Assessment and Management Prioritization Regime for the Bar-built Estuaries of San Mateo County Summary Report San Pedro Creek Prepared for: United States Fish and Wildlife Service San Francisco Area Coastal Program by: Central Coast Wetlands Group Moss Landing Marine Labs 8272 Moss Landing Rd. Moss Landing, CA 95039 November 2016 Summary Report: Bar-Built Estuaries of San Mateo County TABLE OF CONTENTS Table of Contents ........................................................................................................................................... 1 Figures and Tables .......................................................................................................................................... 2 Background and Need .................................................................................................................................... 3 What are BBEs and Why are they Important ............................................................................................................ 3 BBE are the most dominant estuarine resource on the San Mateo County coastline .............................................. 4 Purpose ........................................................................................................................................................... 5 Methods .......................................................................................................................................................... 7 Site Selection ............................................................................................................................................................. 7 Existing plans and reports ......................................................................................................................................... 7 Wetland Habitat Condition ....................................................................................................................................... 7 Watershed Stressors ................................................................................................................................................. 8 Wetland Habitat Loss and Change ............................................................................................................................ 8 Special Status Species ............................................................................................................................................... 8 Results ............................................................................................................................................................. 9 Existing plans and reports ......................................................................................................................................... 9 Wetland Habitat Condition ..................................................................................................................................... 10 Stressors .................................................................................................................................................................. 14 Watershed Stressors ........................................................................................................................................... 14 CRAM Stressor Checklist ...................................................................................................................................... 15 Wetland Habitat Loss and Change .......................................................................................................................... 16 Special Status Species ............................................................................................................................................. 18 Prioritization Strategy ................................................................................................................................... 19 Description of Prioritization Methods ..................................................................................................................... 20 Initial Steps .......................................................................................................................................................... 20 Prioritization #1: Threshold Evaluation ............................................................................................................... 20 Prioritization #2: Condition-Vulnerability Evaluation .......................................................................................... 20 Prioritization #3: EPA Decision support tool ........................................................................................................ 21 Results ..................................................................................................................................................................... 22 Prioritization #1: Threshold Evaluation ............................................................................................................... 22 Prioritization #2: Condition-Vulnerability Graph ................................................................................................. 22 Prioritization #3: EPA Decision support tool ........................................................................................................ 23 Prioritization Support Tool .................................................................................................................................. 23 Management Opportunities ......................................................................................................................... 24 General Priority Actions .......................................................................................................................................... 24 Wetland Habitat Condition-CRAM ...................................................................................................................... 24 Watershed Stressors ........................................................................................................................................... 24 Wetland Habitat Loss and Change ...................................................................................................................... 25 Prioritization of Sites for Restoration Actions ......................................................................................................... 25 Assessment of Selected Sites .................................................................................................................................. 25 Habitat Loss and Recovery .................................................................................................................................. 25 References .................................................................................................................................................... 27 Appendix 1: CCWG Wetland Classification Chart ........................................................................................ 28 1 Summary Report: Bar-Built Estuaries of San Mateo County Appendix 2: Site-Specific Data Summaries .................................................................................................. 29 FIGURES AND TABLES FIGURE 1.CONCEPTUAL FIGURE OF A) OPEN, B) PARTIALLY OPEN, AND C) CLOSED BAR-BUILT ESTUARY. .............................................................. 3 FIGURE 2.HYDROGRAPH INDICATING VARIABILITY IN DEPTH AND SALINITY OF A BBE OVER TIME. ...................................................................... 3 FIGURE 3. LOCATIONS OF ALL COASTAL CONFLUENCES IN SAN MATEO COUNTY. (BLUE=BBE, GREEN=CREEK MOUTH, RED=BAY/HARBOR, PINK=OPEN ESTUARY, YELLOW=COASTAL DEPRESSION). .................................................................................................................................. 5 FIGURE 4.COASTAL CONFLUENCE AREA (HECTARES) BY CONFLUENCE CLASSIFICATION TYPE IN SAN MATEO COUNTY ............................................ 5 FIGURE 5 SELECTED SITES IN SAN MATEO COUNTY ................................................................................................................................. 7 FIGURE 6.CUMULATIVE FREQUENCY DISTRIBUTION OF BBE CRAM SCORES FOR SAN MATEO COUNTY (ORANGE) AND THE CENTRAL COAST OF CALIFORNIA (BLUE). .............................................................................................................................................................. 12 FIGURE 7.CUMULATIVE FREQUENCY DISTRIBUTION OF BBE CRAM SCORES FOR SAN MATEO COUNTY (ORANGE) AND CALIFORNIA AS A WHOLE (BLUE). ............................................................................................................................................................................... 12 FIGURE 8. GRAPH OF TOTAL NUMBER OF CRAM STRESSORS COMPARED TO CRAM INDEX SCORE FOR ALL SITES. ............................................. 16 FIGURE 9. GRAPH OF WATERSHED AREA COMPARED TO HISTORICAL WETLAND AREA FOR ALL SITES. ................................................................ 17 FIGURE 10. TOTAL WETLAND AREA FOR ALL SITES FOR THE HISTORICAL (1850’S) AND CURRENT TIME PERIODS. ................................................ 17 FIGURE 11. HISTORICAL (A) AND CURRENT (B) LEVEL 2 HABITAT COMPOSITION FOR ALL SITES. PERCENT CHANGE IN LEVEL 2 HABITAT COMPOSITION BETWEEN TIME PERIODS (C AND D). ........................................................................................................................................