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<br />24 <br />Appendix A: Methods & Data Sources <br />Methods <br />The San Leandro climate hazards analysis was conducted using a digital mapping tool called the <br />Vizonomy Climate Risk Platform (Vizonomy). This platform overlays geographical representations of sea <br />level rise and rainfall-induced inland flooding with the location of citywide assets throughout San <br />Leandro, creating a visual representation of the spatial extent and the number of specific assets that <br />could be affected by each hazard throughout the city. The asset data was collected from open data <br />sources available through various federal agencies, OpenStreet Map and local data provided by the City <br />of San Leandro and Alameda County. Hazard projections and data were collected from the data sources <br />explained in the next section of this appendix. In addition, statistical analysis of downscaled climate <br />models and graphical representations of projected temperature and precipitation changes throughout <br />the 21st century were provided by Four Twenty Seven. <br />The spatial evaluation of hazards and assets limited this analysis to the consideration of asset exposure. <br />In order to assess vulnerability to climate change hazards, more information is needed on the sensitivity <br />and adaptive capacity of affected communities and assets. This analysis provides a thorough <br />examination of the city’s potential spatial exposure to a variety of climate hazards and is meant to <br />complement further analysis of overall vulnerability and the appropriate adaptive responses. <br /> <br />Data Sources <br />Rainfall Induced Inland Flooding <br />FEMA creates Flood Insurance Rate Maps as part of the National Flood Insurance Program to determine <br />flood insurance requirements and inform local hazard mitigation actions that address flood risks. These <br />flood maps incorporate statistical information on river flow, storm surge, hydrology and topography in <br />order to delineate 100-year and 500-year floodplains, or areas that will experience floods with a one <br />percent or 0.2 percent chance respectively of being exceeded in a given year. The statistical information <br />and associated maps are based on historical data and do not incorporate climate projections into <br />floodplain delineations, yet do provide an accurate depiction of where floodwaters are likely to <br />concentrate, even if recurrence intervals change. <br />Sea Level Rise <br />The 2012 NRC Report Sea-Level Rise for the Coasts of California, Oregon, and Washington: Past, Present, <br />and Future identified likely sea level rise estimates throughout the 21st century for the west coast of the <br />United States based on moderate greenhouse gas emissions and continued acceleration of glacial melt <br />patterns. These values are accompanied by ranges of possible sea levels based on low and high <br />emissions scenarios and ice melt scenarios. Figure A1 presents these projections: six inches of sea level <br />rise by 2030 (range: 2-12 in), 11 inches by 2050 (range: 5-24 in), and 36 inches by 2100 (range: 17-66 in) <br />relative to the year 2000. <br /> <br />68