Flood safety rules for new subdivisions and developments

(a) All subdivisions and other developments within areas of special flood hazards and flood prone areas where special flood hazard areas have not been defined, water surface elevations have not been provided, and there is insufficient data to identify the floodway or coastal high hazard areas but there are verifiable physical indications that such hazards are present as determined by the flood plain administrator, shall: (1) Be consistent with the need to minimize flood damage; (2) Have public utilities and facilities, such as sewer, gas, electrical, and water systems, located and constructed to minimize flood damage; and (3) Have adequate drainage provided to reduce exposure to flood damage. (b) All subdivision and other development applications shall identify the areas of special flood hazards and base flood elevations on the proposed site. If such information is not provided by the Flood Insurance Rate Maps, the director of public works may request and the applicant shall provide such information. (c) Finally approved subdivision plats for subdivisions within areas of special flood hazards shall provide base flood elevations within the lots. (d) All new subdivision proposals and other proposed developments within areas designated as Zone A or a flood prone area where special flood hazard areas have not been defined, water surface elevations have not been provided, and there is insufficient data to identify the floodway or coastal high hazard areas but the flood plain administrator has determined that there are verifiable physical indications that such hazards are present shall comply with the following: (1) Be reviewed to assure that all necessary permits have been received from those governmental agencies from which approval is required by Federal or State law, including section 404 of the Federal Water Pollution Control Act Amendments of 1972, 33 U.S.C. 1334; (2) For all proposed developments and/or subdivisions greater than either fifty lots or five acres, the developer and/or subdivider shall include base flood elevation data within their proposal. (3) Comply with the requirements of section 27-24. (e) All developments requiring a site drainage plan under section 25-2-72(3) shall submit such a plan for review and approval by the director of public works. The site drainage plan shall comply with sections 27-20(a) and (b) and section 27-24, and shall include a storm water disposal system to contain run-off caused by the proposed development, within the site boundaries, up to the expected one-hour, ten year storm event, as shown in the department of public works “Storm Drainage Standards,” dated October 1970, or any approved revision, unless those standards specify a greater recurrence interval. The amount of expected runoff shall be calculated according to the department of public works “Storm Drainage Standards,” dated October 1970, or any approved revision, or by any nationally- recognized method meeting with the approval of the director of public works. Runoff calculations shall include the effects of all improvements. (f) Storm water shall be disposed into drywells, infiltration basins, or other approved infiltration methods. The development shall not alter the general drainage pattern above or below the development. (1993, ord 93-78, sec 3; am 2001, ord 01-108, sec 1; am 2007, ord 07-169, sec 12.)27-20