California State Water Resources Control

and Office of Research and Development. It has been subjected to the Agency’s peer review and administrative review processes. This document contains information relating to water quality assessment. It does not substitute for the Clean Water Act or EPA regulations, nor is it a regulation itself. Thus, it cannot impose legally binding requirements on EPA, States, authorized Tribes or the regulated community, and it may not apply to a particular situation or circumstance. Acknowledgements The EPA Office of Water (OW) and Office of Research and Development (ORD) would like to thank the many people who contributed to this project. Without the collaborative efforts and support by state and tribal environmental agencies, federal agencies, universities and other organizations, this groundbreaking assessment of lakes would not have been possible. In addition, the survey could not have been done without the dedicated help and support of enumerable field biologists, taxonomists, statisticians and data analysts, as well as program administrators, regional coordinators, project managers, quality control officers, and reviewers. To the many participants, EPA expresses its gratitude