Application Guidelines HydrogeologicalStudies PrivateServices

2

GUIDELINES

FOR

HYDROGEOLOGICAL STUDIES AND

STANDARDS FOR

PRIVATE SERVICES

June 2000

TABLE OF CONTENTS

PART 1

INTRODUCTION ..........................................................................................................................................................1

PART 2

PRIVATE SERVICING GUIDELINES .................................................................................................3 2.1 PRIVATE SEWAGE DISPOSAL SYSTEMS .............................................................................3 2.2 PRIVATE WELLS ...........................................................................................................................4 2.3 WATER SUPPLY REQUIREMENTS ...........................................................................................4 2.3.1 Quantity .............................................................................................4 2.3.2 Quality ...............................................................................................5 2.4 MINIMUM LOT SIZING .................................................................................................................5

PART 3

REGIONAL GUIDELINES FOR CONDUCTING HYDROGEOLOGICAL STUDIES .............................................................................................................9 3.1 INTRODUCTION ............................................................................................................................9 3.2 TECHNICAL REPORTS ..............................................................................................................13 3.2.1 Preliminary Investigation Report................................................13 3.2.2 Hydrogeological Study Report ....................................................16

PART 4

PRIVATE WATER SUPPLIES .....................................................................................................................17 4.1 INTRODUCTION ..........................................................................................................................17 4.2 PRELIMINARY INVESTIGATION REPORT ..........................................................................17

4.2.1 General .............................................................................................17 4.2.2 Water Quantity...............................................................................20 4.2.3 Water Quality .................................................................................23 4.2.4 Well Construction..........................................................................25 4.2.5 Adjacent Lands & Water Uses.....................................................26 4.2.6 Other Considerations ....................................................................27 4.3 HYDROGEOLOGICAL STUDY REPORT ................................................................................27 4.4 ADDITIONAL INFORMATION ..................................................................................................28

PART 5

PRIVATE SEWAGE DISPOSAL SYSTEMS 5.1 INTRODUCTION ...........................................................................................................................31 5.1.1 Designated Areas Under Notice 3/78 .........................................33 5.1.2 Sewage System Impact Evaluation...............................................33 5.2 PRELIMINARY INVESTIGATION REPORT ...........................................................................35 5.2.1 Site Suitability ................................................................................35 5.2.2 Ground Water Quality Assessment............................................36 5.2.3 On-Site Predictive Assessment Residential Development...............................................................37 5.2.4 Off-Site Predictive Assessment...................................................39 5.3 HYDROGEOLOGICAL STUDY REPORT ................................................................................40 5.4 ADDITIONAL INFORMATION ..................................................................................................41

APPENDICES ........................................................................................................................................................................60

PART 1

INTRODUCTION

This document is intended to provide information to those persons who are seeking approval to develop land by way of private water supplies and/or private sewage disposal systems (septic systems). Such approvals are typically associated with plans of subdivision, condominiums, official plan amendments, severance applications and any other forms of development plans which would be based on individual private wells for water supply and/or on individual private subsurface sewage disposal systems. Information is also provided regarding the ground water and surface water interests of other agencies. For the purposes of approving development on private services, the Ministry of the Environment and Energy (MOEE) has delegated responsibility dealing with such matters, to the Regional Municipality of Halton and administered by the Halton Regional Health Department. The information contained in this document is, for the most part, generic in nature and is not intended to provide detailed methodologies for site specific studies. These will need to be developed on a case by case basis for individual development applications by the proponents and/or their consultants. By following the detailed procedures in this document, developers, together with Halton Region staff, will be able to confirm the private servicing potential of development properties. Private servicing capability is a prerequisite to any rural area development. Therefore, other land use planning concerns including Regional and local official plans and zoning and impacts on agriculture, mineral resources, hazard lands, environmentally sensitive areas and roads should be considered after site servicing capability is confirmed. The other planning matters should be integrated with servicing after the site servicing capability has been determined. Halton Region has been delegated by the Minister of Municipal Affairs as the approval authority for local Official Plans and amendments and also land development applications including subdivisions, condominiums, land severances and part-lot control exemptions and others. The Region evaluates and approves these various plans and development applications in comparison to the Halton Region Official Plan and associated policies and guidelines. Plans and applications for development on private services are only approved where the Region's private servicing requirements have been successfully incorporated. Where Regional water and wastewater services are not available, the Regional Official Plan requires all developments to be self-sustaining on private individual water wells and private individual sewage disposal systems. Partial servicing is permitted in some exceptions. Neither Public nor private

communal servicing is permitted.

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PRIVATE SERVICING GUIDELINES1

2.1 EVALUATION OF PRIVATE SEWAGE DISPOSAL SYSTEMS This section refers to conventional septic tank and tile bed systems, defined in the Ontario Building Code Act as the standard for development evaluation. The Region does not support new developments based on other types of private sewage disposal systems. Once new lots are created and registered, the approval of new private sewage disposal system installations is administered by the local municipality as part of the building permit process. (i) All land areas designated as sewage system envelopes to be used for the installation private

sewage disposal systems must meet the minimum dis tance requirements pursuant to the Ontario Building Code.

(ii) New development approvals on private sewage disposal systems require a sewage system

envelope of 700 square metres is maintained of vacant and suitable land be set aside and protected to permit the adequate installation of a conventional septic tank and tile bed system.

(iii) The tile field(s) must be adequately separated from all water supplies (wells) to meet the minimum

requirements of the Ontario Building Code and Ontario Regulation 903 (Wells), made under the Ontario Water Resources Act and as amended from time to time; or such greater distance as the Region may determine, based on such factors as topography, drainage, water table, or soil conditions, placement of services etc.

2.2 PRIVATE WELLS 1) Well construction and abandonment requirements shall be those established by the Ministry of the

Environment and Energy in the Ontario Water Resources Act and Ontario Regulation 903 (Wells) made thereunder and as amended from time to time.

2) All Land Division Committee decisions to approve individual residential severances on a private

water supply, approval is contingent upon compliance with the Regional Health Department's requirement that an "Adequate Private Well" be constructed on the proposed lot. Wells must be constructed in accordance with the requirements of Ontario Regulation 903, (Wells). Wells must also meet the requirements of the Regional Health Department with respect to both quantity and quality as described below. In such cases, the well driller's report, laboratory results of water analysis and inspections by Health Department staff will form the basis of evaluation.

The Regional Health Department will advise the appropriate Municipal Building Department as to whether a particular well meets regional private well water standards and whether the owner/applicant will be required to install a water storage tank (supplemental storage system) for potable water and auxiliary pumping system. 2.3 WATER SUPPLY REQUIREMENTS 2.3.1 Quantity The Medical Officer of Health (MOH), in carrying out his responsibilities under the Health Protection and Promotion

1Reference Appendix H - Urban & Rural Servicing Guidelines

Act, must determine the adequacy of domestic water supplies. The following criteria will be used to make this assessment. (a) Wells with a yield of 13.7 Litres/minute (three I.G./Min.) or greater is considered to be adequate for

normal domestic demands. (b) Wells with a yield of less than 4.5 Litres/minute (one I.G./Min.) are considered to be inadequate to

meet normal domestic needs. (b) Wells with a yield between 4.5 Litres/minute (one I.G./Min.) and 13.7 Litres/minute (three I.G./Min.)

may be approved provided that a water storage tank and auxiliary pumping system are installed to manage peak demands.

(c) Wells with a yield greater than 4.5 Litres/Minute may be considered inadequate where there is a

seasonal water supply problem and/or there is the potential for interference between existing off-site and proposed/existing on-site wells, existing or proposed private sewage disposal systems and other groundwater uses as determined by the hydrogeological assessment described in this document.

2.3.2 Quality A water supply well will be considered inadequate with respect to quality where: (a) a health related parameter of the Ontario Drinking Water Objectives is exceeded; or (b) where an aesthetic parameter of the Ontario Drinking Water Objectives is exceeded and is

above the concentration considered treatable by means of a private water treatment system or,

(c) a health hazard is anticipated due to well construction, or proximity to a private sewage

disposal system or other source of pollution (ie: feed lots, salt storage, industrial sites, etc.) and/or where the Region determines that costs are unreasonable to produce and maintain a satisfactory water supply.

2.4 MINIMUM LOT SIZING (a) General Minimum lot sizing refered to in this section deals with lot sizes solely private servicing. Larger lots than those necessary for private servicing may be required for other, non-servicing related reasons such as official plan or zoning by-law requirements. These Guidelines apply to the creation, expansion and/or alteration of boundaries of private serviced lots. Some existing lots do not conform to this guideline and development may be restricted or denied based on the ability of the lot to be "self-sustaining". The term "self-sustaining" referred in this section, means a lot of sufficient size and shape to accommodate the dwelling, private well and private sewage disposal system envelope; while maintaining compliance with Ontario Building Code requirements and O.R. 903 made under the Ontario Water Resources Act. (b) Single Family Residential Lots All new residential lots within designated Hamlets and Rural Clusters where overall hydrogeological studies have been carried out must meet the minimum lot size recommendations of the overall study, unless more detailed site-specific studies carried out to Halton's satisfaction recommend a smaller lot size. All residential lots within plans of subdivision located outside of Hamlets and Rural Clusters shall meet the minimum size recommendations of the site-specific hydrogeological investigations carried out to Halton's satisfaction.

For individual residential severances, it is not Halton's usual practice to require submission of site-specific hydrogeological studies, but in unusual conditions where servicing feasibility is suspect, such a requirement may be required. It is normal practice for the Health Department to evaluate the merits of a severance application of a particular size based on "minimum physical requirements" plus additional information concerning density and proximity of existing development in the area, lot shape, soil conditions, topography, water table, drainage, available hydrogeological information and the performance of existing private services in the area. (c) Industrial or Commercial Development For industrial or commercial plans of subdivision on private services, lot sizes will be determined based on the hydrogeological studies carried out to Halton's satisfaction. For individual severances for non-residential uses, a hydrogeological study may not be required if the proposed use is small scale with very few employees and only domestic water requirements. Applicants should contact the Halton Regional Health Department to determine the needs for a hydrogeological study prior to the commencement of the on-site investigation. Conditions of Approval As a condition of approval for all rural estate plans of subdivision, to be serviced by individual private services, the owner/applicant will be required to establish a private well, acceptable to the Regional Health Department, on each draft approved lot prior to Final Approval. In the case that no Regionally acceptable well can be established on any draft approved lot, said lot shall not be registered as a separate building lot, but will be either: a) merged with an abutting lot or b) the subdivision will be redesigned to the satisfaction of the Region. Proponents for industrial and commercial plans of subdivision may, as a condition of draft approval, enter into agreement with Halton pertaining to the operation of private wells and sewage disposal facilities and their relationship to site specific constraints or uses which may affect future operation. The agreement will be registered on title and fto ensure the terms will apply to successive owners.

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REGIONAL GUIDELINES FOR CONDUCTING HYDROGEOLOGICAL STUDIES 3.1 INTRODUCTION

In developing this guideline, consideration has been given to the most recent MOEE guidelines and policies. All

applications for development on private services will be assessed in accordance with the requirements of this part of

the guideline.

Preliminary Investigation

Prior to draft approval or an official plan amendment, the Region requires that a Preliminary Investigation be

undertaken and the results documented to demonstrate that the proposed privately-serviced project may be

accommodated on the development lands and will not have adverse effects on groundwater sources.

The most common components of the Preliminary Investigation Report in support of a land development application

or Official Plan Amendment include:

a) study of existing geological, hydrogeological and soil information,

b) soil testing and description through test pitting and/or soil borings,

c) ground water level measurement through ground water monitor and test well

installation,

d) aquifer identification through test drilling,

e) aquifer testing through test well and observation well installation, pump testing,

monitoring on-site and private off-site wells during pump testing,

f) ground water quality sampling of on-site ground water monitors, test wells and

off-site private wells.

g) on-site hydraulic testing of saturated soil through ground water monitors,

h) surficial soil identification through test ie: excavations/boreholes

i) laboratory grain size analysis of soil samples and

j) elevation survey of selected on-site and private wells

The above noted information is used to:

a) interpret the hydrogeological conditions beneath the property,

b) calculate the quantity of ground water available to water-supply wells on the

property

c) determine the prevailing ground water quality on the site and possibly nearby

private wells and/or ground water monitors,

d) predict the loadings of nitrates from subsurface sewage effluent disposal to the

groundwater system

e) assess the suitability of soil conditions and identify limiting factors (bedrock,

water-table proximity) on the property for sewage effluent disposal for purpose

of sewage system design,

f) calculate the potential impact on the shallow and/or deep ground water system

with respect to quantity and quality resulting from the proposed development

and

g) determine the extent to which predicted ground water impacts from the

development will affect existing on and off-site groundwater sources natural

features such as surface water, wetlands or natural areas.

Hydrogeological Study

As a condition of the draft approval or the Official Plan Amendment approval, the Region requires a Hydrogeological

Study be carried out to establish that wells, yielding adequate supplies of potable groundwater on each lot are

feasible. The study will also confirm that the proposed development will have no adverse quality and quantity

impacts in the existing groundwater sources adjacent to the proposed development. In some instances, the Region

may require the Hydrogeological Study prior to draft approval.

The most common components of the Hydrogeological Study include:

a) pump-testing and water-quality sampling of the water-supply wells installed on the individual lots

of the proposed development.

b) water-level monitoring of each pumped well, and nearby on-site observation well(s) and off-site

private well(s) within the potential drawdown-influence catchment of the pumped well.

c) elevation survey of selected on-site wells and private wells near the proposed development.

d) pump testing of any private well that experiences significant drawdown during any on-site well

test.

e) background quality testing of existing private wells downgradient from the proposed development

where adverse impacts are indicated by the mass-balance evaluation.

The above noted information is used to:

a) establish that each lot can provide a perennial water supply.

b) determine the off-site quantity impact and to develop Region-acceptable mitigation procedures

between the applicant and the affected persons.

c) corroborate the initial interpretation of groundwater flux and movement beneath the site and verify

that existing downgradient groundwater sources and natural features will not experience future

adverse ground water quality impacts resulting from the proposed development.

Processing Fees

The proponent will be required to pay the following costs associated with the assessment of his/her application:

• a pro-rated cost of the overall Hamlet Study

• costs associated with carrying out the Preliminary Investigation Report and the Hydrogeological

Study.

• costs associated with the Region's review of the Preliminary Investigation Report and the Study by

an independent hydrogeological consultant/retained by the Region, and associated meetings with

the proponent

3.2 TECHNICAL REPORTS Both the water-supply evaluation and the sewage-impact assessment of either the Preliminary Investigation Report

and the Hydrogeological Study Report must be submitted for review to the Regional Health Department. This

process ensures that water and sewage impact assessments have been comprehensively evaluated by the

proponents consultant.

3.2.1 Preliminary Investigation Report

Reports in support of development utilizing private wells and private sewage disposal systems must include the

following information:

i) Physical Setting

a) Provide regional and local maps which show site location and orientation with Lot and Concession

Numbers. Use maps of the scale that best describe the site and local features from the Ontario

Base Mapping or National Topographic Series.

b) Describe local land uses and servicing, surface topography, surface drainage conditions,

environmental features, wetlands, watercourses, and flood plains within at least 500 metres of the

site.

c) Identify present and previous on-site land uses, and determine possible contamination sources

(spills, refuse, fertilizers) that may necessitate a formal environmental audit.

ii) Water Supply

a) Describe the regional hydrogeologic setting.

b) Plot and locate representative well(s), observation wells and wells on an appropriate scale

(normally for areal well plots 1:10,000 maps should be used)

c) Tabulate local well depth (recorded and unrecorded) listing all relevant information (ie: log, depth,

static level, pumping water levels, pump setting, rated pumping capacity and screen(s).

d) Prepare at least two cross sections extending through the development lands and identify preferred

aquifer for water supply.

e) Estimate the recoverable on-site recharge and comment on the potential of aquifer mining.

f) Assess the susceptibility of the proposed water-supply aquifer to surface-derived contamination.

g) List the well construction particulars for each on-site test well, including:

i) detailed diagrams showing casing length and wall thickness, screen slot size, length and

diameter, top-of-casing elevation

ii) MOEE well logs

h) Provide pumping-test particulars for each on-site well, including:

i) graphical plots of the step test and the prolonged aquifer test (at the design for at least six

hours).

ii) analysis of the pumping test results (by Jacob or Theis method) with justification of

selected methodology. The analysis should discuss and identify the short-duration and

sustained (perennial) capabilities of the tested wells.

i) Discuss the water quality obtained at each test well in regard to the groundwater potability and

treatment requirements.

j) Evaluate the observed water-level responses in the adjacent private wells and determine the

possibility of future water-supply disruptions following completion of the proposed development.

k) Advise on possible mitigation measures where existing well interference occurred during on-site

testing.

iii Sewage Disposal

a) Plot locations of test pits/boreholes and water-table quality monitors, areas of shallow saturation,

and delineate distribution of major surficial soil types (excepting topsoil and/or upper 0.5 metre soil

veneer).

b) Provide graphical plots of grain-size determinations of representative soil samples.

c) Identify major soil types (below the upper veneer) influencing the infiltration of precipitation

(groundwater recharge) beneath the development lands.

d) Provide preliminary documentation on the leaching-bed design and tile-bed area requirements for

sewage-disposal systems conforming to the Ontario Building Code.

iv Quality Impact Assessment

a) Prepare potentiometric maps for the shallow groundwater system and for the water-supply aquifer,

showing the lateral groundwater gradients and direction of groundwater movement beneath the

site and defining the area downgradient of the property limits.

b) Determine the appropriate infiltration rate through the surficial sediments, recognizing the

distribution of the major soil types and possibly the vertical gradients established between the

defined shallow and deep groundwater systems.

c) Calculate the allowable development for the proposed residential or commercial/industrial

development, following the Region-approved direct dilution procedure.

d) Estimate the nitrate impact on downgradient sources, following the Region-approved dilution

procedure.

3.2.2 Hydrogeological Study Report

a) Summarize the pumping-test and water-quality results for each of the private water-supply wells

and confirm that adequate supplies of potable water may be realized on each lot of the proposed

development.

b) List the on-site monitoring results and advise on the significance of the observed water-level

responses.

c) Where significant interference is anticipated, provide a mitigative procedure acceptable to the

impacted persons and the developer.

d) Review the assembled nitrate values for the individual wells and confirm the development density

established in the previous Preliminary Investigation Report.

e) Obtain water-level elevations of selected individual wells to confirm the potentiometric surface and

groundwater flow and flux within the supply aquifer established in the previous Preliminary

Investigation Report.

f) Verify that adequate direct infiltration and/or underflow is available within the defined groundwater

system so that downgradient groundwater sources will not experience adverse nitrate increases as

deduced in the Preliminary Investigation Report.

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PRIVATE WATER SUPPLIES

4.1 INTRODUCTION

Prior to final approval, development proposals which require an on-site source of potable water will require a

complete hydrogeological assessment to determine:

a) the availability and sustainability of adequate groundwater supplies with respect to quantity and

quality; and

b) the potential for interference between water supply wells, existing off-site and proposed on-site

wells, existing or proposed sewage effluent disposal systems, and other uses (e.g., for maintenance

of stream flows where applicable).

This guideline describes the position of the Region regarding the assessment of water supplies for developments on

individual private wells. The guideline is based on past experience with development utilizing individual wells, and

reflects the need to ensure the future owners of lots or homes have a high probability of being able to obtain

adequate quantities of potable water for domestic consumption over both the short and long term.

This guideline applies to development proposals for residential development involving individual private well water

supplies. Development agreements between the proponent and the municipality, shall be used to bind development

to the recommendations of approved hydrogeology studies. This guideline also applies to condominiums and to industrial, commercial or institutional developments where water

is used for human consumption and the taking does not exceed 50,000 Litres in any day. The Region should be

contacted for information on the applicability of this guideline to other types of privately-serviced developments.

4.2 PRELIMINARY INVESTIGATION REPORT

4.2.1 General

A Preliminary Investigation Report will be required by the Region prior to recommendation of draft approval for plans

of subdivision and condominium, and may be required prior to approval of official plan amendments which would

permit development on private services. The study must be performed and a report submitted to the Region at the

time of circulation of the proposed Official Plan Amendment or plan of subdivision. The report must address

concerns relative to the following:

n Future residents must be provided with water for domestic consumption that is of acceptable

quality and of adequate quantity.

n Appropriate well construction techniques must be followed in order to minimise the possibility of

well water quality degradation.

n Developments must not result in water quantity interference conflicts between users in

the development and users on the adjoining lands within 200 metres from any on-site well.

With respect to quality, each test well must provide water that is safe and aesthetically suitable for human

consumption. The suitability of the water for domestic use is determined by comparing the results of the analysis of

ground water samples from test wells with the applicable ODWOs (listed in Part 5 - Appendix A).

With respect to quantity, each test well must provide sufficient water for normal domestic purposes. This will be

determined mainly on the basis of data from pumping tests in test wells. (Reference: Part 2).

Draft approval will depend on the completeness and accuracy of the Preliminary Investigation Report. If the

Preliminary Investigation Report is found to be incomplete, or provides insupportable interpretations the Region will

advise the proponent by letter with regard to the outstanding issues. The advice and recommendations must not be

construed as conditions of approval but rather as suggestions for those cases where the proponent wishes to

continue to pursue approval. The Region may not undertake its review until such time that a report satisfying the

requirements of this guideline has been submitted.

During the Preliminary Investigation Report, the site assessment to establish groundwater availability and quality

must be undertaken as follows:

i) The minimum number of test wells to be pumped and sampled will be:

n 3 for sites up to 15 hectares in area;

n 4 for more than 15 and up to 25 hectares;

n 5 for more than 25 and up to 40 hectares;

n for more than 40 hectares, one additional test well for each additional 20 hectares or

portion thereof.

Where a development comprises five lots or less, the Region should be contacted to determine if fewer test

wells are acceptable in defining the site conditions.

However, as many as one test well per lot may be required by the Region for any development where ground

water quantity or quality is considered marginal with respect to domestic requirements.

ii) The areal distribution of test wells must be such that hydrogeological conditions across the site are

adequately represented. More than the minimum number referred to in section i) above may be

required, depending on the areal configuration and hydrogeological complexity of the site.

iii) Consideration must be given to past or present land uses. Existing improperly abandoned wells are

to be identified since they may impact on ground water. Moreover, any contaminant spills on or

adjacent to the site which may affect water quantity or quality should be identified and evaluated

for their impact on ground water. The test wells are to be located in an area which would permit a

proper assessment of these impacts. The Preliminary Investigation Report should include

recommendations for proper abandoning of existing improperly abandoned wells, and test wells

which are not used for subsequent water supply in the future.

iv) Test wells must be located and constructed in such a way as to permit the prediction of

the quantity and quality of ground water which domestic wells will supply in the future.

Accordingly, the construction of these wells must be typical of wells which will be used in

the development in the future, and must comply with MOEE and Region requirements as

well as any additional specifications recommended by the consultant.

Consideration should be given to having at least one of the test wells drilled to depth to determine the

stratigraphic sequence and the presence of deeper aquifer zones. This information can then be used in

determining the preferred aquifer to ensure longevity of the water supply.

Existing water wells located on the site or in the immediate proximity of the site may be used as test wells, provided

they fulfil i) to iv) above, and are fully incorporated into the well water quantity and quality testing programs

described in the sections below. The use of existing wells and of the data obtained from them must be justified in the

report as being technically appropriate; however, there must be at least one acceptable test well, new or existing,

located on the site. Such wells which are to be used must have a water well record which has been accurately and

fully completed. The integrity of the well and its record are essential to ensure that comparison is being made on the

basis of reliable information, and that wells being established on the development site will not be compromised.

If the consultant and licensed well contractor properly locate and construct the test wells, or if there are pre-existing

wells on the property which meet the requirements of iv) above, the developer may use them later as domestic water

wells. They must, however, yield potable water and meet the construction requirements indicated in the approved

study recommendations, which are implemented by provisions in the development agreement between the

municipality and the proponent. If any such wells are not to be maintained for future use, they must be properly

abandoned as required by Ontario Regulation 903. Abandonment must be recommended in the hydrogeological

study report and must be implemented by the development agreement. To ensure that the recommendations of the

report are properly implemented, the consultant's report may include recommendations for supervision of well

construction by a qualified consultant at the time the well is being constructed by the licensed well contractor.

4.2.2. Water Quantity

Each of the test wells constructed during the Preliminary Investigation Report must be subjected to a pumping test.

The tests may be done sequentially, using the other wells as observation wells, or several wells could be pumped

simultaneously. Consideration should be given to pumping a test well at the total subdivision water demand rate (if

possible) in order to clearly demonstrate the capacity of the aquifer to supply the anticipated demands.

Pump Test Procedure

During the Preliminary Investigation, the following pumping test procedure is required at each test well site:

• a house-to-house survey shall be undertaken to locate accessible water supply wells in the vicinity

of the proposed development. Accessibility of the well for monitoring shall be the responsibility of

the property owner. Should the well remain inaccessible or should the owner not provide

permission for monitoring, the consultant shall document such circumstances in his report.

• the test wells shall be fully developed prior to the pumping test in order to establish the prevailing

turbidity levels in the aquifer.

• the test well shall be step tested at three rates up to the maximum well or pump capacity.

If the water taking during the test will exceed 50,000 L/day a temporary Permit To Take Water will be required

for this type of test. Sufficient information and time should be given to MOEE staff for evaluation and

issuance of the Permit if required. Consideration must be given to where the pumped water is to be

discharged, in order to avoid artificial recharge of the pumped aquifer and any other adverse environmental

impacts.

• the test rate shall be at least the minimum rate discussed in the following subsection.

• the pumping test must begin with a static water level and must be performed at a fixed rate (±5%)

for a minimum period of six hours2 (longer where supplementary storage systems are necessary) of

"continuous" pumping (no stoppages); water levels must be monitored in the test well and any

accessible wells within 200 metres at an appropriate frequency; water must be discharged at an

appropriate distance from the test well to ensure that artificial recharge does not occur;

• immediately following the pumping test, water level recovery must be monitored in the test well

until 95% recovery occurs or for 24 hours, whichever is less. Where sufficient recovery does not

occur, the issue of the long-term safe yield of the aquifer is especially significant and must be

addressed in the Preliminary Investigation Report.

• Should a drawdown exceeding 0.5 metres be recorded in an off-site well during the above testing,

the consultant shall undertake the pump testing of that well to ascertain the effect of such

drawdown on the water-supply availability at the impacted residence or facility.

If water-supply disruptions are observed/predicted, the consultant shall document the proposed

mitigative commitments between the affected person and the developer in the Preliminary

Investigation Report.

Calculation of Minimum Test Rate and Well Yield

The minimum pumping test rate and well yield required for a particular development must be calculated as follows:.

2 The minimum duration of six continuous hours incorporates safety factors with respect to seasonal variables.

The per-person water demand shall be 450 Litres per day. Peak demand occurs for a period of 120 minutes each day3.

This is equivalent to a peak demand rate of 3.75 Litres/minute for each person. The basic minimum pumping test rate

is this rate multiplied by the "likely number of persons per well" which, for a single family residence, shall be the

number of bedrooms plus one. Unless it is otherwise established to Region satisfaction, a minimum of four bedrooms

shall be used in the calculation to calculate the daily and peak demands.

The only instance where a rate lower than the above rate may be used is where preliminary results indicate that the

pumping test rate cannot be sustained in the long term, and consideration is given to systems which would

compensate for low well yields. In this case, the test rate may be decreased to a rate not less than 4.5 Litres/minute,

but the pumping duration must be proportionately increased such that the total volume of water pumped equals the

volume that would have been pumped if the test had been conducted at the above calculated minimum rate for a

continuous six-hour period. The yield requirement must then be applied to the well and to the compensatory system

on a daily basis. These systems and any special water treatment devices that may be necessary for their proper

functioning must be fully described in the report.

An auxiliary system will include storage and repressurization and will be required where the test rate is less than 13.7

litres/minute. It is recommended that the storage system be sized to compensate for peak daily use and any lawn

irrigation.

Regardless of whether systems are required to compensate for low yields, new domestic wells will be required to

sustain repeated pumping at the test rate and duration at 24-hour intervals over the long-term.

Where a test well can safely provide water at the calculated rate, it is not acceptable to conduct a pumping test at a

lower rate and subsequently recommend the use of a system to compensate for low well yield simply in order to limit

the migration of poorer quality water into the well. Consultants must provide a statement in the Preliminary Investigation Report indicating that, in their professional

opinion, the probable well yields determined on the basis of their investigations are representative of the yields

which residents of the development are likely to obtain from their wells in the long term.

4.2.3 Water Quality

The consultant must obtain and analyze sufficient raw-water quality samples during the pumping test on each test

well to determine the physical, chemical and bacteriological quality of the water. At least one sample must be

collected during the last hour of the test. The consultant may wish to periodically obtain additional samples during

the pumping period, since the consultant must address water quality changes over time and demonstrate that the

water quality data are representative of the long-term quality.

Prior to any sampling testing for bacteriological water quality, there must be no chlorine residual in the groundwater.

3 Refer to page 5 of the MOEE publication entitled "Water Wells & Ground Water Supplies in Ontario", 1989. The per-person daily demand use

here is the upper limit of the estimated range.

The consultant shall conduct chlorine residual tests at the well head and shall document that zero chlorine residual

was obtained and the time that bacteriological samples were obtained.

Where there are wells in nearby established developments, information is to be obtained from residents, where

possible, and other sources regarding water quality problems. If on-site sewage systems are used in the existing

development(s) and are also to be used in the proposed development, well water samples from the existing

development should be obtained and analyzed. The consultant should use this information to predict the impact of

the proposed on-site sewage systems on water quality within the proposed development.

Water quality may vary between aquifers or with depth in the same aquifer. The consultant should recommend

appropriate well construction and must comment on the potential for cross-contamination between aquifers.

Shallow and/or unconfined aquifers are susceptible to contamination from sources located at or near the ground

surface. If wells are to be constructed within such aquifers, and especially where individual on-site sewage systems

are also proposed, the consultant must address the risk of contamination and recommend measures which will reduce

that risk.

The minimum set of parameters for which the analyses must be performed is listed in the Part 5, Appendix A.

Analysis procedures must provide results below the applicable Ontario Drinking Water Objectives. Other

parameters, such as heavy metals, pesticides, tannins, sulphide, phenols, and fluoride, may be required by the

Region. The consultant must also determine whether conditions specific to the site or its surrounding area require

the inclusion of additional parameters. Complete documentation of sampling times, any on-site analytical methods,

and all analytical results must also be included in the report.

If methane or other potentially hazardous gases are encountered during the water supply assessment, the consultant

must make recommendations to adequately control this hazard in the Preliminary Investigation Report.

Note: Where health-related ODWOs or treatment limits for aesthetic ODWOs have been exceeded, the areas which

the relevant test wells represent may have to be excluded from the proposed development site. In this case

a justification for the selection of the boundary of the site is required.

Treatment Systems

For some aesthetic parameters, the ODWOs may be exceeded provided that concentrations are below the treatment

limits noted in Table 3, Part 5, Appendix A. The Appendix lists these parameters, the limits for treatment and some

comments on treatment methods. In cases where raw water sodium levels exceed 20 mg/L, warning clauses should be

registered on title. In addition, if water softening is utilized to reduce hardness, a warning should be registered on the

title with a recommendation that a separate tap, which by-passes the softener, be installed to supply unsoftened

drinking water.

The treatment systems mentioned in Table 3, of the Appendix A, are suggested for treatment for single parameters.

When treatment for more than one parameter is required, the systems suggested may not be appropriate due to

treatment process interferences. The consultant must supply recommendations regarding the type of treatment

required.

4.2.4 Well Construction

Construction specifications for future domestic wells in the proposed development must be addressed by the

consultant in the hydrogeological report. Minimally, the construction of both the test wells and future domestic

wells must comp ly with Ontario Regulation 903 made under the Ontario Water Resources Act, and with municipal

requirements - where applicable.

When on-site sewage systems are proposed, or when they already exist on adjacent property, protection of the wells

from contamination by effluent must be addressed.

When shallow and/or unconfined aquifers are to be used, the consultant must recommend construction

specifications and well locations to address the issue of the susceptibility of such aquifers to contamination from

sources at or near the ground surface.

Well locations must be selected in order to minimize the impacts on the location of leaching beds

on adjoining lots.

The consulting hydrogeologist should try to work with the planner or site engineer in producing the

development plan. Well and sewage systems would then be incorporated at an early stage in the site

design, thereby optimizing site resources for water supply and sewage treatment. Storm water management

should also be taken into consideration when siting a well and a sewage system.

Water quality may vary between aquifers or with depth in the same aquifer. The consultant should recommend

appropriate well construction, methods and requirements, and must comment on the potential for

cross-contamination between aquifers.

The consultant or the Region may wish to recommend additional site-specific construction criteria and/or supervision

of well construction by qualified staff. In studies in which the consultant's initial findings show that water quality or

quantity standards cannot be met without special well construction specifications, the initial data which led to these

conclusions must be included in the report. The structure of the test wells on which the final quantity and quality

data are based mu st meet these specifications and the wells must be tested according to the procedures stipulated in

this Guideline, in order for the data to be deemed representative.

Subsections 13(2) and 13(3) of Ontario Regulation 903 require that wells be constructed such that the casing of a

drilled well protrudes at least 30 centimetres above ground surface or above the floor of a well pit. Well water

contamination caused by the entry at the well head of water originating at or near the surface may occur if the well

head is buried. Subsection 20(3) requires that the well owner maintain the well in a manner sufficient to prevent such

contamination. Where well heads are buried, locating, inspecting and servicing the well are difficult and expensive.

Subsections 13(2), 13(3) and 20(3) are often contravened when, after a well is constructed, contractors or residents

bury the well head for reasons of convenience or aesthetics. Contractors and residents should be reminded of the

intent and requirements of these portions of the Regulation, and of their responsibility to ensure that the finished

grade of the ground surface allows the casing to protrude the required distance. This is necessary to prevent

ponding at the well head or, in the case of well pits, prevents flooding of the pit. Where flowing well conditions

occur, the requirements of Regulation 903 must be met. The consultant must address these issues in the Preliminary

Investigation Report and make the appropriate recommendations.

The MOEE requires proper well construction and abandonment of any unused previously existing wells and/or test

wells so that ground water contamination is prevented.

4.2.5 Adjacent Lands & Water Uses

Land uses within a minimum of 500 metres of the site must be described. Where wells exist on or adjacent to the site,

a survey of well owners, static and pumping levels and sampling and analysis of representative well water, should be

performed and reported. Accessible off-site wells within 200 metres from any development well shall be monitored

during the on-site pumping test. The potential for an adverse impact to or by the development must be addressed,

when there have been, are, or may in the foreseeable future be significant potential sources of ground water

contamination (e.g., from old, operating or proposed waste disposal sites, road salt storage facilities, farming

activities, locations of contaminant spills, etc.), or potential causes of quantity interference with ground water

resources or well water supplies (e.g., from municipal wells, dewatering activities, etc.) within a minimum of 500 metres

of the site. The issue of whether additional water quality parameters should be included in the testing must also be

addressed.

4.2.6 Other Considerations

Shallow wells and unconfined aquifers are susceptible to seasonal fluctuations in water level. In these cases, the

consultant must comment on the magnitude of such fluctuations and the effect on well yields and may need to

perform additional investigations to determine the possibility of future well water quantity problems.

Ground water heat pumps which do not return water to the aquifer of origin are not permitted. It is recommended that

the consultant address the potential impact on water quality of the return of water from ground water heat pump

systems to the aquifer of origin. (Provincial regulation and policy with respect to ground water heat pump systems is

under development.) Typical treatment systems requiring "additional water" would be water softeners, iron filtration

units, and reverse osmosis units. If treatment systems which require additional amounts of water for their operation

are to be used, those rates must be added to the calculated minimum well yield.

4.3 HYDROGEOLOGICAL STUDY REPORT

The well construction, test pumping and quality sampling procedures are similar to those described in the Preliminary

Investigation Report, with the following modifications/exceptions:

i) Provided that the well can be tested at the calculated peak demand rate discussed earlier in this guideline a

step test is not required on the well servicing the individual lot.

ii) The well shall be continuously pumped for a minimum period of three hours if drawdown stabilization is

observed during this test interval or otherwise the test should be continued for a minimum duration of six

hours. Water levels must be monitored in the nearest on-site wells and in any accessible off-site well within

a distance of 200 metres from the pumped well.

iii) The well shall be developed to obtain a turbidity level not greater than five (5) NTU, being the concentration

considered to be reasonably treatable by the MOEE (Part 5, Appendix A).

iv) Water quality testing of the individual wells shall be undertaken on one sample collected near the

termination of the pumping test and shall at least include:

• E. Coli and Total Coliform bacteriological determinations (on samples with zero chlorine residual)

• Iron, Manganese, Sodium

• Nitrate, Chloride, Sulphate

• Dissolved Organic Carbon

• Turbidity, Colour

• Hardness & Alkalinity

v) Based on the observed drawdown and recoveries in the pumped wells and the private wells, the consultant

shall confirm that adequate supplies of potable groundwater (with or without treatment) will be continuously

available within the subdivision and the adjoining private properties.

4.4 ADDITIONAL INFORMATION

It should be noted that the Region will not recommend approval for official plan amendments, draft plans of

subdivision or condominium or other development plans, unless the Region is satisfied with the Preliminary

Investigation Report. Where ground water of adequate quality and quantity is demonstrated to be available to

service the proposed development, the Region will require, as a condition of final approval, that the development

agreement between the municipality and the developer, include the recommendations of the Preliminary Investigation

Report.

If groundwater open loop heat pumps are being considered for use in the proposed development, an assessment

must be included in the hydrogeological study to ensure that domestic potable water supplies will not be adversely

impacted. If the issue of ground water heat pumps is not addressed in the report, the Region will request that a

condition be placed in the development agreement indicating that the use of ground water heat pumps has not been

approved as part of the development.

The possibility of using systems to compensate for low well yields (for example, controlled pumping to

supplementary storage) is discussed earlier in this guideline. If the Region agrees to their use, notification will be

given through the development agreement between the municipality and the proponent(s).

With respect to water quality, the following will apply (except for the 20 mg/L warning level for sodium):

Where health and aesthetic ODWO criteria are met, the Region will comment favourably on

approval of the Official Plan Amendment or on draft approval of the Plan Subdivision or

Condominium.

- Where health-related ODWO criteria are not met, the Region will recommend against approval of

the proposal on the basis of individual wells.

- Where health-related ODWO criteria are met but aesthetic objectives are exceeded, it may be

possible to use in-home water treatment systems to reduce the values of the aesthetic parameter(s)

concentrations to a level below the limits, and thereby meet the objectives.

This guideline lists concentrations considered treatable for several aesthetic parameters and some possible treatment

systems (Table 3, Part 5, Appendix A). If the Region agrees to the use of in-home treatment systems, notification will

be given through the development agreement between the municipality and the proponent(s). The local municipality

also shares responsibility for ensuring that the terms of the development agreement are carried out.

PART 5

PRIVATE SEWAGE DISPOSAL SYSTEMS

5.1 INTRODUCTION

Development applications which propose to employ on-site subsurface private sewage disposal systems will be

required to include a terrain analysis and hydrogeological assessment to determine:

a) the suitability of the site conditions for subsurface sewage systems and

b) the potential on-site and off-site impacts on the ground water systems and surface water features.

All proposed development on private services will be reviewed on the basis of being capable of supporting the

installation of a conventional septic tank and tile bed system, maintaining an area of vacant and suitable land of at

least 700 square metres.

The purpose of the guideline is to protect the environment and public health by ensuring that development utilizing

individual on-site sewage systems proceeds at a density and scale which will not result in, or cause degradation of,

ground water resources in exceedance of acceptable limits. Compliance with acceptable limits shall be demonstrated

through predictions of the development's nitrate impact on the ground water at the development boundary and at

existing downgradient residences within 500 metres from the development.

This guideline has been assembled with the recognition that each proposed development site has finite resources

available to treat sewage, and that the resources are highly variable on the development site itself. Evaluation of the

quality impact at the Preliminary Investigation should allow a realistic indication of the supportable development

density before substantial costs are incurred by the proponent.

This guideline applies to:

• the combined or total impact on ground water of a development proposal of more than five units

with individual on-site sewage systems.

• The guideline applies to residential, recreational, institutional, commercial and industrial proposals

which use individual on-site sewage disposal systems for the treatment of domestic waste having

flows of less than 10,000 Litres/day and/or

• Applications for development proposals involving five or fewer units or for individual severances

at the discretion of the Region. This guideline does not apply to: • Large Subsurface Sewage Disposal Systems greater than 10,000 Litres/day.

• the assessment of impacts of existing isolated individual residential sewage systems or

interference between individual home systems on existing neighbouring lots within a

subdivis ion or

Although the Health Department may support a proposal involving individual on-site sewage systems, it

does not assume responsibility for failure of the system(s), for correcting the damage to adjacent properties,

or for the construction of new sewage systems. This is the responsibility of the proponent/owner of the

system.

5.1.1. Designated Area Under Notice 3/87

Deleted

5.1.2. Sewage System Impact Evaluation in Non-Designated Areas

Deleted

5.2 PRELIMINARY INVESTIGATION REPORT

5.2.1 Site Suitability

An assessment of shallow on-site soil conditions, depth to ground water table, depth to bedrock and terrain

conditions must be undertaken to determine the site suitability for sewage effluent leaching bed construction.

The focus of the soil investigation is to assess:

a) the hydraulic capabilities of the on-site soils for subsurface sewage effluent disposal and

b) the infiltration capacity of the surficial soils and the ambient nitrate content at the water table for

establishment of the supportable development density.

The Health Department will review the soil investigation results as a requirement for consideration of draft

approval of the proposed development. The hydrogeological information required for the Preliminary

Investigation Report in assessing the sewage system design and the individual on-site systems include the

following components:

i) the installation of test pits and/or boreholes extending to at least 3.0 metres or to bedrock refusal,

equally distributed at approximately one excavation/borehole per 2.5 hectares of the development

property. A minimum of four test pits and/or boreholes shall be installed for any proposed

development.

ii) the detailed geologic of such installations including soil texture, density, colour and moisture

content, and the grain-size analysis of at least four representative soil samples and one additional

sample per 5 hectares or portion thereof above 10 hectares.

iii) the collection of water samples for background determinations from at least two water-table monitors

equally distributed throughout the development lands and one additional monitor per 5 hectares or

portion thereof above 10 hectares. These monitors may be included as part of the testing described

under i) above. Should the water table occur below the overburden-bedrock contact, samples

collected from the on-site test wells may be considered to represent the background quality

conditions.

5.2.2 Ground Water Quality Assessment

Every proposed development involving individual on-site sewage systems requires an assessment of the

ground water quality impact. The purpose of the assessment is to ensure that the combined effluent

discharges from all the individual on-site sewage systems in a development will have a minimal effect on the

ground water beneath the property and on present or potential uses at the adjacent properties. For the

purposes of this guideline, the ODWO of 10mg/L of nitrate-nitrogen is used as an indicator of the maximum

ground water impact. This guideline sets out the major considerations which should be included in a quality-

impact assessment acceptable to the Region.

a) For the purposes of this guideline, the only exceptions to the use of ground water for anything other

than a drinking water supply shall be reasonable uses which involve water quality more stringent

than defined by the Ontario Drinking Water Objectives (for example: providing baseflow and/or

maintaining quality of a cold water trout stream),

b) Ground water impact predictions shall be calculated for the development downgradient property

boundary and for the area extending 500 metres from the downgradient boundary. c) The consultant must make recommendations regarding the optimum location and orientation of

leaching beds. In general, the attenuative capabilities of a site can be optimized by maximizing

separation distances between individual on-site systems, the on-site wells, and downgradient wells

and property boundaries.

d) The impact of the on-site discharge of sewage effluent into surface water must be evaluated where

the permanent receiving water body occurs within 500 metres from the downgradient property

boundary. This work must be done by qualified individuals and must address potential impact from

phosphorus and other parameters which may be of concern listed in the MOEE Guideline B-1-1

Water Management - Policies, Guidelines, Provincial Water Quality Objectives of the Ministry of

Environment and Energy. The concentration of phosphorus used in assessing the potential impact

of sewage effluent should normally be 15 mg/L.

5.2.3 On-Site Predictive Assessment

Residential Development

In the Preliminary Investigation Report, the Region requires the following considerations and assumptions to

be used in assessing the combined nitrate impact of individual on-site sewage systems at and downgradient

of the development boundary:

a) Nitrate Source: In most cases total nitrogen (all species) converted to nitrate-nitrogen is

considered as the critical contaminant. For the purposes of predicting the potential for

ground water impacts, a nitrate loading of at least 40 grams/ lot/ day per residential dwelling

unit shall normally be used. This is based on expected flows of 1,000 L/day and a minimum

value of 40 mg/L nitrate-nitrogen in the discharge from domestic/household sewage.

b) Nitrate Dilution:

i) In assessing the nitrate impact, only on-site infiltrating precipitation will be

accepted by the Region as a quantifiable dilution mechanism.

ii) Mixing with ground water flowing through the site underflow will not be allowed

as it may not be possible to control upgradient land uses.

iii) The on-site groundwater recharge rates acceptable to the Region without site-

specific investigation are listed in Appendix B, according to the predominant soil

textures.

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Detailed studies will be required if higher rates than listed in this appendix are considered for a

development proposal.

iv) Estimates of the on-site recharge shall consider the post-development

impermeable areas (including roof tops and paved areas).

v) Mathematical (computer) models may be used to demonstrate the on-site

infiltration potential. Although the model selection will be left to the proponent,

the Region must be provided with information on the model, reliability validation,

limitations and assumptions. All model simulations must include appropriate

sensitivity analyses.

vi) Appendix C exemplifies an on-site nitrate-impact evaluation for a privately-

serviced residential subdivision, based on the key Region considerations. The

calculated residential density may not be increased where the water body

receiving the nitrate loading abuts or traverses the subject property.

Industrial/Commercial Development

This guideline only applies to developments in which individual lots have an average daily flow of less than

10,000 L/day/lot, as otherwise the development would be assessed by the MOEE. In addition, the sewage

must only consist of domestic wastes. No industrial/ commercial cooling or process wastewater is to be

considered.

The nitrate loading from industrial/commercial individual on-site systems can vary greatly depending on the

type and intensity of use. Since specific uses for each lot or block may not be known at the planning

document review stage, it is necessary to determine how much nitrate can be discharged from each individual

on-site system without exceeding the maximum limit of 10 mg/L at the property boundary. In the Preliminary

Investigation Report, the following procedure is followed in establishing maximum allowable effluent flow for

each lot:

a) Available Infiltration:

i) The ground water recharge ratio listed in Appendix B, must be used unless

detailed water balance and/or ground water studies, support a higher ratio for the

on-site soils.

ii) Estimates of the ground water recharge must consider the post-development

impermeable areas (including roof tops and paved areas).

b) Maximum Allowable Flow:

The maximum allowable flow for each lot or the entire industrial/ commercial/development can be

calculated by dividing the calculated infiltration by a factor of four.

c) Maximum Number of Users:

To determine the maximum number of persons which can be supported by the calculated allowable

flow, reference should be made to the Ontario Building Code. Restrictions regarding the allowable

number of users will normally be incorporated as recommendations in the consultant's assessment,

and the recommendations shall be implemented by provisions in the development agreement

between the proponent and the municipality.

d) Appendix D exemplifies an on-site nitrate-impact evaluation for a privately-serviced

industrial/commercial development, based on the key Region considerations.

5.2.4 Off-Site Predi ctive Assessment

In the Preliminary Investigation Report for both residential and commercial/industrial developments, the

Region requires an evaluation of the potential nitrate impact that may occur within the existing privately-

serviced areas situated within 500 metres downgradient from the proposed development boundary.

a) Contaminant Source

In predicting the nitrate increase, all residential dwellings shall be considered to produce 40

grams/lot/day of nitrate-nitrogen and commercial/industrial development shall be considered to

produce a nitrate loading equivalent one-quarter of the available on-site infiltration and to contain 40

mg/L nitrate-nitrogen.

b) Nitrate Dilution

In assessing the off-site nitrate impact, the upgradient and downgradient recharge occurring within

groundwater flow channel that frames the development may be utilized to evaluate the

quality impact in the existing downgradient groundwater sources. All residences within the

flow channel 500 metres upgradient and downgradient from the development shall be

included in the mass-balance appraisal. The upgradient recharge contribution may be

deduced by evaluation of i) the soil types and infiltration rates in the defined catchment

area and/or ii) the prevailing lateral gradient and water-transmitting capacity of the

developed aquifer, as appropriate. Ambient nitrate concentrations and impermeable

surfaces may be disregarded in the mass-balance calculation.

If the calculated nitrate concentration exceeds 8 mg/L downgradient of the development, additional studies

will be required during the Hydrogeological Study Report to demonstrate acceptable impact. Where an

acceptable nitrate concentration is calculated, downgradient of the development, the excess groundwater

recharge underflow may not be utilized in determining the development density.

Appendix E provides a simplified mass-balance calculation of the off-site nitrate impact to assist in the

interpretation of this Region requirement.

5.3 HYDROGEOLOGICAL STUDY REPORT

The Hydrogeological Study must evaluate the ability of the site to treat sewage within acceptable on-site and off-site

impacts as identified in this guideline. All data from the Preliminary Investigation Report is to be included with the

Hydrogeological Study Report, including the private water supply evaluation. (Reference section 3.2.2 of this

guideline).

5.4 ADDITIONAL INFORMATION

For development applications (official plan amendments, plans of subdivision or condominium) involving more than

five lots with individual on-site sewage systems, the quality assessment must be completed in accordance with this

guideline to demonstrate that acceptable nitrate levels will occur within the development and downgradient of the

development, and the quality impacts on surface water will be within tolerable limits. Shoreline development

proposals will be reviewed on a case-by-case basis.

The ground water impact assessment must be approved by the Region prior to draft approval of plans of subdivision

and condominium, and prior to approval of most official plan amendments. If calculated nitrate concentration exceeds

10 mg/L within the development or downgradient of the development, the Region will not accept the development

application as submitted for review.

As part of the draft approval, the MOEE will receive a copy of a fully-executed subdivision/ condominium agreement

or other suitable development agreement between the municipality and the developer. The agreement will require

that the recommendations of the impact assessment report as approved by the Region be implemented.

For industrial or commercial development applications involving individual on-site systems, the Region will require that a municipal by-law be enacted for the subject lands restricting the industrial/ commercial uses to "dry industrial/ commercial uses".

APPENDICES Appendix A Groundwater Quality Parameter Tables - Preliminary Investigation Report Appendix B Groundwater Recharge/Infiltration Appendix C Example On-Site Nitrate Calculation For Private Serviced Residential Subdivision Appendix D Example On-Site Nitrate Impact Calculation For Privately Serviced Commercial/Industrial Subdivision Appendix E Example Off-Site Nitrate Impact Calculation For Privately Serviced Residential Subdivision Appendix F Glossary of Terms Appendix G Reference Document Listing

APPENDIX F

GLOSSARY OF TERMS

Accessible Well: A water-supply well in which the water level may be measured by wetted tape or electric depth gauge. Access into the well for such monitoring shall be the responsibility of the well owner.

Adverse Quality Impact: An increase in the off-site concentration of a chemical parameter above the Ontario Drinking Water Objective, deduced to occur from the proposed sewage loading of a development.

Combined Impact: Refers to the blended quality impact of all the individual on-site systems on the development site. The impact effluent discharge on groundwater is not assessed on

a plume-by-plume basis.

Health Department: Ground Water Recharge: Hydrogeologically Sensitive: Potable Water: Private Services:

The Medical Officer of Health of the Regional Health Department and Public Health Inspection staff mandated under the Health Protection and Protection Act The entry of infiltration precipitation into the saturated zone below the water table surface. An area delineated in the Regional Municipality of Halton document titled "Halton Aquifer Management Plan, Phase 1 Report: Background Hydrogeology, February 1995", in which additional sensitive studies may be required by the Region in support of proposed privately serviced developments. Water that meets the MOEE Ontario Drinking Water Objectives for the chemical and bacteriological parameters listed in Appendix A, or that contains aesthetic parameters exceeding these objectives at concentrations considered to be reasonably treatable. Individual on-site private sewage disposal system and private well water supply.

Private Sewage Disposal System: Private Water Supply:

An on-site Septic Tank and Tile Bed System regulated by the Ontario Building Code. Individual On-Site Well constructed in accordance with O.R. 903 under the Ontario Water Resources Act.

Significant Interference: A water level lowering in an off-site well that prevents the previously established abstraction of groundwater supplies by the pumping of an individual well or several wells within the development.

Supply Aquifer: An overburden or bedrock system which is or which may be used to provide domestic water supplies.

APPENDIX G

REFERENCE DOCUMENT LISTING

Conducting Hydrogeological Studies Regarding Development On Private Services 1 - Health Protection & Promotion Act 2 - Ontario Drinking Water Objectives 3 - Ontario Regulation 903 - Wells 4 - Technical Guideline for Individual On-Site Sewage Systems: Water Quality Impact Risk Assessment ( March, 1995 ) 5- Ontario Building Code Act

6 - Technical Guideline for Private Wells: Water supply Assessment ( March, 1995 ) 7 - Guideline B-7 ( Formerly Policy 15-08 ) The Incorporation of the Reasonable Use Concept into the Ground Water Management Activities of the Ministry of the Environment 8 - Notice 3/87: Protection of Ground Water Quality 9- Official Plan of the Region of Halton ( approved by the Ministry of Municipal Affairs and Housing, November 27,1995) 10- Memorandum of Understanding with the MOEE 11 - MOEE Guideline B-1-1: Water Management Policies, Guidelines, Provincial Water Quality Objectives of the Ministry of Environment and Energy ( July, 1994 )

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