LAND Bg, BURFORD LOAM

W at

11

Substation Yard (Point of Common Coupling, Communication Tower)

P.L.I.

erc o

urs e

18

M

n Un

am

Dos, DONNYBROOK SANDY LOAM

ed

Gil, GILFORD LOAM Hs, HARRISTON SILT LOAM Lyl, LILY LOAM M, MUCK P.L.I., PIKE LAKE LOAM SIDERD

P.L.I.

12

ZZ, WATER

THGATE 47 SOU

Lyl M

1:15,000

3 SIDERD

0

B.L.

13

9 SOUT

AD 9 GREY RO

400

600 m

²

MAP CREATED BY: GM MAP CHECKED BY: DYA,MKT MAP PROJECTION: NAD 1983 UTM Zone 17N FILE LOCATION: I:\GIS\149154 - Samsung Southgate\mxd\CPR

SIDERD

Gil

THGATE 41 SOU

A GREY RO

Hs

200

MAP DRAWING INFORMATION: DATA PROVIDED BY MNR

Bg

HGATE

M

100

PROJECT: 149154 STATUS: DRAFT

D 109

P.L.I.

DATE: 12/2/2014

Southgate Solar Project DRAFT Stormwater Management Report

APPENDIX C Hydrologic Modelling Input & V02 Output

Existing Conditions Catchments

Catchment ID

Total Area (ha)

EX-OUT-A EX-OUT-B EX-OUT-C EX-OUT-D EX-OUT-E EX-OUT-F EX-OUT-G

73.1 58.2 35.4 109.8 120.6 115.6 49.1

Long Flow Path Elev Top (m) 2065 1512 854 1420 1380 1692 1189

411.5 425.0 411.5 430.8 429.5 430.8 416.0

Elev 85% Elev 10% 408.8 418.5 410.5 426.5 427.5 429.0 414.5

398.2 405.8 409.7 412.0 413.3 418.0 399.0

Elev Bottom 396.2 402.3 409.5 409.8 414.0 418.0 398.5

Slope 85/10 0.68% 1.12% 0.12% 1.36% 1.38% 0.87% 1.74%

Slope Top to Bottom 0.74% 1.50% 0.23% 1.48% 1.12% 0.75% 1.47%

Ag Lands Row Crops

Paved Roads

59.6 41.2 9.8 70.7 62.2 66.6 31.1

0.0 0.0 0.0 0.0 0.0 0.0 0.0

Area (Ha) Dirt Wetland/Marsh/ Treed Grass/Pasture/M Paved Area (MV Road/Rural Swamp/Open Gravel Road Area/Forest eadow Stations) Residential Water 2.9 5.0 0.7 4.9 0.0 0.0 3.3 2.2 8.6 3.0 0.0 0.0 3.4 10.4 0.0 11.8 0.0 0.0 1.6 24.9 1.9 10.7 0.0 0.0 2.9 20.2 20.8 14.5 0.0 0.0 1.7 23.9 1.0 22.4 0.0 0.0 0.0 6.2 0.2 11.5 0.0 0.0

CN

C 60 59 51 55 59 54 56

Tc- FAA (min) 0.33 0.33 0.24 0.30 0.29 0.27 0.27

129 93 162 89 88 116 78

Tp (hr) 1.43 1.04 1.80 0.99 0.98 1.29 0.87

Proposed Conditions Catchments Area (Ha) Catchment ID

Total Area (ha)

PROP-OUT-A PROP-OUT-B PROP-OUT-C PROP-OUT-D PROP-OUT-E PROP-OUT-F PROP-OUT-G

73.1 58.2 35.4 109.8 120.6 115.6 49.1

Long Flow Path Elev Top (m) 2065 1512 854 1420 1380 1692 1189

411.50 425.00 411.50 430.75 429.50 430.75 416.00

Elev 85% 408.80 418.50 410.50 426.50 427.50 429.00 414.50

Elev 10% 398.20 405.75 409.70 412.00 413.25 418.00 399.00

Elev Bottom 396.20 402.25 409.50 409.75 414.00 418.00 398.50

Slope 85/10 0.68% 1.12% 0.12% 1.36% 1.38% 0.87% 1.74%

Runoff Coefficient, C, for Loams, Silt Loams - flat (