(A) Design criteria for structures.
(1) High water elevations. Structures must be placed in accordance with any floodplain regulations applicable to the site. Where these controls do not exist, the elevation to which the lowest floor, including basement, is placed or flood-proofed must be determined as follows:
(a) For lakes, by placing the lowest floor at a level at least three feet above the highest known water level, or three feet above the ordinary high water level, whichever is higher;
(b) For rivers and streams, by placing the lowest floor at least three feet above the flood of record, if data are available. If data are not available, by placing the lowest floor at least three feet above the ordinary high water level or by conducting a technical evaluation to determine effects of proposed construction upon flood stages and flood flows and to establish a flood protection elevation. Under all three approaches, technical evaluations must be done by a qualified engineer or hydrologist consistent with Minn. Rules parts 6120.5000 to 6120.6200 governing the management of floodplain areas. If more than one approach is used, the highest flood protection elevation determined must be used for placing structures and other facilities; and
(c) Water-oriented accessory structures may have the lowest floor placed lower than the elevation determined in this item, if the structure is constructed of flood-resistent materials to the elevation, electrical and mechanical equipment is placed above the elevation and, if long duration flooding is anticipated, the structure is built to withstand ice action and wind-driven waves and debris.
(2) Water-oriented accessory structures. Each lot may have one water-oriented accessory structure not meeting the normal structure setback in § 154.068(G) of this chapter if this water-oriented accessory structure complies with the following provisions.
(a) The structure or facility must not exceed ten feet in height, exclusive of safety rails, and cannot occupy an area greater than 250 square feet. Detached decks must not exceed eight feet above grade at any point.
(b) The setback of the structure or facility from the ordinary high water level must be at least ten feet.
(c) The structure or facility must be treated to reduce visibility as viewed from public waters and adjacent shorelands by vegetation, topography, increased setbacks or color, assuming summer, leaf-on conditions.
(d) The roof may be used as a deck with safety rails, but must not be enclosed or used as a storage area.
(e) The structure or facility must not be designed or used for human habitation and must not contain water supply or sewage treatment facilities.
(f) As an alternative for general development and recreational development waterbodies, water-oriented accessory structures used solely for watercraft storage, and including storage of related boating and water-oriented sporting equipment, may occupy an area up to 400 square feet; provided, the maximum width of the structure is 20 feet as measured parallel to the configuration of the shoreline.
(3) Stairways, lifts and landings. Stairways and lifts are the preferred alternative to major topographic alterations for achieving access up and down bluffs and steep slopes to shore areas. Stairways and lifts must meet the following design requirements.
(a) Stairways and lifts must not exceed four feet in width on residential lots. Wider stairways may be used for commercial properties, public open space recreational properties and planned unit developments.
(b) Landings for stairways and lifts on residential lots must not exceed 32 square feet in area. Landings larger than 32 square feet may be used for commercial properties, public open space recreational properties and planned unit developments.
(c) Canopies or roofs are not allowed on stairways, lifts or landings.
(d) Stairways, lifts and landing may be either constructed above the ground on posts or pilings or placed into the ground; provided, they are designed and built in a manner that ensures control of soil erosion.
(e) Stairways, lifts and landings must be located in the most visually inconspicuous portions of lots, as viewed from the surface of the public water assuming summer, leaf-on conditions, whenever practical.
(f) Facilities such as ramps, lifts or mobility paths for physically-handicapped persons are also allowed for achieving access to shore areas; provided that, the dimensional and performance standards of divisions (A)(3)(a) through (A)(3)(f) above are complied in addition to the requirements of Minn. Rules Ch. 1340.
(4) Significant historic sites. No structure may be placed in a significant historic site in a manner that affects the values of the site unless adequate information about the site has been removed and documented in a public repository.
(5) Steep slopes.
(a) The City Engineer must evaluate possible soil erosion impacts and development visibility from public waters before issuing a permit for construction of sewage treatment systems, roads, driveways, structures or other improvements on steep slopes.
(b) When determined necessary, conditions must be attached to issued permits to prevent erosion and to preserve existing vegetation screening of structures, vehicles and other facilities as viewed from the surface of public waters, assuming summer, leaf-on vegetation.
(B) Height of structures. All structures in residential districts, except churches and non- residential agricultural structures, must not exceed 30 feet in height.
(2002 Code, § 7.35) (Ord. 42, Fourth Series, effective 5-31-1992; Ord. 7, Seventh Series, passed 6-14-2014; Ord. 34, Eighth Series, effective 2-5-2023)