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

20120723-4002 FERC PDF (Unofficial) 07/23/2012
• a process for documenting and reporting inventory and monitoring results
including periodic plan review and revision. Documentation would include a
Forest Service-compatible GIS database for maps keyed to a narrative
description of detailed, site-specific, erosion treatment measures and sediment
monitoring results; and
• development of erosion control guidelines for new construction or non-routine
maintenance.
Our Analysis
The proposed erosion and sedimentation control measures provide general
principles that, when applied to specific sites, should serve as effective control measures.
However, the commitment to develop an erosion control plan prior to construction
activities is ambiguous as to exactly when the plan would be developed and what
specifically would be included in the plan.
The content of the Alternative 1 erosion and sediment control management plan is
much more clearly specified and would provide for periodic monitoring, inventory, and
prioritized treatment of project-related erosion sites; identification of criteria and
procedures for controlling erosion; development of emergency response protocols to
manage erosion and sedimentation; and annual mechanisms for reporting and agency
review of procedures and actions. The Alternative 1 approach would provide treatment
for existing erosion sites and prevention of erosion and sedimentation associated with
project infrastructure and future project actions. It would also ensure consultation with
appropriate agencies in developing the plan and subsequent periodic annual review by
these agencies of the plan and actions taken. Finally, the Alternative 1 approach would
provide controls necessary to protect water quality and aquatic and riparian habitat from
the effects of project-related erosion and sedimentation. Establishing a specific time
frame for plan development (1 year from license issuance) would enable all potential
ground-disturbing activities that may be included in a new license to be addressed on a
site-specific basis in the plan. PCWA should only be responsible for addressing projectrelated
erosion.
Sediment Management
Sediment management is necessary at the project’s three small diversion pools and
two medium reservoirs to maintain and protect project reliability including: preserving
full diversion capabilities, preventing damage to the turbines caused by coarse sediment
entering the tunnels, preventing sediment accumulation in the tailraces of powerhouses,
and maintaining minimum instream flow releases. Sediment management activities can
also directly and indirectly affect water quality (including erosion, sedimentation, and
possible introduction of hazardous chemicals) and biological resources (including
riparian habitats, sensitive plants, and wildlife) through dewatering of reservoirs to
facilitate sediment removal, equipment access, vegetation removal, mechanical sediment
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