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

20120723-4002 FERC PDF (Unofficial) 07/23/2012
Key differences between the proposed Flow and Reservoir Monitoring Plan and
the Alternative 1 Streamflow and Reservoir Gaging Plan include the following:
• The Alternative 1 plan deletes much of the details about specific flows and
reservoir surface elevations and the supporting rationale for them because
those are included in other measures. Instead, provisions for operating and
maintaining the gages in accordance with applicable USGS protocols are
provided and the USGS protocol documents are attached.
• The Alternative 1 plan includes provisions to provide all 15-minute gage
information to the agencies and the Commission upon request, not just a single
gage on the peaking reach, in a readily accessible electronic format.
• The Alternative 1 plan includes two additional gages on the Rubicon River that
would be used to disseminate real-time flow information to the public; one
near Ellicott Bridge, and one about 900 feet upstream of the Ralston
powerhouse.
Our Analysis
Generally, both monitoring plans would enable compliance with designated
streamflows and water surface elevations to be documented. The simplified approach
taken in the Alternative 1 plan presents the basics of what is needed for monitoring and
avoids redundancy of presenting details that are addressed in other measures that pertain
to flow and reservoir water level monitoring. The primary information that would be
presented in reports under the proposed plan would rely on 24-hour average flows and
reservoir elevations. This could conceivably mask substantial variations of flow or water
surface elevations within a 24-hour period. Raw data would only be available upon
request from a single peaking reach flow monitoring station. The Alternative 1 plan does
not specify that reports would only report 24-hour average data. Reporting average daily
data with the maximum and minimum values within each day would provide a basis for
the agencies and the Commission to decide whether to request files with the raw 15minute
time interval data from PCWA to confirm compliance with instantaneous flow
values that may be specified in a new license.
Two gages on the Rubicon River are included in the Alternative 1 plan are not
intended to document compliance with any specified flow measures. The primary
purpose of both gages is to provide the public with real-time flow data that would be
helpful for making decisions about traveling to the Rubicon River for recreational
purposes in the reach between Ellicott Bridge and the Ralston afterbay. As shown in
figure 3.3.2-7, flows from Hell Hole dam and powerhouse to the Rubicon River would be
measured in the vicinity of the dam, and represent flows over which PCWA has control
of during most circumstances. Flows on the Rubicon River at and downstream of Ellicott
Bridge are not only influenced from project release from the Hell Hole development, but
also from inflows from the South Fork Rubicon River. South Fork Rubicon River flows
are heavily influenced by the operation of the Upper American River Hydroelectric
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