Middle Santa Ana River Watershed Uncontrollable Bacterial Sources Study Final Report Riverside County Flood Control and Water Conservation District 1995 Market Street Riverside, CA 92501 June 2016 Table of Contents Section 1 Introduction .................................................................................................................................... 1-1 1.1 Background ................................................................................................................................................................... 1-1 1.2 Regulatory Framework ............................................................................................................................................ 1-1 1.3 Literature Review ...................................................................................................................................................... 1-3 1.3.1 Direct inputs from wildlife ......................................................................................................................... 1-3 1.3.2 Resuspension from sediment and biofilm .......................................................................................... 1-3 1.3.3 Shedding during swimming....................................................................................................................... 1-4 1.3.4 Equestrian recreational use ...................................................................................................................... 1-4 1.4 Study Framework ....................................................................................................................................................... 1-4 Section 2 Design of Pilot Studies ................................................................................................................. 2-1 2.1 Natural Sources Study .............................................................................................................................................. 2-2 2.1.1 Locations ............................................................................................................................................................ 2-2 2.1.2 Frequency and Schedule ............................................................................................................................. 2-3 2.1.3 Field and Laboratory Constituents ......................................................................................................... 2-3 2.2 Bird Study ...................................................................................................................................................................... 2-4 2.2.1 Locations ............................................................................................................................................................ 2-4 2.2.2 Frequency and Schedule ............................................................................................................................. 2-5 2.2.3 Field and Laboratory Constituents ......................................................................................................... 2-5 2.3 Stormwater Channel Study .................................................................................................................................... 2-6 2.3.1 Locations ............................................................................................................................................................ 2-6 2.3.2 Frequency and Schedule ............................................................................................................................. 2-7 2.3.3 Field and Laboratory Constituents ......................................................................................................... 2-7 2.4 Non-MS4 Flow Study ................................................................................................................................................ 2-8 2.4.1 Locations ............................................................................................................................................................ 2-8 2.4.2 Frequency and Schedule ............................................................................................................................. 2-9 2.4.3 Field and Laboratory Constituents ....................................................................................................... 2-10 2.5 Human Recreation Study ...................................................................................................................................... 2-10 2.5.1 Locations .......................................................................................................................................................... 2-10 2.5.2 Frequency and Schedule ........................................................................................................................... 2-11 2.5.3 Field and Laboratory Constituents ....................................................................................................... 2-11 2.6 Horse Recreation Study ......................................................................................................................................... 2-12 2.6.1 Locations .......................................................................................................................................................... 2-12 2.6.2 Frequency and Schedule ........................................................................................................................... 2-13 2.6.3 Field and Laboratory Constituents ....................................................................................................... 2-13 Section 3 Results ............................................................................................................................................... 3-1 3.1 Natural Sources Study .............................................................................................................................................. 3-1 3.1.1 Biological Assessment .................................................................................................................................. 3-1 3.1.2 Water Quality ................................................................................................................................................... 3-1 3.2 Bird Study ...................................................................................................................................................................... 3-5 3.2.1 Schleisman Road Bridge.............................................................................................................................. 3-5 3.2.1.1 Biological Assessment ................................................................................................................... 3-5 3.2.1.2 Water Quality .................................................................................................................................... 3-6 3.2.2 Mission Boulevard Bridge .......................................................................................................................... 3-8 ii Table of Contents 3.2.2.1 Biological Survey ............................................................................................................................. 3-8 3.2.2.2 Water Quality .................................................................................................................................... 3-9 3.3 Stormwater Channel Study ................................................................................................................................. 3-11 3.3.1 E. coli in Water Samples ............................................................................................................................ 3-11 3.3.2 E. coli in Sediment and Biofilm Samples ............................................................................................ 3-11 3.3.2 Source Tracking ........................................................................................................................................... 3-13 3.4 Non-MS4 Flow Study .............................................................................................................................................. 3-16 3.4.1 Monitoring Activities ................................................................................................................................. 3-16 3.4.2 Historical Flow Record .............................................................................................................................. 3-17 3.5 Human Recreation Study ..................................................................................................................................... 3-20 3.5.1 Visual Observations .................................................................................................................................... 3-20 3.5.2 Water Quality ................................................................................................................................................ 3-22 3.5.3 Transient Encampment Management ................................................................................................ 3-25 3.6 Horse Recreation Study ........................................................................................................................................ 3-26 3.6.1 Visual Observations ...................................................................................................................................