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

20120723-4002 FERC PDF (Unofficial) 07/23/2012
Water Quality
Objective Description
Tastes and
Odor
Water shall not contain taste- or odor-producing substances in
concentrations that impart undesirable tastes and odors to domestic or
municipal water supplies, fish flesh, or other edible products of aquatic
origin, or substances that cause nuisance or otherwise adversely affect
beneficial uses.
Toxicity All waters shall be maintained free of toxic substances in
concentrations that produce detrimental physiological responses in
human, plant, animal, or aquatic life. Compliance with this objective
will be determined by analysis indicator organisms, species diversity,
population density, growth anomalies, and biotoxicity tests as specified
by the Regional Water Quality Control Board.
Turbidity In terms of changes in turbidity (nephelometric turbidity units [NTU])
in the receiving water body: where natural turbidity is less than 1 NTU,
controllable factors shall not cause downstream turbidity to exceed 2
NTU; where natural turbidity is between 1 and 5 NTU, increases shall
not exceed 1 NTU; where 5 to 50 NTU, increases shall not exceed 20
percent; where 50 to 100 NTU, increases shall not exceed 10 NTU;
and where natural turbidity is greater than 100 NTU, increase shall not
exceed 10 percent.
a The criteria listed are secondary maximum concentration levels for California
drinking water quality objectives that do not necessarily indicate a toxic amount of
contaminant. Rather, these standards dictate water quality objectives designed to
preserve taste, odor, or appearance of drinking water.
The Central Valley Regional Water Board’s Clean Water Act Section 305(b) and
303(d) Integrated Report for the Central Valley Region includes the North Fork
American River, Hell Hole reservoir, and Oxbow reservoir (Ralston afterbay) on the
303(d) list of impaired waters for mercury. On October 11, 2011, the U.S.
Environmental Protection Agency (EPA) issued its final decision regarding waterbodies
and pollutants proposed to be added to the current 303(b) list, and the three referenced
waterbodies are included on that list (Water Board, 2012). The source of mercury in Hell
Hole reservoir is listed as unknown, but the likely source for the other two waterbodies is
listed as resource extraction.
Physical and water chemistry conditions in the streams and rivers associated with
the project are of high quality, with low concentrations of mineral constituents and other
substances generally conforming to regulatory water quality objectives and standards.
Historical data show that generally all of the constituents analyzed in project-affected
waters (within and downstream of project impoundments) complied with current
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