Thursday, April 28, 2011

San Antonio Creek Spreading Grounds

On Tuesday April 26, the Ventura County board of Supervisors approved the environmental document for the San Antonio Creek Spreading Grounds project.

Although the project has broad support from the water agencies, the resource agencies (NOAA and DFG) have filed letters on the project. NOAA filed a protest to the State Water Board.

At issue is whether appropriation of surface water will affect endangered steelhead and it's habitat. The final MND environmental document includes these graphs that illustrate the quantity of water that will be diverted into the spreading basins for infiltration and injection into the groundwater basin.

During the hearing it was stated that the project was designed so that diversion flows comply with downstream needs, based upon comments from DFG and the City of Ventura. Quoting the MND;

Surface flow diversion would be a passive system, designed such that water levels
at the intake structure would dictate the timing and amount of the diversion. Therefore, the volume of water diverted would increase as the water level in the creek rises, and decrease as water levels decline. Table 1 provides proposed surface water diversion rates based on the design of the system and placement of the intake structure in San Antonio Creek. Surface flow in San Antonio Creek would need to be 150 cfs for the proposed facility to operate at capacity (25 cfs). A graph of the designed relationship between surface flow rate and diversion rate is provided as Plate 3. Real time operational changes to terminate diversion when minimum flows are reached should not be necessary. Compliance with minimum flows (11 cfs at the point of diversion, 5 cfs at Grand Avenue) would be enforced by the State Water Resources Control Board through monitoring and reporting by the District.

The project still requires additional permits before construction can begin, currently scheduled for Fall 2011.

More info:

COMMENTS: I testified to the Board that they should delay the approval of the environmental document until the water rights issue is worked out. I also said that without a watershed plan, or even a water budget, it is unclear how much benefit or impact this project would have on a watershed scale. If such a plan was in place, along with conjunctive use agreements for surface water/groundwater management, the resource agencies could be assured that in-stream flows would be maintained and/or enhanced with projects like this.