Construction: erosion and sediment control measures

Pre-construction: erosion and sediment control measures

Grooves perpendicular to the grade help prevent the development of rills. If left unchecked, rills can develop into gullies. (Source: CVC)

Establish required perimeter controls, including erosion and sediment control (ESC) measures, prior to construction and adjust accordingly during construction. ESC measures come in two basic types: structural ESC, which slows and holds runoff from the disturbed area, dissipating erosive forces, promoting ponding, and allowing suspended particles to settle out; and non-structural ESC, which primarily minimizes the exposure time of stripped soils. STEP’s Erosion and Sediment Control Guide contains detailed guidance on the design, installation, inspection, maintenance, and decommissioning of ESC measures. This section gives simple, practical advice on structural and non-structural ESC for contractors, inspectors, and those who are new to construction and ESC practices.

For non-structural ESC measures, be sure to:

• Stage clearing and grubbing to minimize exposure of stripped soils.
• Watch the weather and adjust plans accordingly.
• Manage and demarcate heavy equipment routes away from LID practices.
• Use simple, common-sense methods, such as scarifying exposed soils perpendicular to the grade to prevent the development of rills.
• Create and use a pollution prevention plan for any fuels or solvents.

Generally, all exposed soils that are not being actively worked on must have temporary erosion protection or permanent cover within 7 days for slopes 3:1 or greater and 14 days for slopes 3:1 or lesser and 14 days for slopes 3:1 or flatter. This should apply to all exposed soil areas year-round and until the site is stabilized.

The table below gives guidance on common mistakes made when installing structural ESC measures.

Best practices and common errors when installing structural erosion and sediment control measures

Structural ESC measure	Do	Don't	(Pass) Photo Example	(Fail) Photo Example
Sediment fencing	Stake it in, support it, and double it up adjacent to natural heritage features.	Leave vulnerable points with insufficient supports.	This sediment fencing has been doubled up and staked in. As a result, it kept a large amount of sediment from entering the adjacent natural heritage feature. It is in need of immediate maintenance, however. (Photo source: CVC)	This sediment fencing was not staked in at the likely point of failure, resulting in the release of sediment into an adjacent natural heritage feature. (Photo Source: CISEC)
Inlet controls	Support and stake in inlet controls such as sediment socks. Use catch basin inserts as a final line of protection.	Leave inlets to the stormwater management system unprotected or unsupported	This filter stock has been staked in and supported. (Source: CVC)	This catch basin was left unprotected, resulting in the release of sediment into the stormwater management system. (Photo source: CISEC)
Stockpiles	Sling soil and aggregates into the facility when possible. Install soil and aggregates upon arrival to the site when possible.	Store materials within the stormwater management system, e.g., in the roadway. Leave stockpiles unprotected when wet weather is expected	(Photo source: CVC)	If it were to rain, fines from this stockpile would go straight into the downstream catchbasin. (Photo source: CVC)
Protecting features during construction, including using sacrificial filter fabric	Use sacrificial filter fabric when necessary to protect features, and leave ESC measures in place until all construction in the LID's drainage area is complete.	Remove ESC measures early or allow sediment to enter the LID footprint.		ESC measures at this bioretention feature were removed before construction in its drainage was complete, allowing sediment into it.

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.

Credit Valley Conservation

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.

Sustainable Technologies Evaluation Program

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.

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.

Ground depression acting as a flow control and water treatment structure, that is normally dry.

A broad category of particulate material used in construction, including sand, gravel, crushed stone, slag, recycled concrete and geosynthetic aggregates, and available in various particulate size gradations.

Soil particles with a diameter less than 0.050 mm.

Box like underground concrete structure with openings in curb and gutter designed to collect runoff from streets and pavement.

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.

A shallow excavated surface depression containing prepared filter media, mulch, and planted with selected vegetation.