10 Years After


Protecting Water on a Watershed Basis

Lessons Learned from the Walkerton tragedy:

1. Humans are part of the environment


All too often we think that our environment has little or no impact on us. However environmental management is also about human health and safety. We are dependent daily on the environment around us and that we need to pay attention to it.


2. Reliable Science is needed to protect our environment.

It will be ten years from the release of the Walkerton Inquiry Report to the completion of source protection plans. Basically it takes this long because it is a comprehensive, science based, multi-stakeholder approach with mandatory requirements for implementation. Getting the science right and ensuring good stakeholder and public consultation are important, but they take time.


3. Source Protection  is one piece of the puzzle to ensure the protection of Ontario’s watersheds.

Proper management of our environment needs an approach that simultaneously considers the interests of business, society and the environment altogether. This is called Integrated Watershed Management. What we do on the land impacts the quality and sustainability of our natural resources – particularly water - so we can’t ignore these influences when we are making decisions about the environment.


To learn more, read Conservation Ontario’s article, Protecting Municipal Drinking Water Sources – 10 years after Walkerton by Charley Worte. [Municipal World March 2010)


What Happened?

May 2010 marks the 10th anniversary of the Walkerton drinking water tragedy. After a few days of very heavy rainfall in mid-May, 2000, the water supply for the town of Walkerton, Ontario became contaminated with a highly dangerous strain of E. coli bacteria, from farm runoff into a municipal well.  


On May 15th, many residents began to simultaneously experience bloody diarrhea, gastrointestinal infections and other symptoms of E. coli infection. Seven people died from drinking contaminated water and over 2,000 became ill. The effects are still felt today by a number of Walkerton residents.


Many events are being organized to commemorate the Anniversary:

May 19 Walkerton MTO Yard - Rain Barrel Sales to support Walkerton to Haiti Clean Water Project

May 16 Ecumenical Service

June 1 Youth Water Career Day (Keynote speaker: Ryan Hreljac, founder of the Ryan's Well Foundation)

June 12 Walkerton Clean Water Centre Official Public Opening

June 12 Public Water Day in Walkerton


For More Information

Assessing Threats to Ontario’s Drinking Water Sources Today


Since May 2000, Ontario’s system of managing and protecting municipal drinking water has undergone a complete overhaul.


Working with local Source Protection committees and other partners, Conservation Authorities have made significant progress in developing ‘environmental snapshots’ of our watersheds and through watershed assessment reports, we are working towards identifying specific threats to our drinking water sources and what can be done to reduce or eliminate those threats.


Assessment Reports will provide Source Protection Committees with information that will help determine how best to protect the quality and supply of their local water resources. They will be the basis for developing Source Protection Plans and making local policy decisions for protecting drinking water.


Assessment Reports are a key requirement of the Clean Water Act and include information such as the physical characteristics of the land, land uses, where drinking water supplies are located, how much water is being used and how much is available for future uses, where vulnerable water supply areas are located, what issues already compromise drinking water sources and what threatens drinking water sources from overuse and contamination.

The assessment reports will provide the foundation for local source protection plans which are expected to be ready to implement in 2012.

Find Your Local Draft or Proposed Assessment Report

What is the Technical Work Being Done Around Source Protection

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What is a Watershed?

The area of land that drains water in a given region is known as a watershed. A watershed can be thought of as bathroom sink. Any rain or snow that falls within the sink-bowl runs down the sides of the sink and into the drain, which can also be thought of as a water supply intake such as a well or surface water intake pipe.


Watersheds are based on natural boundaries, created by natural features of the land. They do not follow municipal, provincial or even national borders.


Ontario’s 36 Conservation Authorities are local, non governmental agencies who are organized on a watershed basis and deliver a variety of natural resource programs and services in partnership with landowners, agencies and communities.



This newsletter was produced by Conservation Ontario, the umbrella organization that represents Ontario’s 36 Conservation Authorities.  (May 2010)


P.O. Box 11

120 Bayview Parkway

Newmarket ON L3Y 4W3



(905) 895-0716





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Building the Science

Our drinking water comes from lakes, rivers, streams or underground sources (aquifers) located across the province. All of these sources of water are linked in a watershed through the water cycle. Drinking water sources can be easily contaminated and have a limited tolerance for stress. Long terms problems can develop that are costly or even impossible to correct.

In order to make sure we have enough clean water for drinking and other uses, we need to protect sources by managing the influences on them. The best way to protect sources of water is on a watershed basis because water flows across traditional boundaries such as towns and cities. Conservation Authorities are the only natural resource management agencies in Ontario that are organized on a watershed basis.


In order to support the development of plans to protect our sources of drinking water, a great deal of science needs to be done. We need to collect and analyze water and land-related data; develop and use computer models to predict future changes to our environment; and develop or update watershed mapping.


Water Budgets are another critical component of the Assessment Report. A Water Budget looks at how much water enters a watershed, how much water is stored and how much water leaves. This information helps determine how much water is available for human uses, while ensuring there is still enough left for natural processes (e.g. there has to be enough water in a watershed to maintain streams, rivers and lakes and to support aquatic life). A Water Budget is similar to your household budget. How much money do you make? How much have you saved? How much can you afford to spend? Water budgets help us to make sure we have enough water for all our needs today and into the future.

The Clean Water Act

The Source Protection Planning initiative is as a result of the Clean Water Act, part of the Ontario government's commitment to implement all of the recommendations of the Walkerton Inquiry.


As a result of the Clean Water Act, communities in Ontario are required to develop source protection plans in order to protect their municipal sources of drinking water. These plans identify risks to local drinking water sources and develop strategies to reduce or eliminate these risks. Because it is everyone's responsibility to protect our water resources, broad consultation throughout the development of the source protection plans is important and involves municipalities, conservation authorities, property owners, farmers, industry, businesses, community groups, public health officials, First Nations. For more information on Source Protection Planning and the technical studies involved.


Find your Source Protection Region or Area.

Frequently Asked questions on Source Water Protection (French)

For More Information on the Clean Water Act in English (French)