The purpose of the floodplain management overlay zone is to:

A. Restrict or prohibit 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.

B. Require that uses vulnerable to floods, including facilities that serve such uses, be protected against flood damage at the time of initial construction.

C. Control the alteration of natural floodplains, stream channels and natural protective barriers, which help accommodate or channel flood waters.

D. Control filling, grading, dredging and other development that may be subject to or increase flood damage.

E. Prevent or regulate the construction of flood barriers which will unnaturally divert floodwaters or which may increase flood hazards in other areas. (Ord. 619, 2003)

This chapter shall apply to all areas of special flood hazards identified on the flood insurance study and flood insurance rate maps (FIRM) within the jurisdiction of the city of Carlton, Yamhill County, Oregon, and on file at the office of the city recorder. (Ord. 619, 2003)

The degree of flood protection required by this chapter is considered reasonable for regulatory purposes and is based on scientific and engineering considerations. Larger floods can and will occur on rare occasions. Flood heights may be increased by man-made or natural causes. This chapter does not imply that land outside the areas of special flood hazards or uses permitted within such areas will be free from flooding or flood damages. This chapter shall not create liability on the part of the city of Carlton, any officer or employee thereof, or the Federal Insurance Administration, for any flood damages that result from reliance on this chapter or any administrative decision lawfully made thereunder. (Ord. 619, 2003)

Before any start of construction or development shall occur in areas of special flood hazard; a plot plan, drawn to scale, showing the nature, location, dimension, and topographic lines of the area in question, must be submitted to the planning commission for a hearing and approval. The plan shall include as a minimum:

A. Actual elevation (in relation to mean sea level) of the lowest habitable floor (including basement) of all new or substantially improved structures, and whether or not the structure contains a basement.

B. The elevation (in relation to mean sea level) to which any new or substantially improved structure has been floodproofed.

C. Certification by a registered professional engineer or architect that the floodproofing methods for any nonresidential structure meet the floodproofing criteria of this chapter.

D. Description of the extent to which any watercourse will be altered or relocated as a result of a proposed development. (Ord. 619, 2003)

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

A. Anchoring. All new construction and substantial improvements shall be anchored to prevent flotation, collapse or lateral movement of the structure, and shall be installed using methods and practices that minimize flood damage. Anchoring methods may include, but are not limited to, use of over-the-top or frame ties to ground anchors.

B. Construction Materials and Methods.

1. All new construction and substantial improvements shall be constructed with materials and utility equipment resistant to flood damage;

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

3. Electrical, heating, ventilation, plumbing and air conditioning equipment and other service facilities shall be designed and/or otherwise elevated or located so as to prevent water from entering or accumulating within the components during conditions of flooding.

C. Utilities.

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

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

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

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 and planned unit development proposals.

E. Review of Building Permits. Where elevation data is not available, applications for building permits shall be reviewed to assure that proposed construction will be reasonably safe from flooding. The test of reasonableness is a local judgment and includes use of historical data, high water marks, photographs of past flooding, etc., where available. (Ord. 619, 2003)

In all areas of special flood hazards where base flood elevation data has been provided the following provisions are required:

A. Residential Construction. New construction and substantial improvement of any residential structure shall have the lowest floor, including basement, elevated to one foot above base flood elevation.

B. 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:

1. Be floodproofed so that below the base flood level the structure walls shall be substantially impermeable to the passage of water;

2. Have structural components capable of resisting hydrostatic and hydrodynamic loads and effects of buoyancy;

3. Be certified by a registered professional engineer or architect that the design and methods of construction are in accordance with accepted standards of practice for meeting provisions of this chapter based on their development and/or review of the structural design, specifications and plans.

C. Manufactured Homes. All manufactured homes to be placed or substantially improved shall be elevated on a permanent foundation such that the lowest floor of the manufactured home is at or above the base flood elevation and be securely anchored to an adequately anchored foundation system in accordance with the provisions of this chapter.

D. Floodways. Located within areas of special flood hazard are areas designated as floodways. Since the floodway is an extremely hazardous area due to the velocity of floodwaters that carry debris, potential projectiles and erosion potential, the following provisions apply:

1. Prohibit encroachments, including fill, new construction, substantial improvements, and other development unless certification by a registered professional engineer or architect is provided demonstrating that encroachments shall not result in any increase in flood levels during the occurrence of the base flood discharge;

2. If subsection (D)(1) of this section is satisfied, all new construction and substantial improvements shall comply with all applicable flood hazard reduction provisions of this section and Section 17.56.050;

3. Prohibit the placement of any manufactured housing, except in an existing mobile home park or existing mobile home subdivision. (Ord. 619, 2003)

A. Use of Other Base Flood Data. When base flood elevation data has not been provided in accordance with Section 17.56.020, the planning commission shall obtain, review and reasonably utilize any base flood elevation and floodway data available from a federal, state or other source, in order to administer this chapter.

B. Alteration of Watercourses.

1. Adjacent affected communities and the Oregon State Water Resources shall be notified prior to any alteration or relocation of a watercourse, and evidence of such notification shall be submitted to the Federal Insurance Administration.

2. Maintenance shall be required within the altered or relocated portion of said watercourse so that the flood carrying capacity is not diminished.

C. Interpretation of FIRM Boundaries. Interpretations where needed, as to exact location of the boundaries of the areas of special flood hazards (for example, where there appears to be a conflict between a mapped boundary and actual field conditions). The person contesting the location of the boundary shall be given a reasonable opportunity to appeal the interpretation. Such appeals shall be granted consistent with the standards of Section 1910.6 of the rules and regulations of the National Flood Insurance Program (24 CFR 1909, etc.) (Ord. 619, 2003)