The Salton Sea Geology, History, Potential Problems, Politics, and Possible Futures of an Unnatural Desert Salt Lake Larry C. Oglesby Department of Biology, Pomona College, Claremont, California 91711 MEMOIRS OF THE SOUTHERN CALIFORNIA ACADEMY OF SCIENCES VOLUME 10 October 18, 2005 MEMOIRS OF THE SOUTHERN CALIFORNIA ACADEMY OF SCIENCES The MEMOIRS of the Southern California Academy of Sciences is a series begun in 1938 and published on an irregular basis thereafter. It is intended that each article will continue to be of a monographic nature, and each will constitute a full volume in itself. Contributions to the MEMOIRS may be in any of the fields of science, by any member of the Academy. Acceptance of papers will be determined by the amount and character of new information and the form in which it is presented. Articles must not duplicate, in any substantial way, material that is published elsewhere. Manuscripts must conform to MEMOIRS style of volume 4 or later, and may be examined for scientific content by members of the Publications Committee other than the Editor or be sent to other competent critics for review. Because of the irregular nature of the series, authors are urged to contact the Editor before submitting their manuscript. Copies of this memoir may be obtained for $15.00 from the address below. Daniel A. Guthrie, Editor % W.M. Keck Science Center 925 N. Mills Ave. Claremont, Ca. 91711 [email protected] ©2005 Southern California Academy of Science. All rights reserved. THE SALTON SEA Geology, History, Potential Problems, Politics, and Possible Futures of an Unnatural Desert Salt Lake Larry C. Oglesby Department of Biology, Pomona College, Claremont, California 91711 MEMOIRS OF THE SOUTHERN CALIFORNIA ACADEMY OF SCIENCES VOLUME 10 October 18, 2005 CONTENTS Preface i Editor's Note ii Acknowledgments iii Introduction 1 Geological Setting and Geological History of the Salton Trough 3 Origin of the Below Sea Level Salton Trough and its Pleistocene and Ho- locene Lakes 9 Formation of the Salton Sea and its Recent History 20 Sources of Water to the Salton Sea 30 Chemical and Physical Limnology 33 Biology of the Salton Sea 40 Invertebrates and Aquatic Plants 40 Amphibians, Reptiles, and Mammals 58 The Sport Fish and Sport Fishery 58 Other Fish 69 Birds 75 Food Chains and Webs 80 Major Fish and Bird Mortality Events: Toxins, Pathogens, and Parasites 81 Is the Salton Sea Polluted? 87 Public Health 95 Cleaning Up the New River 98 Energy Development at the Salton Sea 99 Water Politics and the Salton Sea 102 Possible Futures for the Salton Sea 107 “Restoration” of the Salton Sea 110 Conclusions 126 Bibliography 126 Tables Table I. Concentrations of major ions in the ocean and in the Salton Sea 186 Table II. Nutrient concentrations in rivers and agricultural waters 186 Table III. Nutrient concentrations in the Salton Sea 187 Table IV. Prokaryotes, unicellular algae, and protozoa of the Salton Sea 188 Table V. Aquatic, semi-aquatic, and riparian plants of the Salton Trough 196 Table VI. Fossil and living aquatic molluscs of the Salton Trough 203 Table VII. Non-molluscan aquatic invertebrates of the Salton Trough.. 206 Table VIII. Fish of the Salton Trough 215 Table IX. Aquatic amphibians, reptiles, and mammals of the Salton Trough 222 Table X. Endangered, threatened, rare, and sensitive birds of the Salton Trough 225 Figures Fig. 1. Political map of the northern Salton Trough 236 Fig. 2. Map of the southern Salton Trough, showing extent of Colorado River deltaic sedimentary deposits in 1908 237 Fig. 3. Fault map of the Salton Trough in California 238 Fig. 4. Map of the southern Salton Trough, showing the new Salton Sea at its largest extent in 1907 239 Fig. 5. Map of the southern Salton Trough, showing the Salton Sea and the Imperial and Mexicali Valleys 240 PREFACE To Larry Oglesby, the Salton Sea was one of the most interesting places on earth. He first became acquainted with it as a graduate student at Berkeley in the 1960s. Later, as a faculty member at Pomona College in Claremont, California, he used it in his research on salt and water balance in several invertebrates in- cluding pileworms and snails. He was the advisor of many senior theses on facets of the biology of the Salton Sea during his thirty years at Pomona College. In addition, he made it an important part of his field class in Aquatic Biology, with a three day field trip there every year during which he and his students measured many parameters of the Sea. Some of the data in the manuscript are from those field trips. Though his main focus was the invertebrates, he became fascinated with every aspect of the sea—its history, geology, and biology. After his early retirement in 1998 due to health problems, he spent his time writing a manuscript which would encompass all his interests in the Sea. He was very concerned about what was happening at the Sea, and incorporated some thoughts about that too. At the time of his death, in April 2001, he had finished the manuscript except for some editing. These are Larry Oglesby’s thoughts on the Salton Sea from the vantage point of one who followed it closely for thirty years. With the rapid changes to the Sea now being proposed, it is a record of the Salton Sea in what may have been its most productive years. Alice Oglesby Claremont, California March 31, 2005 EDITOR’S NOTE A short time after Larry was diagnosed with cancer and retired from college teaching, I approached him about participating in a symposium on the Salton Sea for the Southern California Academy of Sciences. Larry agreed to prepare a paper on the invertebrates, his specialty, but the project grew, eventually incorporating all his lifetime work on the sea and covering not only invertebrates but all aspects of the Sea’s history and wildlife. Larry was a consummate scientist and his manuscript includes much charac- teristic scientific shorthand. He insisted on using the metric system for measure- ments and using d for day, yr for year, etc. He used a notation for salinity con- centration that may not be familiar to those not working in limnology. Rather _1 than g/L (grams per liter), Larry uses g 1 . The Bibliography contains all the works consulted by Larry, not just referenced works and is probably the most complete bibliography of material on the Salton Sea. After Larry’s death it was felt that this manuscript, if published, would be a fitting memorial to his work and to his knowledge of the Salton Sea, and provide a valuable history of the biology, geology, and other aspects of the Sea up to the year of his death (2001). The Southern California Academy of Sciences, of which Larry was a long-time member, agreed to undertake this publication as a memoir with the generous financial support of the Oglesby family. I have done little to Larry’s original manuscript other than some minor editorial corrections. Alice Oglesby has done most of the final preparation as a lasting tribute to her husband. Daniel A. Guthrie, Editor Southern California Academy of Sciences ACKNOWLEDGMENTS It is a great pleasure to thank the many students in 30 years of Pomona College Aquatic Biology classes for their help in making detailed observations, collecting data, and constant good cheer. Their field notes and project reports have been a gold mine of valuable information. I am pleased to thank my research assistants and senior thesis students for their excellent work both in the field and in the laboratory: Charles Anderson, Tanya Bauriedel, John Bishop, Abigail Breuer, Mi- chael Carroll, Douglas Christ, Nicole Dobroski, Margaret “Peggy” Fastnow, Wil- liam Hargreaves, Wayne “Chip” Hogue, Dierdre Kuhl, Mira Liao, Jan Low, Erick Robinson, Lena Shiroma, and Susan Summit, all from Pomona College, Heather Duncan of Swarthmore College, and Judy Swift of Colby College. I have greatly benefited from discussions with James T. Carlton (Director, Wil- liams College-Mystic Seaport Program), Ed Collins (Imperial Irrigation District), Clifton Coney (Malacology Collections Manager, Los Angeles County Museum of Natural History), Barry Costa-Pierce (Director, Mississippi-Alabama Sea Grant Consortium), William Davis (biology. University of California, Irvine), Deborah Dexter (biology, San Diego State University), Brian Ebersole (Science Librarian, Pomona College), Craig Engel (former Manager, Salton Sea State Recreation Area), John Fitch (former Research Director, California Department of Fish and Game), Taber Hand (natural resources. University of Maryland), Ari Hershowitz (Natural Resources Defense Council), Norman Hogg (biology, California State Polytechnic University, Pomona), Gary Hurd (Orange County Natural History Museum), Stuart Hurlbert (biology, San Diego State University), Robert R. Ireland (University of California Lawrence Livermore National Laboratory), Richard C. Johnson (Salton Sea State Recreation Area), the late Charlotte Mangum (biology, College of William and Mary), William A. Newman (Scripps Institute of Ocean- ography), Alice S. Oglesby (microbiology. Western University of Health Sci- ences), David D. Oglesby (geology. University of California, Riverside). Wayne Parker (Manager, former State Warmwater Fish Hatchery), Donald J. Reish (bi- ology, California State University, Long Beach), Paul Remeika (Park Paleontol- ogist, Anza-Borrego Desert State Park), Ginger Ridgeway (Curator, Agua Caliente Cultural Museum), Jerry Schaefer (ASM Affiliates), J. M. “Tex” Ritter (former Manager, Salton Sea State Recreation Area), Michael Rymer (US Geological Sur- vey), Alan Schoenherr (biology, Fullerton College), James G. Setmire (US Geo- logical Survey), the late Ralph I. Smith (zoology, University of California, Berke- ley), Dwight Taylor (California Academy of Sciences), Howard Wilshire (US Geological Survey), William O. Wirtz II (biology, Pomona College), Jay von Werlhof (Director, Imperial Valley College Desert Museum), Fred Worthley, Jr. (Region 5 Manager, California Department of Fish and Game), Jonathan Wright (biology, Pomona College), and Donald Zenger (geology, Pomona College).