CHAPTER 19

 

SENSITIVE AREA DISTRICT, SA

 

 

19.1    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.

 

19.2    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 underlying districts. To this end, any permitted use in a district overlaid by an SA District, with the exception of those uses permitted in Section 19.2 above, is a conditional use.  Conditional uses authorized in districts overlaid by the SA District remain condi­tional uses, and those use prohibited in the underlying the SA District shall also be prohibited in the SA District.

 

19.3    ARTIFICIAL OBSTRUCTIONS WITHIN A FLOODWAY PROHIBITED.

 

(1)       No artificial obstruction shall be located within any floodway, except as provided in Section 19.4.  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.

19.4    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.

 

19.5    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 Zoning Administrator 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.  Mobile home parks that are nonconforming because they are located within a floodway, shall be allowed to place mobile homes in such parks only if they comply with Chapter 10.

 

(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)       Notwithstanding any other provision of this chapter, no mobile home shall be located or relocated within that portion of the floodplain outside of the floodway, unless the following criteria is met:

 

(a)       Ground anchors for tie downs are provided in accordance with Chapter 10 of this ordinance;

 

(b)       The following tie-down requirements are met:

 

i           Over the top ties are required at each of the four corners of the mobile home, with one additional tie per side at an intermediate location, for mobile homes less than fifty (50) feet long.  Two additional ties per side are required for mobile homes more than fifty (50) feet long;

 

ii          Frame ties are required in conjunction with each over-the-top tie; and

 

iii         All components of the anchoring must be capable of carrying a force of 4,800 pounds;

 

(c)       Lots or pads are elevated on compacted fill or by any other method approved by the Building Inspector so that the lowest habitable floor of the mobile home is at or above the base flood level;

 

(d)       Adequate surface drainage and easy access for mobile home hauler is provided; and

 

(e)       Load-bearing foundation supports such as piers or pilings shall be placed in accordance with Chapter 10 of this code, except that if the support height is greater than seventy two (72) inches, the support must contain steel reinforcement.

 

(9)       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.

 

19.6    SETBACKS FROM STREAMS OUTSIDE DESIGNATED FLOODPLAINS.

 

(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.

 

19.7    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.