DSM2 Analysis of Water Level and Water Quality in the South Delta Presented to California Water and Environmental Modeling Forum February 26, 2007 Fingerprinting and Particle Tracking Analysis

Background Concerns with water levels and low flow conditions in the South Delta in current SDIP studies Previously demonstrated that modified barrier operations could alleviate low water level and stagnation events Current investigation focuses on more stringent definition of flow concern in Old River and use of fingerprinting and visualization tools

Compliance Locations Flow only Flow / WL

Definition of Violations Water Level Violation – Daily minimum stage < 0 ft MSL Flow Violation – 3 day average flow –< 50 cfs in MR and GLC –< 100 cfs in OR

Plan C Gate Operations and Circulation Patterns at Low Flow (<2500 cfs) Net Flow Flood Flow Ebb Flow

Revised Circulation Patterns at Low Flow, (when Plan C Ops result in flow violations) [TO 5] Net Flow Flood Flow Ebb Flow

Summary of Changes to Plan C Barrier Operations

Violations Summary (April to November only) RUNDays with Water Level Violations Low Flow Violations Total Violations Grant Line Canal Up- stream of East Barrier (206) Middle River at Mowry (126) Old River at Tracy Road Bridge (71) Grant Line Canal Down- stream of West Barrier (213) Grant Line Canal Up- stream of East Barrier (206) Middle River at Mowry (126) Middle River Up- stream Barrier (133) Old River near Tracy Up- stream of Barrier (79) Old River at Tracy Road Bridge (71) Step 1 (Base Line) cfs OR Trigger [TO2] cfs OR Trigger [TO5] * In TO2, 50 cfs rule was applied even in OR

Fingerprinting Analysis Two planning simulations: –Temporary Barriers –CH2M HILL Modified Plan C Volumetric and Constituent Analysis –Volumetric Analysis provides origin of water at any point through time on a fractional basis –Constituent Analysis provides origin of salt (EC) at any point through time on a fractional basis

Volumetric Fingerprinting Analysis: Old River

Volumetric Fingerprinting Analysis: Middle River

Summary of Period-Averaged Contribution from Various Sources Sacramento River (%) San Joaquin River (%) Delta Islands (%) Location Temporary Barriers Permanent Gates Temporary Barriers Permanent Gates Temporary Barriers Permanent Gates MR DS Barrier OR Tracy GLC DS Barrier Banks PP Tracy PP

Summary of EC Results: DICU Influence in Middle River

Particle Tracking Analysis Three simulation periods: –July/August 1985 – consistent with DWR Delta Modeling analysis –April/May 1987 – VAMP period –June/July 1988 – Extremely low SJR, exports Three DSM2 Simulations: –Temporary Barriers –CH2M HILL Modified Plan C –DWR Modified Plan C –(All runs have consistent BCs with updated SJR flows)

Particle Tracking Analysis General circulation demonstration ANIMATIONS –Temporary Barriers vs SDIP Gates –SDIP Gates with modifications to reduce stagnation

Old River Flows for Temp Barriers and SDIP (Modified Plan C)

Old River Flows for SDIP (Modified Plan C) and CH-SDIP

Cumulative Flows: Old River

Summary of Particle Fate (MR / OR Release)

Conclusions Flexible SDIP gates shown to effectively manage water level and flow Sacramento River influence in South Delta Channels is significantly increased with Permanent Barriers Particle Tracking simulations demonstrate the potential of flushing flows in Middle and Old River Results indicate that one-day flushing flows are not likely to traverse entire length of Middle or Old River; sustained flows are required