Bioretention: Construction checklist

Common construction pitfalls can be avoided with careful construction supervision that focuses on the following aspects:

Erosion and Sediment Control
	Bioretention locations should be blocked from construction traffic and should not be used for erosion and sediment control
	Proper erosion and sediment controls should be in place for the drainage area
Materials
	Gravel for the underdrain should be clean and washed; no fines should be present in the material
	Underdrain pipe material should be perforated and of the correct size (when specified in design)
	A cap should be placed on the upstream (but not the downstream) end of the underdrain (when specified in design)
	Biomedia should be tested to confirm that it meets specifications
	Mulch composition should be correct
Elevations
	Depth of the gravel and invert of the underdrain
	Inverts for inflow and outflow points
	Filter media depth
	Ponding depth provided between the surface of the filter bed and the overflow structure
	Mulch depth
Landscaping and Stabilization
	Correct vegetation should be planted
	Pretreatment area should be stabilized
	Drainage area should be stabilized prior to directing water to the bioretention
The following items should be checked after the first rainfall event, and adjustments should be made as necessary:
	Outfall protection/energy dissipation at concentrated inflow should be stable
	Flow should not concentrate and should spread evenly over the filter bed
	Ponded water at the surface of the bioretenton facility must drain within 24 hours of the end of the storm event. The biomedia should fully drain within a maximum period of 72 hours
	Excessive sediment accumulation should not be present

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.

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

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.

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 perforated pipe used to assist the draining of soils.

Soil particles with a diameter less than 0.050 mm.

A perforated pipe used to assist the draining of soils.

a top dressing over vegetation beds that provides suppresses weeds and helps retain soil moisture in bioretention cells, stormwater planters and dry swales.

The engineered soil component of bioretention cell or dry swale designs, typically with a high rate of infiltration and designed to retain contaminants through filtration and adsorption to particles.

Initial capturing and removal of unwanted contaminants, such as debris, sediment, leaves and pollutants, from stormwater before reaching a best management practice; Examples include, settling forebays, vegetated filter strips and gravel diaphragms.

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.

The point, location, or structure where wastewater or drainage discharges from a sewer pipe, ditch or other conveyance to a receiving body of water.