Rankin County, MS Environmental Rules: Flood Zones (2026)

The Pearl River is Rankin County's defining flood hazard, especially along the western edge in Pearl and low-lying parts of Flowood near the Pearl River Wildlife Management Area. Major flood events include the April 1979 Easter Flood (crest 43.28 feet at Jackson), the February 2020 flood that inundated parts of Richland, Pearl, and north Flowood, and the August 2022 event. The Rankin-Hinds Pearl River Flood and Drainage Control District plus FEMA regulate development in the regulatory floodway and Special Flood Hazard Areas (100-year floodplain). Under the county and city floodplain ordinances, new construction in an SFHA must have the lowest floor elevated at least 1 foot above Base Flood Elevation (freeboard). Substantial improvements exceeding 50% of market value trigger full elevation compliance. Fill in the regulatory floodway is prohibited absent a no-rise certification. NFIP flood insurance is required for federally-backed mortgages in SFHA zones. Ross Barnett Reservoir itself is managed by PRVWSD under the 1958 compact and does not appear as a floodplain in the traditional sense, but Reservoir-area neighborhoods (Castlewoods, Grants Ferry) have specific flood elevation certifications tied to spillway operations.