2,216
edits
Changes
Jump to navigation
Jump to search
Line 232:
Line 232:
→Sediment Accumulation Testing
==Sediment Accumulation Testing==
==Sediment Accumulation Testing==
A primary function of LID BMPs is to capture and retain sediment, trash and debris that are suspended in stormwater runoff. Over time, sediment and natural debris accumulates in certain portions of a BMP, particularly in [[pretreatment]] devices (e.g., [[forebays]], gravel diaphragms, hydrodynamic separators, [[vegetated filter strips]], [[Enhanced grass swales|grass swales]], catchbasin/manhole sumps) and at [[inlets]], where inflowing runoff is slowed down and spread out, which promotes sedimentation of suspended materials by design.
Without adequate inspection and maintenance (at least annually), accumulated sediment and debris in pretreatment devices and inlets can inhibit the flow of stormwater into the BMP or be transported onto the [[filter media|filter bed]] . Extensive sediment accumulation on the surface of a filter bed will eventually lead to drainage problems due to clogging of the filter media with fine-textured sediment. When sediment accumulation on the surface of a filter strip or [[swales]] becomes excessive the BMPs begin to export sediment and associated pollutants into receiving waters rather than retain them.
===Key Components, Test Methods and Equipment===
Key components of LID BMPs that should be the subject of sediment accumulation testing (i.e., depth measurements) are described in the table below along with recommended test methods. Depth measurements should be recorded on inspection field data forms provided on each associated [[Inspection and maintenance#Practice-specific Inspection and Maintenance|BMP's I&M page on the wiki]], used to determine if sediment removal maintenance is needed.
==Surface Infiltration Rate Testing==
==Surface Infiltration Rate Testing==