Federal Emergency Management Agency (FEMA) manages the National Flood Insurance Program (NFIP) and the Canadian County Flood Damage Prevention Regulations are based on NFIP standards for development. Development as defined by the NFIP and listed in our regulations is "Any man-made change to improved or unimproved real estate, including but not limited to buildings or other structures, mining, dredging, filling, grading, paving, excavation or drilling operations or storage of equipment or materials". In 2020 FEMA issued a policy clarifying that agricultural and accessory structures are considered non-residential and are not exempt from NFIP floodplain management requirements as per the definitions of said structures listed in this policy.
Development in the floodplain falls in to one of the following six categories:
1. CONSTRUCTION. Construction is the act by which land is changed by the intervention of man or any man-made change to improved or unimproved real estate. Construction is commonly applied to the erection of buildings and other structures; however, it also includes any action that results in a man-made change to the existing character of a parcel of land.
Floodplain construction may take several forms:
a. Construction, reconstruction, repair, replacement, rehabilitation, or any addition to a
building.
Residential, Non-residential/Commercial, Accessory (parking and storage only, less than 600 sq ft) and Agricultural buildings (that do not meet the exclusive use requirement of the NFIP definition of agricultural structure, such as a residence, public use buildings or multi-use building).
b. Installing a manufactured home on a site or installing a travel trailer or recreational vehicle on a site (for more than 180 days).
c. Construction or erection of levees, dikes, walls, and fences.
d. Mining, dredging, drilling operations, construction of roads, bridges, jetties, or similar projects.
2. FILLING. Filling is the act by which a parcel of land is built-up by the placement of earth, gravel, or man-made substance (i.e., concrete, rubble, trash, etc.).
Placing fill in a floodplain reduces its capacity to store water and can result in higher flood elevations or increased velocities elsewhere in the community, thereby causing new or increased damages.
3. GRADING. Grading or regrading is the act of sloping or shaping the earth's surface. It may be for creating hills or berms or sloping to provide for positive drainage. While grading may not affect storage, it can block conveyance. In addition, grading to remove meanders from a stream or clearing out a channel bottom may cause the velocity of the stream to increase. Increased velocities can increase the danger to lives, increase damage to buildings and structures, and cause erosion. (Such as the redistribution of dirt for a pond.)
4. EXCAVATING. Excavating is the act of removing a portion of the floodplain. Excavation may involve the removal of soil completely from the floodplain or depositing it in another portion of the floodplain. If the borrowed material is placed in another part of the floodplain, conveyance could be affected. In addition, excavation could seriously affect stream or water quality or downstream erosion. (Such as the removal of dirt for a pond.)
5. PAVING. Paving is the act of hardening the surface of a parcel or part of a parcel of land, most often with man-made materials. While paving may not directly affect the flood elevation at the site, it can increase the runoff and velocity which can create downstream erosion and increased flood heights.
6. STORAGE. Storage includes placing supplies, materials, or equipment below the base flood elevation in a floodplain. The community should pay particular attention to the storage of
toxic, flammable, and buoyant materials since they pose a threat to human life and safety.
