(A) These standards apply to riverine regulatory floodplains without a regulatory floodway.
(B) The applicant shall obtain approval from IDNR/OWR for all development any portion of which is located partially or completely within the regulatory floodplain (without a delineated regulatory floodway) with a tributary drainage area of 640 acres or more.
(1) The development shall not singularly or cumulatively result in an obstruction of flood flows or potential flood damages outside the site due to an increase in flood heights, velocities or loss of floodplain area storage.
(2) A professional engineer shall submit a study that demonstrates one of the following:
(a) Determine a floodway which meets the definition of a regulatory floodway and demonstrate that the proposed development meets the floodway standards in § 55.064; or
(b) Determine a BFE and demonstrate that the proposed development will maintain the existing conditions conveyance, will not increase flood velocities, will not increase flood profiles and will compensate for any lost floodplain storage.
(Res. 02-441, passed 10-17-2002; Res. 02-495, passed 11-21-2002; Res. 04-87, passed 3-17-2004)