GRRA_Climate_boundary_scag

The Green Region Resource Areas (GRRAs) dataset consists of information on natural hazards, sensitivities, farmland, tribal nations, military installations, and natural assets. The GRRA datasets are developed to support coordinating regional land use with transportation strategies and address the region’s growth and sustainability challenges to protect the region’s natural assets and reduce future risks from climate change. GRRAs are organized into three Data Categories with seven Topic Areas: Climate Hazards (flood hazard, sea level rise, wildfire risk), Habitat (habitat value, wildlife corridors, aquatic resources), and Agriculture (farmland). The Climate Hazards category highlights areas within the region at risk due to climate change, such as flood hazard, coastal inundation (sea level rise), and wildfire hazard. These risks can significantly influence where future growth occurs, as development may need to avoid or adapt to areas with high vulnerability to climate impacts. Several data sources inform the Topic Areas within the data category of Climate Hazards:Flood Hazard National Flood Hazard Layer (NFHL), 2025, FEMACoastal Inundation (Sea Level Rise) Sea Level Rise (3.5 Feet), 2025, NOAA Office for Coastal ManagementWildfire Hazard Fire Hazard Severity Zones (FHSZs) Local Responsibility Areas, 2025, Cal FIRE Fire Hazard Severity Zones (FHSZs) State Responsibility Areas, 2024, Cal FIRE Priority Landscape – Reduce Wildfire Risk to Ecosystem Services, 2018, Fire and Resource Assessment Program (FRAP) at Cal FIRE Priority Landscape – Reduce Wildfire Risk to Communities, 2018, Fire and Resource Assessment Program (FRAP) at Cal FIRE Wildland Urban Interface and Intermix (WUI), 2025, Cal FIREData sources are merged by Topic Area, and this dataset counts the number of overlapping Topic Areas for impacted locales in the region (Flood Hazard, Coastal Inundation, Wildfire Hazard). Scores range from 1 to 3. This dataset is accompanied by similar versions for Habitat and Agriculture, as well as an overall summary of overlaps amongst the topic areasThe following datasets are a subset of the Green Region Resource Areas (GRRAs). The GRRAs dataset consists of information on natural hazards, sensitivities, farmland, tribal nations, military installations, and natural assets. The GRRA datasets are developed to support coordinating regional land use with transportation strategies and address the region’s growth and sustainability challenges to protect the region’s natural assets and reduce future risks from climate change.Flood Hazard - Flood hazards are a foundational GRRA category because they highlight locations where development would face elevated risks and would not meet National Flood Insurance standards. The National Flood Hazard Layer (NFHL) (2025) is FEMA’s digital geospatial database that consolidates all Flood Insurance Rate Map (FIRM) information and Letters of Map Revisions (LOMRs). It depicts areas of flood risk, including Special Flood Hazard Areas (SFHAs) such as 1-percent-annual-chance flood zones (e.g., A, AE, AH, AO, A99, VE). The definitions for these zones can be found at https://www.fema.gov/flood-zones. FEMA prepares the flood maps to show the extent of flood hazard in a flood prone community by conducting engineering studies called ‘Flood Insurance Studies (FISs).’ From the study, FEMA delineates areas subject to inundation by a flood that has a 1 percent or greater chance of being equaled or exceeded during any given year. This type of flood is commonly referred to as the 100- year flood or base flood. The 100-year flood has a 26 percent chance of occurring during a 30-year period, the length of many mortgages. The 100-year flood is a regulatory standard used by Federal and most State agencies to administer floodplain management programs. The flood maps developed by FEMA are primary tools for state and local governments to mitigate the effects of flooding in their communities. The data are available to the public at FEMA’s Map Service Center (https://msc.fema.gov/portal/home). Please note that the information included in this book includes only 100-year flood data. Coastal Inundation (Sea Level Rise) - Sea level rise represents a growing risk for California’s coastline and is a required consideration for resource areas under SB 375. The Sea Level Rise Data was obtained from NOAA’s Office for Coastal Management (2025) as part of its Sea Level Rise and Coastal Flooding Impacts Viewer, a screening-level tool designed to visualize potential inundation under multiple scenarios. Please note the information included in this book includes only the 3.5-foot sea level rise inundation scenario. This dataset uses a modified bathtub approach that incorporates a Digital Elevation Model (DEM) and a tidal surface model based on Mean Higher High Water (MHHW). Wildfire Hazard - Wildfire represents one of the most critical hazards for Southern California communities, particularly where human development overlaps with fire-prone vegetation. Given the increasing frequency and severity of wildfires under climate change, the GRRA update incorporates multiple datasets to capture risks to both people and ecosystems. Data sources include several Cal FIRE datasets that assess wildfire risk and priority areas for mitigation. The Fire Hazard Severity Zones (FHSZs) for Local Responsibility Areas (2025) and State Responsibility Areas (2024) define wildfire hazard based on fire history, existing and potential fuel (natural vegetation), predicted flame length, blowing embers, terrain, and typical fire weather, with zones classified as Moderate, High, or Very High. The Priority Landscape – Reduce Wildfire Risk to Ecosystem Services by Cal FIRE (2018) identifies watersheds and forestlands most in need of treatment to reduce risks to ecological functions such as carbon storage, timber, water supply, and large tree habitat. The Priority Landscape – Reduce Wildfire Risk to Communities by Cal FIRE (2018) highlights lands where people and infrastructure are most vulnerable to wildfire, based on the intersection of housing density and FHSZs. For the Priority Landscape data, only the areas with the most risks in the region were factored into GRRAs. Finally, the Wildland Urban Interface (WUI) dataset (2025) maps areas of California’s WUI by classifying lands into Interface and Intermix according to housing density, vegetation cover, and Fire Hazard Severity Zones. Interface and Intermix zones factored into GRRAs.