Water Supply and Habitat Resiliency for a Future Los Angeles River: Site-Specific Natural Enhancement Opportunities Informed by River Flow and Watershed-Wide Action Los Feliz to Taylor Yard Funded by a Grant from the Santa Monica Mountains Conservancy December 2016 Los Feliz Blvd to Taylor Yard Los Angeles River Habitat Enhancement Study and Opportunities Assessment The Nature Conservancy’s Urban Conservation Program Team that includes Brian Cohen (Conservation Analyst), Shona Ganguly (External Affairs Manager), Sophie Parker, Ph.D. (Senior Scientist), John Randall (Lead Scientist), Jill Sourial (Urban Conservation Program Director), and Lara Weatherly (Intern) led the process to create this report. Land IQ conducted surveys and analysis on behalf of The Nature Conservancy with the support of the Natural History Museum, WRC Consulting, Travis Longcore at the University of Southern California, and Connective Issue. When referring to this study, cite The Nature Conservancy’s Urban Conservation Program. Contributors Chapter 1: Introduction Travis Brooks and Margot Griswold (Land IQ); Krista Sloniowski (Connective Issue) Chapter 2: Historical Ecology of the Los Angeles River Riparian Zone in the Elysian Valley Travis Longcore (University of Southern California, School of Architecture and Spatial Sciences Institute) Chapter 3: Hydrology and Hydraulics Travis Brooks (Land IQ); Lan Weber (WRC Consulting) Chapter 4: Biota of the Los Angeles River in the Elysian Valley 4.1 Introduction: Travis Brooks, Margot Griswold, and Melissa Riedel-Lehrke (Land IQ); Brian V. Brown, James P. Dines, Kimball L. Garrett, Lisa Gonzalez, Bennett Hardy, Stevie Kennedy-Gold, Miguel Ordeñana, Gregory B. Pauly (Natural History Museum of Los Angeles County) 4.2 Vegetation Communities: Travis Brooks, Margot Griswold, and Melissa Riedel-Lehrke (Land IQ) 4.3 Fish Fauna Review: Margot Griswold (Land IQ) 4.4 Insect Fauna: Brian V. Brown and Lisa Gonzalez (Urban Nature Research Center, Natural History Museum of Los Angeles County) 4.5 Herpetofauna: Gregory B. Pauly, Stevie Kennedy-Gold, and Bennett Hardy (Section of Herpetology and Urban Nature Research Center, Natural History Museum of Los Angeles County) 4.6 Avifauna: Kimball L. Garrett (Section of Ornithology, Natural History Museum of Los Angeles County) 4.7 Mammal Fauna: James P. Dines (Section of Mammalogy, Research and Collections, Natural History Museum of Los Angeles County); Miguel Ordeñana (Citizen Science Office, Education Division, Natural History Museum of Los Angeles County) Chapter 5: Habitat Enhancement Opportunities Travis Brooks, Margot Griswold (Land IQ); Brian V. Brown, James P. Dines, Kimball L. Garrett, Miguel Ordeñana, Gregory B. Pauly (Natural History Museum of Los Angeles County); Travis Longcore (University of Southern California School of Architecture and Spatial Sciences Institute); Krista Sloniowski (Connective Issue) Chapter 6: Habitat Enhancement Specifications Travis Brooks, Margot Griswold, and Melissa Riedel-Lehrke (Land IQ) 1-2 Los Feliz Blvd to Taylor Yard Los Angeles River Habitat Enhancement Study and Opportunities Assessment Table of Contents CHAPTER 1. INTRODUCTION ..................................................................................................................... 1-1 1.1. DEFINITION OF ECOLOGICAL RESTORATION ..................................................................................................... 1-2 1.2. STUDY PURPOSE AND DELIVERABLES ................................................................................................................. 1-4 1.3. STUDY AREA ............................................................................................................................................................ 1-5 1.3.1. Political Boundaries 1-8 1.3.2. Ownership and Management 1-8 1.4. REFERENCES ..........................................................................................................................................................1-10 CHAPTER 2. HISTORICAL ECOLOGY OF THE LOS ANGELES RIVER RIPARIAN ZONE IN THE ELYSIAN VALLEY 2-1 2.1. INTRODUCTION ....................................................................................................................................................... 2-1 2.2. METHODS ................................................................................................................................................................. 2-2 2.3. RESULTS ................................................................................................................................................................... 2-5 2.4. SYNTHESIS .............................................................................................................................................................2-22 2.5. DISCUSSION ...........................................................................................................................................................2-26 2.6. REFERENCES ..........................................................................................................................................................2-28 CHAPTER 3. HYDROLOGY AND HYDRAULICS....................................................................................... 3-1 3.1. INTRODUCTION ....................................................................................................................................................... 3-1 3.2. REVIEW OF AVAILABLE DATA .............................................................................................................................. 3-4 3.2.1. Flood Control Channel Features 3-4 3.2.2. Topography 3-4 3.2.3. Landscape Features, Channel Bars and Low Flow Water Types 3-9 3.2.4. Rainfall Record 3-23 3.2.5. Stormwater Discharge 3-23 3.2.6. Hydraulic Features 3-28 3.2.7. Erosion and Sedimentation 3-28 3.2.8. Water Quality 3-29 3.2.1. Dry Weather Water Supply 3-30 3.3. HYDRAULIC DATA FINDINGS ..............................................................................................................................3-35 3.4. IN-CHANNEL HABITAT RESTORATION STRATEGIES ......................................................................................3-35 3.5. ALTERNATIVE WATERSHED HYDROLOGY SCENARIOS...................................................................................3-37 3.6. REFERENCES ..........................................................................................................................................................3-40 CHAPTER 4. BIOTA OF THE LOS ANGELES RIVER IN THE ELYSIAN VALLEY ............................. 4-1 4.1. INTRODUCTION ....................................................................................................................................................... 4-1 4.1.1. Biological Study Area Segments 4-1 4.2. VEGETATION COMMUNITIES ................................................................................................................................. 4-4 4.2.1. Introduction 4-4 4.2.2. Methods 4-5 4.2.3. Results 4-7 4.2.4. Discussion 4-46 4.2.5. References 4-47 4.3. FISH FAUNA REVIEW ...........................................................................................................................................4-49 4.3.1. Data Summary 4-49 4.3.2. Discussion 4-49 Los Feliz Blvd to Taylor Yard Los Angeles River Habitat Enhancement Study and Opportunities Assessment 4.3.3. References 4-50 4.4. INSECT FAUNA ......................................................................................................................................................4-51 4.4.1. Introduction 4-51 4.4.2. Methods 4-51 4.4.3. Results and Discussion 4-54 4.4.4. References 4-60 4.5. HERPETOFAUNA ...................................................................................................................................................4-61 4.5.1. Introduction 4-61 4.5.2. Methods 4-62 4.5.3. Results 4-63 4.5.4. Discussion 4-75 4.5.5. References 4-76 4.6. AVIFAUNA ..............................................................................................................................................................4-77 4.6.1. Introduction 4-77 4.6.2. Methods 4-77 4.6.3. Results 4-79 4.6.4. Discussion 4-87 4.6.5. References 4-91 4.7. MAMMAL FAUNA ..................................................................................................................................................4-92 4.7.1. Introduction 4-92 4.7.2. Methods 4-93 4.7.3. Results 4-96 4.7.4. Discussion 4-102 4.7.5. References 4-105 CHAPTER 5. HABITAT ENHANCEMENT OPPORTUNITIES ............................................................... 5-1 5.1. WATERSHED HYDROLOGY OPPORTUNITIES ...................................................................................................... 5-1 5.2. IN-CHANNEL HABITAT ENHANCEMENT OPPORTUNITIES ............................................................................... 5-5 5.3. OUTSIDE OF CHANNEL HABITAT CREATION AND ENHANCEMENT OPPORTUNITIES .................................. 5-7 5.4. OTHER ECOLOGICAL CONSIDERATIONS IN THE WATERSHED ......................................................................5-12 5.4.1. Lower Los Angeles River Migratory Shorebird Habitat 5-13 5.5. REFERENCES ..........................................................................................................................................................5-16 CHAPTER 6. HABITAT ENHANCEMENT SPECIFICATIONS ...............................................................