Transport of dissolved and suspended material by the Potomac River at Chain Bridge, at Washington, D.C., water years 1978-81

Abstract

Introduction 1 Background 1 Purpose and scope 3 Characteristics of the Potomac River at the measuring stations 3 Streamflow station and flow characteristics 3 Water-quality station and sample collection 3 Method of load computation 6 Cations and anions 6 Concentration estimation techniques 6 Computed loads 13 Evaluation of computed loads 14 Nutrient species, chlorophyll, and biochemical oxygen demand 14 Concentration estimation techniques 14 Computed loads 18 Evaluation of computed loads 18 Suspended sediment 26 Discussion 26 Frequency analysis of concentrations and loads 26 Seasonal variations in concentrations and loads 26 Storm runoff 28 Examination of selected water quality constituents 30 Phosphorus 30 Nitrogen 33 Silica 34 Suspended sediment 41 Historical extension of the data 41 Summary and conclusion 41 References cited 43 FIGURES 1. Map showing the tidal Potomac River and Estuary 2 2. Map showing location of stations: