Projected low flows are used to evaluate the impact of discharges on water quality. They are, for example, used in the calculation of industrial discharge permit requirements. M orphology, River - the study of the form and structure of a river. Muskingum Method - hydrologic river routing method that uses the continuity equation and a linear storage relationship. N onpoint Source - pollutants carried in runoff characterized by multiple discharge points.
Point sources emanate from a single point, generally a pipe.
O verland Flow - see Runoff . Peak Flow - maximum flow through a watercourse which will recur with a stated frequency. The maximum flow for a given frequency may be based on measured data, calculated using statistical analysis of peak flow data, or calculated using hydrologic analysis techniques. Projected peak flows are used in the design of culverts, bridges, and dam spillways. Perched Ground Water - unconfined groundwater separated from an underlying body of ground water by an unsaturated zone .