In all areas of special flood hazards (SFHA), the following standards are required:
A. Alteration Of Watercourses:
1. Require that the flood carry capacity within the altered or relocated portion of said watercourse is maintained. Require that maintenance is provided within the altered or relocated portion of said watercourse to ensure that the flood carrying capacity is not diminished. Require compliance with sections 5-2-4-2B5 and 5-2-4-2B6.
B. Anchoring:
1. All new construction and substantial improvements shall be anchored to prevent flotation, collapse or lateral movement of the structure resulting from hydrodynamic and hydrostatic loads, including the effects of buoyancy.
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, duct systems, and air conditioning equipment and other service facilities shall be elevated at or above the base flood elevation or shall be designed and installed to prevent water from entering or accumulating within the components and to resist hydrostatic and hydrodynamic loads and stresses, including the effects of buoyancy, during conditions of flooding. In addition, electrical, heating, ventilating, air- conditioning, plumbing, duct systems, and other equipment and service facilities shall:
a. If replaced as a part of a substantial improvement meet all the requirements of this section.
D. Utilities: Water supply, sanitary sewer, and on-site waste disposal systems:
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 consistent with the Oregon Department of Environmental Quality.
E. Tanks:
1. Underground tanks shall be anchored to prevent flotation, collapse and lateral movement under conditions of the base flood.
2. Above-ground tanks shall be installed at or above the base flood level or shall be anchored to prevent flotation, collapse, and lateral movement under conditions of the base flood.
F. Subdivision, Commercial, Industrial And Other Development Proposals:
1. All new subdivision proposals and other proposed new developments (including proposals for manufactured dwelling parks and subdivisions) greater than fifty (50) lots or five (5) acres, whichever is the lesser, shall include within such proposals, base flood elevation data.
2. All new subdivision proposals and other proposed new developments (including proposals for manufactured dwelling parks and subdivision) shall:
a. Be consistent with the need to minimize flood damage;
b. Have public utilities and facilities such as sewer, gas, electrical and water systems located and constructed to minimize flood damage; and
c. Have adequate drainage provided to reduce exposure to flood hazards.
G. Use Of Other Base Flood Data:
1. Where base flood elevation data has not been provided in accordance with section 5-2-3B, the local floodplain administrator shall obtain, review, and reasonably utilize any base flood elevation data available from federal, state, other source, in order to administer section 5-2-5-1. All new subdivision proposals and other proposed new developments (including proposals for manufactured dwelling parks and subdivisions) must meet the requirements of section 5-2-5-1F.
2. Base flood elevations shall be generated for all development proposals that are five (5) or more in size or are fifty (50) lots or more, whichever is lesser iin any A zone that does not have an established base flood elevation. Development proposals located within a riverine A zone shall be reasonably safe from flooding; the test of reasonableness includes use of historical data, high water marks, photographs of past flooding, etc., where available. Failure to elevate at least two (2) feet above grade in these zones may result in higher insurance rates.
H. Structures Located In Multiple Or Partial Flood Zones: In coordination with the State of Oregon Specialty Codes:
1. When a structure is located in multiple flood zones on the community’s flood insurance rate maps (FIRM) the provisions for the more restrictive flood zone shall apply.
2. When a structure is partially located in a special flood hazard area (SFHA), the entire structure shall meet the requirements for new construction and substantial improvements. (Ord. 54, 3-24-1987; amd. Ord. 147, 4-14-2004; Ord. 219, 11-13-2019)