§ 18-75. Provisions for flood hazard reduction.

(a)

Methods of reducing flood losses . In order to accomplish its purposes, this division includes methods and provisions for:

(1)

Restricting or prohibiting uses which are dangerous to health, safety and property due to water or erosion hazards or which result in damaging increases in erosion or in flood heights or velocities;

(2)

Requiring that uses vulnerable to floods, including facilities which serve such uses, be protected against flood damage at the time of initial construction;

(3)

Controlling that alteration of natural floodplain stream channels and natural protective barriers which help accommodate or channel floodwaters;

(4)

Controlling filling, grading, dredging and other development which may increase flood damage; and

(5)

Preventing or regulating the construction of flood barriers which will unnaturally divert floodwater or which may increase flood hazards in other areas.

(b)

General standards . In all areas of special flood hazards the following standards are required:

(1)

All new construction and substantial improvements shall be anchored to prevent flotation, collapse or lateral movement of the structure.

(2)

All mobile homes shall be anchored to resist flotation, collapse or lateral movement by providing over-the-top and frame ties to ground anchors. Special requirements shall be that:

a.

Over-the-top ties be provided at each of the four corners of the mobile home, with two additional ties per side at intermediate locations, with mobile homes less than 50 feet long requiring one additional tie per side;

b.

Frame ties be provided at each corner of the home with five additional ties per side at intermediate points, with mobile homes less than 50 feet long requiring four additional ties per side;

c.

All components of the anchoring system be capable of carrying a force of 4,800 pounds; and

d.

Any additions to the mobile home be similarly anchored.

(3)

All new construction and substantial improvements shall be constructed using methods and practices that minimize flood damage.

(4)

All new and replacement water supply systems shall be designed to minimize or eliminate infiltration of floodwaters into the system.

(5)

New and replacement sanitary sewage systems shall be designed to minimize or eliminate infiltration of floodwaters into the systems and discharge from the systems into floodwaters.

(6)

On-site waste disposal systems shall be located to avoid impairment to them or contamination from them during flooding.

(c)

Specific standards . In all areas of special flood hazards where base flood elevation data have been provided as set forth in sections 18-24(b) and 18-47(b)(4) the following standards are required:

(1)

Residential construction.

a.

New construction and substantial improvements of any residential structure shall have the lowest floor, including basement, elevated to or above base flood elevation.

b.

For new mobile home parks and mobile home subdivisions; for expansions to existing mobile home parks and mobile home subdivisions; for existing mobile home parks and mobile home subdivisions where the repair, reconstruction or improvement of the streets, utilities and pads equals or exceeds 50 percent of value of the streets, utilities and pads before the repair, reconstruction or improvement has commenced; and for mobile homes not placed in a mobile home park or mobile home subdivision, require that:

1.

Stands or lots are elevated on compacted fill or on pilings so that the lowest floor of the mobile home will be at or above the base flood level;

2.

Adequate surface drainage and access for a hauler are provided; and

3.

In the instance of elevation on pilings, that:

(i)

Lots are large enough to permit steps;

(ii)

Piling foundations are placed in stable soil and no more than ten feet apart; and

(iii)

Reinforcement is provided for pilings more than six feet above the ground level.

c.

No mobile home shall be placed in a floodway, except in an existing mobile home park or an existing mobile home subdivision.

(2)

Nonresidential construction . New construction and substantial improvement of any commercial, industrial or other nonresidential structure shall either have the lowest floor, including basement, elevated to the level of the base flood elevation, or together with attendant utility and sanitary facilities, shall be floodproofed so that below the base flood level the structure is watertight with walls substantially impermeable to the passage of water and with structural components capable of resisting hydrostatic and hydrodynamic loads and effects of buoyancy. A registered professional engineer or architect shall submit a certification that the standards of this subsection are satisfied. Such certifications shall be provided to the official as set forth in section 18-47(b)(6).

(d)

Subdivision proposals.

(1)

All subdivision proposals shall be consistent with the need to minimize flood damage;

(2)

All subdivision proposals shall have public utilities and facilities such as sewer, gas, electrical and water systems located and constructed to minimize flood damage;

(3)

All subdivision proposals shall have adequate drainage provided to reduce exposure to flood damage; and

(4)

Base flood elevation data shall be provided for subdivision proposals and other proposed development which contain at least 50 lots or five acres (whichever is less).

(e)

Floodways . Located within areas of special flood hazard established in section 18-24(b) are areas designated as floodways. Since the floodway is an extremely hazardous area due to the velocity of floodwaters which carry debris, potential projectiles and erosion potential, the following provisions apply:

(1)

Encroachments shall be prohibited, including fill, new construction, substantial improvements and other developments unless a technical evaluation demonstrates that encroachments shall not result in any increase in flood levels during the occurrence of the base flood discharge.

(2)

If section 18-75(e)(1) is satisfied, all new construction and substantial improvements shall comply with all applicable flood hazard reduction provisions of section 18-75(b) through (d).

(Code 1977, § 11½-7; Ord. No. 32A, 5-29-1979; Ord. No. 32B, §§ 1, 2, 7-27-1981; Ord. No. 137, 8-26-1985)