DRAFT ENVIRONMENTAL ASSESSMENT AUXILIARY DAM LEFT ABUTMENT PROJECT ISABELLA LAKE, KERN COUNTY, CALIFORNIA September 2010 Approve
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DRAFT ENVIRONMENTAL ASSESSMENT AUXILIARY DAM LEFT ABUTMENT PROJECT ISABELLA LAKE, KERN COUNTY, CALIFORNIA September 2010 Approved for public release; distribution is unlimited DEPARTMENT OF THE ARMY U.S. ARMY ENGINEER DISTRICT, SACRAMENTO CORPS OF ENGINEERS 1325 J STREET SACRAMENTO, CALIFORNIA 95814-2922 REPLY TO ATTENTION OF Environmental Resources Branch FINDING OF NO SIGNIFICANT IMPACT Auxiliary Dam Left Abutment Project Isabella Lake, Kern County, California I have reviewed and evaluated the information in this Environmental Assessment for the Auxiliary Dam Left Abutment Project, Isabella Lake, Kern County, California. The project would involve restoring the height of the Isabella Auxiliary Dam at its junction with the left abutment through the construction of a 200-foot long earthen embankment between the eastern tip of the dam and Highway 178. This work is necessary to correct a potentially dangerous low spot at the left abutment of the Auxiliary Dam which, during a major flooding event, could result in overtopping and the breach of the dam. The embankment and staging area for the work would be located on National Forest System lands and encompass a California Department of Transportation non-exclusive easement adjacent to Highway 178. Fill materials for the work would be obtained from the Kelso Creek Community Material Pit, which is under the jurisdiction of the Bureau of Land Management. Construction would be completed by November 2010 before the start of the rain season. During this review, the possible consequences of the work described in the EA have been studied with consideration given to environmental, social, cultural, and engineering feasibility. In evaluating the effects of the proposed project, specific attention has been given to significant environmental resources that could potentially be affected. I have also considered the views of other interested agencies, organizations, and individuals concerning the project. Any effects on environmental resources would be avoided or minimized by using best management practices. There are no Federally listed species in or near the project area. Based on my review of the EA and my knowledge of the project area, I am convinced that the proposed project is a logical and desirable alternative. Furthermore, I have determined that the project would have no significant effect on the environment. All construction would be implemented in compliance with applicable Federal, State, and local laws, rules, and regulations. Based on the results of the environmental evaluation and completion of interagency coordination, I have determined that the EA and Finding of No Significant Impact provide adequate documentation and that the project may proceed as proposed with no further environmental documentation required. _____________________ _______________________________ Date William J. Leady, P.E. Colonel, U.S. Army District Commander TABLE OF CONTENTS PURPOSE AND NEED ................................................................................................................ 1 BACKGROUND .............................................................................................................................. 1 PROPOSED ACTION....................................................................................................................... 1 LOCATION OF THE PROJECT AREA ............................................................................................... 1 NEED FOR PROPOSED ACTION ...................................................................................................... 2 PROJECT AUTHORIZATION ........................................................................................................... 2 PURPOSE OF THE ENVIRONMENTAL ASSESSMENT ........................................................................ 2 ALTERNATIVES ......................................................................................................................... 2 NO ACTION .................................................................................................................................. 2 AUXILIARY DAM LEFT ABUTMENT (PREFERRED ALTERNATIVE) ................................................. 2 AFFECTED RESOURCES AND ENVIRONMENTAL EFFECTS ....................................... 4 RESOURCES NOT CONSIDERED IN DETAIL ................................................................................... 4 RECREATION ................................................................................................................................ 7 WATER RESOURCES AND WATER QUALITY ................................................................................. 8 VEGETATION AND WILDLIFE ....................................................................................................... 9 THREATENED AND ENDANGERED SPECIES ................................................................................. 11 AIR QUALITY ............................................................................................................................. 15 NOISE ......................................................................................................................................... 17 TRAFFIC ..................................................................................................................................... 19 ESTHETICS ................................................................................................................................. 20 CULTURAL RESOURCES ............................................................................................................. 20 CUMULATIVE EFFECTS ........................................................................................................ 24 COMPLIANCE WITH ENVIRONMENTAL LAWS AND REGULATIONS .................... 25 FEDERAL, STATE, AND LOCAL PERMITS REQUIRED................................................. 26 COORDINATION AND REVIEW OF THE ENVIRONMENTAL ASSESSMENT .......... 27 CONCLUSIONS ......................................................................................................................... 27 LIST OF PREPARERS .............................................................................................................. 27 LITERATURE CITED .............................................................................................................. 28 i TABLES 1. Sensitive animal species with the potential to occur within or near the action area ..............12 2. Sensitive plant species with the potential to occur within or near the action area.................14 3. Estimated Criteria Pollutants…………………………… .....................................................17 4. Truck Trips Estimates for the Auxiliary Dam Left Abutment Project ..................................19 PLATES 1. Auxiliary Dam Abutment Location Map 2. Auxiliary Dam Abutment Vicinity Map 3. Auxiliary Dam Abutment Site Map 4. Auxiliary Dam Abutment Design 5. Haul Route From Construction Site 6. Kelso Creek Community Material Pit Site Map 7. Auxiliary Dam Abutment and Kelso Creek Community Material Pit Site Photographs 8. Auxiliary Dam Recreation Area Photograph 9. Auxiliary Dam Abutment Soil Classification APPENDICES A. Phase I Environmental Site Assessment B. USFWS Species List C. Cultural Resources Documentation D. USFS Standard Form 299 Application E. Caltrans Correspondence F. Mailing List ii LIST OF ACRONYMS AND ABBREVIATIONS BLM Bureau of Land Management BMP Best management practice CARB California Air Resources Board CNDDB California Natural Diversity Database CWA Clean Water Act DFG California Department of Fish and Game DSAP Dam Safety Assurance Program DSM Dam Safety Modification EA Environmental Assessment EPA U.S. Environmental Protection Agency ESA Endangered Species Act FONSI Finding of No Significant Impact FR Federal Register HTRW Hazardous, Toxic and Radioactive Waste IRRM Interim Risk Reduction Measure KCCMP Kelso Creek Community Material Pit KCF Kern Canyon Fault MBTA Migratory Bird Treaty Act NEPA National Environmental Policy Act NGPRA Native American Graves Protection and Repatriation Act NOAA National Oceanic and Atmospheric Administration NPDES National Pollutant Discharge Elimination System NPS National Park Service NRCS Natural Resources Conservation Service NRHP National Register of Historic Places RWQCB Regional Water Quality Control Board SCE Southern California Edison SHPO State Historical Preservation Officer SWPPP Stormwater Pollution Prevention Plan USACE U.S. Army Corps of Engineers USFWS U.S. Fish and Wildlife Service USFS U.S. Forest Service UTM Universal Transverse Mercator VELB Valley Elderberry Longhorn Beetle YBP Years Before Present iii 1.0 PURPOSE AND NEED 1.1 Background The U.S. Army Corps of Engineers (USACE) has been conducting engineering studies since 1996 to determine if the Main and Auxiliary dams at Isabella Lake meet safety regulations regarding earthquake survivability. These studies were authorized under Section 1203 of the Water Resources Development Act of 1986. The conclusions were published in the September 2003 report entitled “Seismic Safety Review: Dam Safety Assurance Program Report for Isabella Dam, Isabella Lake, California”. Further investigation in 2005 of the auxiliary dam discovered that there were higher foundation pressures than originally believed. A USACE Geotechnical Seepage Study completed in March 2006 concluded that the pressures in the foundation of the dam had reached very high consequences associated with dam failure.