Eisele Vineyard Reservoir Maintenance Project, (Lake or Streambed Alteration Agreement No. EPIMS-NAP-30845-R3)

Eisele Vineyard Reservoir Maintenance Project, (Lake or Streambed Alteration Agreement No. EPIMS-NAP-30845-R3)

The California Department of Fish and Wildlife has executed Lake and Streambed Alteration Agreement EPIMS Notification No. EPIMS-NAP-30845-R3, pursuant to Section 1602 of the Fish and Game Code, to Kerwin Estates as represented by Helene Mingot. The Project is limited to Araujo Reservoir No. 1, a reservoir receiving inputs from three upstream ephemeral streams; and dam embankment and infrastructure repairs consisting of excavation and removal of the downstream portion of the existing dam embankment; excavation and establishment of a seepage barrier (cutoff trench) within the embankment; installation of internal drainage features to collect and convey seepage through and away from the dam; and reconstruction of the dam embankment with additional height to provide adequate freeboard. Estimated quantities of Project components include approximately 30,000 cubic yards (cy) of excavation, installation of about 800 cy of internal drainage materials (imported sand and gravel), and placement of approximately 41,000 cy of compacted soil embankment. Approximately 8,000 cy of earth embankment material will be hauled in from an offsite source and staged in an inactive vineyard field approximately 0.25 miles northwest of the dam. Transport of soil from the staging area to the Project Area will occur over existing vineyard access roads, with soil material intermittently stockpiled in the emptied reservoir basin. The existing embankment drain and outfall, and the existing outlet conduit will be removed and replaced. A new concrete drop outfall structure will be installed, entailing the removal of approximately 16 cy of concrete covering 430 square feet (sq. ft.). A 60-foot-long, 4-foot-wide, 3-foot-deep temporary trench will be excavated to construct a 30-inch diameter cast in place outfall pipe. Approximately 50 cy covering 500 sq. ft. of castin-place concrete will be used to construct the new outfall. At the northeast corner of the reservoir, the spillway discharge conduit outlet pipe will also be replaced, which discharges flow from the reservoir into an unnamed intermittent stream. This spillway discharge will tie into existing drainage infrastructure and will not impact the intermittent stream or riparian habitat. Existing rip rap will be removed and replaced to facilitate the spillway work outside of stream and riparian habitat. No rip rap or hardscape rock armoring will be placed in the reservoir or intermittent stream or riparian. To facilitate dewatering during construction, water will be transferred from Araujo Reservoir No. 1 to Araujo Reservoir No. 2, which is another operational irrigation storage facility on the property approximately 950 feet northwest of Araujo Reservoir 1. Water drained from Reservoir 1 will be conveyed to Reservoir 2 through the existing irrigation system. Project activities will result in approximately 301 square feet of permanent impacts to the reservoir from the construction of a new concrete conduit casing structure, and 45,816 square feet (1.05 acres) of temporary impacts to the reservoir from dewatering, equipment access, and earthen embankment material staging. The Project will also result in permanent impacts to 4,285 square feet (0.1 acres) of a seasonal wetland located near the base of the dam embankment; and permanent impacts to 14 square feet and 8 linear feet, and temporary impacts to 15 square feet, of an unnamed ephemeral stream immediately below the dam embankment due to drainage outfall and conduit improvements and access. No riparian trees will be removed by Project activities.

Calistoga

Napa

San Francisco Bay Area

Napa