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-point
sources of pollution. The goal was to develop an approach and program that could be implemented elsewhere
in 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 the
Canal to identify and quantify the point and non-point sources of water quality degradation; development of a
sampling program to collect necessary data to better identify the sources of degradation; and the development
of water quality modeling tools. The data collected was also used to calibrate and compare model simulation
results and to assess the impacts of selected alternatives.
Based on the monitoring results, it was identified that there are two significant sources/areas of degradation
along Rock Slough and the Canal. These two areas are geographically separate and degradation occurs
through two distinct mechanisms. Based on the mechanisms of impact, structural and nonstructural
alternatives were developed to address these two sources. Alternatives identified fell into three categories for
the agricultural drainage (Relocation, Treatment and Operational Modifications) and for the Canal
(Modification, Operational Change and Other). Through a rigorous screening process the eleven agricultural
alternatives and the nine Canal alternatives were narrowed down to a viable three and identified for further
modeling to assess the improvement in water quality prior to selection of the final alternative. Based on the
modeling evaluation of viable structural alternatives, a final project for each source was selected for
environmental permitting, design and implementation.
The Fischer Delta Model (FDM), a water quality model developed for the Bay Delta, was applied in finer
resolution to the study area to assess the direct and indirect impacts of various alternatives. Based on the
modeling, it was found that residual flows, tidal sloshing, barrier operations and other delta operations
impacted the anticipated reduction in salinity entrained at PP1. It is anticipated that the selected alternatives
will reduce salinity concentrations from 5 to 35 mg/l. The paper will present the modeling results (flow and
salinity) 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 to
salinity, as water quality degradation of Delta waterways becomes a bigger issue. This paper discusses the
final phase of the Rock Slough project including the selection and implementation of the preferred structural
and non-structural mitigation measures, the modeling results (water quality), screening criteria,
stakeholder/implementation issues and future regulatory considerations/implications. Includes 7 references, tables, figures.
| Edition : | Vol. - No. |
| File Size : | 1
file
, 1 MB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 19 |
| Published : | 06/17/2004 |
