A BMP selection process based on the granulometry of runoff solids in a separate urban catchment

Abstract

This article presents the methodology and results of the field survey carried out to characterise the pollution associated with the stormwater runoff from an urban catchment in Galicia (Spain). Various instruments were installed in the control section of this catchment measuring some 55 ha and located in the separate sewer system outlet, to obtain samples associated with stormwater events. In particular, precipitation and flow were recorded, in addition to the pollution associated with such flows. On the basis of this information it was possible to determine a series of pollution parameters (solids, BOD5, COD, TOC) and the most important event parameters (event mean concentration, maximum concentration, mobilised load per net hectare) were calculated. These results were compared with those from other similar catchments. The analysis of the results includes the determination of probability distribution as well as the study of the particle size distribution of the samples during different
periods of the event, which thus enabled us to obtain the relationship between the total rainfall and the particle size distribution of each event. Finally, a study of potential best management practices using the process selection diagrams is presented.

Water SA Vol.32 (3) 2006: pp.419-428