Final Mitigated Negative Declaration and Response to Comments

Fish spawning- Other fish potentially utilizing the project area in Emerald Bay are either nonnative
or not listed as sensitive species, however, covering the substrate with benthic mats
could remove potential spawning habitat during the short term. The mouth of Emerald Bay
receives high boat use and associated wake and wave action which reduces the suitability of
the area for spawning. AC can reduce food for fish by filtering planktonic plants and animals
out of the water column, which many species of fish, especially when young, depend on for
growth. Treatment of the AC infestation area would result in a less than significant short term
impact, with potentially substantial long term gains as fish do not have to compete locally with
AC for the plankton-based food source upon which they depend.
Sensitive Natural Plant Communities
Sensitive plant communities are regionally uncommon or unique, unusually diverse, or of
special concern to local, state, and federal agencies. Removal or substantial degradation of
these plant communities constitutes a significant adverse impact under CEQA. A search of the
CNDDB did not show any sensitive natural plant communities near the project area (CNDDB
2009), but the deep water plant communities in Lake Tahoe are of concern because they are
important ecological components in Lake Tahoe and have experienced substantial long term
declines. These plant communities consist of mosses, liverworts, stoneworts, and algae and
are typically found at depths greater than 200 feet. Control activities will occur in waters
generally less than 30 feet deep and research has also indicated that AC may be able to
impact the algal biomass in the lake littoral zone and cause local decreases in the algal
biomass in near shore areas, while also stimulating the growth of undesirable filamentous
algae (Whittmann et al. 2011). Project activities are not expected to impact deep water plant
communities.
Wetlands and Waters of the United States
The Federal Clean Water Act (CWA) defines wetlands as lands that are inundated or saturated
by surface or ground water at a frequency and duration sufficient to support, and under normal
circumstances do support, a prevalence of vegetation typically adapted for life in saturated soil
conditions. The U.S. Army Corps of Engineers (USACE) has jurisdictional authority of
wetlands under provisions found in Section 404 of the CWA. Typically, the USACE
jurisdictional wetlands meet three criteria: hydrophytic vegetation, hydric soils, and wetland
hydrology.
Waters of the U.S. (Other Waters) are regulated by the USACE under Section 404 and by the
state water pollution control authority (Lahontan Regional Water Quality Control Board) under
Section 4041 of the CWA. They are defined as all waters used in interstate or foreign
commerce, waters subject to the ebb and flow of the tide, all interstate waters including
interstate wetlands and all other waters such as: intrastate lakes, rivers, streams, mudflats,
sandflats, wetlands, sloughs, prairie potholes, wet meadows, playa lakes, and natural ponds.
Waters of the U.S. are under the USACE jurisdiction.
Tahoe Regional Planning Agency (TRPA) Goals and Policy, Chapter IV: Conservation
Element, Vegetation Goal #2 is to “Provide for maintenance and restoration of such unique
Asian Clam Control Project IS/MND
Emerald Bay State Park
California Department of Parks and Recreation
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