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<br />Consulting Services Agreement between City of San Leandro and Last revised 10/10/2022]
<br />Terraphase for Tony Lema landfill climate vulnerability assessment Exhibit A – Page 2 of 4
<br />Task 2: Flood Quantification and Justification
<br />This task includes conducting an analysis of surface water inundation (flooding) and groundwater elevation
<br />rise associated with Sea Level Rise (SLR) scenarios for the years 2050 and 2100. The analysis will be
<br />conducted consistent with the Ocean Protection Council (OPC) Guidance (OPC, 2018) using the most
<br />recent and best available climate change projections and trajectories presented in “Global and Regional
<br />Sea Level Rise Scenarios for the United States” (Sweet et.al. 2022).
<br />
<br />For the 2050 and 2100 predictions, the medium-high and extreme risk aversion SLR scenarios will be
<br />considered, and a risk scenario will be selected and identified for the 2050 and 2100 conditions. The
<br />selected magnitudes of SLR will be superimposed onto the groundwater surface to assess groundwater
<br />rise and potential daylighting of groundwater. Quantification of the 100 -year storm event will include
<br />astronomical tides, storm surge, wave run-up, seasonal effects, and discharge from local tributaries. For
<br />the 2100 condition, the impact of climate change on the future 100-year storm event will also be
<br />considered.
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<br />Terraphase will obtain nearby tidal gauge records, precipitation records, and LiDAR topography for use in
<br />the analysis. For each identified scenario, surface water inunda tion maps will be created using the most
<br />updated LiDAR topographic data for the Site. Groundwater surfaces for each scenario will be constructed
<br />based on the best available data for current conditions with the magnitude of SLR superimposed. These
<br />two types of maps will be used together to assess potential future vulnerability to flooding at the Site.
<br />Terraphase will also use data from the Coastal Storm Modeling System (CoSMoS) project (USGS 2021),
<br />which has made predictions of storm-induced coastal flooding, erosion, and cliff failures over large
<br />geographic scales.
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<br />An interim technical memorandum will be provided to describe the approach to the SLR assessment,
<br />justification of SLR scenario selections, and results of our analysis.
<br />
<br />Task 2 references:
<br /> California Ocean Protection Council (OPC). 2018. State of California Sea -Level Rise Guidance,
<br />2018 Update.
<br /> Sweet, W.V., B.D. Hamlington, R.E. Kopp, C.P. Weaver, P.L. Barnard, D. Bekaert, W. Brooks, M.
<br />Craghan, G.Dusek, T. Frederikse, G. Garner, A.S. Genz, J.P. Krasting, E. Larour, D. Marcy, J.J.
<br />Marra, J. Obeysekera,M.Osler, M. Pendleton, D. Roman, L. Schmied, W. Veatch, K.D. White, and
<br />C. Zuzak, 2022: Global and Regional Sea Level Rise Scenarios for the United States: Updated
<br />Mean Projections and Extreme WaterLevel Probabilities Along U.S. Coastlines. NOAA Technical
<br />Report NOS 01. National Oceanic and Atmospheric Administration, National Ocean Service, Silver
<br />Spring, MD, 111 pp.https://oceanservice.noaa.gov/hazards/sealevelrise/noaa -nos-techrpt01-global-
<br />regional-SLR-scenarios-US.pdf
<br /> United States Geological Survey (USGS) 2021. Projecting climate dependent coastal flood risk
<br />with a hybrid statistical dynamical model. DOI 10.1029/2021EF002285.
<br />https://www.usgs.gov/publications/projecting-climate-dependent-coastal-flood-risk-hybrid-
<br />statistical-dynamical-model
<br />
<br />Task 3: Preparation of Long-Term Flood Protection and Adaptation Plan
<br />Task 3 will include preparing the Long-Term Flood Protection and Adaptation Plan (Plan) based on
<br />previously completed Site background review, flood research, and flood quantification/justification tasks.
<br />DocuSign Envelope ID: 974C2867-84D8-4D0B-8A87-C4E791D70B9A
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