Source Water Protection

Image of the 19 Source Protection Regions (SPRs) and Source Protection Areas (SPAs) in Ontario (Conservation Ontario, 2022). Visit the map link here for a higher resolution image.

Overview

In response to the Walkerton tragedy in May of 2000, where 2,500 residents of the town fell ill due to ingesting high levels of E.coli bacteria and 7 individuals died due to poor monitoring and maintenance of the drinking water system, the Province of Ontario enacted new rules and safeguards to ensure drinking water sources are adequately protected. Following an inquiry into the Walkerton tragedy, Justice O'Connor made over 120 recommendations to better protect the province's drinking water, which have formed the foundation of the province's source water protection framework. The first of the Walkerton Inquiry recommendations was that drinking water should be protected by developing watershed-based source water protection plans.

Source Water Protection in Ontario

The Clean Water Act requires municipalities to protect their drinking water sources and supplies through prevention, by developing collaborative, watershed-based source water protection plans.

Ontario’s Clean Water Act is the primary piece of legislation within the province to ensure that there is a multi-barrier approach to protecting drinking water and ensuring water resource usage is sustainable (Photo Source: Conservation Ontario, 2016)

The Clean Water Act defines source water protection areas and source water protection regions as follows:

• Source Protection Region (SPR): Encompass one or more source protection areas (e.g., Credit Valley-Toronto and Region-Central Lake Ontario, or "CTC" Region).
• Source Protection Area (SPA): Smaller geographic areas generally based on the watershed boundaries of Ontario's 36 Conservation Authorities

Under the Clean Water Act, local multi-stakeholder source water protection committees have been established for each source water protection area or region. Each committee is comprised of the region's leading researchers, professionals and technical experts that work together to identify current and potential future threats to municipal drinking water sources. Organizations typically represented on source water protection committees include, but are not limited to the following:

• Conservation authorities;
• Municipalities;
• Local public health boards;
• Indigenous groups, committees and governments;
• Local businesses; and
• Province of Ontario.

The source water protection committee may use a variety of approaches to protect drinking water sources, which can include:

• Prescribed policy instruments (existing provincial approvals such as Environmental Compliance Approvals and Permits To Take Water);
• Requiring landowners to prepare a formal risk management plan (negotiated individually);
• Specified land use planning policies;
• Prohibition of activities within protection areas or zones that may prove detrimental to drinking water sources; and/or,
• Outreach and education activities (webinars, town meetings, pamphlets, online education hubs) (CTC SPR, 2019)

Under the Clean Water Act, 2006 a total of 19 source protection regions and areas have been established across the province (see map above). Each have their own local multi-stakeholder source protection committee, and have developed 38 watershed-based source protection plans. These plans identify various actions to protect over 450 municipal drinking water systems, servicing 95% of Ontario's population. (Government of Ontario, 2021).

Source Protection Plans

A source protection plan (SPP) contains policies developed by the source water protection committee aimed at protecting existing and future sources of municipal drinking water from significant threats to both quality and quantity of the resources. Land use activities that represent threats to drinking water sources have been identified and categorized as significant when located within highly vulnerable areas or zones, such as wellhead protection areas (WHPAs) for municipal groundwater wells, intake protection zones (IPZs) for surface water sources, and significant groundwater recharge areas (SGRAs).

An important first step for designers and approvers of all stormwater management systems in Ontario is to determine if land use activities associated with the proposed development represent significant threats to municipal drinking water sources, and what source water protection plan and associated policies apply to the site. The Province of Ontario's Source Water Protection Information Portal provides a convenient means of screening proposals based on threat subcategory and geographic location, and identifying the source protection plan to consult for further guidance and specific policies.

Based on the most current Drinking Water Threats and Circumstances database tool, development of stormwater treatment and infiltration facilities, outfalls and associated infrastructure, whether servicing an industrial/commercial, residential/institutional or rural development, may represent significant threats to drinking water sources when proposed within certain WHPA and IPZ areas and may need to be located outside of highly vulnerable areas or zones. Proposed developments that include creation of paved areas that will receive road salt applications during winter may also represent a significant threat to drinking water quality in highly vulnerable areas or where source water quality issues already exist (i.e., issue-contributing areas). Furthermore, if the proposed development involves creation of impermeable surfaces to the extent that it will significantly reduce recharge to an aquifer, stormwater infiltration facilities may need to be included.

The Province of Ontario's on-line Source Protection Information Atlas can be used to determine what source water protection area or region a proposed development site is located within, and if it falls within a vulnerable area where source water protection policies would apply. If the proposed development site is located in a vulnerable area or zone, the current source water protection plan in place for the location should be checked and source water protection committee representative should be consulted to determine what policies apply or what protective measures will be required.

A road sign to alert motorists that they are entering a provincially protected Drinking Water Protection Zone (SWPZ) to help raise awareness (Photo Source: Conservation Ontario, 2018)

Once you know what source water protection area or region a proposed development site is located in, and if it includes vulnerable areas or zones, the alphabetical list below of links to dedicated websites of each source water protection areas and region in Ontario can be used to access existing source protection plan documents, recent assessment reports, committee member contacts and other helpful resources:

1. Ausable Bayfield Maitland Valley Source Protection Region
2. Cataraqui Source Protection Area
3. CTC Source Protection Region
4. Essex Region Source Protection Area
5. Greater Sudbury Source Protection Area
6. Halton-Hamilton Source Protection Region
7. Lake Erie Source Protection Region
8. Lakehead Source Protection Area
9. Mattagami Region Source Protection Area
10. Mississippi-Rideau Source protection Region
11. Niagara Peninsula Source Protection Area
12. North Bay-Mattawa Source Protection Area
13. Quinte Region Source Protection Area
14. Raisin-South Nation Source Protection Region
15. Saugeen, Grey Sauble, Northern Bruce Peninsula Source Protection Region
16. Sault Ste. Marie Region Source Protection Area
17. South Georgian Bay Lake Simcoe Source Protection Region
18. Thames-Sydenham Source Protection Region
19. Trent Conservation Coalition Source Protection Region

Source Protection Assessment Reports

Each of the 19 aforementioned SPRs & SPAs has an Assessment Report that acts as a 'living technical document' for that given region. The Assessment report includes:

• Recent research findings and scientific information regarding source water protection;
• A brief overview of each impacted watershed within the SPR/SPA;
• Provides a water budget (which is a way to measure the amount of freshwater water enters, is stored, and leaves a watershed);
• Identifies vulnerable areas near key freshwater sources (municipal wells and intakes);
• Identifies the number of significant threats (agricultural practices, sewage sources, fertilizers, etc.) to water quality near wells and intakes; and,
• Identifies areas that could have varied threat levels (low, moderate, high) (CTC SPR, 2019)

Planning Considerations

When planning any new development within a SPR/SPA its important to follow the following four (4) major steps before moving forward.

Identify and Map Vulnerable Areas

The two major areas of significance that are vulnerable to water/groundwater pollution threats are called Wellhead Protection Areas (WHPAs) and Intake Protection Zones (IPZs). New development must note if any of their proposed activities or future actions will cause potential negative impacts on these important municipal sources of freshwater.

Wellhead Protection Areas (WHPAs)

A cartoon depiction of different WHPAs, and the time it take for a potential contaminants/threat to travel to a pumping well (Photo Source: CTC SPR, 2019)

A Wellhead Protection Area (WHPA) is an area located on the ground surface that denotes a specific zone within a known aquifer where fresh groundwater flows to a pumping well. Any detrimental activities/actions that take place in this zone may contribute to pollutions that can infiltrate into the underlying soil below and in turn contaminate said groundwater source for private and municipal wells alike - hence undertaken in this area may release pollutants that could seep into the soil and contaminate the groundwater used by both domestic and municipals wells. As a result, these areas require high levels of monitoring, protection and enforcement. Accordingly, this area warrants greater protection.

The risk to groundwater quality at the well site is determined by the rate at which a specific pollutant/contaminant can infiltrate and travel to the well and the time it would take to remediate the contaminant from the water supply by trained municipal water operators. If a chemical/contaminant spill were to happen a far distance away from a known well, a follow up assessment will be required, this assessment includes:

• Determining whether the contaminant could reach the well in question and the duration of time it may take to reach it.
• Is the contaminant a human, biological or environmental risk or is it simply an aesthetic nuisance?
• Will the concentration of said contaminant exceed the Canadian Water Quality Guidelines (CWQG) for drinking water standard or the Provincial Water Quality Monitoring Network (PWQMN) standard (i.e chloride levels)?
• Will the current mitigation/treatment protocols currently used be sufficient enough to mitigate/remove the harmful concentration levels of said contaminant from reaching the well?
  • If said mitigation/treatment protocol needs to be amended and time allows a mitigation system can be installed to limit the movement of said chemical to the well or the water treatment process at the receiving Water Treatment Plant (WTP) can be modified to sufficiently decrease the concentrations being received

When it comes to WHPAs one size does not fit all, there are multiple zones that extend in an irregular radius around a well to ensure adequate protection of the source water protection area, which is divided into five (5) zones based upon contaminant travel time within groundwater sources:

1. WHPA-A – an area of 100 metre radius around the wellhead
2. WHPA-B – the zone through which it takes groundwater to travel between two years and the 100 metre distance
3. WHPA-C – the zone through which it takes groundwater to travel between five and two years
4. WHPA-D – the zone through which it takes groundwater to travel between 25 and five years
5. WHPA-E – the area on ground surface through which surface water flows in two hours to a point close to the well. This wellhead protection area is only delineated when studies have shown that surface water can relatively easily seep through the soil and impact the quality of the water at the well. This situation is known as groundwater under the direct influence of surface water, or a GUDI well
   (Halton-Hamilton Source Protection Region, 2010;CTC SPR, 2019)

A picture depicting different types of drinking water sources, including groundwater under the direct influence (GUDI) of surface water, which may be subject to contamination due to the influence of polluted/impacted surface water (Photo Source: Government of Ontario, 2022)

To assist with the pre-development determination of site-specific water balance values, Toronto and Region Conservation Authority (TRCA) and Credit Valley Conservation (CVC) have developed the Toronto Region Source Protection Area (TRSPA) web-based application tool that provides precipitation, evapotranspiration (actual), runoff, and recharge based on outputs from the numerical models developed under the Drinking Water Source Protection Program. Note that these values are based on a regional assessment of the water balance, and may be supplanted by site-specific data or modelling.

Take a look at the online TRSPA Water Budget Tool below, which highlights WHPA-Q (Water Quantity) in the GTA region showcasing areas where activities that take water without returning it to the SPA and/or reduce recharge can be a threat:

Vulnerability
As mentioned, WHPAs identify an area on the surface that reflects a zone within the underlying aquifer below where groundwater flows to a well. That said, this area is generally not equal to the total contributing water area that drains towards the well over a given duration of time. This contributing area is the location seen on the surface where water can infiltrate into the soil and still reach the well far away. Due to its distance there may be more urbanization within this expanded area and other contributing contaminants that can pollute the groundwater as it flows to the well. This area generally requires the most protection by the associated SPR/SPA, Conservation Authorities located within the area and subsequent municipalities as it is the area/zone most prone to surface contamination (Halton-Hamilton Source Protection Region, 2010).

Vulnerability for source water is simply calculated by:

1. Determining the amount of time it takes for water to travel through the "unsaturated zone" above the water table; and,
2. Adding that number to the modelled time it takes for groundwater to flow from the water table to the well based on the WHPA zone (EarthFx Incorporated, 2010).

As a result, these surface to well duration periods are categorized as "low" for over 25 years, "medium" for 5 - 25 years, and "high" for 0 - 5 years. These surface to well advection times are categorized as low for over 25 years, medium for 5 to 25 years, and high for 0 to 5 years of travel. After this mapped groundwater vulnerability areas are then overlain on top of current WHPAs A - D to then assign vulnerability scoring between 2 - 10 (lowest - highest vulnerability scores). The location of a potential development site within the WHPA and its vulnerability score are then used to assign the significance of proposed or future potential actions/activities that have been labelled as potential threats to local drinking water sources. These 22 potential threats as laid out by the province can be seen in the table below in this section (Halton-Hamilton Source Protection Region, 2010).

Intake Protection Zones (IPZs)

A cartoon depiction of IPZs based on their proximity to municipal intake pipes (Photo Source: CTC SPR, 2019)

An Intake Protection Zone (IPZ) is an area that includes both land and surface water around municipalities' intake pipes that lead to a water treatment plant (WTP) and contributes to the municipalities drinking water system and sources. An IPZ on a map delineates where surface water is originating from and how it end up in the municipal water supply. These zones are determined by how far away they are from the intake location and the time it would take to reach it. The resulting size and shape of each of the three (3) zones of a typical IPZ represents either this set distance around the intake or simply the length of time it would take water and potential contaminants from overland flow to reach the intake.

The 3 zones of IPZ are as follows:

1. IPZ‐1: This is the area closest to a municipality's intake pipe and is a set distance which extends one kilometre (Km) upstream and 120 metres onto the shore. IPZ-1 is the most vulnerable to contamination as it is the closest to the intake and allows limited time for dilution to occur to help reduce the concentration of a contaminant released within the zone, this lack of time also doesn't allow municipal water system operators much time to react to this released contamination that is headed towards the municipal intake.
2. IPZ‐2: This area is developed by utilizing both hydrodynamic modelling and a time-of-travel calculation within overland pathways (natural and human-made - i.e. rivers, creeks, swales, storm sewers, etc.) that ultimately lead to and discharge near the municipalities intake(s). Includes both the on and offshore areas where overland flowing water that may be polluted with a concentration of a given number of contaminants would be able to reach the municipal intake within approximately two (2) hours. The 2 hour mark is set as the minimum amount of time to allow municipal water system operators to address a potential contamination concern.
3. IPZ‐3: This area lies outside of IPZ-1 and IPZ-2 and as such contaminants likely could only reach the intake pipe during and/or after a major rainfall/storm event. The size and shape of an IPZ-3 zone is based on associated lakes, streams and other humanmade conveyances that could contribute excess overland flow during an event.
   

(Halton-Hamilton Source Protection Region, 2010; Cataraqui Source Protection Area, 2022)

Vulnerability
The vulnerability of the three IPZs are assigned scores that reflect their susceptibility to allowing contaminants to reach the municipal intake zone and is determined by local knowledge and technical input from industry experts, as well as judgment from the SPA/SPZ committee members.

The source vulnerability scores for IPZ-1 and IPZ-2 is based on multiplying the following factors:

• Distance of the intake from shore/boundary
• the depth of the intake from surface water interaction
• historical water quality conditions and previous incidents/concerns at the intake in questions

hydrological and hydrogeological conditions of the surrounding area

• IPZ-1, due to its close proximity to the intake is set at the maximum vulnerability score value
• IPZ-2, considers the above characteristics along with the percentage of its area that is landcover
  • It also considers land characteristics of this land area (soil permeability, slope and direction, [Soil groups|soil types], vegetation coverage, etc.
• IPZ-3 is not provided a vulnerability score due to its setback distance away from intakes. It's perimeter is designated based on nearby lakes and streams that contribute overland flow to the intake
  

(Halton-Hamilton Source Protection Region, 2010; Cataraqui Source Protection Area, 2022)

Vulnerability for source water is simply calculated by:

• Determining the amount of time it takes for water to travel through the "unsaturated zone" above the water table; and,
• Adding that number to the modelled time it takes for groundwater to flow from the water table to the well based on the WHPA zone (EarthFx Incorporated, 2010).

Identify Threats

There are currently 22 listed "threats" that are outlined in the Clean Water Act, 2006. Please see the table below for further details (Government of Ontario, 2021):

Drinking Water Threats

Threat Type	Threat Number & Description
Agricultural
	1. The application of agricultural source material to land
	2. The storage of agricultural source material.
	3. The management of agricultural source material.
	4. The use of land as livestock grazing or pasturing land, an outdoor confinement area or a farm-animal yard.
Residential/Commercial
	5. The application of non-agricultural source material to land.
	6. The handling and storage of non-agricultural source material.
Sewage & Waste
	7. The establishment, operation or maintenance of a waste disposal site within the meaning of Part V of the Environmental Protection Act.
	8. The establishment, operation or maintenance of a system that collects, stores, transmits, treats or disposes of sewage.
Fertilizer & Pesticides
	9. The application of commercial fertilizer to land.
	10. The handling and storage of commercial fertilizer.
	11. The application of pesticide to land.
	12. The handling and storage of pesticide.
Winter Maintenance / Salt
	13. The application of road salt.
	14. The handling and storage of road salt.
	15. The storage of snow.
Fuel & Chemicals
	16. The handling and storage of fuel.
	17. The handling and storage of a dense non-aqueous phase liquid.
	18. The handling and storage of an organic solvent.
	19. The management of runoff that contains chemicals used in the de-icing of aircraft
	20. The establishment and operation of a liquid hydrocarbon pipeline. O. Reg. 385/08, s. 3; O. Reg. 206/18, s. 1.
Water Extraction
	21. An activity that takes water from an aquifer or a surface water body without returning the water taken to the same aquifer or surface water body.
	22. An activity that reduces the recharge of an aquifer.

Calculate Threat Level

The Interactive Source Protection Information Atlas is a GIS-based mapping tool that provides details on WHPAs, IPZs, issue contributing area score, vulnerability scores and lists drinking water threats while linking directly to the associated area's SPP (Photo Source: MECP, 2022

To calculate your threat level before commencing work there are several steps to take to determine how you can mitigate your impact on the local water supply.

1. Find out if you are in a "Vulnerable Area" as listed under the Clean Water Act, 2006. To do this use the Source Protection Information Atlas tool that shows based on your location vulnerability mapping and scores within already established and mapped source protection areas in your area.
2. If your development site is in a known vulnerable area, look at the threats table provided above in this section and ensure that you are not conducting any of the 22 listed activities as outlined under Ontario Regulation 287/07 Section 1.1 (1), "Prescribed drinking water threats".
3. After referencing the table if you discover that you will (or may) be conducting one or more of the listed activities then continue forward by contacting your local SPR/SPA (their emails and contact information are listed on their associated websites).

• Your SPR/SPA will be able to determine whether the work you are looking to conduct is deemed either a:
  • Low
  • Medium
  • High
  • Significant threat for your vulnerable area under their jurisdiction. Your SPR/SPA will have listed policies of which you will legally be required to follow based upon your vulnerability scoring which they will be able to point you to (TRCA, 2018; MECP, 2022)

You can go into further details learning about the potential risks your work may pose by visiting the MECP's Best practices for source water protection. This webpage set up by the province allows users to help protect freshwater sources and drinking water systems that are not included within an SPP or regulated under the Clean Water Act, 2006. It provides additional information and approaches prospective developers and users can take based upon local soil infiltration rates, groundwater sources in the area, highly vulnerably aquifers, nearby surface water sources, and other potential factors affecting vulnerability.

Below is a table "risk factors" land developers and their consultants should employ that asks eleven (11) questions and a user can rank to determine how at risk a local drinking water source may be given the work they are considering. Anything listed as "High" warrants further information and action to protect the water source (Table adopted from MECP's Best practices for source water protection (MECP, 2022).

Risk Factors - Self Evaluation

Risk questions	Low Risk	Medium Risk	High Risk
How many wells or intakes are located in your area?	None to "a few"	Several	Many
How deep are the wells and are they drilled or dug?	Deep, drilled	Intermediate	Shallow, dug
How deep is the intake and how far is it located from shore?	Deep, far	Intermediate	Shallow, nearshore
What is the vulnerability of your area?	Low vulnerability setting	Moderate vulnerability setting	High vulnerability setting
How sensitive is the population?	Healthy adults only	Typical family or mixed range of ages	Vulnerable populations like the elderly, youth or infants
How many people does the system serve?	A few	Some	Many
How often is the system used?	Occasionally	Seasonally or part time (work hours)	Every day and/or is the only source nearby
What types of activities are located nearby?	Residential	Agricultural	Industrial or Commercial
Any water quality issues? (i.e. algal booms or a boil water advisories, etc.)?	Confirmed none	Possible or Unknown	Confirmed and Present
Are you located in an area where there is pressure for growth? Or are there other water supply and demand issues?	No	Maybe / Unknown	Yes
Is there oversight of the well(s) or intake(s)? For example, licencing, inspections, testing, compliance, and qualified operators.	Yes	Some	None

Apply Appropriate Policies

Policies that must be adhered to are based on several factors:

1. The activity itself
2. The area in which the activity will be taking place
3. The vulnerability of the area in question
4. The risks associated with the activity (does the activity result in one of the listed 22 risks occurring or potentially occurring)
5. Other local factors that can increase the vulnerability to a nearby IPZs or WHPAs

For example, as of December of 2021 the CTC SPR that comprises the regions of Peel, Toronto, and Durham had nearly 130 Source Protection Policies in place within their SPP. These policies address 21 of the 22 types of threats prescribed in O.Reg 287/07 along with two types of local drinking water threats, and include other actions that are considered by the CTC committee as necessary to protect drinking water sources, along with requirements for monitoring. The CTC SPP also contain policies which require the need for Risk Management Plans (RMPs) dependent on the vulnerability of proposed actions/activities to better manage some drinking water threats (CTC Source Protection Region, 2021)

Additional Ontario Source Water Protection Resources

Below, find a list of valuable tools aimed at the general public, landowners, real estate agents, farmers and technical practitioners (consultants, operators, technicians, risk management officials, inspectors etc.) for Source Water Protection in the Province of Ontario:

• All Users - Source Water Protection Information Portal - An all in one hub developed by the Ministry of the Environment Conservation and Parks (MECP) to help users understand drinking water threats, updated SWP policies, access to the Source Protection Information Atlas (SPIA) Tool, and Technical Rules under the Clean Water Act.
• Risk Management Officials and Inspectors - Regulation of Drinking Water Threats under Clean Water Act Part IV
• Technical Practitioners - CTC Source Protection Region Education and Outreach resources including IPZs, WHPAs, Water Quality Threats, Road Salt, Snow Storage, Pesticides, Organic Solvents and DNAPLs.
• Landowners - What landowners can do to protect water quality & quantity
• Real Estate Agents - Drinking Water Source Protection in Ontario: What Every Real Estate Agent Should Know
• Farmers/Agriculturalists - AGRI-ACTION: Protecting water from field to faucet

LID Site Considerations

Installation type	Depth to high water or bedrock (m)i	Ratio of impervious drainage area to permeable facility footprint area	Native soil infiltration rate (mm/hr)ii	Head (m)iii	Space %iv	Slope %v	Applicable in pollution hotspotsvi	Set backs	Karstvii	Drinking Water Source Protection wellhead protection area time of travel
Rain barrels	Not a constraint	Not applicable	Not a constraint	1	0	NA	Yes	None	Yes	None
Cisterns	Not a constraint	Not applicable	Not a constraint	0	0	0	Yes	None	Yes	None
Roof downspout disconnection	Not a constraint	4:1 or less	Decompaction if < 15 mm/hr	0.5	5 to 20	1 to 5	Yes	Building Foundation	Yes	None
Infiltration trenches or Infiltration chambers	1	5:1 to 20:1	Not a constraint	1 to 2	0 to 1	<15 %	Noix	4m- Building Foundation Underground Utilities, Trees, Drinking Water Wellhead Protection Areas	No	2 year - WHPA-B
Bioretention	1 (infiltrating); Not a constraint (non-infiltrating)	5:1 to 15:1	Decompaction and underdrain recommended if < 15 mm/hr (infiltrating)	1 to 2	5 to 10	0 to 2	No (infiltrating)ix; Yes (non-infiltrating)	4m- Building Foundation Underground Utilities, Trees, Drinking Water Wellhead Protection Areas	No (infiltrating); Yes (non-infiltrating)	2 year - WHPA-B (infiltrating); None (non-infiltrating)
Stormwater planters	Not a constraint	5:1	Not a constraint	1 to 2	2 to 5	0 to 2	No (infiltrating)ix; Yes (non-infiltrating)	Building Foundation, Trees	No (infiltrating); Yes (non-infiltrating)	2 year - WHPA-B (infiltrating); None (non-infiltrating)
Vegetated filter strips	Not a constraint	4:1 or less	Decompaction if < 15 mm/hr	0 to 1	15 to 20	1 to 5	Noix	None	Yes	None
Permeable pavements	1 (infiltrating); Not applicable (non-infiltrating)	0 to 1:1	Underdrain recommended if < 15 mm/hr (infiltrating)	0.5 to 1	0	1 to 5	No (infiltrating)ix; Yes (non-infiltrating)	4m-Underground Utilities Drinking Water Wellhead Protection Areas	No (infiltrating); Yes (non-infiltrating)	2 year - WHPA-B (infiltrating); None (non-infiltrating)
Enhanced swales (featuring check dams)	1	5:1 to 10:1	Decompaction if < 15 mm/hr	1 to 3	5 to 15	0.5 to 6	Noix	4m- Building Foundation Underground Utilities	No	2 year - WHPA-B
Bioswales (Dry swales)	1 (infiltrating); Not applicable (non-infiltrating)	5:1 to 15:1	Decompaction and underdrain recommended if < 15 mm/hr (infiltrating)	1 to 3	5 to 10	0.5 to 6	No (infiltrating)ix; Yes (non-infiltrating)	4m (3m if impermeable liner is used) Building foundation, Underground utilities, Drinking Water Wellhead Protection Areas	No (infiltrating); Yes (non-infiltrating)	2 year - WHPA-B (infiltrating); None (non-infiltrating)
Exfiltration trenches	1	5:1 to 10:1	Not a constraint	1 to 3	0	< 15%	Noix	4m- Building Foundation Underground Utilities, Trees, Drinking Water Wellhead Protection Areas	No	2 year - WHPA-B
Stormwater tree trenches	1	5:1 to 15:1	Underdrain recommended if < 15 mm/hr	1 to 2	5 to 10	0 to 2	No (infiltrating)ix; Yes (non-infiltrating)	4m- Building Foundation Underground Utilities, Drinking Water Wellhead Protection Areas	No (infiltrating); Yes (non-infiltrating)	2 year - WHPA-B

Notes
i Minimum depth between the base of the facility and the elevation of the seasonally high water table or top of bedrock
ii Infiltration rate estimates based on measurements of hydraulic conductivity under field saturated conditions at the proposed location and depth of the practice
iii Vertical distance between the inlet and outlet of the LID practice
iv Percent of open pervious land on the site that is required for the LID practice
v Slope at the LID practice location
vi Suitable in pollution hot spots or runoff source areas where land uses or activities have the potential to generate highly contaminated runoff
vii Suitability in areas of karst geologic formations
viii Drinking Water Source Protection wellhead protection area time of travel
ix May be allowed under special circumstances and if appropriate mitigation actions are taken - please contact your local Source Protection Region (SPR) or Source Protection Area (SPA) for further information. You can find your associated SPR/SPA based on your location here and then visit their site here

BMP Selection & Pretreatment for SWP

With respect to potential contaminants or pollutants in stormwater surface runoff the types and levels of these contaminants varies widely depending on the associated activities, characteristics and makeup of the local source water area.

Examples of activities that can lead to a source area being deemed a "Pollution hot spot" when it comes to surface runoff pollution (Photo Source: Müller et al. 2020).

An area, for example that contains a high density of roads and industrial areas that require large amounts of de-icing road salt in the winter and experiences heavy traffic daily, make it a significant source of sodium, chloride, petroleum based hydrocarbons and heavy metals. On the other hand a source area such as a roof is only subject to atmospheric deposition of contaminants and isn't typically subjected to vehicular traffic, sand, salt nor other de-icing agents. As a result, roof runoff typically contains significantly lower levels of heavy metals, petroleum hydrocarbons and salt.

Certain source areas known as "pollution hot spots" have a higher chance to create contaminated surface level runoff due to given activities occurring and associated contaminant types present on site (e.g., vehicle fueling stations, landfills, certain agricultural practices, manufacturing and construction sites). It is important that stormwater management plans be developed with consideration of the different types of runoff source areas that will be present, and recognition of source areas with low to moderate contamination potential that represent opportunities for rainwater harvesting, permeable pavements and other stormwater infiltration practices. Furthermore, it is important to ensure that relatively clean runoff is not mixed with lesser quality runoff from surfaces that are subject to higher levels of contamination, rendering it less suitable for infiltration or harvesting.

A summary of stormwater source area types, associated runoff characteristics and stormwater BMP opportunities and pretreatment requirements is provided in the table below:

Types of Stormwater Source Areas, Runoff Characteristics & Opportunities for Treatment

Stormwater Source Area	Runoff Characteristics	Opportunities	Principles
Foundation drains, slab underdrains, road or parking lot underdrains	Relatively cool, clean water	Suitable for infiltration or direct discharge to receiving watercourses in the area	Should not be directed to stormwater management facility that receives road or parking lot runoff, so as not to mix relatively clean and contaminated runoff waters
Roof drains, roof terrace area drains, overflow from green roofs	Moderately clean water, contaminants may include asphalt granules, low levels of hydrocarbons and metals from decomposition of roofing materials, animal droppings, natural organic matter and fall out from airborne pollutants, potentially warm water.	Infiltration (Bioretention, Enhanced swales, Infiltration trenches, Permeable pavements, Stormwater tree trenches, etc.); Filtration (Bioretention, Stormwater planters, etc.); Harvesting with rain barrels or cisterns and use for both indoor and outdoor non-potable purposes (e.g., irrigation, toilet flushing) after Pretreatment; Attenuation and treatment in wet pond or wetland detention facility.	Runoff should be treated with a sedimentation and/or filtration practice prior to infiltration. Where possible, runoff should not be directed to end-of-pipe facilities to capitalize on potential for infiltration or harvesting. Flow moderation (quantity control) prior to discharge to receiving watercourse is required.
Low and medium traffic roads and parking lots, driveways, pedestrian plazas, walkways	Moderately clean water, contaminants may include low levels of sediment, de-icing salt constituents, hydrocarbons, metals and natural organic matter. Typically warm water.	Infiltration (Bioretention, Enhanced swales, Infiltration trenches, Permeable pavements, Stormwater tree trenches, etc.); Filtration (Bioretention, Stormwater planters, etc.); Harvesting with cisterns or Permeable pavement reservoirs and use for only outdoor non-potable purposes (e.g., vehicle washing, irrigation) after pretreatment; Attenuation and treatment in wet pond or wetland detention facility.	Runoff should be treated with a sedimentation and/or filtration practice prior to infiltration. Flow moderation (quantity control) prior to discharge to receiving watercourse is required. Harvested stormwater quality should be tested prior to use for non-potable purposes.
High traffic roads and parking lots	Potential for high levels of contamination with sediment, deicing salt constituents hydrocarbons and metals. Typically warm water.	Filtration after sedimentation pretreatment; Attenuation and treatment in wet pond or wetland detention facility; Infiltration after pretreatment only where groundwater uses are limited.	Runoff should be treated with a sedimentation and/or filtration pretreatment practice prior to infiltration.
"Pollution hot spots" such as vehicle fueling, servicing or demolition areas, outdoor storage and handling areas for hazardous materials, some heavy industry/construction sites	Potential for high levels of contamination with sediment, deicing salt constituents, hydrocarbons, metals, and other toxins.	Attenuation and treatment in wet pond, wetland or hybrid detention facility; Potential requirement for sedimentation pretreatment; Infiltration and harvesting practices not recommended.	Runoff from these sources should not be infiltrated or used for irrigation. Spill containment or mitigation devices recommended contingent on size of storage facilities.

Source Water Protection in Other Canadian Jurisdictions

Cover page of the final report from the collaborative partnership between the Chippewas of the Thames First Nation, the Oneida Nation of the Thames, the Munsee-Delaware Nation (CMO) and the Canadian Environmental Law Association (CELA) and funded by the Law Foundation of Ontario that highlights the legal toolkit created to provide legal tools which can be implemented in Indigenous communities across Ontario to help residents protect their local source waters and mitigate threats. (Photo Source: CELA et al. 2019)

First Nations On-Reserve Source Water Protection Planning

In 2011 the Federal government issued a national assessment of on-reserve drinking water systems, they found that most First Nations did not have an existing SPP in place. After this assessment was completed, the First Nations On-Reserve Source Water Protection Plan was developed by Aboriginal Affairs and Northern Development in partnership with the Alberta First Nations' Technical Services Advisory Group (TSAG), Siksika First Nation, Alberta and Dr. Robert Patrick from the Department of Geography and Planning of University of Saskatchewan.

The document is both a descriptive guide and real-world template to be used to help develop a SPP on reserve lands. It describes necessary tools in developing a community based SPP by taking a watershed-scale approach to protecting freshwater supplies. The plan development is led by both Chief and Council of the community as the principal decision makers along with others responsible for landuse decisions and community planning initiatives (AAND, 2014)

First Nations Communities (Southwestern Ontario)

Most First Nations' reserves lie outside of Ontario's designated Source Water Protection Regions and Areas. In 2017 the Chippewas of the Thames First Nation, the Oneida Nation of the Thames, the Munsee-Delaware Nation (CMO) and the Canadian Environmental Law Association (CELA) developed a partnership to create a series of Legal Toolkits for Source Water Protection in Indigenous Communities located along the Thames River in Southwestern Ontario. The series of five (5) toolkits discuss a host of issues with SPPs including by-laws, agricultural leases, consultations, environmental rights and appeals. They can be found at the links below (CELA, 2019):

1. Legal Toolkit Report
2. Legal Tool 1: By-laws as an Authority for Environmental Protection and Enforcement
3. Legal Tool 2: Consultation and Accommodation Protocol to Advance Source Water Protection
4. Legal Tool 3: Public Environmental Rights and Appeals Related to Source Waters
5. Legal Tool 4: Considering Source Water within Agricultural Leases on First Nation Reserve Lands
6. Legal Tool 5: Protecting Source Waters Under the Clean Water Act

In the South Georgian Bay Lake Source Protection Region there are three indigenous communities: Beausoleil First Nation, Chippewas of Georgina Island First Nation, and Chippewas of Rama First Nation. At this time, the Chippewas of Rama First Nation has opted into the source water protection process by passing a Band Council resolution in 2011 and announced the inclusion of their drinking water system within the Source Water Protection planning process back in 2014.

Nova Scotia

The Province of Nova Scotia (through Nova Scotia Environment - NSE) released their, Drinking Water Strategy for Nova Scotia, which provides a framework for managing both drinking water supplies, intakes and vulnerable areas across the province. The NSE published five (5) technical documents which provide guidance to practitioners on how to create and deliver source water protection plans, the overall processes it entails and solutions to problems that may occur.

Similar to Ontario the NSE requires either the local water utility company or the municipality itself to create an advisory committee made up of councillors, municipal engineers, landowners residents and businesses along with consultants to carry out technical requirements and steps. The committee must then map out the Water Protection Boundary with optional public consultation and input, after which known and potential contaminants and risks will be assessed dependent upon the activities that may pose a risk to source water supply areas. Then the advisory committee is tasked with developing and implementing a Source Water Protection Management Plan that includes the ABC's of source water protection:

• (A)quisition of land in source water supply areas to improve protection of water quality
• (B)y-laws to develop new municipal planning strategies and create new regulations and permits for work conducted in source water supply areas.
• (B)MPs and guidelines to best manage and monitor activities that take place in the water supply area
• (C)ontingency Plans for when an unexpected event occurs that threatens the source water area and the health of the local population
• (D)esignation, the Environment Act in Nova Scotia allows for areas to be created known as Designated Protected Water Areas. this allows a water utility or municipality to properly regulate activities that occur in these protected regions
• (E)ducation, the committee will work with stakeholders and users in the source water supply area to highlight important piece of information they should know when working in these areas regarding their role in protecting local drinking water and overall water stewardship BMPs.

Title page of B.C's, Ministry of Health Services, and Ministry of Water, Land and Air Protection's Drinking Water Source-to-Tap Screening Tool, which is a ste-by-step questionnaire developed for water suppliers to help aid them in identifying risks to their drinking water sources and systems (Photo Source: Ministry of Health Services and Ministry of Water, Land and Air Protection, 2004)

Finally, the last step is to create a "Monitoring and Evaluation Plan", which sets up specific prescribed procedures for ongoing monitoring of the area to ensure water quality contaminants are mitigated and a formalized source water protection plan review process is implemented (Government of Nova Scotia, n.d.). All of this information and more can be found here on Nova Scotia's Environment and Climate Change's Source Water Protection Home Page

British Columbia

In the province of British Columbia (BC) there are two (2) primary source water protection documents:

1. Drinking Water Protection Act (DWPA) - Covers both water source and system assessments within the province along with response plans to unmitigated risks 2. Drinking Water Protection Plans (DWPP) - Ordered and made required by the Minister of Health under the DWPA, 2001 [SBC 2001] Chapter 9 (Government of British Columbia, n.d.(a))

The government of BC has created an excellent portal for water system operators and suppliers to access current resources and tools that help them understand their role and responsibilities under the DWPA, 2001 and includes the following:

• Drinking Water Source-to-Tap Guideline Document - provides a step by step approach to evaluating risks to drinking water that coincides with requirements within the DWPA, 2001
• Drinking Water Source-to-Tap Screening Tool - An alternative method for assessing risk in drinking water systems, the tool contains 97 questions and is a "question-and-answer" based document that allows drinking water officers to determine if a water supplier submitting the document needed to undertake a comprehensive assessment to further analyze associated risk and vulnerabilities
• Emergency Response Plan - Developed to help water officers develop their own emergency response plan in more rural areas that possess small water systems
• Guidance Document for Determining Ground Water at Risk of Containing Pathogens (GARP) - Developed for drinking water officers to determine if groundwater sources are at risk of certain pathogens.
• Water System Assessment User's Guide - Aids both operators and owners to assess their water system's safety and overall security.
• and more (Government of British Columbia, n.d.(B))

The drainage area of a river.

An area of land that drains into a river or a lake. The boundary of a watershed is based on the elevation (natural contours) of a landscape.

Any person, agency or group who has a direct interest in the purpose of a proposed undertaking.

Increases in groundwater storage by natural conditions or by human activity. See also artificial recharge

The inflow of surface water to a groundwater reservoir or aquifer.

The addition of water to ground water by natural or artificial processes.

The infiltration and movement of surface water into the soil, past the vegetation root zone, to the zone of saturation or water table.

Layer of rock or soil that holds or transmits water.

The mathematical expression of the water balance.

The liquid waste from domestic, commercial and industrial establishments. City of Toronto Wet Weather Flow Management Guidelines November 2006 49

(1) Something that pollutes, especially a waste material that contaminate air, soil, or water. (2) Any solute or cause of change in physical, chemical or biological properties that render water unfit for a given use.

refers to the characteristics and functions of a system prior to urban development.

The accounting of inflow and outflow of water in a system according to the components of the hydrologic cycle.

Toronto and Region Conservation Authority

Credit Valley Conservation

Any form of rain or snow.

The quantity of water transpired (given off). Retained in plant tissues, and evaporated from plant tissues and surrounding soil surfaces. Quantitatively it is usually expressed in terms of depth of water per unit area during a specified period. e.g. mm/day

The combined loss of water to the atmosphere from land and water surfaces by evaporation and from plants by transpiration.

The portion of water precipitated onto a catchment area, which then flows as surface discharge from the catchment area past a specified point.

Water from rain, snow melt, or irrigation that flows over the land surface.

The changing of land cover and land uses from rural to urban; the growth of urban settlements.

The upper surface of the zone of saturation, except where the surface is formed by an impermeable body.

Subsurface water level which is defined by the level below which all the spaces in the soil are filled with water; The entire region below the water table is called the saturated zone.

Open space floodway channels, road reserves, pavement expanses and other flow paths that convey flows typically in excess of the capacity of the Minor Drainage System.

A shallow constructed channel, often grass-lined, which is used as an alternative to curb and channel, or as a pretreatment to other measures. Swales are generally characterized by a broad top width to depth ratio and gentle grades.

Relating to the properties, distribution and effects of water on and below the earth’s surface, and in the atmosphere.

The liquid waste from domestic, commercial and industrial establishments. City of Toronto Wet Weather Flow Management Guidelines November 2006 49

Layer of rock or soil that holds or transmits water.

Refers to the conditions in which an organism lives and survives or the conditions in which an organism resides. These conditions can be described as aspects of a “physical”, “social” or an “economic” environment, depending on the perspective perceived by the observer.

Low Impact Development. A stormwater management strategy that seeks to mitigate the impacts of increased urban runoff and stormwater pollution by managing it as close to its source as possible. It comprises a set of site design approaches and small scale stormwater management practices that promote the use of natural systems for infiltration and evapotranspiration, and rainwater harvesting.

A hard surface area (e.g., road, parking area or rooftop) that prevents or retards the infiltration of water into the soil.

The total surface area upstream of a point on a stream that drains toward that point. Not to be confused with watershed. The drainage area may include one or more watersheds.

The natural ground material characteristic of or existing by virtue of geographic origin.

The rate at which stormwater percolates into the subsoil measured in inches per hour.

Structures constructed of a non-erosive material, such as suitably sized aggregate, wood, gabions, riprap, or concrete; used to slow runoff water. Can be employed in practices such as bioswales and enhanced grass swales.

Linear bioretention cell designed to convey, treat and attenuate stormwater runoff. The engineered filter media soil mixture and vegetation slows the runoff water to allow sedimentation, filtration through the root zone, evapotranspiration, and infiltration into the underlying native soil.

The rate at which stormwater percolates into the subsoil measured in inches per hour.

A parameter that describes the capability of a medium to transmit water.

Best management practice. State of the art methods or techniques used to manage the quantity and improve the quality of wet weather flow. BMPs include: source, conveyance and end-of-pipe controls.

Initial capturing and removal of unwanted contaminants, such as debris, sediment, leaves and pollutants, from stormwater before reaching a best management practice; Examples include, settling forebays, vegetated filter strips and gravel diaphragms.

The land draining to a single reference point (usually a structural BMP); similar to a subwatershed, but on a smaller scale.

Areas where certain land uses or activities have the potential to generate highly contaminated runoff (e.g., vehicle fuelling, service or demolition areas, outdoor storage and handling areas for hazardous materials and some heavy industry sites).

Mineral particles which are smaller than 2 mm, and which are free of appreciable quantities of clay and silt. Coarse sand usually designates sand grains with particle size between 0.2 and 0.02 mm.

Initial capturing and removal of unwanted contaminants, such as debris, sediment, leaves and pollutants, from stormwater before reaching a best management practice; Examples include, settling forebays, vegetated filter strips and gravel diaphragms.

The portion of water precipitated onto a catchment area, which then flows as surface discharge from the catchment area past a specified point.

Water from rain, snow melt, or irrigation that flows over the land surface.

A mixture of mineral aggregates bound with bituminous materials, used in the construction and maintenance of paved surfaces.

The technique of removing pollutants from runoff as it infiltrates through the soil.

Human application of water to agricultural or recreational land for watering purposes. City of Toronto Wet Weather Flow Management November 2006 47

Reduction of peak flow and increase of the duration of the flow event.

The temporary storage of stormwater to control discharge rates, and allow for sedimentation.

The slow movement of water into or through a soil or drainage system.

Penetration of water through the ground surface.

(a) A natural well-defined channel produced wholly or in part by a definite flow of water and through which water flows continuously or intermittently. Also, a ditch, canal, aqueduct, or other artificial channel for the conveyance of water to or away from a given place, as for the draining of a swamp.

(b) A stream or current of water. Legally, a natural stream arising in a given drainage basin but not wholly dependent for its flow on surface drainage in its immediate area, flowing in a channel with a well-defined bed between visible banks or through a definite depression (as a ravine or swamp) in the surrounding land, having a definite and permanent periodic supply of water (the stream may be intermittent), and usually, but not necessarily having a perceptible current in a particular direction and discharging at affixed point into another body of water.

(c) A legal right permitting the use of a flow of a stream (especially of one flowing through one’s land) or the receipt of water discharged upon land belonging to another.

Soil, sand and minerals washed from land into water, usually after rain. They pile up in reservoirs, rivers and harbors, destroying fish-nesting areas and holes of water animals and cloud the water so that needed sunlight might not reach aquatic plans. Careless farming, mining and building activities will expose sediment materials, allowing them to be washed off the land after rainfalls.

Deposition of material of varying size, both mineral and organic away from its site of origin by the action of water, wind, gravity or ice.

Settling-out or deposition of particulate matter suspended in runoff.

The technique of removing pollutants from runoff as it infiltrates through the soil.