EMERGENT ECOLOGIES OF THE BAY EDGE ADAPTATION TO CLIMATE CHANGE AND SEA LEVEL RISE Summer Internship 2019 TABLE OF CONTENTS Preface Research Introduction 2 Approach 2 What’s Out There Regional Map 6 AUTHORS Site Visits ` 9 Sarah Fitzgerald Salt Marsh Section 11 Jeff Milla Plant Community Profiles 13 Yutong Wu PROJECT TEAM Lauren Bergenholtz What’s Changing Ilia Savin Julia Price Impacts of Sea Level Rise 24 Nico Wright Marsh Migration Process 26 This publication financed initiated, guided, and published under the direction of CMG Landscape Architecture. What We Can Do Unless specifically referenced all photographs and Tactical Matrix 29 graphic work by authors. Site Scale Analysis: Treasure Island 34 Site Scale Analysis: Bothin Marsh 46 San Francisco, 2019. Conclusion Closing Statements 58 Acknowledgments 60 Bibliography 62 Cover photo: Pump station fronting Shorebird Marsh. Corte Madera, CA RESEARCH INTRODUCTION BREADTH As human-induced climate change accelerates and impacts regional map coastal ecologies, designers must anticipate fast-changing conditions, while design must adapt to and mitigate the effects of climate change. With this task in mind, this research project investigates the needs of existing plant communities in the San plant communities Francisco Bay, explores how ecological dynamics are changing, of the Bay Edge and ultimately proposes a toolkit of tactics that designers can use to inform site designs. DEPTH landscape tactics matrix two case studies: Treasure Island Bothin Marsh APPROACH Working across scales, we began our research with a broad suggesting design adaptations for Treasure Island and Bothin survey of the Bay’s ecological history and current habitat Marsh. We see these case studies as a thread uniting the research conditions. Beginning with the regional scale, we mapped the scales, drawing upon regional, meso, and site-scale information. historical shoreline, flood risks, shoreline conditions, ecologies, and operational landscape units based on underlying geology Over the course of the internship we also conducted five site and urban conditions documented in SFEI’s Adaptation Atlas. visits, which were crucial in informing our understanding of Bay This regional map informed our understanding of Bay-wide ecologies. We deeply appreciate CMG’s recognition that there is climate change challenges, and illustrates both typical and no substitute for experiencing a place firsthand. By allowing us to unique conditions along the Bay edge. test hypotheses on the ground and generate new questions from observed phenomena, the site visits proved to be invaluable to our Honing in, we next turned our attention to plant community research process. profiles of the Bay. By identifying individual species, their ecological needs, and the ecosystem services of each habitat type, we comprehensively outlined the appropriate uses of these plants in both restoration projects and urban settings. We created a catalogue of this information, organized by plant community, to quickly inform designers working on projects along the coast. Zooming in even further, we next developed a matrix of landscape tactics for adapting the Bay edge to sea level rise (SLR). We applied the matrix to a set of sites, ultimately Above. Visualization of research approach 2 3 WHAT’S OUT THERE CATALOGUING BAY EDGE ECOLOGIES & CONDITIONS montezuma slough suisun slough Grizzly Island petaluma river Wildlife Area novato creek Carquinez North Novato SUISUN BAY SAN PABLO BAY napa river honker bay A CHANGING BAY sacramento river carquinez strait rodeo creek pacheco creek past, present and future conditions Gallinas refugio creek gallinas creek pinole creek san joaquin river Bay Point San Francisco Bay National Estuarine Carquinez South Research Reserve Pinole Walnut San Rafael wildcat creek san rafael creek Wildcat Corte Madera corte madera creek Point Richmond harbor channel richardson bay East Bay Crescent Richardson CENTRAL BAY Golden Gate mission creek San Leandro SHORELINE CONDITION Mission Islais islais creek san leandro bay Historical Shoreline Wetlands Natural Shoreline (e.g., clis, blus) Yosemite - Protected Shoreline (e.g., berm, levee, embankment) Visitacion San Lorenzo FLOOD RISK san lorenzo creek FLOOD ZONE san bruno canal 0’ SLR + 100 yr ood SHORT TERM SLR (2030) SOUTH SAN FRANCISCO BAY 0.5’ SLR + 100 yr ood LONG TERM SLR (2100) 2.5’ SLR + 100 yr ood Eden Landing Ecological Reserve ENVIRONMENT MANAGEMENT Alameda Creek Colma San Bruno seal slough Operational Landscape Units Subtidal bat ray island alameda creek Tidal Flat Mowry Marsh San Mateo redwood creek As climate change and sea level rise continue to accelerate Lagoons ravenswood slough at an alarming rate, the San Francisco Bay Shoreline must Developed Area Don Edwards San Francisco Bay National Wildlife Refuge begin adapting to changing conditions. The complexity of the mowry slough “Bay edge” differs from region to region and neighborhood to neighborhood. In order to fully grasp possible adaptation Belmont Redwood coyote creek strategies, we must understand past historical shoreline San Francisquito conditions, current conditions and future sea level rise scenarios in the short term and long term. Santa Clara Valley 7 0 2 4 10 miles Stevens SITE VISITS SUISUN BAY SAN PABLO BAY POINT SAN PABLO POINT MOLATE BEACH PARK CORTE MADERA MARSH STATE MARINE PARK MILLER KNOX REGIONAL SHORELINE ALBANY BULB BOTHIN MARSH CENTRAL BAY TREASURE ISLAND CLIPPER COVE CRISSY FIELD MARSH MISSION CREEK PARK POTRERO POINT PIER 94 WETLANDS HERON’S HEAD PARK INDIA BASIN SHORELINE PARK YOSEMITE SLOUGH ISLAIS CREEK FLOOD RISK FLOOD ZONE 0’ SLR + 100 yr ood SHORT TERM SLR (2030) SOUTH SAN FRANCISCO BAY 0.5’ SLR + 100 yr ood LONG TERM SLR (2100) 2.5’ SLR + 100 yr ood 9 A COMPLETE TIDAL WETLAND SYSTEM typical cross section through plant communities 11 PLANT COMMUNITIES OF THE BAY EDGE Expertly adapted to local environmental factors like temperature, wind, salinity, soil type and moisture availability, the plant communities along the Bay edge boast a stunning diversity of species and ecosystem services. As climate change tests the ability of these communities to adapt to new environmental conditions, designers working along the Bay edge are grappling with tough questions: is it responsible to plant native species knowing that climate regimes are changing? Would it be Subtidal Tidal Flat (Mudflat) Coastal Salt Marsh better to use species adapted to drier, hotter conditions farther south and begin transitioning local plant communities as climate change accelerates? Through our interviews with native horticulturists and restoration ecologists, we have concluded that these well- intentioned questions should inform planting pallettes only sparingly. Climate change models, while crucial policy tools, are only models; adhering to their predictions too strictly could cause plant designers to cut the residency of some species prematurely, depriving them of the opportunity to adapt to new regimes. Rather than focusing on supplanting certain species, experts currently Brackish Marsh Coastal Grassland Ponds recommend creating large corridors that allow for natural species migration. Landscapes have never been static. While these indigenous plant communities evolved for very specific conditions, they are also hardy and adaptable; with some help, many species may be able to adjust to the coming changes. Even if they don’t last 100 years or 300 years, they are still crucial for bees collecting pollen, for birds foraging on eelgrass and for marshes sequestering our carbon emissions today. Coastal Beach & Dune Coastal Scrub Upland Managed Horticulture 12 13 SUBTIDAL Zostera marina (Zosteraceae) Anas americana Clupea pallasii Ruppia maritima (Ruppiaceae) “Eelgrass” “American Wigeon” “Pacific Herring” “Widgeongrass” Colonizes large areas with little other vegetation Feeds on herring eggs and eats eelgrass directly. Relies on submerged vegetation for eggs. Spawn provide Protected brackish areas. comingling. energy-rich food to birds that winter in the Bay. Supports the Bay’s last commercial fishery. Stuckenia pectinata (Potamogetonaceae) Phyllospadix torreyi (Zosteraceae) “Sago Pondweed” “Surfgrass” Suisun Bay. Fresh and brackish water. Rocky shoreline. Key Benefits / Ecosystem Services Needs Erosion prevention: traps sediment Light: penetration in the water column dictates the lower limit of eelgrass, while turbidity can cause dieback Wave attenuation Temperature: 10-20˚C, threatened by climate change High habitat value for birds, fish, invertebrates: basis for large marine foodchain Salinity: 10-30 ppt (parts per thousand) Water quality improvement: absorbs excess nutrients Substrate: 90% clay (0.001-0.0039 mm), silt (0.0039-0.625 mm) and sand Carbon sink: rough calculations show that the carbon sequestered by restoring (0.0625-2 mm) one hectare of seagrass corresponds to that of 10-40 hectares of dry-land forest 15 TIDAL FLAT (MUDFLAT) Calidris mauri Hemigrapsus oregonensis Diatom Macoma Nasuta Western Sandpiper Mudflat Crab Micro Algae Bent Nose Mocoma Key Benefits / Ecosystem Services Needs Habitat value: cyanobacteria captures nitrogen and supplies bioavailable nutrients Slope: lower slopes and valley bottoms <500 m elevation in coastal waters Sediment supply: sediments move toward areas of weaker energy (tides usually carry Soil binding: cyanobacteria on the surface of the mudflat binds the mud, which sediment landward; waves usually carry sediment seaward) prevents erosion. Salinity fluctuation: rises with evaporation and