SENSITIVE AREA DISTRICT, SA
13.1 Purpose and Intent
13.2 Conditional Use
13.3 Artificial Obstructions Within a Floodway Prohibited
13.4 Permissible Uses Within Floodways
13.5 Construction Within Floodways and Floodplains
13.6 Setbacks from Streams Outside Designated Floodplains
13.7 Natural Drainage System Utilized to Extent Feasible
13.1 PURPOSE AND INTENT.
(1) The purpose of the SA Sensitive Area District is to designate and describe those areas within the municipality that possess physical and/or environmental characteristics which require special public consideration of use applications which might affect the structure or the land; the management of surface or subsurface water; safety of future land occupants due to increased fire, earthquake, or storm hazards from the proposed development or, the uneconomic extension of public facilities and services. Of specific concern is development in flood-prone areas, earthquake zones, landslide areas, areas of steep slope or unstable soils, wetlands, and other sensitive areas requiring careful assessment prior to alteration.
(2) It is the intent of these regulations to permit the widest possible latitude in the use of property, while at the same time requiring design solutions which will avoid detrimental impacts on sensitive natural areas, as well as provide protection from adverse natural forces and hazards.
13.2 CONDITIONAL USES.
(1) The SA Sensitive Area District is an overlay district whose sole effect is to require additional review of proposed uses in the underlaying districts. To this end, any permitted use in a district overlaid by an SA District, is a conditional use. Conditional uses authorized in districts overlaid by the SA District remain conditional uses, and those uses prohibited in the underlying the SA District shall also be prohibited in the SA District.
13.3 ARTIFICIAL OBSTRUCTIONS WITHIN A FLOODWAY PROHIBITED.
(1) No artificial obstruction shall be located within any floodway. For the purpose of this Chapter, an artificial obstruction is any obstruction, other than a natural obstruction, that is capable of reducing the water carrying capacity of a stream. A natural obstruction includes any rock, tree, gravel, or analogous natural matter that is an obstruction and has been located within the floodway by a nonhuman cause.
13.4 PERMISSIBLE USES WITHIN FLOODWAYS.
(1) No permit to make use of land within a floodway may be issued unless the proposed use is listed as permissible both in the underlying zoning district regulations and the following list:
(a) General farming, pasture, outdoor plant nurseries, horticulture, forestry, wildlife sanctuary, game farm, and other similar agricultural, wildlife, and related uses;
(b) Ground-level loading areas, parking areas, rotary aircraft ports, and other similar ground-level area uses,
(c) Lawns, gardens, play areas, and other similar uses; and
(d) Golf courses, tennis courts, driving ranges, archery ranges, picnic grounds, parks, hiking or horseback riding trails, open space, and other similar private and public recreational uses.
13.5 CONSTRUCTION WITHIN FLOODWAYS AND FLOODPLAINS RESTRICTED.
(1) No subdivision, planned unit development, building permit or conditional use permit shall be issued for any development within a floodplain until the Planning Commission has reviewed the plans of the development to assure that:
(a) The proposed development is consistent with the need to minimize flood damage;
(b) The area has had an evaluation by the U. S. Army Corp of Engineers to determine a classification as a wetlands;
(c) All public utilities and facilities such as water, sewer, gas electrical, and water systems are located and constructed to minimize or eliminate flood damage;
(d) Adequate drainage is provided to minimize or reduce exposure to flood hazards;
(e) All necessary permits have been received from those agencies from which approval is required by federal and state law; and
(f) A geological survey establishes fifty (50) and one hundred (100) year flood levels,
(2) No building shall be constructed and no addition to an existing building shall take place within any floodway.
(3) No new residential building shall be constructed and no substantial improvement of a residential building may take place within any floodplain unless the lowest floor (including basement) of the building or improvement is elevated to, or above the base flood level. Other structures shall comply with the following:
(a) Residential accessory structures shall be allowed within floodplains provided that they are firmly anchored to prevent flotation; and
(b) Anchoring of any accessory buildings shall be done by bolting the building to a concrete slab or by over-the-top ties. When bolting to a concrete slab, one-half inch bolts, six (6) feet on center with a minimum of two per side shall be required. If over-the-top ties are used, a minimum of two ties with a force adequate to secure the building is required.
(4) No new residential building shall be constructed and no substantial improvements of a nonresidential building shall take place within any floodplain unless the lowest floor (including basement) of the building or improvement is elevated or flood proof to, or above the base flood level. Where flood proofing is used in lieu of elevation, a registered professional engineer or architect shall certify that any new construction or substantial improvement has been designed to withstand the flood depths, pressure, velocities, impact, and uplift forces associated with the base flood at the location of the building and that the walls below the base flood level are substantially impermeable to the passage of water.
(5) For purposes of this Section, “substantial improvement” means for a building constructed prior to the effective date of this chapter, any repair, reconstruction, addition, or improvement of a building the cost of which equals or exceeds fifty (50) percent of the market value of the structure either:
(a) before the improvement or repair is started; or
(b) if the structure has been damaged and is being restored, before the damage occurred.
(6) “Substantial improvement” occurs when the first alteration on any wall, ceiling, floor, or other structural part of the building commences, whether or not that alteration affects the external dimensions of the building. The term shall not, however, include either:
(a) any project for improvement of a structure to comply with existing state or local health, sanitary, or safety code specifications that are solely necessary to insure safe living conditions; or
(b) any alteration of a building listed on the National Register of Historic Places or a State Inventory of Historic Places.
(7) No building permit or conditional use permit shall be issued for any development within a floodplain until the Building Inspector has reviewed the plans to assure that any new construction or substantial improvements shall be:
(a) Designed (or modified) and adequately anchored to prevent flotation collapse, or lateral movement of the structure;
(b) Constructed with materials and utility equipment resistant to flood damage; and
(c) Constructed by methods and practices that minimize flood damage.
(8) Whenever any portion of a floodplain is filled in with dirt, slopes shall be adequately stabilized to withstand the erosive force of the base flood.
13.6 SETBACKS FROM STREAMS OUTSIDE DESIGNATED FL000PLAINS.
(1) In any area that is located outside a designated floodplain but where a stream is located, no building or fill may be located within a distance of the stream bank equal to five times the width of the stream at the top of the bank or twenty (20) feet on each side, whichever is greater, or outside of the one hundred (100) year flood area if a geological survey has been conducted.
13.7 NATURAL DRAINAGE SYSTEM UTILIZED TO EXTENT FEASIBLE.
(1) To the extent practicable, all development shall conform to the natural contours of the land and natural and preexisting man-made drainage ways shall remain undisturbed. Drainage shall be directed to on-site containment and flow from there to the natural contours of the land.