SAN JOAQUIN RIVER RESTORATION PROGRAM: February Pulse Flows to be Released from Friant Dam

From the San Joaquin River Restoration Program:

The Bureau of Reclamation is preparing for pulse flows below Sack Dam beginning February 10, 2019 and lasting for at least 12 days. This updated flow schedule has been recommended and approved by the Restoration Administrator.

Over the past few days, Friant Dam releases have ranged between 300 and 365 cubic feet per second (cfs). Beginning February 10, Friant Dam releases will be increased to approximately 650 cfs. The exact flow release will depend on the water use demand of Holding Contracts below Friant Dam and any potential inflow from tributaries of the San Joaquin River such as Cottonwood Creek and Little Dry Creek.

The objective of this pulse will be to hold flows below Mendota Dam in Reach 3 at a constant level of up to, but not exceeding, 520 cfs to investigate groundwater response. Reclamation has made commitments in its Seepage Management Plan to avoid adverse impact to agriculture adjacent to the river by limiting the depth that groundwater can rise due to Restoration Flows. By tightly regulating flows in the most groundwater-sensitive reach of the river, Reclamation can gather accurate data about the relationship between river flows and nearby shallow groundwater levels.

This pulse is intended to result in groundwater conditions at least 0.3 feet below the most stringent groundwater threshold in Reach 3 as indicated by groundwater models. This buffer of 0.3 feet allows for some uncertainty in groundwater models and survey elevations. Subsequent Restoration Flows in 2019 will be informed by this pulse flow evaluation.

The table below shows the flow rates we expect during this pulse release. These values may vary considerably in response to various irrigation diversions and tributary inflows.

Date Friant Dam Release Gravelly Ford Flow Flow Below Mendota Dam Flow Below Sack Dam
Feb 10-21 650-750 cfs 526 cfs 520 cfs 345 cfs

For Information about Restoration Flows, please visit http://www.restoresjr.net/restoration-goal/restoration-flows/.

For the Restoration Administrator recommendations, please visit http://www.restoresjr.net/documentsreports/ra-recommendations/

For additional information about the San Joaquin River Restoration Program, please visit http://www.restoresjr.net or contact Josh Newcom, Public Affairs Specialist, at 916-978-5508 or snewcom@usbr.gov.

 

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