Final Site Information Package for National Remedy Review Board ...

SITE INFORMATION PACKAGE FOR NATIONAL REMEDY REVIEW BOARD
PART B, SECTION 11: PREFERRED ALTERNATIVE
would lower the potential routes of exposure to contamination by humans and
ecological receptors and address concerns about the protectiveness of the existing
selected remedies.
• Fewer implementability issues – Alternative RP-2 would have relatively fewer
implementability issues compared to Alternative RP-1. Alternative RP-2’s only technical
implementation issue is that it would be beneficial to implement the remedy protection
projects during the low-flow season in order to minimize cost. Alternative RP-2 would
have administrative implementability issues associated with O&M of the water
conveyance improvement projects. Prior to construction, the local and state agencies
would need to determine which parties would perform O&M tasks and ensure that
sufficient resources were available. In addition, there would be issues associated with
the construction of remedy protection projects on private property. Access and easement
agreements would have to be obtained prior to the implementation of Alternative RP-2.
The above implementation issues for Alternative RP-2 are relatively minor.
• Significantly lower cost – The estimated cost of Alternative RP-2, in terms of 30-year
NPV, is $33.9 million, which is significantly less ($16.2 million) than the estimated cost
for Alternative RP-1 ($50.1 million).
11.2.2 Side Gulches
Potential remedy protection actions in the side gulches to the SFCDR would also be
included as part of Alternative RP-2, the Preferred Remedy Protection Alternative. Detailed
analyses were not conducted for the side gulches in the FFS to determine the area of existing
selected remedies that is vulnerable to damage from storm events. The framework for
evaluation and implementation of the remedy protection technologies and process options
in the side gulches will be applied to these areas in the future as more detailed information
is gathered for the side gulches or as the result of changing environmental conditions,
stakeholder input, and other emergent considerations. This section describes the general
steps and criteria for future evaluation and development of Alternative RP-2 actions for the
side gulches similar to those developed and conducted for the eight Upper Basin
communities.
It should be noted that the side gulches and associated selected remedies generally have
similar physical and topographical characteristics to the drainages that were analyzed in
detail in the eight Upper Basin communities. It is expected that similar technologies and
process options would be applicable to the side gulches.
The process for applying technologies and process options to the side gulches in the future
should include (1) completing hydrologic and hydraulic analyses and field reconnaissance
to determine the areas of remedy at risk, and (2) if warranted, mitigating the risks posed to
the selected remedies using the results of the hydrologic and hydraulic analyses, the specific
physical constraints of the site, and engineering judgment to select appropriate process
options. The process for developing these remedy protection projects should follow the
framework used to develop Alternative RP-2 for the eight Upper Basin communities.
B11-9