Farrell Stream Crossings, Water Diversion, Ponds, and Restoration Project (Lake or Streambed Alteration Agreement No. 1600-2020-0147-R1)

Farrell Stream Crossings, Water Diversion, Ponds, and Restoration Project (Lake or Streambed Alteration Agreement No. 1600-2020-0147-R1)

The project is limited to 8 encroachment(s) (Table 1). One encroachment is for water diversion from an on-stream pond (Pond 1) located on tributaries to Blue Rock Creek. Water is diverted for irrigation. CDFW could find no records of water rights associated with this diversion. Water enters the pond through two streams. Water is diverted from the pond via a submerged intake pimp with a screened intake. Work for the water diversion will include use and maintenance of the water diversion infrastructure. Another encroachment associated with Pond 1 involves decommissioning the current spillway, re-connecting the two streams that enter the pond, and constructing a new spillway which will connect pond overflow to the historic stream channel below. The current spillway has a damaged and failing culvert that has created an eroded gully through a manmade non-native channel that connects to a stream downhill. The western stream that flows towards the pond had been diverted around the pond and flowed directly into the eroded gully. The flow of the eastern stream into the pond has been impaired by sediment that had been placed within the stream channel when cattails were removed from the pond. Once the current spillway culvert has been excavated, the existing gully will be treated to minimize and reduce erosion and sediment delivery. The western stream will be recontoured and reconnected so that it flows into the pond. The existing artificial bypass channel for the western stream will be treated to minimize and reduce erosion and sediment delivery. The sediment within the eastern stream will be removed to allow unimpaired flow into the pond. Work on the dam will include raising the dam height and installing a new overflow spillway culvert with an energy dissipation feature at the outlet. The overflow from the pond through the new spillway will discharge into the historic channel below the dam and converge with receiving waters upstream of stream crossing 3 (STX-3). New spillway and dam improvement design plans will be provided for Pond 1 (see measures 2.51 and 3.8). One encroachment is to replace the existing spillway culvert for Pond 2. Pond 2 does is a rainwater catchment pond with an overflow spillway that connects to Pond 3 below and mixes with waters of the State. The existing spillway culvert is damaged, failing, and undersized. It will be replaced with a new appropriately sized spillway culvert. Work for this encroachment will include excavation, removal of the failing crossings, replacement with new properly sized crossings, backfilling and compaction of fill, and rock armoring as necessary to minimize erosion. One other encroachment is to fully remove an on-stream pond (Pond 3) and to restore the stream channel through the pond. Work for this encroachment will include pumping water from Pond 3 using a screened intake, excavating and removing the dam and berm surrounding the pond, removal of the spillway culvert and downspout, recontouring the impoundment area to original contours, and revegetating the slopes with native vegetation. The excavation work will be conducted during the dry season when there will be no flowing water. The material in the berm originated from the area that became the impoundment, so all the excavated material will be used to return the slopes to original grades. No spoils will be hauled off site. The encroachment will also include reestablishing the original stream channel (approximately 90 ft long) through the former impoundment. To: From: Office of Planning and Research Department of Fish and Wildlife For U.S. Mail: Northern Region P.O. Box 3044 619 Second Street Eureka, California 95501 Sacramento, CA 95812-3044 Contact: John Herrera Street Address: Phone: 707-962-9044 1400 Tenth Street Sacramento, CA 95814 Lead Agency (if different from above) County of Mendocino 860 N. Bush Street Ukiah, CA 95482 Contact: Julia Acker Phone: 707-234-6650The four other proposed encroachments are to upgrade failing and undersized stream crossings. Final construction plans will be provided for STX 1, 2, & 3 and Spillway 2 (see measures 2.72 and 3.9). Work for these encroachments will include excavation, removal of the failing crossings, replacement with new properly sized crossings, backfilling and compaction of fill, and rock armoring as necessary to minimize erosion. Project activities for Ponds 1, 2, & 3 shall require pre-construction surveys by a Designated Biologist. Project activities at all other stream crossings shall require pre-construction surveys by a Designated Biologist if surface water is or becomes present during construction.

Laytonville

Mendocino

Northern California

Alameda, Mendocino