Source Water Protection

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Image of the 19 Source Protection Regions (SPRs) and Source Protection Areas (SPAs) in Ontario (Conservation Ontario, 2022)[1]. Visit the Map link here for a higher resolution image.

Overview[edit]

Spurred mainly by 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 (Scarfone, 2020)[2] took major overhauling actions to ensure Ontarians drinking water was adequately protected.

Following an inquiry into the Walkerton event, Justice, O'Connor at the time made over 120 recommendations to better protect the province's drinking water, which have now been implemented and are the foundation of the province's drinking water protection framework. The first of these recommendations was that drinking water should be protected by developing watershed-based source water protection plans, which have been in place since 2006 with the adoption of the Clean Water Act (Government of Ontario, 2021)[3]

Source Water Protection in Ontario[edit]

Since the Clean Water Act, 2006 was adopted within the province the original recommendations of the "Walkerton Inquiry" were able to begin to be implemented. The legislation required municipalities protect their drinking water sources and supplies through prevention by developing collaborative large-scale watershed-based source protection plans or source water protection (SWPP) based on monitoring results and the latest science. When the Clean Water Act was first established the province paid for the cost of developing the preliminary SWPPs.

Under the Clean Water Act the legislation describes newly developed source water protection areas and source water protection regions.

  • Source Protection Region (SPR): Encompass one or more source protection areas (ex. Credit Valley-Toronto and Region-Central Lake or simply the CTC Region).
  • Source Protection Area (SPA): Smaller geographic areas generally based on the watershed boundaries of Ontario's 36 Conservation Authorities
Ontario’s Clean Water Act, 2006 is the primary piece of legislation within the province to ensure that there is a multi-barrier approach to ensure not only clean and safe drinking water, but by ensuring usage is sustainable and protects lakes, rivers, wells and other major sources of freshwater for ~14.5 million residents (Photo Source: Conservation Ontario, 2016)[4]

Under the Clean Water Act local multi-stakeholder source protection committees were developed for each region. Each committee is comprised on the region's leading researchers, professionals and technical personnel that help identify significant current and potential future threats to their local municipal drinking water sources. Their job is to regularly meet and develop preventative plans to address identified and theorized threats (Lake Erie Source Protection Region, 2022)[5]

Source Protection Plans (SPP)[edit]

Source protection plans (SPPs) contain a number of policies that are locally developed by their local technical committees aimed at protecting existing and future spruces of adequate drinking water sources for impacted municipalities.

The associations who are reporting and implementing SPP policies and progress annually include:

  • Conservation Authorities;
  • Municipalities;
  • Source protection authorities;
  • Local health boards;
  • Indigenous groups, committees and governments;
  • Local businesses
  • The Province of Ontario; and,
  • Others (Government of Ontario, 2021)[3]


The Source Protection Committee generally uses varied approaches to protect drinking water sources within each SPR/SPA, which can include:

  • Prescribed policy instruments (existing provincial approvals such as Environmental Compliance Approvals and Permits To Take Water);
  • Requiring any owners/developers present a formalized risk management plan (negotiated individually);
  • Specified land use planning;
  • Prohibition of activities that may prove detrimental to SPZs; and/or,
  • Current outreach and education activities (webinars, town meetings, pamphlets, online education hubs) (CTC SPR, 2019)[6]


Under the Clean Water Act, 2006 a total of 19 SPRs and SPA's have been established across the province. Each of these 19 SPRs/SPAs contain their own local multi-stakeholder source protection committees across the province which have developed 38 local source protection plans. These specialized plans identify various actions to protect over 450 affected municipal drinking water systems (covering 95% of Ontario's population) (Government of Ontario, 2021)[3].

Ultimately, SPPs are plans to help reduce or eliminate significant drinking water threats within its associated zone/area. These drinking water threats are listed in the following and the SPPS have policies place which must also be enforced. These policies when implemented help to both manage and/or prohibit significant threats as a result of various activities to ensure that they cannot pollute or deplete necessary sources of municipal drinking water within the zone/area.

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)[7]

SPRs & SPAs in Ontario[edit]

Listed below are 19 different SPRs and SPAs in Ontario, where you can visit each Region's/Area's dedicated Sourcewater protection website for information on their committee members, recent reports, helpful documents, informational videos and the like:

  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[edit]

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)[6]

Planning Considerations[edit]

Inclusion of the tools and atlas

  • Recommendations - refer to SPP (pull from B.C's recommended practices)
  • Top lessons and maintenance (setback distances / replacing media)

Talk about pretreatment - filtration before being sent directly to groundwater source (bioretention/swale -> infiltration trench) Online vaults from minor system flows (filter and target specific pollutants) - before infiltration.

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

1) Identify and Map Vulnerable Areas[edit]

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)[edit]

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 Network's (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 once 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;[8]CTC SPR, 2019[6])

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[8]).

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[9]).

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[8]).

Intake Protection Zones (IPZs)[edit]

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.


Vulnerability of the Intake’s Source Water

The vulnerability scores assigned to the IPZ-1 and IPZ-2 intake protection zones reflect the susceptibility of the intakes to contaminants and is determined based on local knowledge and professional judgment. The score is based on multiplying the following factors:

an area vulnerability factor, which is set at the maximum value for an IPZ-1 and considers the percentage of the IPZ-2 that is land, the land characteristics (cover, soil type, permeability, slope), and the hydrological and hydrogeological conditions a source vulnerability factor, which considers the distance of the intake from shore, the depth of the intake from water surface, and the historical water quality concerns at the intake A vulnerability score is not given to an IPZ-3.

2) Identify Threats[edit]

3) Calculate Threat Level[edit]

4) Apply Appropriate Policies[edit]

Site Considerations[edit]

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 yr
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 yr (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 Yr (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 Yr (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 Yr
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 Yr (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 Yr
Stormwater tree trenches 1 5:1 to 15:1 Underdrain recommended
if < 15 mm/hr
1 to 2 5 to 10 0 to 2 Noix 4m- Building Foundation
Underground Utilities,
Drinking Water Wellhead
Protection Areas
No 2 yr
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

Site Specific Jurisdictions[edit]

Source Water Protection Nationally[edit]

Nova Scotia[edit]

British Columbia (B.C)[edit]

Pretreatment Features[edit]

Design Features[edit]

LID BMPs

References[edit]

  1. Conservation Ontario. 2022. Best Practices for Source Water Protection. Accessed 27 May 2022: https://conservationontario.ca/conservation-authorities/source-water-protection/
  2. Scarfone, K. 2020. 20 years after the Walkerton Tragedy, Ontario could be setting itself up for a new water crisis. Safeguarding Freshwater. Environmental Defence. 1 June 2020. Accessed 26 May 2022. https://environmentaldefence.ca/2020/06/01/walkerton-tragedy-ontario-new-water-crisis/
  3. 3.0 3.1 3.2 Government of Ontario. 2021. Source protection. Environment and Energy - Drinking Water. 13 October 2021. Accessed: 26 May 2022. https://www.ontario.ca/page/source-protection#section-0
  4. Conservation Ontario. 2016. Protecting Our Sources of Drinking Water: Implementation of Source Protection Plans across Ontario. Written by: Chitra Gowda, 11 Oct. 2016. Accessed 27 May 2022: https://ijc.org/en/protecting-our-sources-drinking-water-implementation-source-protection-plans-across-ontario
  5. Lake Erie Source Protection Region. 2022. The Clean Water Act. Accessed 26 May 2022. https://www.sourcewater.ca/en/how-it-works/The-Clean-Water-Act.aspx
  6. 6.0 6.1 6.2 Credit Valley-Toronto and Region-Central Lake Ontario (CTC) Source Protection Region (SPR). 2019. Protecting our Drinking Water Sources. Accessed 26 May 2022. https://ctcswp.ca/app/uploads/2019/06/DOC_20190328_Magazine_DigitalSpreads_FNL.pdf
  7. Conservation Ontario. 2018. SWP Education & Outreach - Road Signage (English). Accessed 31 May 2022. https://conservationontario.ca/resources?tx_fefiles_files%5Baction%5D=show&tx_fefiles_files%5Bcontroller%5D=File&tx_fefiles_files%5Bfile%5D=389&cHash=88b06a201529f054e0a87582376f6c2a
  8. 8.0 8.1 8.2 Halton-Hamilton Source Protection Region. 2010. Wellhead Protection Areas (WHPAs). Planning Process - Vulnerable Areas. Accessed 02 June 2022. http://protectingwater.ca/planning.cfm?smocid=1440&parentcatid=841#:~:text=A%20wellhead%20protection%20area%20(WHPA,both%20domestic%20and%20municipals%20wells.
  9. Vulnerability Assessment and Scoring of Wellhead Protection Areas - City of Hamilton, Ontario. Published April 2010. Prepared for the City of Hamilton - Public Works Department, Environment and Sustainable Infrastructure Division. http://protectingwater.ca/uploads/Documents/swp03%20-%20Appendix%20B%20-%20Hamilton%20Vulnerability%20Report%20v32-final.pdf