Construction

• The site of the infiltration practice should remain outside the limit of disturbance until construction of the facility begins, to prevent soil compaction by heavy equipment.
• This area must not be used as the site of sediment basins during construction, as the concentration of fines will reduce post-construction infiltration.
• This area must not be use as a staging area, for storing materials.
• To prevent sediment from clogging the surface, stormwater must be diverted away from the facility until the drainage area is fully stabilized.
• As many infiltration facilities are installed in the road right-of-way or tight urban spaces, considerations of traffic control and utility conflicts must be part of the plans and inspections.

The following is a typical construction sequence to properly install an infiltration practice:

1. The area should be fully protected by silt fence or construction fencing to prevent compaction by construction traffic and equipment,
2. Installation may only begin after entire contributing drainage area has been either stabilized or flows have been safely routed around the area. The designer should check the boundaries of the contributing drainage area to ensure it conforms to original design,
3. The pretreatment part of the design should be excavated first and sealed until full construction is completed,
4. Excavators or backhoes working adjacent to the proposed infiltration area should excavate to the appropriate design depth,
5. The soil in the bottom of the excavation may be ripped to promote greater infiltration,
6. Any accidental sediment accumulation from construction should be removed at this time,

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.

Soil particles with a diameter less than 0.050 mm.

The slow movement of water into or through a soil or drainage system.

Penetration of water through the ground surface.

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.

Soil or media particles smaller than sand and larger than clay (3 to 60 m)

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.