Sherman, TX Environmental Rules: Flood Zones (2026)

Article 3.12 of the Sherman Code, Flood Damage Prevention, governs building in flood hazard areas of the City of Sherman, Texas. Section 3.12.006 applies it to all areas of special flood hazard within city limits and the city's extraterritorial jurisdiction. Section 3.12.007 adopts the FEMA Flood Insurance Study for Grayson County, Texas and Incorporated Areas dated September 1, 2022, with its flood insurance rate maps and later revisions, plus areas not yet mapped but known to be flood hazard areas. The city engineer is the floodplain administrator under section 3.12.041.

Section 3.12.043 requires a floodplain development permit for all proposed development in a floodplain, issued by the engineering department. The application goes to the floodplain administrator on city forms and can include scaled plans showing landscape alterations including fences, existing and proposed structures, the lowest floor elevation of new and substantially improved structures, and the floodproofing elevation of any nonresidential structure. It can also require an engineer or architect certificate for floodproofed nonresidential structures, a description of any watercourse alteration, a HEC-RAS or equivalent model showing no negative impact outside the project area, and a CLOMR approved by the floodplain administrator and FEMA where required. Section 3.12.042 lets the city require a third-party review fee depending on project complexity.

The administrator approves or denies on listed factors, including danger to life and property from flooding or erosion, susceptibility of the facility to flood damage, safety of access in times of flood for ordinary and emergency vehicles, and availability of alternative locations not subject to flooding. Variances go to the board of adjustments under section 3.12.044, which bars any variance in a designated floodway if flood levels would rise during the base flood discharge. Section 3.12.072 also bars importing fill into the 1% annual chance floodplain, with a sand exception for an approved foundation. Substantial improvement means work costing 50 percent or more of the structure's market value.