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Stormwater Management 

Stormwater is any water resulting from precipitation that flows over land, buildings, roadways, golf courses and other surface features and is not treated by any wastewater management techniques.

As it flows over the land and its features, the water picks up sediments, nutrients and bacteria, which it transports to nearby waterbodies on its route through the endless water cycle. This can cause increased nutrient and bacteria loading in lakes and rivers. Increased sediments cause turbidity, cloudiness in the water, and can destroy fish habitat.

Stormwater is both an urban and rural problem and must be addressed differently in each situation.

Urban Stormwater ManagementRural Stormwater Management

Urban stormwater is managed through a network of drainage pipes and inflow and outflow points. In the urban environment, stormwater often gets an "out of sight, out of mind" attitude.

Rural stormwater is managed by natural topography including slope, elevation and land cover. All stormwater eventually ends up in nearby waterbodies, but this is more prevalent in a rural environment.





Learn more about managing your stormwater.


Stormwater management on individual lots

Individual property owners must take stormwater management into their own hands. Whether you have waterfront property or not, all stormwater will eventually end up in nearby lakes and rivers. However, waterfront property owners have the most direct effect on stormwater runoff in their lakes.

To help prevent and minimize the impact of stormwater runoff, ALL property owners should follow the these guidelines:

Increase building setbacks

Buildings and the cleared area around them have the greatest impact on stormwater runoff. By setting buildings back from the lake and maintaining a shoreline buffer zone, the landscape has more time to absorb and clean the runoff before it reaches the lake.

Maintain vegetation

Trees and grass along hillsides and waterways act as buffer zones and are an effective method for reducing runoff, removing sediments and slowing soil erosion. Wetlands are nature's water filter. Maintaining their existence and health is an important way to protect our lakes from stormwater runoff. To protect and preserve an existing wetland, grow vegetation around its boundary and eliminate detrimental activities that would destroy a wetland, such as filling it in for development purposes.

Use stormwater management during construction

Reduce the amount of vegetation removed during construction, especially on steep slopes. Direct output eavestroughs away from the lake. Create a pond area or dig trenches away from both the lake and the building's foundation.


Urban stormwater

Urban stormwater management is generally the responsibility of the Area Municipality. Muskoka is responsible for stormwater along District roads and the Ministry of Transportation is responsible along provincial highways. Large property owners are responsible for stormwater from their own sites, including parking lots.

In high density areas, stormwater can be channeled, collected and filtered through traps and grates, usually located at the end of a pipe system, but it usually flows directly from streets and gutters into our lakes and rivers untreated.

The urban landscape is characterized by numerous impermeable surfaces - the "concrete jungle." Impermeable means that it is a surface that does not and cannot absorb water, such as streets, driveways, sidewalks, walkways, and roofs.

Impermeable surfaces increase the flow rate and volume of the stormwater runoff by channeling the water and eliminating any slow down time and filtering that would normally occur on permeable surfaces. Impermeable surfaces cause surges of water and flood problems.

It is important for urban property owners to be aware that all those gutters and street grates lead directly to our river and lakes without treatment. There are many different actions to take in reducing the impact of urban stormwater runoff, including:

  • Grass or re-vegetate any disturbed soils
  • Do not use pesticides or fertilizers on lawns or gardens
  • Use only natural, safe alternatives to pesticides or fertilizers
  • Make sure no fluids are leaking from your car
  • Wash your car at a car wash facility or on the grass with minimum detergent

Find out what else you can do to reduce stormwater pollution.

To combat stormwater management issues, both urban and rural residents must do their part to ensure runoff does not impair the water quality of our lakes and rivers.

The Ministry of the Environment and Climate Change has a publication called Stormwater Management Planning and Design Manual, which provides technical and procedural assistance for the planning, design, and review of stormwater management practices.


Retention ponds

A retention pond withholds water, allowing it to slowly seep into the ground after a heavy rain event. They are often used in golf courses, subdivisions and various residential settings.

Retention Ponds in Residential Settings

Retention ponds are created to capture diverted stormwater runoff. These types of ponds provide two major services. First, they hold the runoff before releasing it into nearby lakes and rivers at flow rates and occurrences like those that exist under natural conditions.

The second benefit is that they assist pollutant removal through settling of suspended particulates and reduction of turbidity in local lakes and streams. They initiate biological uptake by plants, algae and bacteria and aid in the decomposition of some pollutants.

Pollutant Removal in Retention Ponds

The table below describes pollutant removal levels for nutrients, sediment, metals, organic matter, oil and grease, and bacteria.

Pollutant Removal Efficiency
  Plant Nutrients  
          Total Phosphorus   Moderate to High
          Total Nitrogen   Moderate
          Total Suspended Solids   High
          Lead   High
          Zinc   Moderate
  Organic Matter  
          Biochemical & Chemical Oxygen Demand   Moderate
  Oil & Grease   High
  Bacteria   High

Source: Compiled from Schueler 1987; Schueler, et al. 1992; US EPA 1990; Phillips 1992; Birch, et al. 1992 and others.



Muskoka and stormwater management

All plans of subdivisions require a stormwater management plan prepared by a qualified engineer. For more information on the subdivision process visit the District Municipality of Muskoka website. Muskoka also has a stormwater management strategy that identifies how Muskoka and the six Area Municipalities can collectively better review, implement and manage stormwater.