Adopt Higher Floodplain and Drainage Standards
To participate in FEMA’s National Flood Insurance Program (NFIP), Delaware local governments are required to adopt minimum floodplain standards. However, communities are encouraged to adopt higher floodplain standards to reduce flood damage and lower flood insurance premiums. Many adaptation activities earn a community more credit points in the National Flood Insurance Program’s (NFIP) Community Rating System (CRS). The CRS incentivizes adaptation activities that exceed the minimum NFIP requirements by offering discounted flood insurance premium rates to active communities. Depending on the level of safety provided through floodplain management activities that a community provides, premium discounts can range from 5%-45%.
FEMA identifies different types of flood zones based on flood risk. DNREC has developed several model floodplain ordinances for jurisdictions to adopt, depending on their flood zones. Communities that adopt ordinances with higher floodplain standards are better positioned for both flood readiness and NFIP premium discounts. Local officials should review the Delaware Model Ordinance NFIP Consistency Review Checklist and check with their city solicitor to ensure their regulations are in compliance with the standards and legally sound.
While minimum NFIP standards require that the lowest floor be elevated to the Base Flood Elevation (BFE), many Delaware jurisdictions have adopted ordinances requiring freeboard elevation above the BFE. According to FEMA, “freeboard” is a floodplain management strategy that involves elevating a structure’s lowest floor above predicted flood elevations by a small additional height (generally 1-3 feet above NFIP minimum height requirements). Elevating a home a few feet above legally mandated heights can significantly decrease the chance the property will be damaged by storms and flooding, protect it against the impacts of sea level rise, and reduce flood insurance premiums—sometimes as much as 50 percent.
This GIS Story Map explains the benefits of Freeboard as a floodplain management strategy:
The City of New Castle’s Code, in addition to 20 other communities, requires the lowest floor of structures in special flood hazard areas to be elevated 18 inches above the BFE. The Town of Henlopen Acres requires buildings to be elevated three feet above the BFE. A total of 17 jurisdictions in Delaware adopted 12 inches of freeboard. These ordinances are in accordance with one of the proposed floodplain standards resulting from Senate Bill 64 and earn local governments more points in the CRS, qualifying the community for greater discounts on insurance premiums.
Some citizens are averse to freeboard requirements, citing concerns over government intrusion. However, for many, obtaining reduced flood insurance rates and avoiding nearly inevitable flood impacts make freeboard a sensible design option, whether it is mandatory or optional. Jurisdictions that are considering the adoption of a freeboard ordinance need to consider conformity or compliance with existing laws and ordinances such as the Americans with Disabilities Act (ADA), building height restrictions, and historic preservation provisions.
A report on Delaware Floodplain and Drainage Standards and Recommendations finds that inadequate drainage standards and inconsistent local codes contribute to chronic and nuisance flooding throughout the state. In addition, a local drainage code is often confused with local stormwater management requirements. While stormwater management is planned at the onset of a land development plan, drainage problems may emerge due to blocked outlet conditions, deteriorating infrastructure, adverse impacts of land grading to adjacent properties, or lots being built upon with no or inadequate drainage outlets. It’s recommended that local jurisdictions coordinate the review and oversight of existing drainage patterns during both the subdivision planning and building permit processes. DNREC has prepared a Model Drainage Code that is designed to complement and be consistent with a community’s stormwater management standards. Six drainage standards have been recommended that address the need for:
- Easements to allow for future maintenance of all drainage conveyance systems
- Restrictions against obstructions in drainage conveyance systems
- Drainage conveyance systems within proposed subdivisions to meet the minimum 10-year storm event standards
- Lot grading standards to ensure adequate drainage
- Topographic plan submittals
- Requirement for as-builts with an approved topographic plan
Update Zoning and Building Codes
Review Zoning Codes
Zoning is a regulatory tool that controls the use of and development of land in a community. Local governments can use zoning to manage land use and prevent development in flood-prone areas. Assessing the Legal Toolbox for Sea Level Rise Adaption in Delaware, analyzes eight legal tools for adapting to sea level rise, including zoning and building restrictions, with discussion on their effectiveness and legal issues that may arise. It describes the use of downzoning to reduce the current intensity of land use and development in a zoning district to minimize the impact of flooding and sea level rise.
Overlay zoning, as described in Georgetown Climate Center’s Sea Level Rise Adaptation Tool Kit, enables local governments to impose additional regulatory requirements on an existing zone with special characteristics. Floodplain management overlay zones establish development regulations in addition to those prescribed within the existing zoning district where the property is located. These zones are intended to protect lives and property improvements from flood hazards, preserve the integrity of the floodway to carry floodwaters, preserve riparian vegetation along coastlines, and prevent displacement of floodwaters onto other properties. Other regulations could address the need for setbacks, limit the density or intensity of new development, or require that structures be retrofitted to be more resilient to floods. Elected officials should consult with their city solicitor and seek guidance from their OSPC circuit-rider planner prior to considering a zoning code or regulatory change.
Review Subdivision and Land Development Provisions
Local jurisdictions should review provisions within subdivision and land development ordinances to ensure that subdivisions are planned and designed to minimize risk of flood damage to property and safeguard lives. The preferred option, and a key recommendation the Delaware Floodplain and Drainage Advisory Committee (created through Senate Bill 64) is to avoid construction within floodplains rather than setting standards and allowing building in the floodplain. For example, subdivision and land development provisions within the Kent County (DE) Code prohibits the development on land located within the one-hundred year floodplain as identified on the current Federal Emergency Management Agency’s (FEMA) Flood Insurance Rate Maps (FIRMs). This land must remain unsubdivided, open space, or natural areas to minimize the potential damage to structures in areas vulnerable to flooding. Because many communities are concerned about home owner association (HOA) managed open space, the Delaware Floodplain and Drainage Advisory Committee recommended approaches that allow individual lots to extend into the floodplain, but would prohibit construction in that area.
The preferred option of avoiding construction, however, may not be realistic in coastal communities or historic, maritime towns situated along inland waterways. For example, using the 2014 FEMA approved flood map, 85% of the Town of Bethany Beach is now in a floodplain. Rather than avoiding construction in this town that relies on tourism and seasonal business, the most viable option is to protect existing structures and to create standards that meet and/or exceed NFIP guidelines for future construction. Decision makers have a difficult task of balancing the need to protect people and property along with respecting individual rights to improve and develop private property.
Review Building Codes
Often, flooding is considered a zoning code issue, but not adequately addressed within a jurisdiction’s building code. Building codes can be used to improve chances that structure will survive an extreme storm or flood event. A local jurisdiction’s building code should be reviewed to ensure adequate regulation of floor elevation requirements, building foundation, freeboard, and design and construction of building foundations to protect a building’s structural integrity. Regulations may also be adopted to prohibit the reconstruction of structures that are destroyed in flood or storm events and require buildings at risk of severe damage to be relocated.
FEMA recommends that jurisdictions update building codes to incorporate flood resistant provisions of the International Codes® (I-Codes), the referenced standard American Society of Civil Engineers (ASCE) 24, Flood Resistant Design and Construction, and the National Flood Insurance Program (NFIP) requirements. Building codes should also be integrated with floodplain management regulatory processes. For example, if a jurisdiction has implemented freeboard regulations, it needs to ensure that other building code regulations (e.g. setbacks, building height) are consistent with this higher standard.