Final Mitigated Negative Declaration and Response to Comments

Freezing clams in place has been suggested as a potential method because the technology is
used in non-restoration actions to freeze sediment under the surface of water bodies in order
to conduct construction activities such as tunneling or installing piers. Since this method has
not been tested on clams, we cannot provide the detail requested. We will remove freezing as
a potential alternative method to test with pilot research under this project. Freezing will be
removed from the Project Description, 2.4 Project Objectives, 2.4 Project Description and
Implementation under design and testing of alternative treatment methods, and from the
Section V Cultural Resources discussion.
SAND BAGS COMMENT
Concern was expressed that if sand bags were used to weigh barriers down, degradation of
the bags could impede full recovery of these project materials from the site. This could result
in potential discharge of pollutants and the sand bags would be considered fill when applying
for Water Quality Certification.
RESPONSE
Mitigation Measure Hydro-1: Water Quality states that underwater AC control activities in
Lake Tahoe require permits from the Army Corps of Engineers, Lahontan Regional Water
Quality Control Board, Tahoe Regional Planning Agency, and the California Department of
Fish and Game. All of these permits require monitoring and protective measures to ensure
that project activities do not result in significant impacts to water quality. Project activities will
not commence until all required permits are attained.
All clam work to date in Emerald Bay has used rebar to weigh down barriers, which can all be
recovered at the completion of work. The IS/MND did not mention the use of sand bags and
sand bags were not considered as a potential option for weighing down barriers due to the
issues mentioned in the reviewers comment, but the document also did not specifically remove
sand bags as an option. This project will not use sand bags to weigh down benthic barriers
and this will be considered as a permit requirement.
POTENTIAL TO IMPACT SUBSURFACE PIPES OR UTILITY LINES COMMENT
The comment from the LRWQCB noted that the lead agency adequately identifies utilities
present near the project area. LRWQCB states that at the time the project is submitted to the
Water Board for Water Quality Certification, the applicant must affirmatively document whether
any subsurface utilities are present in the project area and provide documentation to the Water
Board.
RESPONSE
Mitigation Measure Hydro-1: Water Quality states that underwater AC control activities in
Lake Tahoe require permits from the Army Corps of Engineers, Lahontan Regional Water
Quality Control Board, Tahoe Regional Planning Agency, and the California Department of
Fish and Game. All of these permits require monitoring and protective measures to ensure
that project activities do not result in significant impacts to water quality. Project activities will
not commence until all required permits are attained.
The Lead Agency will affirmatively document whether any subsurface utilities are present in
the project area at the time the project is submitted for coverage under the requirement of
Mitigation Measure Hydro-1: Water Quality. The closest current distance from any utility to
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Asian Clam Control Project
Final Mitigated Negative Declaration and Response to Comments