Floodplain Management

Virginia’s floodplain management program sets floodplain management zoning requirements for participation in the National Flood Insurance Program (NFIP). The federal government encourages state & local governments to establish more restrictive floodplain regulations [44 CFR 10.1(d)] & rewards these ‘higher standards’ through premium discounts for locality participation in the voluntary Community Rating System Program (CRS). The CRS incentivizes smart floodplain management.

Localities can adopt higher standards in ordinances to protect against SLR impacts. Resilient floodplains = reduced flooding, safer investments, enhanced natural beauty, & lower flood insurance premiums. Examples of higher standards in the floodplain: restricting or reducing development, incentivizing open space, adopting freeboard, prohibiting enclosures, adopting V Zone building standards in Coastal A Zone, adopting cumulative substantial improvement restrictions, limiting or prohibiting fill, protecting critical facilities, & setbacks.

Adopting locality specific floodplain management plans can help prioritize adaptation policies & programs & earn CRS credit.

Portsmouth: Portsmouth Floodplain Management Plan included as an addendum to Comp. plan. Gloucester: Floodplain Management Plan referenced in comprehensive plan.

Freeboard + limitation of fill: Virginia Beach Floodplain Ordinance (uses DRC model) - 2 feet freeboard + limits fill in southern part of City, minimizing impacts on floodplain storage volume.

Sample freeboard language: "New construction or substantial improvement ... shall have the lowest floor, including basement, elevated to a minimum of two (2) feet above the base flood level" (Virginia Beach)

Sample limitation language: "The combined areas of fill and mitigation shall not exceed five (5) percent of the total area within the floodplain located on the site that will incur the fill"

Expand the regulated floodplain by adopting higher standards in areas of less risk (outside FEMA designated floodplain): Several localities adopted V flood zone (3 + ft wave height) building standards in coastal A flood zone (< 3 ft wave height).

Gloucester County sample language: In the coastal high hazard area district (V, VE and Coastal A zones), the following regulations shall apply...

Freeboard in rural locality with low political will: Lancaster County - regulates to lowest horizontal structure member, rather than lowest floor.

Sample freeboard language: Buildings and structures within this zone shall have the lowest horizontal structural member or ductwork of the lowest floor… elevated to or above the base flood elevation plus 1.5 ft of freeboard


Charlotte-Mecklenburg County, NC: limits future flood risk in existing properties by prohibiting new development from increasing FEMA & Community Base Flood Elevations. Strategy I (Phase 1) of the County's Floodplain Management Guidance is to manage new development so that flood problems are not increased.

Cedar Falls, IA: expands the regulatory floodplain to include both the 100-year floodplain and 500-year floodplain, called the "Floodway Fringe Overlay District." Higher standards include: 1 foot of freeboard, based on the 500 year flood zone elevation. No critical facilities constructed in the floodway fringe overlay district. Fill is also limited: 3 foot maximum fill height and only in 1/3 of the lot area. Platting of lots is limited to keep large developments outside the 100 & 500 year flood zones.


Emergency Watershed Protection (USDA): up to 75% of emergency measures construction costs. Funds can be used for floodplain easements, jeopardized water control structures & public infrastructure, damaged vegetated buffer strips & more.

Hazard Mitigation Grants (FEMA): available for floodplain management strategies -  housing elevation, acquisition & relocation, green infrastructure, & more.

VA Clean Water Revolving Loan Fund: available/affordable (interest rates as low as 0%) - useful for projects where matching funds aren’t available; repayment required.

Watershed Protection & Flood Prevention Program (USDA): provides technical & financial assistance for planning & installing watershed projects.


Buildings meeting minimum NFIP requirements suffer approx. 80% less damage than buildings predating NFIP regulation enforcement. Localities can earn up to a 45% annual discount on flood insurance premiums in the CRS


Locality feedback: CRS program is beneficial, but compliance is time consuming & tedious; frustrating to work with slow response time from FEMA.

Locality feedback: Updated FEMA maps often expand floodplain to include more properties; this new requirement to buy flood insurance is potentially cost-prohibitive to homebuyers, thereby weakening real estate market

 
 

  • Participation in NFIP = flood insurance coverage for residents, businesses, locality + federal mitigation/disaster aid available pre & post events
  • Protecting undeveloped land in floodplains significantly reduces property damage (11-year study of 450 communities nationwide: $200,000 per year in property damage caused by floods) (Brody & Highfield, 2013)

  • Flood insurance premiums increasing due to NFIP $23 billion debt (no longer subsidizing rates)
  • No data on financial benefit of joining & excelling in CRS; quantifying benefits important to justify administrative costs of participation

  • Hard to incorporate life-cycle costs of developments in high risk zones

NFIP substantial damage or improvement requirement helps make structures more resilient to flooding. Requirement: damage/improvements where cost of restoring structure to its before-damaged or pre-improved condition equals or exceeds 50% of FMV of pre-damaged or pre-improved structure.

Higher standard: (1) Requiring substantial improvements are cumulative over specific # of years OR (2) Reducing the 50% threshold. Tool to monitor requirement: Southern Shores, NC requires building/floodplain development permit.

Building siting is important when adapting to SL. NFIP requirement: new development in V-Zones is “landward of the reach of the mean high tide.”

Higher standard: landward of a long-term erosion setback. Localities can increase setbacks & buffers over time to reflect updated SLR projections. See Resilient Zoning.

FEMA has recommended that buildings in flood zones subject to wave heights less than 3 feet are constructed to V Zone (3 ft wave heights) building standards.

Prohibiting all construction in the floodplain without acceptable mitigation measures can ensure resilience of future development + safeguard land with high ecological values for flood mitigation & floodwater absorption.

Strategic open space in floodplain: Identifying specific areas for acquisition &/or relocation = contiguous parcels = better absorb flood waters, reduce risk, & earn more CRS points

Rising sea levels = more frequent 100-year flood events = insufficient standard 

Higher standard: The California Department of Water Resources is now required to release 200-year floodplain maps for urban areas, with the intent of informing locality decisions on flood protection. Additionally, CA law requires that all levees must protect against a 200-year flood


1: Up to 2,042 points (Activity 430, Higher Regulatory Standards, Manual pg. 430-1):

Credit for regulations or ordinances that protect current & future development in the floodplain & protect natural floodplain functions. 15 higher standards eligible.

2: Up to 1,450 points (Activity 420, Open Space Preservation (OSP), pg. 420-3):

Credit for preserving open space in the floodplain.

3: Up to 650 points (Activity 430, Coastal A Zones (CAZ), pg. 430-32):

Credit for adopting some or all NFIP V-zone requirements in the coastal A-zone.


Code of Virginia, § 10.1-602:

Enabling language for DCR to manage locality programs

Code of Virginia, § 36-98:

Statewide Building Code shall not supersede local floodplain regulations adopted as a condition of participation in NFIP


Sample floodplain ordinance & high standards guidance (VDCR)

Coastal Virginia CRS Workgroup: Learn about how to join & succeed in the CRS.

Guide to the Community Rating System in VA (Wetlands Watch): informs localities on a range of actions to generate CRS credit.

FEMA Substantial Damage Estimator: for residential & nonresidential structures
Evaluation of the National Flood Insurance Program Final Report: evaluates the efficacy & cost/benefits of the regulation required by the NFIP.

FEMA supplemental guidance: benefit-cost analysis for floodplain & stream restoration projects.

Digital Coast elevation data: Inventory for the entire US

Watershed Management Optimization Tool (EPA): Tool for water resource managers to compare potential management options across watersheds, for cost-effectiveness & environmental sustainability. 


Brody, S., and Highfield, W., (2013). Open Space Protection and Flood Mitigation: A National Study. Land Use Policy. 32, 89-95.   Study under peer review

City of Alexandria, Va. . (2015). CRS Activity 510 Floodplain Management Plan Annual Report.

FEMA. (2013). Floodplain Management and the Endangered Species Act: A Model Ordinance. FEMA Region 10.

FEMA. (2013). National Flood Insurance Program Community Rating System Coordinator’s Manual.

FEMA. (2005). NFIP Floodplain Management Requirements: A Study Guide and Desk Reference for Local Officials . FEMA.

International Code Council. (2014). Reducing Flood Losses Through the International Codes: Coordinating Building Codes and Floodplain Management Regulations.

Silton, A., & Grannis, J. (2010). Stemming the Tide: How Local Governments Can Manage Rising Flood Risks . Georgetown Climate Center.

Wetmore, Bernstein, Conrad, DiVincenti, Larson, Plasencia, et al. (2006). The Evaluation of the National Flood Insurance Program Final Report. American Institutes for Research.