Warrick County, IN Environmental Rules: Flood Elevation Requirements (2026)

Warrick County Code Chapter 56 defines the terms that drive flood-elevation compliance in unincorporated Warrick County. Under § 56.05, BASE FLOOD ELEVATION is "the elevation delineates the flooding level from the 100-year flood," and the county layers a safety margin on top of it: FLOOD PROTECTION GRADE, or FPG, is defined as the base flood elevation plus two feet, giving the county its own two-foot freeboard benchmark above FEMA's 100-year line. The REGULATORY FLOOD, also called the Base Flood, is defined as the flood with a one percent annual chance of being equaled or exceeded, as shown on the Federal Insurance Rate Maps (FIRMs) or as approved by the Local Floodplain Administrator, the Executive Director of the Warrick County Area Plan Commission.

Anyone submitting a drainage plan for review must translate those definitions onto paper: § 56.12 requires the site drawings to show floodplains "as shown on Flood Insurance Rate Maps (FIRMs) with the FIRM panel noted, along with the regulatory base flood elevation and the regulatory flood zone," so the Drainage Board can confirm a project respects the mapped hazard before approving construction. Freeboard also governs engineered stormwater structures directly: § 56.21(D)(2) requires detention and retention basin design to carry "a minimum freeboard of one-half foot above the calculated maximum of the design storm detention high water level to the elevation of the emergency overflow spillway," a distinct, smaller freeboard standard that applies to pond and spillway design rather than to a building's lowest floor.