Sebastian County, AR Environmental Rules: Stormwater Management (2026)

Sebastian County handles stormwater and drainage control for the unincorporated county through Chapter 151, Flood Damage Prevention, rather than a stand-alone stormwater ordinance. A floodplain development permit under Section 151.12 is required before any structural development, clearing, grading, mining, drilling, dredging, placement of fill, excavating, watercourse alteration, drainage improvement, roadway or bridge construction, or individual water or sewer installation inside a mapped special flood hazard area. Anyone platting a new subdivision, commercial business park, or manufactured home park in the county must go further: Section 151.20(R) requires the plat to include an adequate drainage plan that reduces the development's exposure to flood hazards, and Section 151.20(Q) requires those same proposals to locate and build sewer, gas, electrical and water systems to minimize flood damage.

Where a structure sits on sloped ground in an AH or AO risk zone, Section 151.21(C)(5) adds a further duty to build in drainage paths around the structure that guide floodwaters around and away from it. The Floodplain Administrator reviews every permit application against the factors in Section 151.11(D), including whether the project will change flooding patterns, change erosion rates, or sweep debris onto other land, and can deny a permit on that basis. Before anyone alters or relocates a watercourse, Section 151.11(F) requires the Administrator to notify adjacent communities and the Arkansas Natural Resources Commission at least 60 days ahead and send FEMA proof of that notice, and Section 151.11(G) bars any alteration that would reduce the channel's flood-carrying capacity or harm other land.

A permit denial can be appealed under Section 151.13(C) to the county's Appeal Board, made up of the County Judge, the County Assessor, and a member of the Western River Valley Board of Realtors.