(A) The following information shall be supplied in addition to the requirements in § 150.028 when the proposed subdivision is located within a flood hazard area as designated on the flood hazard boundary map in § 441 (refer to Ordinance 1488 Flooding) of these regulations. This information should be provided by the developer’s engineer:
(1) Additional topographic information for areas adjoining both sides of the channel;
(2) Three valley cross sections including the channel of the stream at points specified by the Village Engineer;
(3) Cross sections of the land to be occupied by the proposed development;
(4) High water information;
(5) Estimate of the discharge of the regional flood; and
(6) Determination of the specific flooding threat at the site of the proposed subdivision and determination of whether the subdivision is located in a floodway or flood fringe area by:
(a) Calculations of water surface elevations and flood protection elevations based upon a hydraulic analysis of the capacity of the stream channel and overbank areas to convey the regional flood. Flood protection elevations shall be one foot above the water surface elevations of the regional flood; or
(b) 1. Computation of the floodway required to convey this flood without increasing flood heights to an extent which would cause substantial upstream and/or downstream damage to existing development or reasonably anticipated future development.
2. Computations of increases in flood heights caused by any encroachment shall be based upon the reasonable assumption that there will be an equal degree of encroachment on both sides of the stream within that reach. Generally, any increase in flood stages attributed to encroachments on the floodplain of any river or stream shall not exceed six inches in any one reach or for the cumulative effect of several reaches.
(B) The Planning Commission shall transmit this information to the Village Engineer for technical assistance, where necessary, in evaluating the proposed project in relation to flood heights and velocities; evaluating the potential for flood damage to the proposed development and the village the adequacy of plans for protection against flood damage and other technical matters.
(Ord. 1235, passed 7-16-2002)