Bio Detention Basins – how do they work?

Is there a Bio Detention Basin near your home?    Do you know how they work?   It takes three years before these basins are fully established in the MBRC area. The basins are designed to fill up with rain water and treat the storm water prior to it being discharged into our waterways.   It does this by filtering the water through a layer of media (usually sand) and vegetation to capture sediments and pollution.   In the swales there are a number of underground pipes siting below the layer of plants and sand which are there to collect the water that has passed through this media, these pipes then connect to a normal stormwater outlet.

When the basin is first installed it usually has a grass cover, this remains in place until 80% of the blocks are built, the reason for this is this is when a large amount of silt is captured within the swales.   The swales are then stripped and planted out, the media is usually sand which has very little nutrients for the plants so it is covered with mulch and jute matting to provide some organic matter for the plants while they establish.  There are five specific species of sedges planted that will take up the pollutants that run off the roads during rain.

23.6.16 Beaufort Bio Basin (3)  20160628_150642  20160628_150919