Requirements
To protect life and property, promote open space and habitat conservation, and enhance water quality and natural hydrological systems.
Option 1. Sites without floodplains
Locate on a site that does not contain any land within a 100-year high- or moderate-risk floodplain as defined and mapped by the Federal Emergency Management Agency (FEMA) (or a local equivalent for projects outside the U.S.) or a state or local floodplain management agency, whichever is more recent. For projects in places without legally adopted flood hazard maps or legal designations, locate on a site that is entirely outside any floodplain subject to a 1% or greater chance of flooding in any given year.
OR
Option 2. Infill or previously developed sites with floodplains
Locate the project on an
infill site or a previously developed site or in a nonconveyance area of river or coastal floodplain without storm surge potential where compensatory storage is used in accordance with a FEMA-approved mitigation plan (or a local equivalent for projects outside of the U.S.). Comply with the National Flood Insurance Program (NFIP) requirements (or a local equivalent for projects outside of the U.S.) for developing any portions of the site that lie within a 100-year high-or moderate-risk floodplain, as defined in Option 1. If the project includes construction of any critical facility, such as a hospital, water and sewage treatment facility, emergency center, or fire or police station, the critical facility must be designed and built so as to be protected and operable during a 500-year event.
OR
For any portion of the site within the flood hazard area, design buildings in accordance with American Society of Civil Engineers Standard 24-05 (ASCE 24). If the project includes construction of a critical facility that is intended to remain operational in the event of a flood, or whose function is critical for post flood recovery, design the facility to be protected and operable at the floodwater levels specified in ASCE 24, or at the water levels represented by a 0.2% annual chance (500-year) flood, whichever is higher. For the purpose of this requirement, critical facilities include, but are not limited to, hospitals, emergency operations centers, building or portions of buildings designated as emergency shelters, water and sewage treatment facilities, and fire and police stations.
OR
Option 3. All other sites with floodplains
If any part of the site is located within a 100-year high- or moderate-risk floodplain, as defined above, develop only on portions of the site that are not in the floodplain, or that have been previously developed, or that are in a nonconveyance area of river or coastal floodplain without storm surge potential where compensatory storage is used in accordance with a FEMA-approved mitigation plan (or a local equivalent for projects outside of the U.S.).
Previously developed portions in the floodplain must be developed according to NFIP requirements (or a local equivalent for projects outside of the U.S.). If development includes construction of any critical facility, as described above, the critical facility must be designed and built so as to be protected and operable during a 500-year event.
OR
For any portion of the site within the flood hazard area, design buildings in accordance with American Society of Civil Engineers Standard 24-05 (ASCE 24) or local floodplain management entity. If the project includes construction of a critical facility that is intended to remain operational in the event of a flood, or whose function is critical for post flood recovery, design the facility to be protected and operable at the floodwater levels specified in ASCE 24, or at the water levels represented by a 0.2% annual chance (500-year) flood, whichever is higher. For the purpose of this requirement, critical facilities include, but are not limited to, hospitals, emergency operations centers, building or portions of buildings designated as emergency shelters, water and sewage treatment facilities, and fire and police stations.
