Hydrogeological Investigation Winston Park West, Oakville Ontario Proposed Development planning/da-SU11003... · 2020-05-26 · Norbert M. Woerns, M.Sc., P.Geo. Winston Park West,

Hydrogeological Investigation Winston Park West, Oakville Ontario

Proposed Development

Prepared For : Beacon Environmental

Prepared By: Norbert M. Woerns M.Sc. P.Geo.

Hydrogeologist

February 26, 2008

Distribution 3 Client 1 File

Norbert M. Woerns 96 Lund Street, Richmond Hill, Ontario, L4C 5V9

Ph: (905) 883- 0276

February 26, 2008 Jo-Anne Lane Beacon Environmental. 8 Main St. North Markham, Ontario L3P 1X2 Dear Ms. Lane: Re: Winston Park West, Oakville Ontario, Proposed Development Hydrogeological Investigation

I am pleased to present the attached summary report for the above noted study. Included in this study is the result of a review of available geological and hydrogeological information. Hydrogeological characterization of the site is provided along with a preliminary assessment of impact of the proposed development. Conclusions and recommendations for mitigation of anticipated impacts are provided. I trust the attached report meets your needs at this time. Please call the undersigned at (905) 883-0276 should you have any questions or require additional information. Yours very truly,

Norbert M. Woerns M.Sc., P. Geo. Hydrogeologist Attach:

Table of Contents Letter of Transmittal Page No.

1.0 Introduction …………………………………………………………………….. 1 1.1 Background ………………………………………………………… 1

2.0 Methodology ………………………………………………………………… 1 2.1 Data Review …..….………………………………………………... 2 2.2 Field Investigation ………..………………………………………... 2

3.0 Results ………………………………. ……………………………..…………... 4 3.1 Physical Setting………………………………………….………...... 4 3.2 Geological Setting ………………………………………………..... 4 3.3 Hydrogeological Setting ……………………………………………. 6 3.4 Groundwater Recharge/Discharge ………………………………….. 6

4.0 Pre-development Water Balance ……………………………………………….. 10 4.1 Meteorological Data and Climatic Water Balance …………………. 10 4.2 Infiltration Factors ………………………………………………….. 11

5.0 Post-development Water Balance ………………………………………………. 13 5.1 Proposed Land Uses …………………………………………….. 13 5.2 Water Movement from Impervious Surfaces …………………… 16 5.3 Post-development Water Balance Results ……………………… 17 5.3.1 Area 1 – Water Balance ………………………………….. 17 5.3.2 Area 2 – Water Balance ………………………………….. 18 5.3.3 Infiltration Summary ……………………………………... 19

6.0 Impact Assessment ……………………………………………………………... 20 6.1 Water Balance …………………………………………………... 20 6.2 Private Well Interference ……………………………………….. 20 6.3 Water Quality …………………………………………………… 21

7.0 Conclusions ………………...…………………………………………………… 21

8.0 Recommendations ……………………………………………………………… 22

9.0 References ……………………………………………………………………… 23

List of Figures Page No.

Figure 1 Location Map ……………………………………………………….. 3 Figure 2 Surficial Geology …………………………………………………… 5 Figure 3 Section AA’ and BB’………………………………………………. 7 Figure 4 Section CC’ and DD’………………………………………………. 8 Figure 5 Groundwater Flow…..………………………………………………. 9 Figure 6 Development Concept …..…….……………………………………. 14

List of Tables Page No. Table 1 Water Balance Summary, 1940-2007, Pearson International …..…... 11 Table 2 Average Infiltration Factors – Pervious Areas .……………………... 12 Table 3 Water Balance Existing Conditions ………………………………… 13 Table 4 Proposed Land Uses ………………………………………………… 13 Table 5 Functional Categories for Post-development Land Use …………….. 15 Table 6 Water Balance Summary - Area 1 …………………………………. 17 Table 7 Water Balance Summary - Area 2 …………………………………. 18 Table 8 Summary of Infiltration for Water Balance Analysis ………………. 19

Appendices Appendix 1 Records of Boreholes (Terraprobe, December 2007) Appendix 2 MOE Well Record Summary Appendix 3 Climatic Water Balance Appendix 4 Ontario Building Code, Supplementary Guide SC-6 Appendix 5 Water Balance Analysis

Norbert M. Woerns, M.Sc., P.Geo.

Winston Park West, Hydrogeological Investigation, February, 2008 1

Hydrogeological Investigation Winston Park West, Oakville Ontario

1.0 Introduction 1.1 Background

The Province, under the management of the Ontario Reality Corporation (ORC), currently owns about 94.6 ha (234 acres) of land located in the vicinity of Highway 403 and Upper Middle Road in Oakville, Ontario. The properties include two areas and three parcels of land as shown on Figure 1. The first parcel of land, Area 1, consists of 16.19 ha (40 acres) and is located on the southeast corner of Joshua’s Creek Drive and Upper Middle Road. The second parcel, Area 2, consisting of 11.74 ha (29 acres) is located along the west side of Highway 403 between Upper Middle Road on the south and a gas pipeline corridor on the north. A previous study commissioned by ORC recommended a development concept including mixed uses (residential, commercial and employment) with the majority of uses dedicated to employment. The ORC is seeking to obtain approvals for draft plans of subdivision at the block plan level and severances and amendments to the Official Plan, Secondary Plan and Zoning By-Law for the above noted areas in support of a development concept. ORC would like to concentrate efforts on Area 2. Area 1 A portion of this area including 13.45 ha (33.24 acres) is leased to Creative Golf Projects as a practice golf range and mini-putt facility. The remainder of this parcel, 2.74 ha (6.77 acres) is unoccupied and is comprised of a large dirt pile which is being investigated through an environmental site assessment and remedial work in a separate study. Total development area is 16.19 ha. The proposed development concept includes a mixture of employment and commercial land use. The proposed development will be serviced with municipal sewer and water services. Area 2 This area is comprised of two provincially owned parcels of about 11.74 ha (29 acres). Directly to the west, an adjoining privately held parcel of about 10.12 ha (25 acres) was previously included in the development proposal and has since been removed. The subject property has been used as agricultural lands and consists of cultivated fields. There is a drainage ditch marking the western boundary, a natural gas pipeline along the northern boundary, Highway 403 lies directly east of the property, and Upper Middle Road marks the southern boundary. The proposed development concept includes a mixture of employment and commercial development. The proposed development will be serviced with municipal sewer and water services. 2.0 Methodology The hydrogeological evaluation is in support of a preferred development concept ultimately leading to Draft Plan approval of the development concept. The hydrogeological evaluation includes the following:


1) Assessment of the hydrogeological setting through secondary source information, on-site subsurface investigations, and a reconnaissance site visit and identify areas where infiltration can occur and areas where site conditions limit or preclude infiltration,

2) Quantification of the existing groundwater recharge contributions through an appropriate long term water balance assessment,

3) Assessment of the potential groundwater contributions to nearby Joshua’s Creek, 4) Preliminary impact assessment to quantify the potential change in groundwater quantity on-site and

the effects on adjacent streams and the potential for affecting groundwater users, 5) Screening of infiltration mitigation measures based on available site information collected through

background sources and field work, and 6) A mitigation strategy including appropriate infiltration measures where necessary. This investigation does not include an assessment of the contamination potential of on-site fill materials or the dirt pile within Area 1. 2.1 Data Review Available geological and hydrogeological maps and reports of the area were obtained and reviewed to provide a characterization of the site in the context of the local and regional setting. Stereo air photography obtained from Northway Maps for the property and examined to determine site terrain conditions. Previous subsurface investigations recently completed on the property by Terraprobe Limited as well as Ministry of the Environment well record summaries for the area were reviewed and utilized to characterize local groundwater conditions. Details of the proposed development including a detailed breakdown of the area of land use categories with percent pervious and impervious areas for each proposed land use on the property were provided by Planning Alliance. This information was taken from a conceptual development plan. The resulting water balance analysis is therefore considered to represent a preliminary assessment. Monthly climatic information and a climatic water balance based on climatic data from the nearest long term climate station was provided by Environment Canada, Meteorological Service of Canada. 2.2 Field Investigation Field investigation was limited to a reconnaissance site visit on February 12, 2008. Access to the properties was limited and the properties were snow covered at the time of the site visit. Drilling of a total of eight boreholes was completed in December 2007 by Terraprobe Limited. Three boreholes, BH 1, BH 2, and BH 3, were completed in Area 1, three boreholes including BH 4, BH 6, and BH 8, were completed in Area 2, and two boreholes, BH 5 and BH 7, were completed in the adjacent private property on the west side of Area 2 which is no longer part of this study. Groundwater monitors were installed in all boreholes except BH 6 and BH 7. Description of the drilling techniques used, soil sampling, and groundwater monitor installations, are described in the Preliminary Geotechnical Investigation by Terraprobe Limited, January 25, 2008. A copy of the boreholes logs from the Terraprobe report are attached in Appendix 1.


Winston Park West Location Plan

Figure 1

February 2008

Norbert M. Woerns 96 Lund Street Richmond Hill, Ontario L4C 5V9 Ph: (905) 883-0276


NN

0 250 500 750 1000

Scale in Metres

Legend

Area 2

Area 1

Property Boundary

MOE Well No. and Location

Borehole No. and Location(Terraprobe 2007)

Geological Cross Section AA’

2291

2292

6701

23612359

2288

5857

5858

5888

5859

2357

5881

2358

2283

2291

5880

5008

5008

5286

23623594

2360

2356

2355

2354

5884

5882

5883

5853

55555421

2287

7499

6789

BH8

BH7

BH5

BH5

BH2

BH1

BH4

BH3

BH6

2286

2285

2289

2290

8467

3675

7995

2284

A

A’

B

B’D’

D

C

C’

l

d

Upper

Mid

de

Roa

East

e

g

Que

en E

lizab

th H

ihw

ay

Upp

Mi

dl

Rd

erd

eoa

Josu

s Cr

ekrive

ha’

e D

a

Dun

dsS

treet

(Hwy

5)

A’

A

Ford Drive

(Topographic Base Map fromFirst Base Solutions Inc.)

3


3.0 Results 3.1 Physical Setting The two sites are located within the south slope physiographic region (Chapman and Putnam, 1984). Both sites are within a shale plain with relatively thin soil cover over shale bedrock. The northernmost site, Area 2 is relatively flat with a gentle slope to the south with a drop in elevation from about 164 mASL to about 144 mASL. This site is drained primarily by overland flow with a small drainage ditch along the western property boundary. There are no permanent streams on this property. The extent to which the drainage ditch contains flowing water on an annual basis is not known. No flow was observed in this drainage channel on February 12, 2008 although snow cover may have obscured any possible flow at this time. The surface topography of the southerly site, Area 1 has been substantially modified through grading to accommodate the golfing facilities. The topography generally slopes in an easterly direction from an elevation of about 140 mASL at the western corner at Joshua’s Creek Drive and Upper Middle Road East to about 125mASL at the eastern edge of the site. Joshua’s Creek crosses the northern edge of the site where Ford Drive meets Ninth Line. Joshua’s Creek was observed to have substantial flow during the site visit February 12, 2008. The channel was partly frozen along its edges however a channel width of between two to four metres and a water depth of about 15 cm was observed. A small intermittent drainage channel is shown on the topographic base map flowing in an easterly direction in the southern portion of the property. The forested slope west of the site showed minor seepage that drains eastward toward Area 1. 3.2 Geological Setting Bedrock Geology The underlying bedrock consists primarily of red shale of the Queenston Formation and the grey and green shale and limestone of the Georgian Bay Formation (Telford, P.G. et.al., 1976). Outcrops of the Georgian Bay formation occur along Joshua’s Creek in the northern portion of Area 1. Elsewhere there is a thin cover of soil overlying the bedrock. According to MOE well record information, Georgian Bay Formation underlies Area 1 and low lying areas to the south of Area 1 with the presences of blue and grey shale and grey dolostone. Surficial Geology The thickness of surficial overburden deposits within the area is relatively thin between about 0.5m to 4.5 m thick within the boreholes completed on the two properties. Surficial soil consists primarily of clayey silt which is locally overlain by between 0.5 to 0.7 m of sandy silt. Surficial geological mapping of the southern part of the site was completed by Karrow, 1987 and the northern part of the property was mapped by Karrow and Easton , 2005 as shown on Figure 2. Area 1 is located within an area of surficial deposits mapped as shale and dolomite bedrock. A large pile of soil at the southern end of Area one rises about 15 m above the surrounding area. The source of this material is not known but may have been derived from the grading that has occurred on the remainder of the property or is possibly from construction activities that have occurred locally.


Figure 2 Surficial Geology

Winston Park West -ORC Oakville Proposed Development

Norbert M. Woerns 96 Lund Street, Richmond Hill, Ontario, Ph (905) 883- 0276

N

February 2008

LegendNorth South

Stream DepositsStream Deposits

Lacustrine/Outwash Sand Lacustrine/Sand

Lacustrine, Silt/clay

Beach Gravel Beach Gravel

Halton Till, Clay/silt

Halton Till, Clay/silt Bedrock, Shale/dolomite

Bedrock,Shale/dolostone

(from OGS Map, 2223) (from OGS Map, 2509)

Area 2

Area 1

Property boundary

N

0 1 2

Scale (km)

5


Shallow subsurface conditions were determined by Terraprobe Limited with the completion of eight boreholes to depths of between three to six metres. Borehole and water well locations are shown on Figure 1. The subsurface stratigraphy is illustrated in geological cross sections shown in Figures 3 and 4. The local subsurface conditions are illustrated in Section AA’ and Section BB’, on Figure 3. Information shown is taken from Ministry of the Environment (MOE) well record information as summarized in Appendix 2. Most well records show fine grained soil at surface locally described as red, brown, and grey clay. These units are interpreted as glacial till deposits and/or weathered shale bedrock which vary in thickness between about 1.2 m to 11 m. A buried gravel deposit encountered at a depth of 8.5 m to 8.8 m in well no. 6701 located west of Area 2. On-site subsurface stratigraphy is illustrated in Section CC’ and Section DD’, Figure 4. Boreholes completed in Area 1 shows surficial deposits consisting of sandy silt and clayey silt 1.8 m to 4.0 m thick. A thin layer of 0.7 m of sandy silt occurs at surface in the eastern and southern portion s of the property. This is underlain by a clayey silt layer that covers the entire site. Reddish brown shale underlies the clayey silt layer. A dirt pile up to about 15m thick is located at the southern end of the property. No boreholes were completed into this material to confirm its composition. It is understood that this will be the subject of separate investigations. Boreholes completed in Area 2 indicate that the property is underlain by a thin layer of surficial deposits consisting of sandy silt and clayey silt between 0.5 m and 4.0m thick. Air photos of the property indicate that grading of the property has occurred and preliminary roadbed preparation has occurred with the localized placement of sand and gravel base material as found at Borehole 8 (see Appendix 1). Area 2 is underlain by reddish brown shale of the Queenston Formation. 3.3 Hydrogeological Setting Hydrogeological conditions are shown on the four sections noted above. Groundwater levels within local wells vary between about 7.6 m to about 1.2 m. Groundwater elevations generally reflect the surface elevations. Groundwater flow is therefore interpreted to flow toward the southeast with local flow toward Joshua’s Creek. Groundwater elevation contours and inferred groundwater flow directions are shown on Figure 5. Well records show that most wells are completed into the shallow bedrock and vary in depth between about 8 m to about 35 m. Well yields are generally less than 0.38 L/sec and are most wells are in the range of 0.076 L/sec to 0.15 L/sec. A few wells were tested at rates in the range of 1.5 L/sec and 5.3 L/sec. The bedrock aquifer generally produces relatively small quantities of water. Water quality is generally reported as ‘fresh’ in the well records but is occasionally reported as salty’. The bedrock aquifer appears to be marginally suitable for domestic use in quantity and quality. Water use is reported to be primarily for domestic use although minor industrial, commercial, public supply and stock watering use is also reported in the well records. 3.4 Groundwater Recharge/Discharge Water levels as recorded in local wells and in the on-site boreholes indicates that the area is primarily a groundwater recharge area. Groundwater levels are generally within the range of one to nine meters below surface. Locally within streams groundwater discharge conditions are expected to occur. This is


Winston Park West Cross Sections AA’ and BB’

Figure 3

February 2008



0 250 500 750 1000

Horizontal Scale in Metres(vertical exaggeration 1:16 approx.)

7

LegendA’

ASouthwest

Northwest

Northeast

Southeast

Elev.(mASL)

Elev.(mASL)

Elev.(mASL)

Elev.(mASL)

Elev.(mASL)

922

2

2354

822

1

822

1

822

3

55

83

523

9

822

8

557

8

7995

8467

29

20

28

29

259

3

623

0

508

0

553

8

39

54

254

1

6701

822

6

150

160

150

160

140

130

120

110

100

90

110

120

130

140

150

160

170

140

130

120

110

100

90

110

120

130

140

150

160

shale red

clay

clay

clayclay

clay clay

clay

clayclay

clay

clay

shale blue

clayclay

gravel

clay

clay,redclay,red

clay

clayclayclay

shale red

shale red

shale red

shale red

shale red

shale red

shale red

shale red shale

red shale red

shale red shale

red

shale red

shale red

shale red

shale grey

shale grey

shale/dolostone grey

dolostone grey

shale grey

shale grey

shale blue

12.2

12.2

1.2

1.2

27.4

31.7

3.0

7.6

17.7

22.6

18.3

25.911.6

8.5

8.8

13.1

1.8

2.1

7.6

35.4

10.7

2.4

12.2

29.9

3.76.1

17.7

18.9

6.1

22.9

18.6

5.8

30.5

28.3

29.6

7.0

7.9

10.7

15.2

3.7

11.0

2.7 6.1

2.1

3.4

Area 1

Area 1

Area 2

Area 2

5002500 750 1000

Horizontal Scale in Metres(Vertical Exaggeration 1 : 16 approx.)

QWE

HYW

.

QEW

YW

.H

Section AA’ Looking Northwest

Section BB’ Looking Northeast

B

B’

MOE Well No.

Water LevelGeological Contact

Depth(metres from surface)

Groundwatersurface(interpreted)

Elevation(meters above sea level)

Groundwater Flowdirection(inferred)

2.4

Figure 4Sections CC’ and DD’

Winston Park West - ORC Oakville Proposed Development


February 2008

165

160

155

160

155

150

145

140

145

140

135

130

125

120

150

145

140

165

145

140

135

130

125

120

Elev.(mASL)

Elev.(mASL)

Elev.(mASL)

Elev.(mASL)

C’

D’

C’

D’Area 1

Area 2(Northwest) (Looking Northeast)

(Looking North and East)

(Southeast)

BH

8

BH

4

BH

2

BH

2

BH

1

Up

pe

r M

idd

le

Ro

ad

Ea

st

Up

pe

r M

idd

le R

oa

d

East

Josh

ua

’s C

ree

k D

rive

BH

3

BH

6

0.7

0.7

1.8

5.8

5.8

1.84.0

6.1

0.7

5.8

5.3 shale, reddish brown

shale, reddish brown




sandy silt

sandy silt

Dirt Pile

sandy silt

sandy silt

clayey silt

clayey silt

clayey silt

clayey silt

4.0

0.5

2.9

1.0

(133.5 mASLJan 10/08)

(157.4 mASL Jan 10/08)

(144.8 mASLJan 10/08)

(123.1 mASLJan 10/08)

(127.3 mASLJan 10/08) 5.8


(dry)

0 250

Horizontal Scale (m)

(Vertical Exaggeration approx. 2.3 times)

Legend

Borehole BH2

Depth (m)Geological Contact

Water Level

Groundwater Surface (interpreted)

8

Figure 5 Groundwater Flow



N

February 2008

Legend

Well Location

Groundwater Level Elevation(metres above sea level)

Borehole Location

Groundwater Elevation Contour(Interpreted)

Groundwater Flow Direction(Interpreted)

Area 2

Area 1

Property boundary

N0 250 500

Scale (metres)

145.1

145.1

128.6

127.3127.7

133.5

0

145.

140.0

150.0

0155.

155.0

(NA)

126.5126.2

127.7

100.1

129.9

310.

0

215.

0

120.0

120.0

351.0

410.

0

145.

0

510.

0

120.4

(NA)

152.9

126.3

123.1

125.0

013

.0

140.0

131.0

(NA)

129.5

132.3

(NA)

(NA)

134.8

144.8

132.6

(NA)

137.9

138.9

(NA)

144.3

148.8

148.9

(NA)

(NA)

157.4

145.1 150.3

144.8

151.2151.2

150.0

9

139.6


evidenced with the occurrence of watercress at localized locations within surface water drainage channels and Joshua’s Creek (Beacon Environmental, 2008). The mean hydraulic conductivity of the Queenston shale bedrock is 2.3E 10-6 m/sec and as low as 6.0E 10-9 m/sec. The mean hydraulic conductivity of the Georgian Bay Formation is 5.1E 10-6 m/sec and as low as 6.0E 10-9 m/sec as reported by Ostry (1979). Due to the relatively poor aquifer characteristics of the underlying shale bedrock, the amount of discharge is expected to be restricted and very localized. The surficial soil consisting mostly of silt clay has low permeability with a limited groundwater recharge potential. Typical recharge rates for the silty clay soil are in the range of 100 mm/yr or less (MOEE 1995). Recharge rates could vary depending upon the density of the soil, the degree of weathering and local topographic conditions. The mean hydraulic conductivity of the till, clay, and silt soil of the Oakville area is 6.8E 10-6 m/sec with a range of values from 2.3E 10-7 to 2.2E 10-5 m/sec (Ostry 1979). Maintenance of the recharge and discharge functions of the property, and maintenance of the groundwater movement under the site, is important in maintaining the ecological health of the local down stream aquatic and wetland/terrestrial habitats. The recharge function of the two properties is considered to be limited by the fine grained surficial soils and the poor aquifer characteristics of the underlying shale bedrock. 4.0 Pre-Development Water Balance 4.1 Meteorological Data and Climatic Water Balance Long term meteorological data from the Pearson International Airport Meteorological Station (43º67’N, 79º60’W) was used to prepare the water balance. The data from this station was selected as it represents the longest period of record available locally and is considered representative of long term climatic trends for the area. These data include temperature and precipitation data for the period between 1940 and 2007. The mean annual water surplus was calculated using the method described in Thornthwaite and Mather (1957). These data were tabulated on a monthly basis which is summarized in Appendix 3. Soil moisture storage of 200 mm/yr is assumed for medium rooted plants including cultivated crops such as corn and soy beans. This is considered representative of in relatively fine grained silty clay surficial soils found on the property as documented in subsurface soil investigations. A summary of the climatic water balance for existing conditions is provided in Table 1 below. This table shows average conditions from the meteorological data for medium rooted plants. Area 2 consists entirely of agricultural fields which in the current condition are represented as a pasture. Existing land use in Area 1 consists of fairways, greens and open space related to golf facilities. Pre-development conditions for Area 1 are assumed to be similar to Area 2. For purposes of the water balance soil moisture of 200mm/yr has been used to represent the predominant cover type and soil texture. Total annual surplus is the amount of water available after evapotranspiration has occurred. Evapotranspiration is the largest component of the water balance, 584 mm/yr for areas of medium rooted plants such as pasture and cultivated agricultural crops. The remaining surplus of 188 mm/yr is available for runoff and infiltration. The predevelopment climatic water balance is summarized below:



Table 1 Water Balance Summary 1940 – 2007, Pearson International Airport, Ontario Soil Moisture

Precipitation(mm/yr)

Potential ET (mm/yr)

Actual ET (mm/yr)

Surplus (mm/yr)

Soil Moisture 200mm/yr (medium rooted plants - silty clay) 772 622 584 188

Notes : Data from Meteorological Service of Canada, October 2007

ET – Evapotranspiration Numbers rounded off The potential evapotranspiration is the amount of evapotranspiration that could take place if there was sufficient precipitation available during the drier summer months. This becomes relevant where runoff from impervious surfaces is directed to pervious areas under post-development conditions as discussed below. There are no significant areas of standing water on the property and no storm ponds are included in the development concept. Pond evaporation is therefore not significant and has not been factored into the pre- and post-development water balance. 4.2 Infiltration Factors The partitioning of the water surplus between runoff and infiltration depends upon soil type, topography and cover type. Water infiltrates relatively easily through sands compared to clay. Flatter slopes tend to promote infiltration over steeper slopes and naturally vegetated areas promote infiltration over bare soils and urban areas. Infiltration factors take into account these main factors in estimating the amount of infiltration that will occur under given site conditions. Infiltration factors were calculated according to a method cited in MOEE (1995), and MOE (2003). Infiltration factors were calculated by summing individual sub-factors representative of the topography, soil type, and cover conditions. Area 2 has relatively uniform site conditions across the property. Infiltration factors reflect typical or average conditions. The topography is gently sloping at an approximate rate of about 16m /km. An average sub-factor of 0.15 is assigned to the topography. Some flattening of the topography is anticipated under post-development conditions from minor localized grading. For purposes of the water balance analysis, the post-development topography is assumed to remain unchanged with the application of the same infiltration sub-factor. Surface soil conditions are relatively uniform across the site with a thin layer of clayey silt to silty clay underlying most of the property. Locally at Borehole 6 there is a very thin layer of sandy silt. The



hydraulic conductivity of the surface layer of clayey silt to silty clay silt was estimated to be in the range of 1.0E-09 m/s to 1.0E-10 m/s (Freeze and Cherry, 1979). Shallow weathered soil typically has hydraulic conductivities significantly greater than unweathered soil. Mean hydraulic conductivities of till, clay and silt soil within the Oakville Creek area is 6.79 E -6 m/s (12 Igpd/ft2) as reported by Ostry (1979). l The equivalent soil percolation rate for the clayey silt to silty clay (ML to CL soil classification) is estimated in the range of 30 mm/hr to less than 12 mm/hr (20 min/cm to greater than 50 min/cm) as per Supplementary Guide SG-6 of the Ontario Building Code 1997 (Appendix 4). Infiltration measures such as infiltration trenches, soakaway pits and pervious pipe infiltration systems require a minimum percolation rate of 15mm/hr (MOE, 2003). The clayey silt to silty clay are considered to be unsuitable for infiltration trenches and pervious pipe infiltration systems. An infiltration sub-factor of 0.15, representative of the surficial clayey silt to silty clay soil was selected for pre-development conditions. Grading of the property and compaction of the soil due to heavy equipment movement may reduce the infiltration capability of the surficial soil until weathering processes and the action of roots from vegetation restore the pre-development conditions. As a conservative measure, a slightly lower infiltration sub-factor for the soil component of 0.10 has been selected to account for the reduced infiltration capacity under post-development conditions. Pre-development cover conditions consist predominantly of cultivated fields with agricultural crops such as corn and soybeans which are characterized as containing plants with roots of moderate depth. This cover type is assigned an infiltration sub-factor of 0.1. The change in cover type from cultivated crops to urban lawns will result in a slight increase in runoff and a reduced infiltration factor of 0.05. Summation of the infiltration sub-factors for the study area provides an infiltration factor of 0.40 for the property under pre-development conditions. This will be reduced slightly under post-development conditions to 0.30 due to the change in soil compaction and the change in cover type from cultivated fields to manicured lawns. These infiltration factors are consistent with the Base Flow Index for the area (Moin and Shaw, 1986) which indicates 0.3 to 0.35 of the water surplus is accounted for as stream base flows for this area. The Moin and Shaw analysis is based upon stream flows which are influenced by a wider variety of soil conditions within the stream catchment areas. Infiltration factors for the site under pre-and post-development conditions are summarized in Table 2.

Table 2. Average Infiltration Factors – Pervious Areas * Represents Compaction under Post Development Conditions

Sub Factors Description Pre-Development (Cultivated Fields)

Post-development (Urban Lawns)

Topography 0.15 0.15 Soil silt/sandy, clayey, silt till 0.15 0.10* Cover Cultivated/Lawns 0.10 0.05 Total 0.40 0.30

The pre-development water balance calculated for average annual conditions is summarized in Table 3.



Evapotranspiration is the largest component of the water balance representing about 75.7% of the total precipitation under pre-development conditions. The remaining water surplus represents about 24.3 % of total precipitation. Under pre-development conditions 40 % of the water surplus, will infiltrate according to the infiltration factors. The remaining runoff will constitute 60% of the surplus. Under post-development conditions, 30% of the water surplus will infiltrate and 70% will runoff.

Table 3. Water Balance - Existing Conditions

Area

(ha) Precipitation

(m3/yr) Evapotranspiration (m3/yr)

Infiltration (m3/yr)

Runoff (m3/yr)

Area 1 16.19 124,986.80 94,549.60 12,174.88 18,262.32 772 mm/yr 584 mm/yr 75.2 mm/yr 112.8mm/yr % of Total Precip. 100% 75.7% 9.7% 14.6% Area 2 11.74 90,632.80 68,561.60 8,828.48 13,242.72 772 mm/yr 584 mm/yr 75.2 mm/yr 112.8mm/yr % of Total Precip. 100% 75.7% 9.7% 14.6%

* Numbers rounded off Precip = Precipitation 5.0 Post-development Water Balance The distribution of water under post-development conditions was modeled for the proposed development. Post-development conditions were compared to pre-development conditions specifically with respect to changes in infiltration, runoff, evapotranspiration and evaporation. The water balance analysis also addresses measures that will promote the maintenance of groundwater recharge under post-development conditions. 5.1 Proposed Land Uses Details of the proposed development were based upon a conceptual development plan provided by Planning Alliance. The proposed development plan includes a mixture of employment lands and arterial commercial development. A number of development options are being considered therefore a generic water balance analysis has been completed. It is assumed that the proposed land uses cover the majority of the properties unless otherwise indicated within the development concept. Typical impervious coverage was assigned to each land use categories. The proposed land use areas were estimated from the development concept plan and are summarized in Table 4 below. Table 4. Proposed Land Uses

Land Use Area 1 (ha) Area 2 (ha) % Impervious* Employment (Prestige) 4.25 3.41 70 Employment (General) 9.55 2.68 80 Commercial (Arterial) 0 1.10 80 Open Space (easement/natural area) 0.77 3.38 0 Road Right of Way 1.62 1.17 70 Total 16.19 11.74

Note: * Data represent typical values.


Figure 6Development Concept



February 2008

(Modified From Planning Alliance)

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AREA 1

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a

Ninth Line Road

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4

Hi hy

03

Q

ue

en

Eliz

ab

eth

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Joshua’sreek

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.The percent imperviousness of each land use category was taken as typical values based upon previous experience. The Arterial commercial and general employment areas typically have impervious coverage in the range of 60 to 90%. A conservative value of 80% impervious cover has been selected. The prestige employment areas are considered to have slightly more open space with an estimated impervious cover of 70%. Road areas also have varying impervious coverage depending upon the arrangement of sidewalks ands boulevards. A typical value of 70% has been selected for impervious road coverage to include sidewalks and driveway entrances. In Area 1 open spaces include lands associated with Joshua’s Creek. In Area 2, open space areas include easements potential lands required for MTO as shown on Figure 6. It is assumed that all open spaces will have no impervious surfaces. The MTO lands are likely to be shoulder areas adjacent to paved surfaces. The change in land use with the proposed development will result in the creation of impervious surfaces through the creation of roof areas and paved surfaces. This will affect the water balance by redistributing the infiltration, runoff and evapotranspiration. Without any mitigation measures, runoff will increase while the infiltration and evapotranspiration will decrease. In order to account for the movement of water on the property under post-development conditions, three functional categories, pervious, impervious connected, and impervious disconnected, were defined. The pervious category assumes that the surplus water will runoff or infiltrate according to the appropriate infiltration factors. Runoff from pervious surfaces will ultimately flow into the storm water management system. The ‘Impervious Connected’ areas are those impervious surfaces that are connected to or drain directly into storm sewers. These consist primarily of roadways but may also include portions of the residential areas including the roof areas and driveways. Concrete sidewalks are also considered to be connected to the storm sewer system. This is a conservative assumption since some of the runoff from sidewalks will find its way onto the adjacent grassed boulevards and provide opportunities for infiltration. ‘Impervious Disconnected’ areas are impervious surfaces such as roof areas that are disconnected from the storm water system with runoff from these areas directed onto pervious surfaces. Functional categories are summarized in Table 5. Table 5. Functional Categories for Post - Development Land Use

Pervious** Impervious** Land Use Category % Connected % Disconnected %

Employment (Prestige) 30 30 - 70 0- 40 Employment (General) 20 45 - 80 0 - 35 Commercial (Arterial) 20 45 - 80 0 – 35 Road Right of Way 30 100 0 Open space 100 0 100 Average (Area 1) 72.6* Average (Area 2) 53.1*

* Average Calculated from Water Balance ** Percentage expressed as % of total land use category area



The residential areas shown in Table 5 above indicate a range of connected and disconnected impervious areas. This reflects different development scenarios used in the water balance analysis which are calculated in a spreadsheet format in Appendix 5. 5.2 Water Movement from Impervious Surfaces The surplus water for both pervious and impervious surfaces is partitioned for the various land uses in the post-development water balance. Paved surfaces such as driveways and parking area shed water relatively rapidly. These are relatively flat surfaces with very gentle slopes toward catch basins that lead directly to storm sewers. A runoff factor of 0.85 is used for these areas to account for minor depression storage of water and evaporation. The remaining 15% is assumed to be lost to evaporation. Sloped roofs typical of residential units will have less opportunity for depression storage and more rapid runoff of precipitation. Sloped roofs are therefore given a runoff coefficient of 0.9 with the remaining 10% lost to evaporation. Flat roofs are treated similar to paved parking areas and driveways. All developments proposed for this project are assumed to have flat roofs. Runoff factors are consistent with commonly accepted runoff coefficients for urban areas (MTC Drainage Manual, 1984). In pervious areas, infiltration and runoff are partitioned according to soil type, topography, and cover as described in Section 2.2 and summarized in Table 2 above. Precipitation and evapotranspiration as well as pond evaporation components are provided by Meteorological Service of Canada (MSC). Where runoff from roof areas is directed onto pervious areas, there will be additional water available for infiltration, runoff, and evapotranspiration. In these instances the roof runoff is assumed to be directed either to the storm sewer or to pervious surfaces for infiltration after accounting for15% evaporation loss from the typical flat roof of a commercial building. As a mitigation measure, roof runoff can be directed onto pervious surfaces such as lawns. The additional roof runoff added to the normal precipitation was used to calculate an ‘effective precipitation’ for the pervious areas receiving this water. Roof runoff was used to calculate the amount of ‘effective precipitation’ that would be available for infiltration. The resulting effective precipitation was partitioned using a Thornthwaite and Mather (1957) analysis provided by the MSC. It was assumed that the distribution of the effective precipitation was proportional to the normal monthly precipitation. The resulting surplus water from this analysis was then modeled to either infiltrate or runoff using the post-development infiltration factor. The ‘effective precipitation’ was used to calculate a theoretical surplus using the potential evapotranspiration as the upper limit of evapotranspiration. The ‘effective precipitation is the amount of water directed onto pervious surfaces that includes the normal precipitation plus any additional water directed from rooftops. Surplus water was calculated by subtracting the theoretical evapotranspiration from the effective precipitation. Infiltration was calculated on the resulting surplus by applying an infiltration factor to the surplus. A maximum infiltration value is based upon the soil hydraulic conductivity. The mean hydraulic conductivity of the weathered shallow silty clay soil, estimated to be in the order of 6.8E-06 m/s (Ostry, 1979) was used as a guide to establish a maximum theoretical infiltration. This hydraulic conductivity suggests the weathered soil has a potential infiltration capacity in excess of 60 m/yr assuming a porosity of about 0.3. Assuming a worst case hydraulic conductivity of 2.3E 10-7 m/sec for the silty clay soil, the maximum theoretical infiltration is about 2 m/yr. Under a worst case scenario in the water budget analysis it was estimated that the soil would be required to infiltrate less than 0.5m /yr. This indicates that average soil conditions on the property are capable of infiltrating the surplus water calculated from the effective precipitation values.



It is intuitively recognized that excess water generated from roof runoff may not infiltrate as efficiently as under normal precipitation conditions due to higher peak runoff volumes. There is no established method to accurately account for this loss of efficiency in infiltration. One method used in previous studies proposed a reduced infiltration factor for incrementally higher volumes of water directed onto pervious surfaces. In these studies relatively minor changes to infiltration were observed for values of additional water that are less than twice the normal precipitation. In the current analysis, the additional water directed onto pervious areas is in the order of two to three times the normal precipitation. The control of roof runoff through roof top storage and release of roof runoff over a long period of time will minimize this effect. It was therefore not considered necessary to adjust the infiltration factor for the effective precipitation. 5.3 Post-development Water Balance Results The water balance analysis for post-development conditions for the proposed development on the Winston Park West properties was completed by considering two development scenarios to assess the impact of the proposed development. The result of this analysis is presented in spreadsheets in Appendix 5. 5.3.1 Area 1 – Water Balance A summary of water balance changes is provided for Area 1 in Table 6.

Table 6 Water Balance Summary – Area 1

Area 1 Pre-Development

Post-development Change

(m³/yr) (m³/yr) (m³/yr) % Scenario 1 Infiltration 12,175 2,978 -9,197 -75.5 Evapotranspiration 94,550 37,960 -56,590 -59.9 Runoff 18,262 84,041 65,779 360.2 Scenario 2 Infiltration 12,175 14,122 1,947 16.0 Evapotranspiration 94,550 40,170 -54,380 -57.5 Runoff 18,262 70,687 52,425 287.1

Scenario 1 Initially it was assumed that under worst case conditions, all runoff from roofs and impervious surfaces would be directed to the storm water system via storm sewers. The results of this analysis indicate a loss of infiltration of 9,197 m3/yr. This represents a reduction of about 76% from pre-development conditions. The loss of infiltration is equivalent to a flow of 0.29 L/sec. Pre-development infiltration represents 9.7 % of total precipitation compared to post-development infiltration of 2.4 % of total precipitation. Evapotranspiration was also reduced by 37,960 m3/yr about 60% lower than pre-development conditions. These changes resulted in a significant increase in runoff of about 360 % over pre-development conditions.



Scenario 2 Subsequent analysis considered different methods to promote infiltration. Directing runoff from roof areas onto the pervious surfaces was found to be an effective and practical method. Scenario 2 of the water balance analysis included all roof areas directed to grass areas. The calculated result indicates that there will be a significant improvement in the groundwater infiltration such that there will be an increase in infiltration under post development conditions of about 16 %. This represents an increase of about 1,947 m3/yr over the entire property which is equivalent to 0.06 L/sec. The Scenario 2 analysis relies upon surface runoff from roofs being directed onto pervious surfaces. It is assumed that the roof runoff could feasibly be directed toward pervious surfaces. This additional runoff is assumed to infiltrate according to the infiltration factors as discussed in Section 4.2. This takes into account the slightly reduced infiltration potential of the pervious areas due to soil compaction from construction activities. 5.3.2 Area 2 – Water Balance A summary of water balance changes is provided for Area 2 in Table 7.

Table 7 Water Balance Summary – Area 2

Area 2 Pre-Development

Post-development

Change

(m³/yr) (m³/yr) (m³/yr) % Scenario 1 Infiltration 8,828 3,383 -5,445 -61.7 Evapotranspiration 68,562 38,487 -30,075 -43.9 Runoff 13,243 48,794 35,551 268.5 Scenario 2 Infiltration 8,828 9,068 240 2.7 Evapotranspiration 68,562 39,637 -28,925 -42.2 Runoff 13,243 41,928 28,685 216.6

Scenario 1 Similar to Area 1, it was assumed that under worst case conditions, all runoff from roofs and impervious surfaces would be directed to the storm water system via storm sewers. The results of this analysis indicate a loss of infiltration of 5,445 m3/yr. This represents a reduction of about 62% from pre-development conditions. The loss of infiltration is equivalent to a flow of 0.17 L/sec. Pre-development infiltration represents 9.7 % of total precipitation compared to post-development infiltration of 3.7 % of total precipitation. Evapotranspiration was also reduced by 30,075 m3/yr about 44% lower than pre-development conditions. These changes resulted in a significant increase in runoff of about 268 % over pre-development conditions. Scenario 2 Scenario 2 of the water balance analysis for Area 2 included all roof areas directed to grass areas. The calculated result indicates that there will be a significant improvement in the groundwater infiltration such that there will be an increase in infiltration under post development conditions of about 3 %. This represents an increase of about 240 m3/yr over the entire property which is equivalent to 0.01 L/sec.



The Scenario 2 analysis relies upon surface runoff from roofs being directed onto pervious surfaces. It is assumed that the roof runoff could feasibly be directed toward pervious surfaces. This additional runoff is assumed to infiltrate according to the infiltration factors as discussed in Section 4.2. This takes into account the slightly reduced infiltration potential of the pervious areas due to soil compaction from construction activities. 5.3.3 Infiltration Summary The surficial soil units consist predominantly of silty clay with minor local areas of sandy silt. Infiltration trenches are considered to be unsuitable for these soil conditions. The local groundwater table is near surface locally and may provide seasonally high conditions that limit groundwater infiltration. Monitoring of groundwater levels during seasonally high water table conditions is required to confirm the extent to which shallow water table conditions occur on the properties. The resulting change in infiltration between pre- and post-development conditions is summarized in Table 6 for both Area 1 and Area 2. Two post-development scenarios are presented, one with no mitigation and one with roof runoff directed onto pervious surfaces. Detailed results of each water balance scenario are presented in Appendix 5.

Table 8. Summary of Infiltration for Water Balance Analysis

Infiltration Change Pre- to Post-development Conditions

Infiltration % of Total Ppt.

Development Scenario

Description

(m3/yr) L/s % of Ppt.

AREA 1 Pre-development 0 0 0 9.7

1 Runoff to Storm Sewers (No mitigation)

-9,167 -0.29 7.4 2.4

2 Runoff to pervious areas from 100% of roof areas

1,947 0.06 1.6 11.3

AREA 2 Pre-development 0 0 0 9.7

1 Runoff to Storm Sewers (No mitigation)

-5,445 -0.17 6.0 3.73

2 Runoff to pervious areas from 100% of roof areas

240 0.01 0.3 10.0

Note : Ppt. = Precipitation In the above post-development scenarios, infiltration losses of 9,167 m3/yr and 5,445 m3/yr with no mitigation under Scenario 1 for Area 1 and Area 2 respectively. With mitigation measures there is a post-development gain in infiltration of 1,947 m3/yr and 240 m3/yr under Scenario 2 for Area 1 and 2 respectively. Scenario 2 offers a significant improvement in post–development infiltration for both Area 1 and 2 resulting in a net gain in infiltration. The infiltration volume change under post-development mitigation measures although positive are relatively small compared to precipitation. Therefore is unlikely that the



effects of these changes will be measurable as base flow in Joshua’s Creek. This is considered within the range of accuracy of the water balance analysis and does not represent a measurable impact. Further infiltration measures such as an infiltration trench, soakaway pits, and 3rd pipe infiltration systems are not considered feasible for implementation on either Area 1 or Area 2. The on-site hydrogeological conditions provide relatively poor conditions for infiltration. 6.0 Impact Assessment 6.1 Water Balance The proposed development will result in a slight increase in infiltration under post-development conditions with the implementation of mitigation measures. Evapotranspiration will decrease under post development conditions and runoff will increase substantially. A summary of the water balance changes under post-development conditions is provided in Table 7. Both Area 1 and Area 2 have relatively uniform subsurface conditions. The shallow soils are relatively fine grained and have low infiltration potential. Similarly the underlying bedrock is considered to have limited infiltration potential. Site conditions are therefore limited with respect to infiltration techniques and are considered unsuitable for such measures as infiltration trenches, soakaway pits, and third pipe infiltration schemes. The water balance analysis also shows that shallow soil conditions will provide for infiltration of roof runoff and potentially result in a slight increase in infiltration. The water balance analysis indicates that without mitigation there would be a significant loss of infiltration, with a reduction of about 62% to 76% of the pre-development infiltration. Mitigation measures including the directing of all roof runoff toward the pervious surfaces will result in a substantial improvement in post-development infiltration with an increase in infiltration of 16% and 3% for Area 1 and Area 2 respectively. This is a relatively minor quantity of water compared to the total amount of precipitation and is therefore not expected to have a measurable impact on the discharge to the local stream. The groundwater system that supports Area 1 extends well off-site, receiving recharge from areas to the north and west. Provided that groundwater movement is not intercepted, these areas will continue to contribute groundwater through flow to this property. The results of the water balance analysis shows that mitigation measures such as directing all of the roof runoff to pervious surfaces will provide significant benefits to groundwater recharge such that there will be no negative impacts from the proposed development on infiltration within the two properties. Base flow to Joshua’s Creek will be marginally enhanced although the benefits are not likely to be measurable. The water balance analysis shows a significant increase in runoff under post-development conditions. Control of runoff should be addressed through a storm water management plan for the two properties. Additional mitigation measures as infiltration trenches, soakaway pits, and third pipe infiltration systems are not feasible for the site conditions on either property and are also not required. 6.2 Private Well Interference The surrounding area is serviced by municipal water systems although there may be individual private wells that are locally still in use. Since the properties are to be serviced by municipal water and sewer services and there are relatively few wells completed in this area, there is very little potential for well interference from the proposed development. There may be potential for localized impacts on nearby shallow wells from excavations for the installation of buried services. Prior to construction, a survey to



locate private wells on adjacent and nearby properties should be completed to asses the potential for localized well interference from proposed construction activities. To ensure that there are no unanticipated impacts on the groundwater system, routine groundwater level monitoring prior to and during the construction phase of this development should be undertaken at selected groundwater monitor locations. Quarterly monitoring is recommended to establish seasonal variations in groundwater levels. 6.3 Water Quality Urban landscaping practices as well as winter road maintenance can potentially result in groundwater quality and surface water quality impacts. Winter road salting practices pose some risk to groundwater quality. A community wide approach is required to reduce the level of road salt applied to local roads and highways 7.0 Conclusions The results of this hydrogeological investigation provide the following conclusions:

1) Area 1 and Area 2 are underlain by a relatively thin layer of silty clay soil at surface underlain at shallow depths of between one meter to 10 m by shale bedrock.

2) The two properties have low infiltration potential with relatively shallow depth to water table.

3) The properties contribute relatively small quantities of shallow groundwater as potential base

flow to Joshua’s Creek due to the low infiltration potential.

4) Shallow groundwater flow is generally to the south and east and locally toward Joshua’s Creek.

5) There are relatively few wells completed within the area and most are completed into shale bedrock at depth of between 10 m to 35 m deep. .

6) The bedrock aquifer appears to be marginally suitable for domestic use in quantity and quality.

Water use is reported to be primarily for domestic use although minor industrial, commercial, public supply and stock watering use is also reported in the well records.

7) The proposed development will result in the creation of impervious surfaces which will impact

the natural water balance for the site.

8) The proposed development, without mitigation measures, is expected to result in a significant loss of infiltration with corresponding increase in runoff.

9) Directing roof runoff onto pervious surfaces provides significant benefit to the maintenance of

infiltration on both properties.

10) Site conditions are not suitable for implementing groundwater infiltration mitigation measures such as infiltration trenches, and infiltration systems due to the relatively low infiltration potential.



9.0 References Barnett, P.J., 1992: Quaternary Geology of Ontario, in Geology of Ontario, Ontario Geological Survey Special Volume 4, Part 2, pp.1011-1088. Chapman, L.J. and D.F. Putnam, 1984: The Physiography of Southern Ontario, Third Edition, Ontario Geological Survey Special Volume 2, 270 p. Accompanied by Map P. 2715 (coloured), scale 1:600,000. Karrow, P.F. 1987: Quaternary Geology of the Hamilton Area, Southern Ontario, Ontario Geological Survey, Map 2509 (revised), scale 1:50,000. Karrow , P.F., and J. Easton 2005: Quaternary Geology of the Brampton Area, Southern Ontario, Ontario Geological Map 2223, scale 1:50,000. Ministry of the Environment (MOE), 2003: Stormwater Management Planning and Design Manual, 8 Chapters and 9 Appendices. MOEE, 1995: MOEE hydrogeological Technical Information Requirements for Land Development Applications, unpublished document prepared for the Ontario Ministry of the Environment and Energy and the Ontario Ministry of Municipal Affairs, by Gartner Lee Limited, 6 Chapters with 4 Appendices. Moin, S.M.A. and M.A. Shaw, 1986: Regional Flood Frequency Analysis for Ontario Streams, Volume 2, Multiple Regression Method, Water Management and Planning Branch, Inland Waters Directorate, Environment Canada, 34 p. with Appendices C,D,E,F,G, and H. Ontario Building Code,1997: Supplemental Guideline SG-6 Percolation Time and Soil Descriptions Ontario Geological Survey, 1991: Bedrock Geology of Ontario, southern sheet, Ontario Geological Survey, Map 2544, scale 1:1,000,000. Sanford, B.V.,1969: Geology Toronto-Windsor Area, Ontario, Geological Survey of Canada, Map1263A, Scale 1:250,000. Telford, P.G., and B.A. Liberty, 1976: Paleozoic Geology, Hamilton Area, southern Ontario, Ontario Division of Mines Map 2336, scale 1:50,000. Thornthwaite C.W., and Mather, J.R., 1955: The Water Balance, Publications in Climatology, Volume VIII, Number 1, Drexel Institute of Technology, Laboratory of Climatology, Centerville, New Jersey, 104 p.



Thornthwaite C.W., and Mather, J.R., 1957: Instructions and Tables for Computing Potential Evapotranspiration and the Water Balance, Publications in Climatology, Volume X, Number 3, Drexel Institute of Technology, Laboratory of Climatology, Centerville, New Jersey, 311 p. Toronto and Region Conservation Authority (TRCA) 2002: Performance Assessment of a Swale and Perforated Pipe Stormwater Infiltration System, Toronto, Ontario, prepared by Stormwater Assessment Monitoring and Performance (SWAMP) Program, 30p with 6 Appendices.



Winston Park West, Hydrogeological Investigation, February, 2008

APPENDICES Appendix 1 Records of Boreholes (Terraprobe, December, 2007)

Appendix 2 MOE Well Record Summary

Appendix 3 Climatic Water Balance

Appendix 4 Ontario Building Code, Supplementary Guide SC-6

Appendix 5 Water Balance Analysis



APPENDIX 1

RECORDS OF BOREHOLES (TERRAPROBE, DECEMBER 2007)



APPENDIX 2 MOE WELL RECORD SUMMARY



APPENDIX 3

CLIMATIC WATER BALANCE

Climatic Water BalanceToronto International Airport (1940 - 2007)

Soil Moisture 125 mm/yr

Month Temperature Precipitation Potential Actual Deficit Surplus(Degrees C) ET ET

(mm) (mm) (mm) (mm) (mm)January -6.2 53 1 1 0 24February -5.5 47 1 1 0 36March -0.7 57 8 8 0 72April 6.4 67 33 33 0 41May 12.6 75 75 75 0 16June 18.2 66 113 111 -3 2July 20.9 74 134 112 -23 0August 20.1 74 119 86 -34 0September 15.8 70 79 61 -18 2October 9.5 61 42 36 -5 3November 3.4 68 14 14 0 11December -3 60 3 3 0 24Total 772 622 541 -83 231

Notes:ET - EvapotranspirationData From Meterological Service of CanadaNumbers rounded off

Climatic Water BalanceToronto International Airport (1940 - 2007)

Soil Moisture 200 mm/yr

Month Temperature Precipitation Potential Actual Deficit Surplus(Degrees C) (mm) ET ET (mm) (mm)

(mm) (mm)

January -6.2 53 1 1 0 15February -5.5 47 1 1 0 25March -0.7 57 8 8 0 63April 6.4 67 33 33 0 40May 12.6 75 75 75 0 16June 18.2 66 113 114 0 2July 20.9 74 134 128 -7 0August 20.1 74 119 102 -18 0September 15.8 70 79 67 -13 2October 9.5 61 42 38 -4 2November 3.4 68 14 14 0 7December -3 60 3 3 0 16Total 772 622 584 -42 188

Notes:ET - EvapotranspirationData from Meterological Service of Canada, 2007Numbers Rounded Off

Climatic Water BalanceToronto International Airport (1940-2007)

SoilMoisture 400 mm/yr

Month Temperature Precipitation Potential Actual Deficit Surplus(Degrees C) (mm) ET ET (mm) (mm)

(mm) (mm)January -6.2 53 1 1 0 12February -5.5 47 1 1 0 19March -0.7 57 8 8 0 50April 6.4 67 33 33 0 35May 12.6 75 75 75 0 14June 18.2 66 113 113 0 1July 20.9 74 134 134 -1 0August 20.1 74 119 118 -2 0September 15.8 70 79 76 -3 2October 9.5 61 42 41 -1 2November 3.4 68 14 14 0 6December -3 60 3 3 0 14Total 772 622 617 -7 155

Notes:ET - EvapotranspirationData from Meterological Servicecs of Canada, 2007Numbers Rounded Off



APPENDIX 4

ONTARIO BUILDING CODE SUPPLEMENTARY GUIDE SG-6



APPENDIX 5

WATER BALANCE ANALYSIS

Winston Park West Water Balance Analysis - Area 1

ORC Oakville Water Balance AREA 1 (Scenario 1 - Roof Runoff to Storm Sewers - Infiltration Factors 0.4 to 0.3)Shallow rooted plants Medium rooted plants Deep rooted plants-trees Pond Impervious Area

(not applicable) Roof Roads & Flat RoofsClimate Data from Richmond Hill (mm) (mm) (mm) (mm) (mm) (mm)(1960 to 2004) Soil Moisture 125 Soil Moisture 200 Soil Moisture 400 N/A NA NAEvaporation Data from Bowmanville Total Precip. 772 Total Precip. 772 Total Precip. 772 772 772 772

Evapotrans. 541 Evapotrans. 584 Evapotrans. 615 746 77.2 115.8Surplus 231 Surplus 188 Surplus 155 26Pot Evapotr 622

Pre-development Post-development Post-development Pre/post-developmentInfiltration Factor 0.4 Infiltrn factor 0.3 Infiltrn Factor 0.3 Infiltrn factor 0.5 0.0 0 0Runoff factor 0.6 Runoff factor 0.7 Runoff factor 0.7 Runoff factor 0.5 1.0 0.9 0.85

(meadow) (shrub meadow) (forest)

Pre-development Water Balance Areas Total Pervious Pervious Impervious Impervious Perv. Infil. Perv. R/O Perv. ET Imperv Infil Imper R/O Imperv ET Total

(m²) % Area (m2) % Area (m2) (m3) (m3) (m3) (m3) (m3) (m3) (m3)Open Space (cultivated/meadow) 161,900 100 161,900.00 0.00 12,174.88 18,262.32 94,549.60 0.00 0.00 0.00 124,986.80Other 0 100.00 0.00 0.00 0.00 0.00 0.00

Total 161,900 161,900.00 12,174.88 18,262.32 94,549.60 0.00 0.00 124,986.80Volume check( area X precip) 124,986.80 Percent Error 0.00

Post-development Water BalanceScenario 1- Runoff to Storm Sewers1) Open Space 7,700 a) Open Space (river valley) 7,700 100.00 7,700.00 0.00 0.00 579.04 868.56 4,496.80 5,944.40

2) Prestige Emplpoyment - Total 42,500 a) Roof (to SWMS) 17,000 40.00 17,000.00 0.00 11,155.40 1,968.60 13,124.00 b) Paved Areas (to SWMS) 12,750 30.00 12,750.00 0.00 8,366.55 1,476.45 9,843.00 c) Pervious (non roof areas) 12,750 30.00 12,750.00 883.58 2,061.68 6,897.75 9,843.00

3) General Employment - Total 95,500 a) Roof (to SWMS) 42,975 45.00 42,975.00 0.00 28,200.20 4,976.51 33,176.70 b) Paved Areas (to SWMS) 33,425 35.00 33,425.00 0.00 21,933.49 3,870.62 25,804.10 c) Pervious Areas 19,100 20.00 19,100.00 1,323.63 3,088.47 10,333.10 14,745.20

4) Arterial Commercial 0 a) Roof (to SWMP) 0 45.00 0.00 0.00 0.00 0.00 b)Paved areas (to SWMP) 0 35.00 0.00 0.00 0.00 0.00 c) Pervious (non roof areas) 0 20.00 0.00 0.00 0.00 0.00 0.00

5) Roads - total 16,190 a) Roads (impervious) 11,333 0.00 70.00 11,333.00 0.00 7,436.71 1,312.36 8,749.08 b) Pervious 4,857 30.00 4,857.00 336.59 785.38 2,627.64 3,749.60

Column Check 124,979.08

Total 161,890 44,407.00 117,483.00 3,122.84 6,804.08 24,355.29 0.00 77,092.34 13,604.53 124,979.08Volume Check (area X precip.) 124,979.08Percent Error 0.00Volume Difference (m3/yr) 0.00% Change Pre to Post-dev Pre-dev Post-dev %Change (m3/yr) (L/sec) % of total precip % of total precip

(m3/yr) ` pre-development post-developmentInfiltration 12,174.88 3,122.84 -74.35 -9,052.04 -0.29 9.74 2.50Evapotransporation 94,549.60 37,959.82 -59.85 -56,589.78 75.65 30.37Runoff 18,262.32 83,896.43 359.40 65,634.11 14.61 67.13Total 124,986.80 124,979.08 100.00 100.00


ORC Oakville Water Balance AREA 1 (Scenario 2 - Roof Runoff to Grassed Areas Residential - Infiltration Factors 0.4 to 0.3)Shallow rooted plants Medium rooted plants Deep rooted plants-trees Pond Impervious Area

(mm) Roof Roads & Flat RoofsClimate Data from Richmond Hill (mm) (mm) (mm) (mm) (mm)(1960 to 2004) Soil Moisture 125 Soil Moisture 200 Soil Moisture 400 N/A NA NA

Total Precip. 772 Total Precip. 772 Total Precip. 772 772 772 772Evaporation Data from Bowmanville Evapotrans. 541 Evapotrans. 584 Evapotrans. 615 746 77.2 115.8

Surplus 231 Surplus 188 Surplus 155 26Pot Evapotr. 622 Pot Evapotr. 622 Pot Evapotr. 622

Pre-development Post-development Post-development Pre/Post-developmentInfiltration factor 0.4 Infiltrn factor 0.3 Infiltrn factor 0.3 Infiltrn factor 0.5 0.0 0 0Runoff Factor 0.6 Runoff factor 0.7 Runoff factor 0.7 Runoff factor 0.5 1.0 0.9 0.85



(ha) % Area (m2) % Area (m2) (m3) (m3) (m3) (m3) (m3) (m3) (m3)Open Space (cultivated/meadow) 161,900 100 161,900.00 0.00 12,174.88 18,262.32 94,549.60 0.00 0.00 0.00 124,986.80Other 0 100.00 0.00 0.00 0.00 0.00 0.00


Post-development Water BalanceScenario 2- Runoff to Pervious Surfaces1) Open Space 7,700 a) Open Space (park) 7,700 100.00 7,700.00 434.28 1,013.32 4,496.80 5,944.40

2) Prestige Employment - Total 42,500 a) Roof (to pervious area) 17,000 40.00 17,000.00 1,968.60 1,968.60 b) Paved Area (to SWMP) 12,750 30.00 12,750.00 8,366.55 1,476.45 9,843.00 c) Pervious Areas 12,750 30.00 12,750.00 4,019.82 9,379.54 7,599.00 20,998.36

3) General Employment - Total 95,500 a) Roof (to pervious areas) 42,975 45.00 42,975.00 4,976.51 4,976.51 b) Paved Areas (to SWMS) 33,425 35.00 33,425.00 21,933.49 3,870.62 25,804.10 c) Pervious Areas 19,100 20.00 19,100.00 9,331.02 21,772.38 11,842.00 42,945.40

4) Arterial Commercial 0 a) Roof (to pervious area) 0 45.00 0.00 0.00 0.00 b) Paved (to SWMP) 0 35.00 0.00 0.00 0.00 0.00 c) Pervious Areas 0 20.00 0.00 0.00 0.00 0.00 0.00

5) Roads - total 16,190 a) Roads (impervious) 11,333 0.00 70.00 11,333.00 7,436.71 1,312.36 8,749.08 b) Pervious 4,857 30.00 4,857.00 336.59 785.38 2,627.64 3,749.60



(m3/yr) ` pre-development post-developmentInfiltration 12,174.88 14,121.71 15.99 1,946.83 0.06 9.74 11.30Evapotransporation 94,549.60 40,169.97 -57.51 -54,379.63 75.65 32.14Runoff 18,262.32 70,687.36 287.07 52,425.04 14.61 56.56Total 124,986.80 124,979.04 100.00 100.00


ORC Oakville Water Balance AREA 2 (Scenario 1 - Roof Runoff to Storm Sewers - Infiltration Factors 0.4 to 0.3)Shallow rooted plants Medium rooted plants Deep rooted plants-trees Pond Impervious Area

(not applicable) Roof Roads & Flat RoofsClimate Data from Richmond Hill (mm) (mm) (mm) (mm) (mm) (mm)(1960 to 2004) Soil Moisture 125 Soil Moisture 200 Soil Moisture 400 N/A NA NAEvaporation Data from Bowmanville Total Precip. 772 Total Precip. 772 Total Precip. 772 772 772 772

Evapotrans. 541 Evapotrans. 584 Evapotrans. 615 746 77.2 115.8Surplus 231 Surplus 188 Surplus 155 26Pot Evapotr 622

Pre-development Post-development Post-development Pre/post-developmentInfiltration Factor 0.4 Infiltrn factor 0.3 Infiltrn Factor 0.3 Infiltrn factor 0.5 0.0 0 0Runoff factor 0.6 Runoff factor 0.7 Runoff factor 0.7 Runoff factor 0.5 1.0 0.9 0.85



(m²) % Area (m2) % Area (m2) (m3) (m3) (m3) (m3) (m3) (m3) (m3)Open Space (cultivated/meadow) 117,400 100 117,400.00 0.00 8,828.48 13,242.72 68,561.60 0.00 0.00 0.00 90,632.80Other 0 100.00 0.00 0.00 0.00 0.00 0.00


Post-development Water BalanceScenario 1- Runoff to Storm Sewers1) Open Space 33,800 a) Open Space (MTO) 19,200 100.00 19,200.00 1,082.88 2,526.72 11,212.80 0.00 0.00 0.00 14,822.40 b) Open Space (easement) 14,600 100.00 14,600.00 823.44 1,921.36 8,526.40 11,271.20

2) Prestige Emplpoyment - Total 34,100 a) Roof (to SWMS) 13,640 40.00 13,640.00 0.00 8,950.57 1,579.51 10,530.08 b) Paved Areas (to SWMS) 10,230 30.00 10,230.00 0.00 6,712.93 1,184.63 7,897.56 c) Pervious (non roof areas) 10,230 30.00 10,230.00 708.94 1,654.19 5,534.43 7,897.56

3) General Employment - Total 26,800 a) Roof (to SWMS) 12,060 45.00 12,060.00 0.00 7,913.77 1,396.55 9,310.32 b) Paved Areas (to SWMS) 9,380 35.00 9,380.00 0.00 6,155.16 1,086.20 7,241.36 c) Pervious Areas 5,360 20.00 5,360.00 371.45 866.71 2,899.76 4,137.92

4) Arterial Commercial 11,000 a) Roof (to SWMP) 4,950 45.00 4,950.00 3,248.19 573.21 3,821.40 b)Paved areas (to SWMP) 3,850 35.00 3,850.00 2,526.37 445.83 2,972.20 c) Pervious (non roof areas) 2,200 20.00 2,200.00 152.46 355.74 1,190.20 1,698.40

5) Roads - total 11,740 a) Roads (impervious) 8,218 0.00 70.00 8,218.00 0.00 5,392.65 951.64 6,344.30 b) Pervious 3,522 30.00 3,522.00 244.07 569.51 1,905.40 2,718.98



(m3/yr) ` pre-development post-developmentInfiltration 8,828.48 3,383.24 -61.68 -5,445.24 -0.17 9.74 3.73Evapotransporation 68,561.60 38,486.57 -43.87 -30,075.03 75.65 42.45Runoff 13,242.72 48,793.86 268.46 35,551.14 14.61 53.82Total 90,632.80 90,663.68 100.00 100.00

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ORC Oakville Water Balance AREA 2 (Scenario 2 - Roof Runoff to Grassed Areas Residential - Infiltration Factors 0.4 to 0.3)Shallow rooted plants Medium rooted plants Deep rooted plants-trees Pond Impervious Area

(mm) Roof Roads & Flat RoofsClimate Data from Richmond Hill (mm) (mm) (mm) (mm) (mm)(1960 to 2004) Soil Moisture 125 Soil Moisture 200 Soil Moisture 400 N/A NA NA

Total Precip. 772 Total Precip. 772 Total Precip. 772 772 772 772Evaporation Data from Bowmanville Evapotrans. 541 Evapotrans. 584 Evapotrans. 615 746 77.2 115.8

Surplus 231 Surplus 188 Surplus 155 26Pot Evapotr. 622 Pot Evapotr. 622 Pot Evapotr. 622

Pre-development Post-development Post-development Pre/Post-developmentInfiltration factor 0.4 Infiltrn factor 0.3 Infiltrn factor 0.3 Infiltrn factor 0.5 0.0 0 0Runoff Factor 0.6 Runoff factor 0.7 Runoff factor 0.7 Runoff factor 0.5 1.0 0.9 0.85



(ha) % Area (m2) % Area (m2) (m3) (m3) (m3) (m3) (m3) (m3) (m3)Open Space (cultivated/meadow) 117,400 100 117,400.00 0.00 8,828.48 13,242.72 68,561.60 0.00 0.00 0.00 90,632.80Other 0 100.00 0.00 0.00 0.00 0.00 0.00


Post-development Water BalanceScenario 2- Runoff to Pervious Surfaces1) Open Space a) Open Space (park) 19,200 100.00 19,200.00 1,082.88 2,526.72 11,212.80 14,822.40 b) Open Space ( easement) 14,600 100.00 14,600.00 823.44 1,921.36 8,526.40 11,271.20

2) Prestige Employment - Total 34,100 a) Roof (to pervious area) 13,640 40.00 13,640.00 1,579.51 1,579.51 b) Paved Area (to SWMP) 10,230 30.00 10,230.00 6,712.93 1,184.63 7,897.56 c) Pervious Areas 10,230 30.00 10,230.00 3,225.31 7,525.70 6,097.08 16,848.09

3) General Employment - Total 26,800 a) Roof (to pervious areas) 12,060 45.00 12,060.00 1,396.55 1,396.55 b) Paved Areas (to SWMS) 9,380 35.00 9,380.00 6,155.16 1,086.20 7,241.36 c) Pervious Areas 5,360 20.00 5,360.00 2,618.55 6,109.94 3,323.20 12,051.69

4) Arterial Commercial 11,000 a) Roof (to pervious area) 4,950 45.00 4,950.00 573.21 573.21 b) Paved (to SWMP) 3,850 35.00 3,850.00 2,526.37 445.83 2,972.20 c) Pervious Areas 2,200 20.00 2,200.00 1,074.78 2,507.81 1,364.00 4,946.59

5) Roads - total 11,700 a) Roads (impervious) 8,190 0.00 70.00 8,190.00 5,374.28 948.40 6,322.68 b) Pervious 3,510 30.00 3,510.00 243.24 567.57 1,898.91 2,709.72



(m3/yr) ` pre-development post-developmentInfiltration 8,828.48 9,068.20 2.72 239.72 0.01 9.74 10.01Evapotransporation 68,561.60 39,636.73 -42.19 -28,924.87 75.65 43.73Runoff 13,242.72 41,927.83 216.61 28,685.11 14.61 46.26Total 90,632.80 90,632.77 100.00 100.00

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Documents

Hydrogeological Investigation Winston Park West, Oakville Ontario Proposed Development planning/da-SU11003... · 2020-05-26 · Norbert M. Woerns, M.Sc., P.Geo. Winston Park West,