A. Site Improvements And Subdivisions:
1. All proposed new development and subdivisions shall be consistent with the need to minimize flood damage and ensure that building sites will be reasonably safe from flooding.
2. Building lots shall have adequate buildable area outside of floodways.
3. New development proposals and subdivision development plans shall include the mapped flood hazard zones from the effective FIRM, if available.
4. Base flood elevation data shall be generated and/or provided for subdivision proposals and all other proposed development, including manufactured home parks and subdivisions, greater than fifty (50) lots or five (5) acres, whichever is less.
5. New development and subdivisions shall have public utilities and facilities such as sewer, gas, electric and water systems located and constructed to minimize flood damage.
6. On site waste disposal systems shall be located and constructed to avoid functional impairment, or contamination from them, during flooding.
7. Subdivisions shall have adequate drainage provided to reduce exposure to flood hazards. In AO and AH zones, drainage paths shall be provided to guide floodwater around and away from all proposed and existing structures.
B. Development In Floodways:
1. Except as provided in subsection B4 of this section, encroachments, including fill, new construction, substantial improvements, and other development are prohibited unless certification by a registered professional civil engineer is provided demonstrating through hydrologic and hydraulic analyses performed in accordance with standard engineering practice that such encroachment shall not result in any increase in flood levels during the occurrence of the base flood discharge.
2. Any fill allowed to be placed in the floodway shall be designed to be stable under conditions of flooding, including rapid rise and rapid drawdown of floodwaters, prolonged inundation, and flood related erosion and scour.
3. Applicants shall obtain a conditional letter of map revision (CLOMR) from FEMA before an encroachment, including fill, new construction, substantial improvement, and other development, into the floodway is permitted that will cause any increase in the base flood elevation.
4. Projects for stream habitat restoration may be permitted in the floodway provided:
a. The project qualifies for a department of the army, Portland district regional general permit for stream habitat restoration (NWP-2007-1023); and
b. A qualified professional (a registered professional engineer; or staff of NRCS; the county; or fisheries, natural resources, or water resources agencies) has provided a feasibility analysis and certification that the project was designed to keep any rise in 100-year flood levels as close to zero as practically possible given the goals of the project; and
c. No structures would be impacted by a potential rise in flood elevation; and
d. An agreement to monitor the project, correct problems, and ensure that flood carrying capacity remains unchanged is included as part of the local approval.
5. Fences shall not cause any rise in base flood elevation and are subject to the no rise and CLOMR provisions of subsections B1 and B3 of this section.
C. Zones With Base Flood Elevations But No Floodway: In areas within zones A1-30 and AE on the community's FIRM with a base flood elevation, or where a base flood elevation is developed according to subsection E of this section, but where no regulatory floodway has been designated, new construction, substantial improvements, or other development (including fill) shall be prohibited, unless it is demonstrated that the cumulative effect of the proposed development, when combined with all other existing and anticipated development, will not increase the water surface elevation of the base flood more than one foot (1') at any point within the community.
1. Applicants of proposed projects that increase the base flood elevation more than one foot (1') should obtain from FEMA a conditional letter of map revision (CLOMR) before the project may be permitted.
D. Zones Without Base Flood Elevations:
1. The following standards apply in riverine areas of special flood hazard where no base flood elevation data have been provided (approximate A zones):
a. When base flood elevation or floodway data have not been identified by FEMA in a flood insurance study and/or flood insurance rate maps, the floodplain administrator shall obtain, review, and reasonably utilize scientific or historic base flood elevation and floodway data available from a federal, state, or other source, in order to administer this chapter. If base flood elevations are not available, subsection D1b of this section shall apply.
b. Where the floodplain administrator has obtained base flood elevation data, subsections C and E through M of this section shall apply.
c. In special flood hazard areas without base flood elevation data:
(1) No encroachments, including structures or fill, shall be located in an area of special flood hazard within an area equal to the width of the stream or fifty feet (50'), whichever is greater, measured from the ordinary high water mark, unless a base flood elevation is developed by a licensed professional engineer,
(2) The lowest floor of any insurable building or structure, including manufactured dwellings, shall be elevated a minimum of three feet (3') above highest adjacent grade. Below grade crawl spaces are not allowed.
E. Building Design And Construction:
1. Buildings and structures, including manufactured dwellings, within the scope of the building codes, including repair of substantial damage and substantial improvement of such existing buildings and structures, shall be designed and constructed in accordance with the flood resistant construction provisions of these codes, including, but not limited to, section R324 of the residential specialty code and section 1612 of the structural specialty code.
F. Manufactured Dwellings:
1. New and replacement manufactured dwellings are within the scope of the building codes; and
2. All new manufactured dwellings and replacement manufactured dwellings shall be installed using methods and practices which minimize flood damage and shall be securely anchored to an adequately anchored foundation system to resist flotation, collapse and lateral movement. Methods of anchoring include, but are not limited to, use of over the top or frame ties to ground anchors. This requirement is in addition to applicable state and local anchoring requirements for resisting wind forces.
G. Below Grade Crawl Spaces:
1. Below grade crawl space foundations are allowed, unless no base flood elevations are available, provided that they conform to guidelines in FEMA TB 11-01, crawl space construction for structures located in special flood hazard areas and building codes.
H. Accessory Structures: Relief from the elevation or dry floodproofing standards may be granted for an accessory structure containing no more than two hundred (200) square feet. Such a structure must meet the following standards:
1. It shall not be subject to building codes;
2. The accessory structure shall be located on a property, or an adjacent property with same owner, as a dwelling;
3. It shall not be used for human habitation and may be used solely for parking of vehicles or storage of items having low damage potential when submerged;
4. Toxic material, oil or gasoline, or any priority persistent pollutant identified by the Oregon department of environmental quality shall not be stored below BFE, or where no BFE is available lower than three feet (3') above grade, unless confined in a tank installed in compliance with this chapter;
5. It shall be constructed of flood resistant materials;
6. It shall be constructed and placed on the lot to offer the minimum resistance to the flow of floodwaters;
7. It shall be firmly anchored to prevent flotation;
8. Services such as electrical and heating equipment shall be elevated or floodproofed to or above the base flood elevation; and
9. It shall be designed to equalize hydrostatic flood forces on exterior walls by allowing for the automatic entry and exit of floodwater. Designs for complying with this requirement must be certified by a licensed professional engineer or architect or:
a. Provide a minimum of two (2) openings with a total net area of not less than one square inch for every square foot of enclosed area subject to flooding;
b. The bottom of all openings shall be no higher than one foot (1') above the higher of the exterior or interior grade or floor immediately below the opening;
c. Openings may be equipped with screens, louvers, valves or other coverings or devices provided they permit the automatic flow of floodwater in both directions without manual intervention.
I. Recreational Vehicles:
1. In all areas of special flood hazard, recreational vehicles that are an allowed use or structure under the zoning ordinance must either:
a. Be placed on the site for fewer than one hundred eighty (180) consecutive days;
b. Be fully licensed and ready for highway use, on its wheels or jacking system, attached to the site only by quick disconnect type utilities and security devices, and have no permanently attached structures or addition; or
c. Meet all the requirements of subsection F, "Manufactured Dwellings", of this section including the anchoring and elevation requirements.
J. Critical Facilities:
1. Construction of new critical facilities shall be, to the extent possible, located outside the limits of the area of special flood hazard. Construction of new critical facilities shall be permissible within the area of special flood hazard if no feasible alternative site is available. Critical facilities constructed within the areas of special flood hazard shall have the lowest floor elevated three feet (3') above BFE (or depth number in AO zones) or to the height of the 0.2 percent (500-year) flood, whichever is higher. Access to and from the critical facility should also be protected to the height utilized above. Floodproofing and sealing measures must be taken to ensure that toxic substances or priority organic pollutants as defined by the Oregon department of environmental quality will not be displaced by or released into floodwaters. Access routes elevated to or above the level of the base flood elevation shall be provided to all critical facilities to the extent possible.
K. Tanks:
1. Underground tanks in flood hazard areas shall be anchored to prevent flotation, collapse or lateral movement resulting from hydrostatic loads, including the effects of buoyancy assuming the tank is empty, during conditions of the design flood.
2. Aboveground tanks in flood hazard areas shall be:
a. Attached to and elevated to or above the base flood elevation (or depth number in AO zones) on a supporting structure that is designed to prevent flotation, collapse or lateral movement during conditions of the design flood; or
b. Anchored or otherwise designed and constructed to prevent flotation, collapse or lateral movement resulting from hydrodynamic and hydrostatic loads, including the effects of buoyancy assuming the tank is empty, during conditions of the design flood.
3. Tank inlets, fill openings, outlets and vents shall be:
a. A minimum of two feet (2') above BFE or fitted with covers designed to prevent the inflow of floodwater or outflow of the contents of the tank during conditions of the design flood; and
b. Anchored to prevent lateral movement resulting from hydrodynamic and hydrostatic loads, including the effects of buoyancy, during conditions of the design flood.
L. On Site Sewage Systems:
1. Soil absorption systems shall be located outside of flood hazard areas. Where suitable soil absorption sites outside of the flood hazard area are not available, the soil absorption site is permitted to be located within the flood hazard area provided it is located to minimize the effects of inundation under conditions of the base flood.
2. Mound systems in flood hazard areas shall be prohibited.
M. Fences And Walls:
1. New fencing shall be designed to collapse under conditions of the base flood or to allow the passage of water by having flaps or openings in the areas at or below the base flood elevation sufficient to allow floodwater and associated debris to pass freely.
N. Other Development In Noncoastal High Hazard Areas:
1. All development in noncoastal high hazard areas (A zones) for which specific provisions are not specified in this chapter or building codes, shall:
a. Be located and constructed to minimize flood damage;
b. Be designed so as not to impede flow of floodwaters under base flood conditions;
c. If located in a floodway, meet the limitations of subsection C of this section;
d. Be anchored to prevent flotation or lateral movement resulting from hydrostatic loads, including the effects of buoyancy, during conditions of the design flood;
e. Be constructed of flood damage resistant materials; and
f. Have electric service and/or mechanical equipment elevated above the base flood elevation (or depth number in AO zones), except for minimum electric service required to address life safety and electric code requirements.
O. Temporary Structures, Storage, And Bridges:
1. A floodplain development permit is required for construction or placement of temporary structures, temporary storage associated with nonresidential uses, and temporary bridges located in areas of special flood hazard.
2. Temporary structures, not including bridges, shall be limited as to time of service, but shall not be permitted for more than ninety (90) days. The floodplain administrator is authorized to grant extensions for demonstrated cause; such cause shall reaffirm the temporary nature of the structure. Temporary structures shall be anchored to prevent flotation, collapse, or lateral movement.
3. Temporary storage of five (5) cubic yards or more shall be limited as to time of service, but shall not be permitted for more than ninety (90) days. The floodplain administrator is authorized to grant extensions for demonstrated cause; such cause shall reaffirm the temporary nature of the storage. Stored material shall be anchored or contained to prevent flotation or release outside the assigned storage area. Hazardous materials priority persistent pollutants identified by the Oregon department of environmental quality shall not be stored in the floodway.
4. Temporary encroachments in the floodway for the purposes of capital improvement projects (including bridges) require a floodplain development permit. No CLOMR/LOMR is required.
P. Requirement To Submit New Technical Data:
1. It is the responsibility of the applicant to have technical data prepared in a format required for a conditional letter of map revision or letter of map revision and to submit such data to FEMA on the appropriate application forms. Submittal and processing fees for these map revisions shall be the responsibility of the applicant.
2. Applicants shall be responsible for all costs associated with obtaining a conditional letter of map amendment (CLOMR) or letter of map revision from FEMA.
3. The city of Umatilla shall be under no obligation to sign the community acknowledgement form, which is part of the CLOMR/LOMR application.
4. Within six (6) months of project completion, an applicant who obtains an approved CLOMR from FEMA, or whose development modifies floodplain boundaries or base flood elevations shall obtain from FEMA a letter of map revision (LOMR) reflecting the as built changes to the FIRM.
Q. Watercourse Alterations:
1. A watercourse is considered altered when any change occurs within its banks, including installation of new culverts and bridges, or size modifications to existing culverts and bridges (as shown on effective FIRM).
2. The bankfull flood carrying capacity of the altered or relocated portion of the watercourse shall not be diminished. Prior to issuance of a floodplain development permit, the applicant must submit a description of the extent to which any watercourse will be altered or relocated as a result of the proposed development and submit certification by a registered professional engineer that the bankfull flood carrying capacity of the watercourse will not be diminished.
3. Adjacent communities, the U.S. army corps of engineers, Oregon department of state lands, and Oregon department of land conservation and development must be notified prior to any alteration or relocation of a watercourse. Evidence of notification must be submitted to the floodplain administrator and to the federal emergency management agency.
4. The applicant shall be responsible for providing the necessary maintenance for the altered or relocated portion of the watercourse so that the flood carrying capacity will not be diminished.
5. The applicant shall meet the requirements to submit technical data in subsection P of this section when an alteration of a watercourse, including the placement of culverts, results in the relocation or elimination of the special flood hazard area.
R. Nonconversion Of Enclosed Areas Below The Lowest Floor:
1. To ensure that the areas below the BFE continue to be used solely for parking vehicles, limited storage, or access to the building and not be finished for use as human habitation without first becoming fully compliant with the floodplain management ordinance in effect at the time of conversion, the floodplain administrator shall:
a. Determine which applicants for new construction and/or substantial improvements have fully enclosed areas below the lowest floor that are five feet (5') or higher;
b. Enter into a "nonconversion agreement for construction within flood hazard areas" or equivalent with the city of Umatilla. The agreement shall be recorded with the Umatilla County as a deed restriction. The nonconversion agreement shall be in a form acceptable to the floodplain administrator and county counsel; and
c. Have the authority to inspect any area of a structure below the base flood elevation to ensure compliance upon prior notice of at least seventy two (72) hours.
S. Periodic Floodplain Inspections And Enforcement Actions:
1. The floodplain administrator or designee shall make periodic inspections of floodplain areas to establish that development activities within the floodplain are being performed in compliance with an approved floodplain development permit. The floodplain administrator or designee shall prepare a field report listing noncomplying conditions to be delivered to the Umatilla code enforcement officer. Upon receipt of the report, the Umatilla code enforcement officer or designee shall proceed with enforcement actions including, but not limited to: the issuance of a stop work order; the issuance of a citation; and the commencement of civil legal proceedings.
2. Within thirty (30) days of discovery of a violation of this chapter, the floodplain administrator shall submit a report to the city council which shall include all information available to the floodplain administrator which is pertinent to said violation. Within thirty (30) days of receipt of this report, the city council shall:
a. Take any necessary action to effect the abatement of such violation; or
b. Issue a variance to this chapter in accordance with the provisions of section 12-1-6, "Variance And Appeal Procedures", of this chapter; or
c. Order the owner of the property upon which the violation exists to provide whatever additional information may be required for their determination. Such information must be provided to the city manager within thirty (30) days of such order, and he shall submit an amended report to the floodplain board within twenty (20) days. At their next regularly scheduled public meeting, the governing body shall either order the abatement of said violation or they shall grant a variance in accordance with the provisions of section 12-1-6, "Variance And Appeal Procedures", of this chapter.
If a variance cannot be granted according to section 12-1-6 of this chapter, submit to the administrator of federal insurance administration a declaration for denial of insurance, stating that the property is in violation of a cited statute or local law, regulation or ordinance, pursuant to section 1316 of the national flood insurance act of 1968 as amended. (Ord. 760, 8-17-2010)
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