Treatment of Agriculture Stormwater Runoff by Cascading System of Stormwater Containment Basins

A series of four cascading basins were installed at Hambleton Creek Farm in Chestertown, Maryland, to treat agricultural stormwater from a 45.4-ha watershed. The basin system was monitored from July 2013 to April 2015 for concentrations and mass loads of suspended sediments, phosphorous, and nitrogen species. Over the duration of the study, 26 storm events were successfully sampled and tested. During this time, the basin system provided statistically significant reductions of sediments, total phosphorus, and total nitrogen mass loads. The total volume reduction exhibited by the system was 56%; total mass reductions based on an input and output approach for suspended solids, total phosphorus, and total nitrogen were 65%, 59%, and 64%, respectively. Volume reduction appears to be the main mechanism of removal for suspended sediments, phosphorus, and nitrogen. Evidence of sedimentation and nutrient processing between storm events was found.