Water Quality Modeling for the Napa River 100-Year Flood Control Project.

Abstract : The objective of the study was to compare dissolved oxygen (DO), and other water quality variables between existing and project conditions. The twowater quality model cE-QUAL-W2 was selected for the study. Constituents simulated included temperature, total suspended solids cr55), salinity, DO, and biochemical oxygen demand (BOD). The study consisted of two steps: (1) calibration to existing conditions and (2) comparison of existing and project conditions. The period of simulation extended from July 1 through September 30, 1994. The 100-year flood control project increases the channel conveyance needed to carry flood flows. Increased conveyance is achieved by excavating and widening the channel above the mean-tide level, and creation of a floodway through the city. Temperatures between existing and project conditions were equivalent except for an increase of less than 1 CC in the project reach. TSS and salinity comparisons revealed no differences. DO comparison revealed a DO decrease of less than 1 gm 3in the proposed project reach.