Draft EIS_072312.pdf - Middle Fork American River Project ...

20120723-4002 FERC PDF (Unofficial) 07/23/2012
2.0 PROPOSED ACTION AND ALTERNATIVES
2.1 NO-ACTION ALTERNATIVE
The no-action alternative is the baseline from which to compare the proposed
action and all action alternatives that are assessed in the environmental document. Under
the no-action alternative, the project would continue to operate under the terms and
conditions of the current license.
2.1.1 Existing Project Facilities
The existing Middle Fork Project consists of five developments: French
Meadows, Hell Hole, Middle Fork, Ralston, and Oxbow. These developments include
seven diversion structures, various water conveyance tunnels, pipes and penstocks, and
five powerhouses. The locations of the various facilities and features are shown in
figure 1, and a schematic of project facilities is provided in figure 2.
2.1.1.1 French Meadows Development
The French Meadows development is on the Middle Fork and a tributary, Duncan
Creek, and includes: (1) the Duncan Creek diversion consisting of: (a) a 32-foot-high,
165-foot-long, concrete gravity diversion dam with a crest at elevation 5,275 feet 8 and a
100-foot-wide uncontrolled ogee spillway; (b) a 2-acre pool at elevation 5,265 feet with
20-acre-feet of gross storage and negligible active storage; (c) a 10-inch-diameter
instream flow maintenance pipe conveying flows to Duncan Creek with a maximum
discharge of 8 cubic feet per second (cfs); (d) a 60-inch-diameter low level outlet pipe
with a maximum discharge of 310 cfs; (e) the 1.5-mile-long, 9-foot-wide by 10-foot-high
Duncan Creek-Middle Fork tunnel, routing water from the Duncan Creek diversion to the
French Meadows reservoir with a maximum discharge capacity of 400 cfs; (2) the French
Meadows dam and reservoir on the Middle Fork consisting of: (a) a 231-foot-high, 0.5mile-long
rock and gravel-filled dam with a crest at elevation 5,273 feet and a 40-footwide
spillway (extending to the Middle Fork American river about 1,000 feet
downstream of the dam) with two 20-foot-wide radial gates; (b) a 1,408-acre reservoir at
elevation 5,262 feet with 134,993 acre-feet of gross storage and 127,358 acre-feet of
active storage; (c) an 8-inch-diameter instream flow maintenance pipe conveying flows to
the Middle Fork with a maximum discharge capacity of 8 cfs; and (d) a 72-inch-diameter
low level outlet pipe with a maximum discharge capacity of 1,430 cfs; (3) the 2.6-milelong,
12.3-foot-wide French Meadows-Hell Hole tunnel, which routes water from the
French Meadows reservoir through the French Meadows powerhouse to the Hell Hole
reservoir with maximum discharge capacity of 800 cfs; (4) a 6.25-foot-diameter, 691foot-long
penstock conveying water from the reservoir to the powerhouse; (5) the
8 All elevations are referenced to mean sea level.
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