Iowa Admin. Code r. 571-16.18
This rule provides for exemptions from the general requirement in Iowa Code section 462A.27 that nonpermanent structures be removed on or before December 15 of each year Docks and other structures subject to destruction or damage by ice movement must be removed. Where a dock may be left in ice without damage to the dock, it must have reflective material visible from all directions to operators of snowmobiles, other motorized machines, or wind-propelled vessels lawfully operated on the frozen surface of the water body. Generally, ice damage is greatest on Iowa's rivers and natural lakes. Docks must be removed by December 15 of each year unless they have the required reflective materials and are specifically exempted by a condition of a dock permit or are located in one of the areas listed as follows: artificial lakes; Upper Gar Lake; canals off West Okoboji Lake; Okoboji Harbor; Lazy Lagoon portion of Triboji dock management area; Smith's Bay on West Okoboji Lake; area between the trestle and U.S. Highway 71 bridges on Okoboji lakes; Templar Park on Big Spirit Lake; Venetian Village Canal and Harbourage Inlet on Clear Lake; Casino Bay of Storm Lake; Black Hawk Marina at Black Hawk Lake; and canals off Lake Manawa and Carter Lake. A permit shall not authorize an exception from the winter removal requirement unless the applicant provides adequate documentation that the dock will not be damaged by normal ice movement.
Iowa Admin. Code r. 571-16.18