AWWA ACE59891

This paper describes a multi-year multifaceted program implemented by the Rock Slough Water Quality Improvement Project (Project), which is an integral part of the CALFED program. The program identifies and quantifies the sources of degradation at Rock Slough and develops an effective water quality improvement plan for Rock Slough, which would address non-pointsources of pollution. The goal was to develop an approach and program that could be implemented elsewherein the Sacramento-San Joaquin Bay Delta to address similar concerns.Phase 1 of the program involved implementing a comprehensive monitoring study of Rock Slough and theCanal to identify and quantify the point and non-point sources of water quality degradation; development of asampling program to collect necessary data to better identify the sources of degradation; and the developmentof water quality modeling tools. The data collected was also used to calibrate and compare model simulationresults and to assess the impacts of selected alternatives.Based on the monitoring results, it was identified that there are two significant sources/areas of degradationalong Rock Slough and the Canal. These two areas are geographically separate and degradation occursthrough two distinct mechanisms. Based on the mechanisms of impact, structural and nonstructuralalternatives were developed to address these two sources. Alternatives identified fell into three categories forthe agricultural drainage (Relocation, Treatment and Operational Modifications) and for the Canal(Modification, Operational Change and Other). Through a rigorous screening process the eleven agriculturalalternatives and the nine Canal alternatives were narrowed down to a viable three and identified for furthermodeling to assess the improvement in water quality prior to selection of the final alternative. Based on themodeling evaluation of viable structural alternatives, a final project for each source was selected forenvironmental permitting, design and implementation.The Fischer Delta Model (FDM), a water quality model developed for the Bay Delta, was applied in finerresolution to the study area to assess the direct and indirect impacts of various alternatives. Based on themodeling, it was found that residual flows, tidal sloshing, barrier operations and other delta operationsimpacted the anticipated reduction in salinity entrained at PP1. It is anticipated that the selected alternativeswill reduce salinity concentrations from 5 to 35 mg/l. The paper will present the modeling results (flow andsalinity) and the estimated reduction in at PP1.This Project has set the stage in the Delta on how to address non-point source pollution issues related tosalinity, as water quality degradation of Delta waterways becomes a bigger issue. This paper discusses thefinal phase of the Rock Slough project including the selection and implementation of the preferred structuraland non-structural mitigation measures, the modeling results (water quality), screening criteria,stakeholder/implementation issues and future regulatory considerations/implications. Includes 7 references, tables, figures.

Product Details

Edition:

Vol. - No.

Published:

06/17/2004

Number of Pages:

19

File Size:

1 file , 1 MB