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Created page with "Common construction pitfalls can be avoided with careful construction supervision that focuses on the following aspects: <table table class = wikitable> <tr><th colspan =2>Ero..."
Common construction pitfalls can be avoided with careful construction supervision that focuses on the following aspects:
<table table class = wikitable>
<tr><th colspan =2>Erosion and Sediment Control<th>
<tr><td></td><td>Bioretention locations should be blocked from construction traffic and should not be used for erosion and sediment control.</td></tr>
<tr><td></td><td>Proper erosion and sediment controls should be in place for the drainage area.</td></tr>
</table>
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.
• A cap should be placed on the upstream (but not the downstream) end of the underdrain.
• Biomedia should be tested to confirm that it meets specifications.
• Mulch composition should be correct.

Elevations
Elevations of the following items should be checked for accuracy:
• Depth of the gravel and invert of the underdrain
• Inverts for inflow and outflow points
• Filter depth after biomedia is placed
• 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 should drain within 24 hours of the end of the storm event. The filter media bed should fully drain within a maximum period of 72 hours.
• Excessive sediment accumulation should not be present.
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