This lecture will discuss policies for controlling pollution of surface water and groundwater.
Point sources are generally far easier to identify and regulate than non-point sources.
DO indexes stream quality at various points. Oxygen sags are downstream points with low DO readings. Stock pollutants include heavy metals which may bioaccumulate in the food chain. Surface waters can assimilate various pollutants which groundwater cannot. Thus some contaminants which are fund pollutants in surface waters are essentially stock pollutants in aquifers.