Most estuaries and major streams in California provide habitat for one or more fish species listed as threatened or endangered under the federal Endangered Species Act (ESA) or California ESA (CESA), or species managed under the essential fish habitat (EFH) provisions of the Magnuson-Stevens Fisheries Management and Conservation Act (MSFMCA). The potential for death or injury of fish resulting from driving piles has elevated the public and resource agency concerns relative to effects on listed species populations. Required development of minimization measures to protect fish species listed under the ESA has resulted in costly project delays and has increased project implementation costs for California Department of Transportation (the Department) and other transportation departments and ports on the West coast. The purpose of this technical guidance manual is to provide Department engineers, biologists, and consultants with guidance related to the environmental permitting of in-water pile driving projects. Specifically, this manual provides guidance on:
- Fundamentals of hydroacoustics;
- Fish hearing and hydroacoustic impacts on fish;
- Environmental documentation and permit applications required for pile driving projects;
- Assessment of potential impacts on fish and their habitat from sound generated from pile driving;
- Measures to avoid or minimize pile driving impacts; and
- methods to assess impacts, mitigation, and compensation for pile driving on fish.