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GeotechnicalEngineering
EnvironmentalEngineering
Hydrogeology
GeologicalEngineering
Materials Testing
Building Science
Archaeological Services
Paterson Group Inc.Consulting Engineers154 Colonnade Road SouthOttawa (Nepean), OntarioCanada K2E 7J5
Tel: (613) 226-7381Fax: (613) 226-6344www.patersongroup.ca
patersongroup
Terrain Evaluation StudyProposed Commercial / Industrial Subdivision
Boundary Road at Highway 417Ottawa, Ontario
Prepared For
East Gateway Properties Limited
August 10, 2015
Report: PH2108-REP.01 (Update No. 1)
patersongroup Terrain Evaluation StudyOttawa North Bay Kingston Proposed Commercial / Industrial Subdivision
Boundary Road (Carlsbad Springs) Ottawa, Ontario
TABLE OF CONTENTS
PAGE
1.0 INTRODUCTION.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.1 Terms of Reference. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2 Background. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.3 Proposed Development. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.4 Available Water Supply. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
2.0 SITE DESCRIPTION.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.1 Surface Conditions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.2 Surrounding Land Uses. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3.0 METHOD OF INVESTIGATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3.1 Field Investigation.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3.2 Field Survey. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
3.3 Laboratory Testing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
4.0 TERRAIN ANALYSIS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
4.1 Surficial Geology. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
4.2 Bedrock Geology. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
4.3 Regional Groundwater Flow Direction. . . . . . . . . . . . . . . . . . . . . . . . 8
5.0 GROUNDWATER IMPACT ASSESSMENT. . . . . . . . . . . . . . . . . . . . . . . . . 8
5.1 Hydrogeological Sensitivity.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
5.2 Isolation of Bedrock Aquifer. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
5.3 Predictive Impact Assessment for Nitrate.. . . . . . . . . . . . . . . . . . . . . 9
5.4 Impacts on Surface Water Features.. . . . . . . . . . . . . . . . . . . . . . . . 11
5.5 Sewage System Design. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
5.6 Development Restrictions.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
6.0 SUMMARY. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
7.0 RECOMMENDATIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Report No: PH2108-1
August 10, 2015 Page i
patersongroup Terrain Evaluation StudyOttawa North Bay Kingston Proposed Commercial / Industrial Subdivision
Boundary Road (Carlsbad Springs) Ottawa, Ontario
APPENDICES
Appendix 1 Soil Profile & Test Data Sheets
Symbols and Terms
Appendix 2 Grain Size Distribution Test Result Sheets
Background Nitrate Test Results
Appendix 3 MOE Water Well Records
Nitrate Impact Calculations
Appendix 4 Figure 1: Key Plan
Drawing No. PH2108-FIG.1: Site Location Plan
Drawing No. PH2108-FIG.2: Surficial Soil Delineation Mapping
Drawing No. PH2108-FIG.3: Regional Bedrock Mapping
Drawing No. PH2108-FIG.4: Surficial Groundwater Flow
Drawing No. PH2108-1: Test Hole Location Plan
Report No: PH2108-1
August 10, 2015 Page ii
patersongroup Terrain Evaluation StudyOttawa North Bay Kingston Proposed Commercial / Industrial Subdivision
Boundary Road (Carlsbad Springs) Ottawa, Ontario
1.0 INTRODUCTION
1.1 Terms of Reference
Paterson Group Inc. (Paterson) was retained by Mr. Michel Pilon representing East
Gateway Properties Ltd., to carry out a terrain evaluation study, in support of a
proposed commercial / industrial subdivision. The subject property is located
southeast of the intersection of Boundary Road, and Highway 417 in Ottawa (Carlsbad
Springs), Ontario, as shown on Figure 1 - Key Plan in Appendix 4.
The proposed development is currently being proposed under a split servicing
scenario, with municipal water being supplied to the site through the proposed
extension of the Carlsbad Trickle System, and on-site septic systems being used for
sewage disposal. The purpose of this study is to determine the capability of the site
to provide for on-site sewage disposal in accordance with provincial guidelines.
1.2 Background
As part of this study, several reports were used as part of the assessment of the site
capability to support on-site sewage systems. Specifically, those reports used consist
of the following:
� Paterson Group Inc. Report titled “Geotechnical Investigation, Proposed
Building and Pavement Structure, Boundary Road at Highway 417 - Ottawa”,
dated September 11, 2012.
� Paterson Group Inc. Report titled “Geotechnical Investigation, Proposed
Roadway Widening, Westbound On-Ramp for Highway 417 at Boundary Road -
Ottawa”, dated July 22, 2014.
� Paterson Group Inc. Report titled “Preliminary Geotechnical Investigation,
Proposed Industrial Park, Boundary Road at Highway 417, Ottawa, Ontario”,
dated September 15, 2012.
� Golder Associates Draft Report 12-1125-0045 (4000) titled “Geology,
Hydrogeology and Geotechnical Report, Capital Region Resource Recovery
Centre”, dated June 2014.
Report No: PH2108-1 (Update No. 1)August 10, 2015 Page 1
patersongroup Terrain Evaluation StudyOttawa North Bay Kingston Proposed Commercial / Industrial Subdivision
Boundary Road (Carlsbad Springs) Ottawa, Ontario
� Novatech Engineers, Planners & Landscape Architects Report entitled
“Proposed Commercial / Industrial Subdivision, 5341 Boundary Road, City of
Ottawa” dated October 30, 2014.
� Stantec Report titled “Feasibility Study for an Extension of the Carlsbad Springs
Trickle Feed Water System - Boundary Road Industrial Park”, dated April 14,
2015.
� Carlsbad Trickle Feed System, Assessment of Capacity Available to
Accommodate New Severance Applications, Ottawa Infrastructure Policy Group,
October 31, 2014
1.3 Proposed Development
The proposed planning rationale for this site comprises a multi-lot commercial /
industrial subdivision. At the time of this submission, the details of the development are
not known. While the actual number of lots may vary at the end of the day, this
submission will identify constraints that should be considered at the planning stage.
The current site plan calls for 5 blocks as shown on Drawing No. PH2108-1 in Appendix
4. Under the proposed usages for this site, the actual development could incorporate
typical industrial park development such as a mix of manufacturing, service and
warehouse facilities, as well as fast-food and/or coffee/donut shop establishments with
drive-through windows. Due to the proximity with respect to Highway 417, a
gasoline/service station could also be considered as part of the overall development.
1.4 Available Water Supply
The City of Ottawa Trickle System currently has restrictions in place, limiting the
amount of water that can be delivered. The 2015 Stantec Report has identified the long
term potential of the system, and concludes that a total of 61 Equivalent Units (each
unit comprising 2,700 litres per day), can be assigned to and distributed amongst the
landowners in this area. At this time, we are unaware of the makeup of this future
distribution, but this report will identify any restrictions that might exist from a
hydrogeological perspective for the proposed development, to assist in this regard.
Report No: PH2108-1 (Update No. 1)August 10, 2015 Page 2
patersongroup Terrain Evaluation StudyOttawa North Bay Kingston Proposed Commercial / Industrial Subdivision
Boundary Road (Carlsbad Springs) Ottawa, Ontario
Based on the findings of the Ottawa Infrastructure Policy Group, it is evident that the
capacity of the system is under-utilized. Based on the monitoring of usage between
1999 and 2013, the average usage is no higher than 45% of the design usage, or
approximately 1200 litres/day per hookup (versus the 2,700 litres/day design), and the
conclusion of that study was that the existing system could accommodate the potential
112 severance opportunities that exist along the existing network.
As part of the proposed development, it is expected that a typical small office /
warehouse facility would likely only require one unit on the trickle system (i.e. 2,700
litres/day), whereas a commercial development with fast food restaurants and a service
station could require several equivalent water units.
2.0 SITE DESCRIPTION
2.1 Surface Conditions
The topography of the site is generally flat lying, with only a slight slope from west to
east. The measured average slope, based on topographical information is less than
0.2%. The site is cleared of trees on the western portion of the site, but to the east, the
site is presently wooded.
Drainage of the property is presently handled with a ditch that runs from west to east
through the centre of the site, and eventually outlets through a corrugated steel pipe
that runs under Highway 417. This outlet forms part of the Regimbald Municipal Drain,
which is part of the Bearbrook Subwatershed.
Currently, there is a cellular telephone tower on the site with the land being leased to
Rogers Communications.
2.2 Surrounding Land Uses
The site is bordered to the north by Highway 417, to the west by Boundary Road and
to the east by vacant treed property. The site is bordered to the south by Pomerleau
Construction Limited within the west parcel and bordered to the south by both vacant,
treed and agricultural property within the east parcel of the subject site.
Report No: PH2108-1 (Update No. 1)August 10, 2015 Page 3
patersongroup Terrain Evaluation StudyOttawa North Bay Kingston Proposed Commercial / Industrial Subdivision
Boundary Road (Carlsbad Springs) Ottawa, Ontario
The Pomerleau site is an aggregate recycling facility, where materials such as crushed
concrete are produced and stockpiled. North of the 417 is the Grey Hawk Golf Course
property, and there is a gas station situated on the opposite side of Boundary Road
opposite the southwest corner of the site.
With the exception of the gas station on Boundary Road, there are no obvious
indicators of potential groundwater contamination present on the surrounding lands
within 500 m of the subject property. The presence of the service station will have no
impact on the commercial / industrial development as proposed, and is generally
considered to be complementary to the proposed land use for the subject site.
3.0 METHOD OF INVESTIGATION
3.1 Field Investigation
The field program was conducted in conjunction with geotechnical works for the site,
and was carried out on July 15, 2014. At that time, a total of six (6) test pits were
completed using a hydraulic shovel to a maximum depth of 5.2 m below existing
ground surface. A previous geotechnical field investigation was completed on June 26,
2012, within the west portion of the subject site, and there were a total of nine (9) test
pits put down as part of that 2012 investigation. The relevant test holes have been
appended to the current report. All fieldwork was conducted under the full-time
supervision of Paterson personnel under the direction of a senior engineer from this
firm. The test hole locations were distributed in a manner to provide general coverage
of the subject site. The locations of the test holes are shown on Drawing PH2108-1 -
Test Hole Location Plan included in Appendix 4.
Sampling and In Situ Testing
Soil samples from the test pits were recovered from the side walls of the open
excavation and all soil samples were initially classified on site. The grab samples were
placed in sealed plastic bags and all samples were transported to our laboratory. The
depths at which the grab samples were recovered from the test holes are shown as ‘G’,
on the Soil Profile and Test Data sheets presented in Appendix 1.
Report No: PH2108-1 (Update No. 1)August 10, 2015 Page 4
patersongroup Terrain Evaluation StudyOttawa North Bay Kingston Proposed Commercial / Industrial Subdivision
Boundary Road (Carlsbad Springs) Ottawa, Ontario
Undrained shear strength testing was carried out at regular depth intervals in cohesive
soils. Undrained shear strength testing in test pits was completed using a handheld,
portable vane apparatus (field inspection vane tester Roctest Model H-60). Where it
was not possible to obtain undrained shear strength testing within the test pit locations,
either due to safety or density of the subsurface soils, the density and consistency was
determined in accordance with ASTM D2488-00 - Standard Practice for Description
and Identification of Soils (Visual-Manual Procedure). Table 5 in the aforementioned
ASTM Standard indicates that a ‘thumb test’, or the procedure of pushing a thumb into
the undisturbed soil and measuring how far the thumb penetrates, is an indication of
the consistency of the subsurface soil. All soil samples were classified on site, placed
in sealed plastic bags and were transported to our laboratory for visual inspection.
Subsurface conditions observed in the test holes were recorded in detail in the field.
Reference should be made to the Soil Profile and Test Data sheets presented in
Appendix 1 for specific details of the soil profile encountered at the test hole locations.
Groundwater
Groundwater infiltration levels were noted during the excavation of the open test holes.
In addition, 51 mm diameter rigid standpipes were installed in each test hole during the
current field investigation to monitor the groundwater conditions upon subsequent
completion of the test holes. In that the upper aquifer is unconfined, the standpipes
were surrounded with the cuttings in such a manner that the existing soil profile is
replicated. The groundwater observations are noted on the Soil Profile and Test Data
sheets presented in Appendix 1, and are also indicated on Drawing PH2108-FIG.4 in
Appendix 4.
Sample Storage
All samples will be stored in the laboratory for a period of one month after issuance of
this report. They will then be discarded unless we are otherwise directed.
3.2 Field Survey
The ground surface elevation at test hole locations completed during our current field
investigation were interpolated from topographic information prepared by Annis
O’Sullivan Vollebekk Limited.
Report No: PH2108-1 (Update No. 1)August 10, 2015 Page 5
patersongroup Terrain Evaluation StudyOttawa North Bay Kingston Proposed Commercial / Industrial Subdivision
Boundary Road (Carlsbad Springs) Ottawa, Ontario
The test holes completed during our previous geotechnical field investigation were
located and surveyed in the field by Paterson personnel. Ground surface elevations
at the test hole locations were referenced to a temporary benchmark (TBM), consisting
of the invert of the existing culvert with an assumed geodetic elevation of 76.49 m
illustrated on the plan prepared by Annis O’Sullivan Vollebekk Limited.
The test hole locations and ground surface elevation at each test hole location are
presented on Drawing PH2108-1 - Test Hole Location Plan in Appendix 4.
3.3 Laboratory Testing
The soil samples recovered from the subject site were examined in our laboratory to
review the results of the field logging.
A total of seven (7) grain size distribution analyses were carried out within the overlying
fill, silty sand and the silty clay deposit throughout the subject site. The results of the
grain size distribution analysis are presented in Appendix 2.
Samples of the near surface groundwater were recovered from the standpipes at three
(3) locations (TP2, TP3 and TP6) on August 12, 2014, subsequent to the purging of
the standpipes, and were submitted to Exova Laboratories to determine the
background nitrate levels. The results of all laboratory testing are provided in Appendix
2. The results of the nitrogen testing are summarized in Table 1 below.
TABLE 1: SUMMARY OF NITROGEN SPECIES TESTING WITHIN THE SHALLOW
OVERBURDEN AQUIFER - AUGUST 12, 2014
Parameter TP2-14 TP3-14 TP6-14 Guideline
N-NO2 (mg/l) #0.10 #0.10 #0.10 #0.10 1
N-NO3 (mg/l) #0.10 #0.10 #0.10 10
pH 7.62 7.63 7.42 6.5-8.5
N-NH3 (mg/l) 0.12 0.35 0.18
TKN (mg/l) 0.56 0.56 0.52
Report No: PH2108-1 (Update No. 1)August 10, 2015 Page 6
patersongroup Terrain Evaluation StudyOttawa North Bay Kingston Proposed Commercial / Industrial Subdivision
Boundary Road (Carlsbad Springs) Ottawa, Ontario
4.0 TERRAIN ANALYSIS
4.1 Surficial Geology
The primary stratigraphic unit in the area of the site comprises silty clays of marine
origin (Champlain Sea clays). This deposit, generally speaking, is of the order of 25
metres thick, based on published geologic information. Typically, the marine clays are
overlain by a veneer of fine sand material, and transecting the area, in an east-west
direction, a significant deposit of medium to fine grained estuary and deltaic deposits
overlies the Champlain Sea clays. The published regional surficial geology, in the
vicinity of the site, is shown on Drawing No. PH2108-FIG.2 in Appendix 4.
The majority of the west portion of the subject site is overlain by varying thicknesses
of imported fill material with several stockpiled fill piles. The east portion remains
predominately vacant and treed at the time of our current field investigation on July 15,
2014.
Generally, below the fill and/or topsoil, the native soils comprise a thin intermittent layer
of silty sand over a deep deposit of silty clay soil. Studies by others indicate that the
silty clay layer could be of the order of 25 metres thick. Reference should be made to
the Soil Profile and Test Data sheets in Appendix 1 for the details of the soil profile at
each test hole location.
Any information pertaining to soils and all test hole logs are furnished as a matter of
general information only, and test hole descriptions or logs are not to be interpreted as
descriptive of conditions at locations other than those described by the test holes
themselves.
4.2 Bedrock Geology
The primary bedrock unit underlying, and surrounding the site is the Carlsbad
Formation, which comprises thinly bedded shale, with some limestone layers.
Published bedrock elevation data would suggest that the bedrock elevation would
probably be in the vicinity of elevations 45 m to 50 m, which would imply that the drift
thickness in this area is of the order of 30 metres.
According to published mapping, there is a fault located in the Carlsbad Formation
south of the site, as indicated on Drawing No. PH2108-FIG.3 in Appendix 4.
Report No: PH2108-1 (Update No. 1)August 10, 2015 Page 7
patersongroup Terrain Evaluation StudyOttawa North Bay Kingston Proposed Commercial / Industrial Subdivision
Boundary Road (Carlsbad Springs) Ottawa, Ontario
4.3 Regional Groundwater Flow Direction
Groundwater data compiled by Golder Associates as part of the Capital Region
Resource Recovery Centre study indicates that the flow directions in the silty clay
stratum are generally in an easterly direction. Site specific data obtained as part of this
study, would corroborate this conclusion, as shown on Drawing PH2108-FIG.4 in
Appendix 4.
A review of available well information on file with the Ministry of Environment suggests
that there are approximately eleven (11) water supply wells surrounding the site. The
well locations are plotted on Drawing PH2108-FIG.3 in Appendix 4. The applicable
Water Well Records are contained in Appendix 3. As can be seen on Drawing
PH2108-FIG.3, there are no water supply wells located immediately downgradient of
the site.
On review of the MOE Water Well Records, it is evident that the groundwater from the
Carlsbad Formation produces a somewhat poor quality water, with many of the wells
being reported as salty or sulphurous. For this reason, it is quite common throughout
the area to terminate the wells in the till soils above the bedrock.
5.0 Groundwater Impact Assessment
5.1 Hydrogeological Comments with Respect To Potential Impacts
In accordance with Section 5.0 of the MOE publication, entitled, “Procedure D-5-4
Technical Guidelines for Individual On-site Sewage Systems: Water Quality Impact
Risk Assessment”, the groundwater impacts from on-site sewage systems should be
addressed in a step-wise manner.
This guideline was intended primarily for residential use, but nonetheless, comments
are contained herein, subject to the assumption that the expected flows would be
similar to that of a residential development. There is a prevision for commercial
development in the guideline, and that methodology has been used to establish the
maximum capability (or number of users for the development) and is discussed later
in this report. The comments contained herein with respect to the three-step
assessment are for information purposes to lend support to the various levels of
protection built in to the overall conservatism of the analysis.
Report No: PH2108-1 (Update No. 1)August 10, 2015 Page 8
patersongroup Terrain Evaluation StudyOttawa North Bay Kingston Proposed Commercial / Industrial Subdivision
Boundary Road (Carlsbad Springs) Ottawa, Ontario
As part of the review, a search of nearby wells was undertaken (both upgradient and
downgradient), and the locations are plotted on Drawing No. PH2108-FIG.3 in
Appendix 4. Based on this review, there are no wells located immediately
downgradient of the site. Also, given the fact that a deep clay deposit underlies the
site, as evidenced in the regional Water Well Records, the site would not be considered
to be a recharge area, and as such, it is our opinion that the site is not considered to
be hydrogeologically sensitive. It should also be noted that with the absence of water
supply aquifers in the area, the risk associated with impacts on the water supply are
minimal.
As discussed, the proposed lot sizes based on our understanding of the development
range from 1.76 ha to 7.60, with an average lot size of 3.65 ha. These lot sizes are
generally considered more than adequate to provide adequate attenuation of effluent
on the site.
5.2 Isolation of Bedrock Supply Aquifer
As determined through laboratory grain size distribution testing, the silty clay stratum
is opined to have a very low hydraulic conductivity. Water Well Records, as well as
studies conducted by others, support the fact that this silty clay stratum is widespread
throughout the area. As such, the water supply aquifer(s) in the Carlsbad bedrock and
overlying till strata are considered to be confined aquifers with the overburden material
acting as an aquitard. By definition, the term aquitard has been coined to describe the
less-permeable beds in a stratigraphic sequence. The deep clay deposit that underlies
the site, by nature of its very low hydraulic conductivity is considered to be an aquitard,
providing protection to the underlying Carlsbad Shale rock formation and till stratum.
5.3 Predictive Impact Assessment for Nitrate
It should be noted that much of the development in the area of the site is municipally
serviced through the “trickle system”. It is our understanding that at this time, the
proposed development application will see the extension of the system to this site.
In conducting an assessment of the impact of the proposed development, the estimate
of groundwater recharge, by infiltration of precipitation, is the primary site-specific input
parameter. The available surplus water for the silty sand materials on site used in the
calculation is 376 mm, based on water budget means from Environment Canada based
on 70 years of data. In general terms, the rate of infiltration will be dependent upon
the following:
Report No: PH2108-1 (Update No. 1)August 10, 2015 Page 9
patersongroup Terrain Evaluation StudyOttawa North Bay Kingston Proposed Commercial / Industrial Subdivision
Boundary Road (Carlsbad Springs) Ottawa, Ontario
� surficial soil type(s), especially within the depth of influence of the sewage
systems;
� ground covers and their distribution;
� site topography
In this regard, the following infiltration factors were used in the calculation of nitrate
impacts.
Category Average Condition Infiltration Factor
Topography Between Flat and Rolling
1.6 m in 1 kilometer
0.25
Surficial Soil Silty Sand to Sand 0.30
Soil Cover Primarily Wooded
with some Open Areas
0.15 0.15
Total Infiltration Factor 0.7
As part of this study, background nitrate level testing was undertaken for the
overburden receiving aquifer, as shown in Table 1 in Section 3.3 above. In all three
samples, nitrates were not detected, which indicates that the lands have not been
impacted by off-site sewage systems.
To remain consistent with the defined flows in the Stantec report for equivalent flows
under the trickle system, it was also assumed for purposes of this assessment that
sewage flows would also be of the order of 2,700 litres / day, with nitrate laden effluent
being of the order of 1,000 litres / day, as is the case with residential development. For
illustration purposes, if there were a total of 10 individual septic systems, similar in size
to a typical residential system, the cumulative nitrate impact is estimated to be of the
order of 1.3 mg/l, which is well below provincial guidelines of 10 mg/l.
To provide a further assessment of the overall capability of the site to accommodate
development, the approach for commercial development as detailed in Section 5.6.3
of MOE Guideline D-5-4 was undertaken. Only one-third of the available precipitation
was used in the calculation (125 mm) which is a very conservative approach, and given
the presumption that individual units of 2700 litres/day will be considered as per the
Stantec study, the calculations indicate that up to 32 units (86,400 litres/day) could be
Report No: PH2108-1 (Update No. 1)August 10, 2015 Page 10
patersongroup Terrain Evaluation StudyOttawa North Bay Kingston Proposed Commercial / Industrial Subdivision
Boundary Road (Carlsbad Springs) Ottawa, Ontario
accommodated on this site, while providing suitable on-site sewage disposal capability
using a maximum cumulative nitrate impact of 10 mg/l. The applicable analyses are
included in the spreadsheets in Appendix 3.
It should be noted as part of the development of the lots, a site specific sewage system
design would be required, and if daily sewage flows exceed 10,000 litres / day, then the
potential off-site impacts would be required to be addressed in accordance with MOE
Policy 15-08.
5.4 Impacts on Surface Water Features
Drainage of the property is presently handled with a ditch that runs from west to east
through the centre of the site, and eventually outlets through a corrugated steel pipe
that runs under Highway 417. This outlet forms part of the Regimbald Municipal Drain,
which is part of the Bearbrook Subwatershed.
With respect to the potential for nitrate impacts on surface water features, we are notaware of provincially mandated objectives for nitrates in surface water. In fact, inMOE's review of Reasonable Use Studies undertaken by this firm, they have used therationale that if nitrate bearing groundwater exits as surface water before it leaves thesite, then no further analysis is required, in the absence of criteria for surface water.
With respect to the potential for phosphorus impacts, it is our opinion that this wouldnot be a concern. In a publication entitled Septic System Impact on Surface Waters(2005 Tri-State Water Quality Council), it states that:
"Phosphorus in wastewater effluent tens to attach itself, or sorb to soil particlesin the unsaturated zone below septic drainfields. It is common for this processto remove 85 - 95% of phosphorus, and complete removal typically occurs longbefore effluent reaches surface water."
The presence of the in situ sand / silty sand stratum throughout most of the site should,in our opinion provide adequate phosphate reduction treatment, so as to have minimalimpact on any surface water features. In areas where raised septic systems areutilized, the imported sand fill will have the same phosphate reducing capabilities.
As such, it is our opinion that the surface water features will not be adversely impactedas a result of the on-site sewage disposal systems.
Report No: PH2108-1 (Update No. 1)August 10, 2015 Page 11
patersongroup Terrain Evaluation StudyOttawa North Bay Kingston Proposed Commercial / Industrial Subdivision
Boundary Road (Carlsbad Springs) Ottawa, Ontario
5.5 Sewage System Design
Sewage systems must be designed according to Part 8 of the Ontario Building Code(OBC). The OBC sets out minimum design and construction standards for all approvedclasses of sewage systems. It is proposed that this site be serviced with traditionalClass 4 sewage systems consisting of a septic tank and separate leaching bed.
OBC requirements state that the there must be a minimum of 900 mm of suitable soilor leaching bed fill present between the base of the absorption trenches and the highgroundwater table, bedrock or soil with a percolation rate greater than 50 min/cm. Some lots are located in areas with permeable cover which may permit either in-groundor partially raised leaching beds, however, depending on site grading, it may benecessary to use fully raised leaching beds due to high groundwater levels. In thesecases, an imported sand mantle having a minimum thickness of 250 mm and extendinga minimum of 15 m beyond the absorption trenches in the direction of effluent flowwould also be required.
5.6 Development Restrictions
Given the constraints on consumption that exist with the Carlsbad Trickle System, thedevelopment of the commercial / industrial subdivision is seen to be viable, as typically,water usage is low for this type of development. There should be restrictions in placehowever, that would limit the usage type, particularly if it could result in an exceedanceof the available capacity of water units assigned to this subdivision. Such high volumeuses that rely exclusively on water from the trickle system, that should be avoided areirrigation systems and industrial uses that rely on water as part of the production ormanufacturing process.
6.0 SUMMARY
Based on the results of this investigation, it is evident that the site is well suited to acommercial / industrial subdivision that will be serviced by on-site sewage disposal. Areview of existing land uses, particularly down-gradient of the site, would indicate thatthe proposed development will have minimal impact on off-site development. Highway417 provides for a forced barrier to development downgradient of the site, and a largeportion of the lands on the opposite side of Highway 417 have been developed as agolf course. Currently, there is no residential development in the downgradientdirection.
Report No: PH2108-1 (Update No. 1)August 10, 2015 Page 12
APPENDIX 4
FIGURE 1: KEY PLAN
DRAWING NO. PH2108-FIG.1: SITE LOCATION PLAN
DRAWING NO. PH2108-FIG.2: SURFICIAL SOIL DELINEATION MAPPING
DRAWING NO. PH2108-FIG.3: REGIONAL BEDROCK MAPPING
DRAWING NO. PH2108-FIG.4: SURFICIAL GROUNDWATER FLOW
DRAWING NO. 2108-1: TEST HOLE LOCATION PLAN