Chapter 17.48 - FLOODPLAIN (FP) OVERLAY ZONE

17.48.010 - Purpose.

The floodplain (FP) overlay zone is a superimposed zone applied in combination with existing identified zones for the purpose of promoting the public health, safety and general welfare and to minimize public and private losses due to flood conditions in specified areas.

(Ord. 5-1983 § 12.01)

17.48.020 - Areas of special flood hazard.

A. The boundaries of areas recognized as floodplains (FP) shall be the boundaries of special flood hazard areas which are areas subject to a one percent or greater chance of flooding in any given year, identified by the Federal Emergency Management Agency (FEMA) in a scientific and engineering report entitled "Flood Insurance Rate Map, City of Elgin, Oregon, Union County, November 15, 1978" (to be updated by a revised map due for adoption on September 30, 1987).

B. The floodplain overlay zone is identified as a superimposed zone over the existing Elgin plan/zoning map. In addition, where base flood elevation data has been provided by FEMA the Federal Flood Insurance and Floodway Maps are adopted by reference and declared to be a supplemental part of this title.

C. Where base flood elevation data has not been provided by FEMA, the building inspector shall obtain, review and reasonably utilize any base flood elevation and floodway data from federal, state or other sources, in order to administer residential and nonresidential construction within potential special flood hazard areas. When no base data exists, either through the Flood Insurance Study or from another authorized source, the zoning and building permit applications shall be reviewed to assure that proposed construction will be reasonably safe from flooding. The test of reasonableness shall be made, where available, through the use of historical data, high water marks, photographs of past flooding, etc. Failure to elevate at least two feet above grade in these zones may result in higher insurance rates.

(Ord. 5-1983 § 12.02)

17.48.030 - Limitations.

The areas within the FP overlay zone shall be regulated by the following general and specific standards in combination with the applicable underlying zone, e.g., FP/R. The outright and conditional uses permitted in accordance with the provisions of the underlying zones shall be permitted only where the FP general and specific standards can be complied with. Where prior approval is required, all necessary permits should first be obtained from applicable federal, state or local governmental agencies.

(Ord. 5-1983 § 12.03(part))

17.48.040 - General standards.

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

A. Filing of a development permit or building permit, where applicable, shall be obtained before construction or development begins within any area of special flood hazard. Development permits are required for all structures including manufactured homes and for all other development including fill, except low investment structures; building permits shall be for all structures. Application for a development and building permit shall be made to and maintained by the building inspector and findings submitted to the city clerk. The city clerk will record and maintain actual elevation of the lowest habitable floor (including basement) of all new or substantially improved structures and record and maintain the actual elevation of floodproofing certification for floodproofed structures. Specifically, the following information is required for development permits:

1. Elevation in relation to mean sea level, of the lowest floor, including basement, of all structures;

2. Elevation in relation to mean sea level to which any structure has been floodproofed;

3. Certification by a registered professional engineer or architect that the floodproofing methods for any nonresidential structure meet the floodproofing criteria in Section 17.48.050(B);

4. Description of the extent to which any watercourse will be altered or relocated as a result of proposed development; and

5. If the building inspector determines an alteration to a watercourse could have an effect on a neighboring community, such community shall be involved in the review of the development permit.

B. Anchoring.

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

2. All manufactured homes must likewise be anchored to prevent flotation, collapse or lateral movement, 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 (reference FEMAS's "Manufactured Home Installation in Flood Hazard Areas" guidebook for additional techniques).

C. 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.

D. 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 floodwaters into the systems and discharge from the systems into floodwaters.

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

E. 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.

4. Where base flood elevation data has not been provided or is not available for another authoritative source it shall be generated for subdivision proposals and other proposed developments which contain at least fifty (50) lots of five acres, whichever is less.

F. Alteration to Watercourses.

1. No development activity shall alter a watercourse which will reduce its carrying capacity.

2. Notify adjacent communities and the Department of Land Conservation and Development prior to any alteration or relocation of a watercourse, and submit evidence of such notification to the Federal Insurance Administration.

G. Low Investment Accessory Structures.

1. Obtain a building permit prior to construction.

2. Be anchored in compliance with subsection (B)(1) of this section.

(Ord. 5-1983 § 12.03(part))

17.48.050 - Specific standards.

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

A. Residential Construction.

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

2. Fully enclosed areas below the lowest floor that are subject to flooding are prohibited, or shall be designed to automatically equalize hydrostatic flood forces on exterior walls by allowing for the entry and exit of floodwaters. Designs for meeting this requirement must either be certified by a registered professional engineer or architect or must meet or exceed the following minimum criteria:

a. A minimum of two openings having a total net area of not less than one square inch for every square foot of enclosed area subject to flooding shall be provided.

b. The bottom of all openings shall be no higher than one foot above grade.

c. Openings may be equipped with screens, louvers, or other coverings or devices; provided, that they permit the automatic entry and exit of floodwaters.

B. Nonresidential Construction.

1. New construction and substantial improvement of any commercial, industrial or nonresidential structure other than low investment accessory structures shall either have the lowest floor, including the basement, elevated to the level of the base flood elevation, or together with the attendant utility and sanitary facilities, shall:

a. Be floodproofed so that below the base flood level the structure is watertight with walls substantially impermeable to the passage of water;

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

c. 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 subsection based on their development and/or review of the structural design, specifications and plans. Such certifications shall be provided to the county building inspector.

2. Nonresidential structures that are elevated, not floodproofed, must meet the same standards for space below the lowest floor.

3. Applicants floodproofing nonresidential buildings shall be notified that flood insurance premiums will be based on rates that are one foot below the floodproofed level (e.g., a building constructed to the base flood level will be rated as one foot below that level).

C. Manufactured Homes. All manufactured homes to be placed or substantially improved within Zones A1-30, AH and AE 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 Section 17.48.040(B).

D. Floodways. Since the floodway is an extremely hazardous area due to the velocity of floodwaters which carry debris, potential projectiles, and have erosion potential, the following provisions apply:

1. Encroachments are prohibited, including fill, new construction, substantial improvements, and other development unless certification by a registered professional engineer orarchitect 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 Sections 17.48.040 and 17.48.050 limitations.

3. Prohibit the placement of any manufactured homes, except in an existing manufactured home park or existing manufactured home subdivision.

(Ord. 5-1983 § 12.03(part))

17.48.060 - Warning and disclaimer of liability.

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 Elgin, or the Federal Emergency Management Agency for any flood damages that result from reliance on this chapter or any administrative decision lawfully made thereafter.

(Ord. 5-1983 § 12.04)