The following report on the Temporary Barriers Project is for your information and action, as appropriate. This report will be transmitted whenever changes occur to the operation of the barriers, and as a result of modeling and/or field monitoring of water levels in the south Delta.
http://baydeltaoffice.water.ca.gov/sdb/tbp/web_pg/tempmesr.cfm.

STATUS AS OF: June 30, 2005

Head of Old River Barrier (HORB):

No HORB was installed this spring due to high San Joaquin River flows.

Agricultural Barriers (Old River near DMC, Middle River, Grant Line Canal):

All barriers are installed, although the center portion of the Grant Line Canal barrier remains open until the need to close it for water level improvement is demonstrated in accordance with our permits. Closure will occur at the Grant Line barrier when water levels are too low for adequate agricultural diversions and the closure does not adversely affect fisheries. The culverts at all the barriers have been tied open because water levels have been very high in June. However, water levels are slowly dropping as SJR flows are reduced, ag demand increases due to the hot weather, and tide strength increases as we approach a new moon. We plan on untying the flap gates on the OR and MR barriers tomorrow. We will be contacting our construction staff to begin planning to close the GLC barrier as early as the end of next week.

Modeling:

Modeling results for this week are attached. Water levels are currently above the trigger level (0.0 feet MSL) but are slowly dropping toward the trigger point. SJR flows will continue to drop, along with higher ag water supply demands as the weather heats up. Tide strength is increasing as we approach a new moon next week. Based upon the modeling and the expected higher ag demand, we will modify barrier operations as described above.

Modeling Outputs:

Middle River at Howard Road Bridge
Doughty Cut above GLC Barrier
Old River near Tracy Road Bridge


Notes:

These weekly updates are also available for your information on our website http://baydeltaoffice.water.ca.gov/sdb/tbp/web_pg/tempmesr.cfm