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.
STATUS AS OF: July 3 , 2008
Head of Old River Barrier (HORB):
The spring HOR barrier work will not be installed this year due to a court decision by US District Court Judge Wanger that prohibited the installation of the spring barrier to increase protections for delta smelt. This is an interim decision that effects the 2008 season only. The fall HORB is not effected.
Agricultural Barriers (Old River near Tracy [ORT], Middle River [MR], Grant Line Canal [GLC]):
Work began May 12 at the DMC barrier with closure being completed on Wednesday, June 4. The Middle River barrier construction began on May 20 and was completed May 21. Crews began construction of the Grant Line Canal north abutment (boat ramp) on May 19. Partial closure (completion of the boat ramp) was completed on Monday, June 2. Full closure of the GLC barrier was complete on Thursday, June 26. All the GLC culvert flap gates are untied and operating tidally. The order to untie the flap gates on the MR barrier was given late Tuesday but I don’t have verification that this has been completed yet. The flap gates on the culverts at the ORT barrier remains tied open at the request of the fishery agencies for the benefit of delta smelt, however, we will revisit the need to keeping the flap gates tied open early next week.
A look at CDEC data for this week shows water levels have been rising steadily since June 27 and are now peaking with the strong spring tides and the closing of the GLC barrier last Thursday. We expect low water levels into next week will unlikely be below the trigger levels at the stations we monitor in spite of not having modeling forecast information. You can check out the CDEC date for the three real-time stations we monitor (Station I.D.’s: OLD, DGL, and MHR) at: http://leva.water.ca.gov/queryQuick.html.
We included actual water levels through mid-day 7/7/08. Actual water levels at all the barriers are slightly better than modeled forecasts. The modeling shows water levels remaining above the level of concern at the ORT station (0.0 feet MSL) as well as the MR station (0.3 feet MSL) and GLC monitoring station (0.0 feet MSL). Conditions on Old River will be better than the modeled forecasts after 7/9/08 because we untied six of the nine culverts at the ORT barrier today. Three culverts on the ORT barrier will continue to have their flap gates tied open to improve circulation on Old River and perhaps improved water quality slightly on Old River.
Click here to see modeling outputs
Fishery agencies and DWR will be closely monitoring conditions for Delta smelt which might effect operations of the barriers during May/June. At this late date, changes in flap-gate operations on the culverts are the only likely action that might be taken to protect smelt if necessary.
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Mark A. Holderman, P.E.
Chief, Temporary Barriers Project and
California Department of Water Resources
Phone: (916) 653-7429 FAX: (916) 653-6077
Cell/Pager: (916) 601-6036 E-Mail: email@example.com