Muller Water Diversion, Micro-hydroelectric, and Stream Crossings Project (Lake or Streambed Alteration Agreement No. 1600-2018-0454-R1)

Muller Water Diversion, Micro-hydroelectric, and Stream Crossings Project (Lake or Streambed Alteration Agreement No. 1600-2018-0454-R1)

This Agreement relies on the Notification materials and a desk review without a CDFW site inspection. The project involves eight encroachments :1) direct diversion of channel surface water from School House Creek for nonconsumptive micro-hydroelectric power generation at Point of Diversion One (POD1) or POD2, 2) direct diversion of channel surface waters from School House Creek for small domestic use at POD2 and 3-8) maintenance and/or replacement of six stream crossings. Micro-hydroelectric Diversion Water enters the hydroelectric turbines from POD1 by flowing into a gravity-fed, 4-inch pipe and from POD2 by flowing into a 2-inch gravity-fed pipe. The combined diversion rate from POD1 and POD2 for hydroelectricity generation is approximately 140 gallons per minute (gpm). Only one POD is in use at a time with a maximum diversion rate of 120 gpm. The existing season of diversion for hydroelectricity generation is Jan. 1 – Dec 31 of each year, but water can only be diverted if measures 2.73 to 2.77 below can be met. Water exiting the hydroelectric turbines is discharged into the stream channel at a low gradient downstream location. The water discharged from the turbines is dispersed into a mist and does not cause erosion or scour to the stream bed, bank or channel. Water is returned to the stream from POD1 and POD2 at 2,300 and 2,000 feet downstream respectively. Small Domestic Diversion Water is directly diverted from POD2 into a 1-inch gravity-fed, above-ground pipe to supply four separate residences at a maximum rate of 10 gpm. This diversion of water is made year-round under small domestic use registration and riparian right in the amount of 6.46 acre-feet per year and is not to exceed 4,440 gallons per day as stated on the water right. Stream Crossings (six) Four proposed encroachments are to upgrade failing and undersized stream crossings. 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. One proposed encroachment is to modify and stabilize a vertically incised streambank upstream of an existing stream crossing. Work for this encroachment will include excavation, reshaping the stream banks, compaction of material, employing erosion control measures including slash packing exposed banks, and rock armoring as necessary to minimize erosion. The final proposed encroachment is to do maintenance on an exiting 40’ long metal bridge. Work for this encroachment will include adding 3” minus road rock to both sides of bridge edges/approaches to prevent undermining of the bridge. A survey by the Designated Biologist may be needed for any of these crossings if surface water is or becomes present during construction. The Permittee disclosed additional features of interest that are not covered by this Agreement. The Notification states that Pond 1 is in good condition and meeting current performance standards. Permittee states Pond 2 on APN 011-900-41 is not in use, has no streams entering, and the spillway connects to waters of the State. While Pond 2 does exist on APN 011-900-41, the points of diversion were the only projects evaluated on that parcel. The small domestic use registration for POD-2 lists Pond 1 as a storage location for diverted water. Permittee states that diverted water was priory stored in the pond, but not currently. Existing pond spillways disclosed in the Notification, but not included as 1602 projects with fees, are not covered under this Agreement. If spillway maintenance (such as armoring) is needed for ponds with outlets connected to waters of the State, replacement of spillways becomes necessary, and/or Pond 1 is determined to be on-stream by the Water Board, that work and the diversion for irrigation must be covered by a major amendment or a separate Notification. No other projects that may be subject to FGC section 1602 were disclosed. This Agreement does not retroactively permit any constructed reservoirs (including “ponds”), stream crossings, water diversions, modifications to riparian buffers, or other encroachments not described in Table 1.

Piercy

Mendocino

Northern California

Mendocino