Standards for Streams Without Base Flood Elevations and Floodways

Standards for Streams Without Base Flood Elevations and Floodways. When base flood elevation data and floodway data are not available in accordance with Part 208, Rule 3.1, in Special Flood Hazard Areas and Community Flood Hazard Areas without base flood elevation data, new construction and substantial improvements shall be elevated or floodproofed to elevations established by the community. The following provisions in addition to the standards of Part 208, Rule 5.1 and the enclosure standards of Part 208, Rule 5.2 (4) shall apply: (1) Require that all new subdivision proposals and other proposed developments (including proposals for manufactured home parks and subdivisions) greater than five (5) lots or five (5) acres, whichever is lesser, include within such proposals base flood elevation data; (2) The Floodplain Administrator shall obtain, review, and reasonably utilize any base flood elevation and floodway data available from a federal, state, or other source, in order to administer the provisions of Part 208, Rule 5. When such data are available, standards of Part 208, Rule 5.2, shall apply. If data is not available from Part 208, Rule 5.2 (1) or outside sources, then the following provisions shall apply. 3986829.1/00520.00006 (3) No encroachments, including fill material or other development, shall be located within a distance of the stream bank equal to five times the width of the stream at the top of the bank or twenty feet each side from the top of the bank, whichever is greater, unless certification by a registered professional engineer is provided demonstrating that such encroachment shall not result in any increase in flood levels during the occurrence of the base flood discharge. The enclosure standards of Part 208, Rule 5.2 (4) shall apply. (4) Fill within the area of special flood hazard shall result in no net loss of natural floodplain storage. The volume of loss of floodwater storage due to filling in the special flood hazard area shall be offset by providing an equal volume of flood storage by excavation or other compensatory measures at or adjacent to the development site. (5) Notify, in riverine situations, adjacent communities and the State Coordinating Office prior to any alteration or relocation of a watercourse and submit copies of such notifications to FEMA. Assure that the flood carrying capacity within the altered or relocated portion of any watercourse is maintained. (6) Require that all manufactured homes be placed or installed using methods and practices which minimize flood damage. Manufactured homes must be elevated and anchored to resist flotation, collapse, or lateral movement. Dry stacked blocks (stacked without the use of mortar or cement to bond them together) are not allowed within the Special Flood Hazard Area.