Connecticut General Statutes Title 8. Zoning, Planning, Housing and Economic and Community Development § 8-2l. Zoning regulations re structures or uses located in floodplain

(1) Within a designated floodplain, encroachments resulting from fill, new construction or substantial improvements, as defined in 44 CFR Part 59.1, involving an increase in footprint to the structure shall be prohibited unless the applicant provides to the zoning commission certification by a state licensed engineer that such encroachment shall not result in any increase in base flood elevation;

(2) The water holding capacity of the floodplain shall not be reduced by any form of development unless such reduction (A) is compensated for by deepening or widening the floodplain, (B) is on-site, or if adjacent property owners grant easements and the municipality in which the development is located authorizes such off-site compensation, (C) is within the same hydraulic reach and a volume not previously used for flood storage, (D) is hydraulically comparable and incrementally equal to the theoretical volume of flood water at each elevation, up to and including the hundred-year flood elevation, which would be displaced by the proposed project, and (E) has an unrestricted hydraulic connection to the same waterway or water body; and

(3) Work within adjacent land subject to flooding, including work to provide compensatory storage, shall not result in any increase in flood stage or velocity.