Water-quality trends in the nation’s rivers and streams, 1972-2012 Data preparation, statistical methods, and trend results analyzes surface water quality trends in the United States. The report includes a discussion of 1) the compilation and processing of water quality data, 2) statistical methods used to analyze the data, 3) modeling considerations, 4) sensitivity analysis, and 5) quantitative results for each site analyzed. The study includes water quality metrics for water quality concentrations and loads (i.e., salinity, sediment, nutrient, major ion, carbon), aquatic habitats (i.e., algae, invertebrates, fish), and pesticide concentrations and loads.
