FERC Project No. 2079 - PCWA Middle Fork American River Project ...

Application for New License Middle Fork American River Project (FERC Project No. 2079)
maximum estimated hydraulic capacity is 1,025 cfs. Water to the powerhouse is
delivered from the Ralston Afterbay via the Ralston – Oxbow Tunnel. The
above-grade portion of the powerhouse includes an approximately 60-foot by
98-foot concrete slab, a small rectangular entry building, and transformer. A
moveable metal gantry crane stands over the powerhouse. Water passing
through the Oxbow Powerhouse is discharged to a short channel that joins the
Middle Fork American River.
Electricity generated at the powerhouse is increased to 60 kV at the powerhouse
main transformer bank and interconnected to PG&E’s 60 kV Transmission
System at the switchyard adjacent to the powerhouse. The switchyard includes
metal towers and electrical switching gear. The powerhouse and switchyards are
contained within a 120-foot by 145-foot fenced area that is graded.
4.1.1.6 Gaging Stations
PCWA currently maintains a network of nine gaging stations that measure streamflow;
two gaging stations that measure diversion flow; six gages that measure reservoir
elevation; four that measure flow at powerhouses; and seven weirs that measure dam
leakage. Pole-mounted photovoltaic arrays (referred to as photovoltaic poles) and
powerlines provide power to some of the gages. Refer to BA/BE Table 4 for additional
information on the location of these facilities. All stream gaging stations have been
incorporated into the United States Geological Survey (USGS) gaging network.
Stream Gages
Project stream gages are installed at the following locations:
• Duncan Creek near French Meadows (USGS Gage No. 11427700) – verifies
compliance with FERC-required instream flows
• Duncan Creek below Diversion Dam (USGS Gage No. 11427750) – verifies
compliance with FERC-required instream flows
• Middle Fork American River at French Meadows (USGS Gage No. 11427500) –
verifies compliance with FERC-required instream flows
• Rubicon River below Hell Hole Dam (USGS Gage No. 11428800) – verifies
compliance with FERC-required instream flows
• North Fork Long Canyon Creek below Diversion Dam (USGS Gage
No. 11433085) – verifies compliance with FERC-required instream flows
• South Fork Long Canyon Creek below Diversion Dam (USGS Gage
No. 11433065) – verifies compliance with FERC-required instream flows
• Middle Fork American River below Interbay Dam (USGS Gage No. 11427770) –
verifies compliance with FERC-required instream flows
February 2011 4-10