ilt and sediment refers to the fine-grained soil particles that form the beds of lakes, rivers and streams. It is natural to find silt and sediment in water but problems result when excess amounts are introduced into the water. Excess amounts can harmfully affect water quality, an essential component of fish habitat.

This fact sheet provides information on how to avoid the introduction of silt and sediment into a waterway when working in or around water and who to contact for more information.

Be aware of the Fisheries Act and other legislation

The federal Fisheries Act provides for the protection of fish habitat. Under this Act, no one may carry out any work or undertaking that results in the harmful alteration, disruption or destruction of fish habitat (HADD), unless authorized by the Minister of Fisheries and Oceans Canada. The Act also states that no one is permitted to deposit a deleterious (harmful) substance into water containing fish. Violations to the Fisheries Act can result in substantial fines, and/or the risk of imprisonment. If found guilty, then the violator may also be required to cover the costs of restoring the habitat at the site and/or be required to fulfill other court ordered remedies. Other legislation that may be relevant to building a dock, boathouse or boat launch is outlined in the introductory Fact Sheet: What you should know about Fish Habitat.

Contacts and approvals

Keep in mind that approval from one government agency does not guarantee that you will be able to obtain approval from another agency. As well as the Fisheries Act, other agencies have legal requirements that may affect how to proceed with projects in and around water. The lead review agency for project proposals and their areas of responsibility, listed in the table on the next page, will assist you in determining what other agencies need to be contacted for permits and approvals. Remember you should obtain all approvals before starting work.

Suspended sediment can be harmful

Silt and sediment are sometimes transported in water, and depending on the quantity, can cause cloudiness or turbidity. Silt, sediment and turbidity can result in a variety of harmful impacts to fish and fish habitat. Some of the negative effects of excessive suspended sediments and turbidity include:

• clogging and abrasion of the gills of fish and other aquatic organisms
• behavioural changes, including movement and migration
• decreased resistance to disease
• impairment of feeding, for example, turbidity interferes with feeding for visual feeders such as trout and bass
• poor egg and fry development
• fatal impacts to small aquatic animals that are food for fish.

Deposited silt and sediment can be harmful

Deposited silt and sediment can also be harmful to fish habitat. Some of the harmful impacts of silt and sediment deposits are:

• The clogging of the small spaces between gravel particles prevents the free flow of oxygenated water and the removal of waste products from developing eggs deposited in the gravel. This often suffocates the eggs and may make gravel beds unsuitable for egg incubation.
• The destruction of habitat for bottom dwelling organisms such as crayfish and insects. Fish rely on these organisms for food.
• The clogging of sheltered areas between boulders and gravel. Young fish need these areas as protection to survive.

Avoid introducing silt and sediment into lakes and rivers

Since silt and sediment and the resulting turbidity can create a variety of harmful impacts to fish and fish habitat, it is important to avoid the introduction of these materials into the water. Planning and designing work projects with care and implementing environmentally friendly practices will protect fish and fish habitat.

For most construction or development projects that cause the release of silt and sediment, there are effective methods for removing suspended sediment from the work site and preventing it from entering streams or lakes.

Protect shoreline vegetation

Disturbance of vegetation or other stabilizing soil cover often results in erosion of the exposed soils. For example, the building of improper stream crossings or clearing trees and vegetation to a stream bank or lake shoreline can result in soil erosion. If shoreline vegetation is disturbed, ensure sediment and erosion control measures such as silt curtains are properly in place to prevent silt and sediment from entering the water. Once the work is completed, it is important to revegetate the area as soon as possible. Protecting the riparian or buffer zone along the water is an important component in protecting water quality and fish habitat.

Use clean materials

Ensure all equipment and materials going into the water are clean and free of fine particles.

Protect water quality

If your activity causes the exposure of soil then there is a risk of your work causing the mobilization of silt or sediment into a waterbody. Prevent mobilization of material by rain or wind by covering the exposed soil. In addition, an upland filter barrier or sediment or silt screen may be required around the entire work area. The screen should be carefully removed after the work is completed and all of the silt or sediment has stabilized. If the work is done in the water, it will be necessary to isolate the work area using a silt fence or impermeable barrier. If using a silt fence, plan to work on calm days. This will help prevent the suspension of fine sediment particles into the water by wave action and will ensure the silt screens used in the water are not disturbed by wave action. Sediment or silt screens should be inspected daily and maintained to prevent the spread of suspended sediments to adjacent water and fish habitat.

If you are planning a project in or near water, you must use environmentally friendly practices to avoid the introduction of silt or sediment into waterbodies. Your local provincial regulatory authority(ies) will be able to provide more detailed advice on environmentally friendly practices specific to your project proposal. Be sure to apply for all necessary approvals and permits before undertaking any work around water.

This fact sheet does not constitute any DFO or other regulatory authority(ies) approval. It is your responsibility to contact all appropriate regulatory authorities.

Working together to protect fish habitat

Help maintain the quality and quantity of fish habitat in our lakes and streams. For more advice on how to construct an environmentally friendly dock, boathouse, or boat launch, contact your local agency staff directly.

What is Fish Habitat?

Contact information - Ontario

Other Working Around Water Fact Sheets:

What you should know about Fish Habitat
C-1 Fish Habitat & Docks, Boathouses and Boat Launches
C-2 Fish Habitat & Building a Beach
C-3 Fish Habitat & Building Materials
C-4 Fish Habitat & Shoreline Stabilization
C-5 Fish Habitat & Constructing Ponds
I-1 Fish Habitat & Dredging
I-2 Fish Habitat & Controlling Aquatic Plants
I-3 Fish Habitat & Sunken Log Retrieval
I-4 Fish Habitat & Stream Cleanup
L-1 Obtaining a Fisheries Act Authorization
L-2 Municipal Drains in the Southern Ontario Region
T-1 Fish Habitat and the Effects of Silt and Sediment
T-2 Fish Habitat & Fluctuating Water Levels on the Great Lakes

www.dfo-mpo.gc.ca/canwaters-eauxcan

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