General Design Standards for Sand Filters

The primary purpose of this storm water BMP is to improve internal soil drainage in low areas of a site. This is done by taking advantage of the internal flow of capability of sand rather than the native silts and clays which are typical in Louisiana communities. The usual method of construction of this feature is to excavate native soil areas designated in the site plan for this type of drainage feature and backfill with sand over a gravel base. In some instances concrete walls are used to stabilize the edge of the facility and allow for a straight edge.

Sand filters can be placed in any location that may intercept the flow of water. They may be constructed along drainage swales, in flats within larger drainage basins, along walkways and adjacent to open roadway ditches.  And of course, one of the better places to develop sand filters is near, around or under planting areas where plant roots can take advantage of the loose soil conditions, minerals, good drainage and access to surface air. Friable soil and moisture are ideal horticultural mediums for plant root growth.   In many recreations parks, these BMP’s can be worked into the design of recreation fields in ways that either improve the appearance of the play space or co-exist with it without detracting from the sport.

Sand filters can also be used to remove chemicals and other pollutants from storm water. Sand filters can be constructed with a settlement basin, sand layer and a chemical removal barrier. The barrier can be removed from time to time and disposed so that trapped chemicals can be eliminated and lawfully disposed.

 

Click Here for more Technical Standards