603. E-1.1 PREPARING FOR AND RESPONDING TO NATURAL HAZARDS

603 E-1.1 PREPARING FOR AND RESPONDING TO NATURAL HAZARDS 603.1 In the coming decades, changing climate is likely to increase tidal flooding, cause more heavy rainstorms, and increase risks to human health. Portions of Washington, DC are within the Federal Emergency Management Agency (FEMA) designated 100-year flood plain and are subject to inundation during hurricanes and other severe storms, and as a result of sea level rise, some low-lying areas are subject to minor, recurrent flooding. Low-lying interior areas may experience more frequent and severe stormwater flooding events. It is important to use an equity lens to assess natural hazards and climate risks by race, income, and vulnerability to develop and implement strategies that result in equitable environmental outcomes. 603.2 Undeveloped floodplain areas can provide significant flood protection, allowing floods to pass through those areas while causing minimal harm. When development does occur in floodplain areas, floodplain regulations help ensure individuals living and doing business in those areas comply with safe building practices designed to prevent injury, loss of life, and property damage from flooding. Washington, DC’s current floodplain regulations apply only to the FEMA-designated 100-year floodplain. 603.3 However, communities across the country are experiencing floods that reach beyond the extents of the 100-year floodplain with increasing regularity. What is now considered a 100-year rainfall event will become considerably more common in the years to come, and interior flooding events from significant storms may increase Given these trends, expanding the regulated floodplain areas in Washington, DC beyond the 100-year floodplain will be an important step in ensuring Washington, DC is resilient to increased flood risk. Additional flood adaptation measures include integrating new natural shorelines and buffers, reducing erosion, replacing undersized culverts, and keeping streambeds free of debris. 603.4 Furthermore, increasing urbanization that replaces vegetated space with concrete and pavement can result in heat islands, or spaces that reach higher temperatures and retain heat longer than the surrounding areas and can reduce local health quality and negatively impact air quality. 603.5 Policy E-1.1.1: Resilience to Climate Change as a Civic Priority Advance the District’s resilience to climate change as a major civic priority, to be supported through improved mitigation, adaptation, and human preparedness. 603.6 Policy E-1.1.2: Urban Heat Island Mitigation Wherever possible, reduce the urban heat island effect with cool and green roofs, expanded green space, cool pavement, tree planting, and tree protection efforts, prioritizing hotspots and those areas with the greatest number of heat-vulnerable residents. Incorporate heat island mitigation into planning for GI, tree canopy, parks, and public space initiatives. See Map 6.1 for Average Land Surface Temperature July 2014-2018. 603.7 Policy E-1.1.3: Natural Assets and Ecosystems for Hazard Mitigation Expand and leverage the ability of natural landscape features, such as vegetated land cover and wetlands, and the beneficial ecosystem services they provide to mitigate natural hazards. This includes supporting and encouraging design and construction choices that conserve, restore, and enhance the protective functionality of natural assets to absorb, reduce, or resist the potentially damaging effects of wind, water, and other hazard forces. Such approaches, including natural shorelines, should be incorporated into all waterfront development projects, where possible. 603.8 Policy E-1.1.4: Non-Structural Land Uses Incorporate non-structural uses within designated special flood hazard areas to help protect and enhance the natural and beneficial functions of floodplains, wetlands, and other undeveloped landscape features. These uses include but are not limited to parks, recreation areas, and permanently protected open spaces. 603.9 Policy E-1.1.5: Resilient Infrastructure Design infrastructure, such as roads and parks, to withstand future climate impacts, and increase Washington, DC’s’ resilience by having roads and parks serve multiple purposes where possible, including flood risk reduction, urban heat island mitigation, and stormwater management. See the Infrastructure Element for more information on resilient infrastructure. 603.10 Policy E-1.1.6: Floodplains, Waterfronts, and Other Low-Lying Areas Consistent with the Federal Elements of the Comprehensive Plan, prohibit activities within floodplains, waterfronts, and other low-lying areas that could pose public health or safety hazards in the event of a flood. Regulation of land uses in floodplains, waterfronts, and other low-lying areas should consider the long-term effects of climate change—including sea level rise, increasingly heavy rain events, and more severe coastal storms—on flood hazards. 603.11 Action E-1.1.A: Update Regulations for Resilience Continue to monitor and update Washington, DC’s regulations to promote flood risk reduction, heat island mitigation, stormwater management, renewable energy, and energy resilience, among other practices, where appropriate. 603.12 Action E-1.1.B: Development in Floodplains Evaluate expanding restrictions and/or require adaptive design for development in areas that will be at increased risk of flooding due to climate change. Analyses should weigh the requirement to account for climate risks with the needs of a growing District. 603.13 Action E-1.1.C: Waterfront Setbacks Ensure that waterfront setbacks and buffers account for future sea level rise, changes in precipitation patterns, and greater use of nature-based and adaptive flood defenses. 603.14 Action E-1.1.D: Covenant for Climate and Energy Implement policies recommended by Clean Energy DC and Climate Ready DC to achieve Washington, DC’s goal of reducing GHG emissions by 50 percent below 2006 levels by 2032, and achieving carbon neutrality by 2050 while preparing for the impacts of climate change. Maintain compliance with the Global Covenant of Mayors for Climate & Energy, signed by Washington, DC in 2015, which commits Washington, DC to measure and reduce GHG emissions and address climate risks. 603.15 Action E-1.1.E: Update Floodplain Regulations Update flood hazard rules to reflect the increased risk of flooding due to climate-related sea level rise, increasingly frequent and severe precipitation events, and coastal storms. 603.16 Action E-1.1.F: Comprehensive and Integrated Flood Modeling Develop, and regularly update, Washington, DC’s floodplain models, maps, and other tools to account for climate change, including projections for increased precipitation and sea level rise, to ensure any future building in the floodplain is done sustainably. Integrate existing, and develop new, floodplain models to better understand the interplay between coastal, riverine, and interior flooding and potential climate impacts. Consider revising the regulatory flood hazard areas for Washington, DC’s Flood Hazard Rules. 603.16a Text Box: Flood Elevations In new or substantially renovated buildings, design flood elevation is the minimum height at which residential units may be constructed and utilities like the boiler, the water heater, and electrical equipment may be located. It also sets the minimum height for dry or wet flood-proofing measures for buildings generally. The margin between this and the base flood elevation is called freeboard. 603.17 Action E-1.1.G: Design Guidelines for Resilience Develop guidelines for new development and substantial land improvements that consider the threat of naturally occurring stressors and hazards (e.g., flooding, extreme heat, and wind), determine potential impacts to assets over the expected life cycle of the asset, and identify cost-effective risk-reduction options. Use updated and integrated flood risk models to determine potential flood extents and depths for riparian, coastal, and interior flood events and to inform design flood elevations for a development in flood hazard areas. 603.18 Action E-1.1.H: Update Climate Vulnerability and Risk Assessment Update the vulnerability and risk assessment completed for Climate Ready DC as new data on potential climate impacts becomes available. Regularly assess the vulnerability of infrastructure, critical facilities (including hospitals and emergency shelters), vulnerable populations, and large developments to climate-related hazards. 603.19 Action E-1.1.I: Resiliency Evaluation Review projects including Washington, DC capital projects and large-scale developments, for potential climate risks and adaptation strategies. 603.20 Action: E-1.1.J: Resiliency Incentives Expand existing incentives and regulations to include thermal safety and urban heat island mitigation measures, such as green and cool roofs, solar shading, shade trees, alternatives to concrete, and other innovative building design strategies. 603.21 Action: E-1.1.K: Interagency Temperature Management Strategy Develop an interagency heat management strategy to minimize the adverse health impacts associated with extreme cold and heat temperature days. The District government will work to ensure that residents can prepare for these events by more broadly communicating extreme heat and cold response plans that clearly define specific roles and responsibilities of government and nongovernmental organizations before and during these events. Plans should identify local populations at high risk for extreme temperature-related illness and death and determine the strategies that will be used to support such individuals during emergencies, particularly in underserved communities. Furthermore, explore strategies, including the use of technology, to help build communities’ adaptive capacity before, during, and after extreme temperature days. SOURCE: District of Columbia Comprehensive Plan Act of 1984, effective April 10, 1984 (D.C. Law 5-76; 31 DCR 1049 (March 9, 1984)); as amended by District of Columbia Comprehensive Plan Act of 1984 Land Use Element Amendment Act of 1984, effective March 16, 1985 (D.C. Law 5-187; 32 DCR 873 (February 15, 1985)); as amended by District of Columbia Comprehensive Plan Amendments Act of 1989, effective May 23, 1990 (D.C. Law 8-129; 37 DCR 55 (January 5, 1990)); as amended by District of Columbia Comprehensive Plan Amendments Act of 1989 NCPC-Recommended Amendments, and Closing of Public Alleys in Square 669, S.O. 88-452, Act of 1990, effective May 23, 1990 (D.C. Law 8-132; 37 DCR 2213 (April 6, 1990)); as amended by District Government Land Use Temporary Amendment Act of 1994, effective October 1, 1994 (D.C. Law 10-190; 41 DCR 5360 (August 12, 1994)); as amended by Comprehensive Plan Amendments Act of 1994, effective October 6, 1994 (D.C. Law 10-193; 41 DCR 5536 (August 19, 1994)); as amended by District of Columbia Comprehensive Plan Act of 1984 Land Use Amendment Act of 1994, effective March 21, 1995 (D.C. Law 10-235; 42 DCR 30 (January 6, 1995)); as amended by Technical Amendments Act of 1996, effective April 18, 1996 (D.C. Law 11-110; 43 DCR 530 (February 9, 1996)); as amended by Second Technical Amendments Act of 1996, effective April 9, 1997 (D.C. Law 11-255; 44 DCR 1271 (March 7, 1997)); as amended by Comprehensive Plan Amendment Act of 1998, effective April 27, 1999 (D.C. Law 12-275; 46 DCR 1441 (February 19, 1999)); as amended by Technical Amendments Act of 1999, effective April 12, 2000 (D.C. Law 13-91; 47 DCR 520 (January 28, 2000)); as amended by Comprehensive Plan Amendment Act of 2006, effective March 8, 2007 (D.C. Law 16-300; 54 DCR 924 (February 2, 2007)); as amended by Technical Amendments Act of 2008, effective March 25, 2009 (D.C. Law 17-353; 56 DCR 1117 (February 6, 2009)); as amended by Comprehensive Plan Amendment Act of 2010, effective April 8, 2011 (D.C. Law 18-361; 58 DCR 908 (February 4, 2011)); as amended by Comprehensive Plan Amendment Act of 2021, effective August 21, 2021 (D.C. Law 24-20; 68 DCR 006918 (July 16, 2021)). District of Columbia Municipal Regulations Comprehensive Plan 10-A DCMR § 603