Information synthesis and priorities regarding steelhead trout (Oncorhynchus mykiss) on the Santa Clara River Photo by: EJ Remson By Elise Kelley, Ph.D. Post – doctoral researcher University of California, Santa Barbara February 2004 for The Nature Conservancy Acknowledgements The author would like to thank Ron Bottorff, Mark Capelli, Matt Carpenter, Murray McEachron, Lorraine Rubin, Denise Steurer, and Karen Waln for review of, and comments on, an earlier draft. This work was funded by the Ralph M. Parsons Foundation and the Edwin W. Pauley Foundation. 2 Acknowledgements ......................................................................................................... 2 Abbreviations .................................................................................................................. 6 Introduction ..................................................................................................................... 7 Executive Summary ........................................................................................................ 7 Methods and Sources ..................................................................................................... 9 Analysis and Priorities..................................................................................................... 9 I. Physical Impediments To Steelhead Passage....................................................... 10 II. Steelhead Ecology................................................................................................ 11 III. River Water Flow and Balance ............................................................................ 12 IV. Point source and non-point source pollution ...................................................... 14 The Priority Actions ....................................................................................................... 14 Habitat and Population Assessments ........................................................................ 14 River Barriers Assessment ........................................................................................ 15 Water Balance and Flow............................................................................................ 15 Conclusion .................................................................................................................... 16 Appendix ....................................................................................................................... 17 A Brief Introduction........................................................................................................ 18 Map ............................................................................................................................... 19 Conceptual Model of Steelhead Trout on the SCR ....................................................... 21 Santa Clara River Timeline ........................................................................................... 23 Santa Clara River Watershed Factsheet....................................................................... 25 Sespe Creek Subwatershed Factsheet......................................................................... 27 Santa Paula Creek Subwatershed Factsheet................................................................ 28 Piru Creek Subwatershed Factsheet............................................................................. 29 Ecology and Population of Steelhead ........................................................................... 31 Issues ........................................................................................................................ 31 Potential Research Questions ................................................................................... 31 Section I. Santa Clara River ..................................................................................... 32 Fish Counts............................................................................................................ 32 Migration timing...................................................................................................... 32 Return spawners.................................................................................................... 33 Habitat.................................................................................................................... 33 Santa Paula Creek ................................................................................................. 33 Pole Creek ............................................................................................................. 36 Hopper Canyon Creek ........................................................................................... 36 Piru Creek .............................................................................................................. 36 Estuary................................................................................................................... 36 Aggregate Mining................................................................................................... 38 Climate................................................................................................................... 38 Section II. General Information .................................................................................. 38 Southern Steelhead ............................................................................................... 38 Regulation.............................................................................................................. 39 Habitat Qualities..................................................................................................... 40 Migration and Spawning......................................................................................... 40 Feeding .................................................................................................................. 41 Native fish and hatchery stock ............................................................................... 41 3 Effects of sediment and turbidity ............................................................................ 41 Ocean Life.............................................................................................................. 42 Ocean Climate ....................................................................................................... 43 Fish surveys and counts on the Santa Clara River.................................................... 44 Mainstem: Hydrology and Human Impacts................................................................... 45 Issues ........................................................................................................................ 45 Potential Research Questions ................................................................................... 45 Section I. Santa Clara River ..................................................................................... 45 Diverted Water ....................................................................................................... 45 In-stream Flow ....................................................................................................... 46 Groundwater Basins............................................................................................... 47 Rising Groundwater ............................................................................................... 47 How groundwater basins get replenished .............................................................. 47 Groundwater in the Oxnard Plain........................................................................... 48 Groundwater Overdrafts......................................................................................... 48 Groundwater Usage ............................................................................................... 49 Geomorphology...................................................................................................... 49 Water Use and Availability ..................................................................................... 49 Urbanization Effects............................................................................................... 50 Agricultural Effects ................................................................................................. 51 Effects of Recreation.............................................................................................. 52 Homelessness........................................................................................................ 52 Aggregate Mining Effects ....................................................................................... 53 Section II. General Information ................................................................................. 53 Habitat and water flow............................................................................................ 53 List of Major Water users along the Santa Clara River.............................................. 55 Smaller Diversions..................................................................................................... 55 Graphic of Lower Santa Clara Flow of Water ............................................................ 56 Amount of rainfall in the Lower Santa Clara River ..................................................... 57 Amount of water diverted at the Vern Freeman Diversion ......................................... 57 Average Acre-Feet diverted