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

20120723-4002 FERC PDF (Unofficial) 07/23/2012
downstream of Ralston afterbay, and sediment transport and channel sediment condition
monitoring associated with the augmentation areas.
Alternative 1 includes the same proposed Sediment Management Plan, including
the same Forest Service BMPs and avoidance and protection measures.
Our Analysis
Proposed project infrastructure modifications at the three small diversions would
reduce and potentially eliminate the need for future sediment management activities.
This would reduce future suspended sediment increases that would result from periodic
sediment removal events. During modification of the infrastructure at the diversion
dams, erosion and sedimentation could temporarily increase turbidity levels in the
adjacent water bodies. In addition, the accidental release of hazardous materials from
heavy equipment used during these activities could degrade water quality.
The Forest Service BMPs, avoidance and protection measures, diversion of
instream flow and silt screen placement downstream of the Middle Fork interbay
augmentation sites prior to placing sediment as specified in the proposed Sediment
Management Plan would protect water quality during sediment management activities to
the extent possible. Provisions in the plan for water quality monitoring would confirm
the effectiveness of implemented water quality protective measures during sediment
management activities and identify the need for additional protective measures.
Protecting Water Quality during Vegetation and Pest Management
Use of herbicides, surfactants, rodenticides, fungicides, and manual techniques as
part of routine vegetation and pest management could potentially degrade water quality if
used adjacent to surface waters. PCWA proposes to implement its Vegetation and
Integrated Pest Management Plan (VIPMP), which is discussed in detail in section
3.3.3.2, Terrestrial Resources. The plan includes Forest Service BMPs and the following
measures to protect water quality:
• Restrictions on the use of herbicides, surfactants, rodenticides, and fungicides
within protective buffers around reservoirs, streams, and bypassed and peaking
reaches.
• Restrictions on the use of herbicides, surfactants, rodenticides, and fungicides
during periods of forecasted weather outside of the label requirements.
• Restrictions on the use of mechanical equipment on steep slopes and within
riparian conservation areas to reduce gully and sheet erosion.
• Limiting the use of mechanical equipment in wetlands, springs, and meadows
to limit turbidity and sediment production.
• Proper care, cleaning, and disposal of all pesticide and surfactant containers,
contaminated water, and equipment.
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