Chapter 18.80
FLOOD HAZARD OVERLAY DISTRICT (FH)
Sections:
18.80.030 Establishment of the flood hazard overlay district.
18.80.040 Warning and disclaimer of liability.
18.80.050 Flood hazard ordinance administrator.
18.80.060 Floodway and floodplain regulations.
18.80.070 Flood hazard development permit.
18.80.080 Stream alteration permit.
18.80.090 Violation – Penalty.
18.80.010 Introduction.
The flood hazard areas of the city of Donnelly are subject to periodic inundation which may result in loss of life and property, health and safety hazards, disruption of commerce and governmental services, extraordinary public expenditures for flood protection and relief, and impairment of the tax base, all of which adversely affect the public health, safety, and general welfare. These flood losses are caused by (A) the cumulative effect of obstructions which affect flood heights and velocities, and (B) the occupancy of flood hazard areas by uses vulnerable to floods. [Ord. 230, 2016.]
18.80.020 Purpose.
The purpose of the flood hazard overlay district is to guide development in the designated floodplain in order to promote the public health, safety and general welfare, minimize public and private losses, and prevent environmental damage due to flood conditions. The city finds that the flood hazard overlay district is extremely hazardous due to the velocity of floodwaters, the potential of erosion and the dangers associated with debris in floodwaters. The provisions of this chapter are intended to protect human life and health, minimize the expense and inconvenience to property owners and the general public associated with increased water flow and velocity, ensure that the potential buyers are notified that property is subject to flood conditions, ensure that those who occupy the areas of flood hazard assume responsibility for their actions, preserve the inherent natural characteristics of watercourses and natural protective barriers which help channel floodwater, preserve, protect, and enhance the fish, wildlife, and riparian plant habitats, and provide a formal procedure for proposed developments and stream alterations. [Ord. 230, 2016.]
18.80.030 Establishment of the flood hazard overlay district.
A. The flood hazard overlay district is hereby established. The regulations of this district apply to all lands within the jurisdictions of the city of Donnelly that lie within floodplain boundaries as determined by the flood insurance rate map (FIRM).
B. Floodway and Floodplain Regulations. The flood hazard overlay district is divided into two subdistricts, the floodway subdistrict and the floodplain subdistrict. The boundaries of these subdistricts are indicated on the FIRM map.
C. The precise boundaries of the floodplain boundary may be determined by on-site elevations as interpreted from the adopted FIRM flood insurance study. All land within the external boundary of the floodplain shall be considered to be within the floodplain and governed by the provisions of this district. [Ord. 230, 2016.]
18.80.040 Warning and disclaimer of liability.
The degree of flood protection required by this chapter is considered reasonable for regulatory purposes and is based on engineering and scientific methods of study. Larger floods may occur on rare occasions or flood heights may be increased by manmade or natural causes, such as ice jams and bridge openings restricted by debris. This does not imply that areas outside the flood hazard districts or land uses permitted within such districts will be free from flooding or flood damages. There shall not be any liability on the part of the city of Donnelly or any officer or employee thereof for any flood damages that result from reliance on the regulations of the flood hazard overlay district or any decision lawfully made hereunder. [Ord. 230, 2016.]
18.80.050 Flood hazard ordinance administrator.
A. Designation of Flood Hazard Ordinance Administrator. The flood hazard ordinance administrator, as designated by the Donnelly planning and zoning administrator, shall administer and implement this chapter by granting or denying applicable permit applications in accordance with its provisions. The flood hazard ordinance administrator may transmit one copy of the information described in DCC 18.80.070(A) to a designated engineer or other expert person or agency for technical assistance, where necessary, in evaluating a proposed project.
B. Duties and Responsibilities of the Flood Hazard Ordinance Administrator.
1. Permit Review.
a. Review all development permits to determine that the permit requirements of this chapter have been satisfied, and to issue any flood hazard development permits.
b. Review all development permits to determine that all necessary permits have been obtained from those federal, state, or local governmental agencies when prior approval is required.
2. Use of Other Base Flood Data. When base flood elevation data has not been provided in the flood insurance study or FIRM map, the flood hazard ordinance administrator 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 the regulations of this chapter.
3. Information to Be Obtained and Maintained.
a. Where base flood elevation data is provided through the flood insurance study or FIRM map, obtain and record the actual elevation (in relation to the mean sea level) of the lowest floor (including basement) of all new or substantially improved structures.
4. For all new or substantially improved floodproofed structures, verify and record the actual elevation (in relation to mean sea level), and maintain the floodproofing certification required in this chapter.
5. Maintain for public inspection all records pertaining to the provisions of this district.
6. In certain instances, there may be the need for expert review by a third party of the technical data submitted by the applicant. It shall be at the sole discretion of the flood hazard ordinance administrator to determine whether such review is required. Such technical review shall be paid for by the applicant. The applicant shall pay the city the estimated cost of the expert review prior to further processing of the application by the city. If additional costs are incurred, the applicant shall pay those prior to issuance of a floodplain development permit. [Ord. 230, 2016.]
18.80.060 Floodway and floodplain regulations.
A. Floodway Subdistrict Use Regulations. Uses in the floodway subdistrict are limited to the following:
1. Permitted Uses. Agricultural uses and open space recreation uses; provided, that no structure is constructed or maintained; and any other structure that has received a stream alteration permit.
2. Prohibited Uses. All other uses are strictly prohibited.
B. Floodplain Subdistrict Use Regulations. Uses in the floodplain subdistrict are limited to the following:
1. Permitted Uses. Agricultural, recreational and residential accessory (nondwelling) uses, provided they are not subject to substantial flood damage and will not cause flood losses on other land or to the public; or provided, that they can be readily removed from the flood hazard areas prior to the time of flooding.
2. Uses Requiring a Flood Hazard Development Permit.
a. Sand and gravel extraction.
b. Single-family dwellings and residential accessory dwelling uses in accordance with the requirements of the underlying zone district and this chapter.
c. Commercial and industrial uses only as permitted in the underlying zone district and this chapter.
d. Subdivisions.
e. Fill associated with a building or structure and deposited in accordance with the standards set forth herein.
3. Prohibited Uses.
a. Any use not mentioned herein that is susceptible to flood damage from the 100-year flood or that could potentially cause flood damage from such a flood to other property.
b. Travel trailers and recreational vehicles stored or kept on any property more than 180 consecutive days; any vehicle must be fully licensed and ready for highway use.
c. Any fill, unless the fill is associated with a building or structure and deposited in accordance with the standards set forth herein.
4. Bulk Requirements.
a. Minimum lot size: 20,000 square feet.
b. Minimum lot width: 75 feet.
c. Maximum building or structure height: 35 feet.
d. Minimum front yard setback: 25 feet.
e. Minimum side and rear yard setback: The setback from the adjacent property line shall be 10 feet for a single-story structure. The vertical walls of subsequent stories of a multistoried structure shall be set back an additional five feet.
f. Riparian Setback. Unless otherwise provided for herein, all permanent buildings and structures in the flood hazard overlay district shall have a 100-foot-wide riparian setback from the mean high water mark of all applicable waterways. Removal of live vegetation or excavation within the riparian setback is prohibited, except for the removal of leaning or hazardous trees. Pruning of trees and planting of riparian trees, shrubs and ground cover within the riparian setback are allowed; provided, however, that all plantings conform to the criteria for evaluation in DCC 18.80.070.
C. Nonconforming Uses in the Flood Hazard Overlay District. A structure or the use of a structure or premises which was lawful before the passage or amendment of the ordinance codified in this chapter, but which is not in conformity with the provisions of this district, may be continued subject to the following conditions:
1. No such use shall be expanded, changed, enlarged or altered in a way which increases its nonconformity.
2. If any nonconforming use or structure is partially or completely destroyed, it shall not be reconstructed except in conformity with the provisions of this chapter.
3. Uses which are or become nuisances shall not be entitled to continue as nonconforming uses.
4. Any alteration, addition or repair to any nonconforming structure which would result in substantially increasing its flood damage potential shall be required to obtain a flood hazard development permit pursuant to this chapter.
5. Where the application of the 100-foot riparian setback and other applicable setbacks will result in a building site of 1,000 square feet or less, the riparian setback may be reduced to such an extent that the building site is 1,000 square feet; provided, however, the riparian setback shall not be less than 50 feet. [Ord. 230, 2016.]
18.80.070 Flood hazard development permit.
A. Procedure. A flood hazard development permit shall be obtained before construction or development begins within or upon any area located within the floodplain subdistrict. All applications for a flood hazard development permit for a subdivision shall be evaluated and approved or denied by the commission and council. All other flood hazard development permit applications shall be evaluated and approved or denied by the flood hazard ordinance administrator. An application for a flood hazard development permit shall be made on a form furnished by the flood hazard ordinance administrator. Such application shall contain, at a minimum, the following (if applicable):
1. Plans drawn in duplicate and to scale showing:
a. The existing contours with intervals of one foot or less of the elevation of the entire property;
b. The proposed contours with intervals of one foot or less of the elevation of the entire property; and
c. The location, dimensions and elevations (measured from mean sea level) of the proposed improvements, including buildings, structures, fill, drainage facilities, driveways and streets.
2. Certification by a registered professional engineer that the floodproofing methods meet the flood hazard reduction provisions of this chapter.
3. A description of the extent to which any watercourse would be altered or relocated.
4. All required and necessary federal and state permits, including studies and mitigation plans for wetlands (e.g., 404 permits).
5. A fee which shall be established by city council resolution.
B. Criteria for Evaluation. The flood hazard ordinance administrator, the commission or the council, as the case may be, shall evaluate and find adequate evidence to support each of the following criteria:
1. There will be no danger to life and property due to increased flood heights or velocities or any materials may be swept onto other lands or downstream to the injury of others.
2. All subdivision proposals shall have adequate drainage provided to reduce exposure to flood damage.
3. The proposed water supply and sanitation systems and the ability of these systems will prevent disease, contamination and unsanitary conditions.
4. The proposed facility and its contents will not be susceptible to and shall minimize flood damage.
5. The proposed location represents the safest location for the proposed use.
6. The proposed use is compatible with existing development and development anticipated in the foreseeable future.
7. The proposed use is harmonious and in accordance with the general objectives or any specific objective of the comprehensive plan.
8. Safe access to the property shall be available in times of flood for ordinary and emergency vehicles.
9. Inherent natural characteristics of the watercourses and floodplain areas will be preserved.
10. Existing riparian vegetation and wildlife habitat along the stream bank and within the required 100-foot riparian setback shall be preserved.
11. New landscaping shall include plantings that are low growing and have dense root systems to stabilize stream banks and to repair any damage previously done to riparian vegetation.
12. The proposed use shall not be susceptible to the risk of obstruction by landslides, avalanches, ice jams or timber.
13. All new construction, manufactured homes as defined and permitted in this title, accessory buildings, and substantial improvements shall be anchored to prevent flotation, collapse or lateral movement.
14. All new construction and substantial improvements shall be constructed with materials and utility equipment resistant to flood damage and shall be constructed using methods and practices that minimize flood damage.
15. Utilities.
a. All new and replacement water supply systems shall be designed to minimize or eliminate infiltration of floodwaters into the system.
b. New and replacement water sanitary sewage systems shall be designed to minimize or eliminate infiltration of floodwaters into the systems and discharge from the systems into floodwaters.
c. On-site waste disposal systems shall be located to avoid impairment to them or contamination from them during flooding.
d. All subdivision proposals shall have public utilities and facilities such as sewer, gas, electrical and water systems located and constructed to minimize flood damage.
16. Any structural storage facility for chemicals, explosives, buoyant materials, flammable liquids, or other toxic materials which could be hazardous to the public health, safety and welfare shall be located in a manner which will assure that the facilities are situated at elevations one foot above the base flood elevation and are adequately floodproofed to prevent flotation of storage containers or damage to storage containers which could result in the escape of toxic materials into floodwaters.
17. The lowest portion of a floor system of new construction or substantial improvement of any structure shall be elevated to a level at least two feet above the base flood elevation. Any fill shall not exceed the base flood elevation. Any fill shall not extend more than 25 feet beyond the limits of any structure erected on a lot or property (“backfill”); provided, however, fill may extend more than 25 feet beyond the limits of any structure erected on a lot or property only if the cumulative amount of the fill does not exceed the amount of backfill allowed by the 25-foot perimeter. Any electrical, heating, ventilation, plumbing and air-conditioning equipment and other service facilities shall also be designed and elevated at least one foot above the base flood elevation.
18. Fully enclosed areas below the lowest floor 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 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 the proposed grade.
c. Openings may be equipped with screens, louvers or other coverings or devices; provided, that they permit the automatic entry and exit of floodwater.
C. Conditions. Upon consideration of the criteria in subsection (B) of this section, the flood hazard ordinance administrator, the commission or the Donnelly City council, as the case may be, may attach such conditions to the permit as deemed necessary to further the purposes of this district, including but not limited to:
1. Modification of water disposal and water supply facilities to minimize or eliminate infiltration of floodwaters.
2. Limitations of periods of use and operation.
3. Imposition of operational controls, sureties and deed restrictions.
4. Requirements or prohibition of construction of channel modification dikes, levees and other protective measures.
5. Submission of a plan or document certified by a registered professional engineer stating that the floodproofing measures comply with this chapter.
6. Floodproofing measures for structures such as the following:
a. Installation of watertight doors, bulkheads, shutters, and similar structures.
b. Reinforcement of walls to resist water pressure.
c. Use of paints, membrane or mortars to reduce seepage of water through walls.
d. Addition of mass or weight to structures to resist flotation.
e. Installation of pumps to lower water levels in structures.
f. Construction of water supply and waste treatment systems so as to prevent the entrance of floodwaters.
g. Installation of pumping facilities or comparable subsurface drainage systems for buildings to relieve external foundation wall flood pressures.
h. Construction to resist rupture or collapse caused by water pressure or floating debris.
i. Installation of valves or controls on sanitary and storm drains which will permit the drains to be closed to prevent backup of sewage and storm waters into the building or structures.
j. Location of all electrical equipment, circuits, and installed electrical appliances in a manner which will assure they are not subject to flooding and to provide protection from inundation by the floodwaters.
k. Location of any structural storage facilities for chemicals, explosives, buoyant materials, flammable liquids, or other toxic materials which could be hazardous to public health, safety and welfare in a manner which will assure that the facilities are situated at least one foot above the base flood elevation and/or are adequately floodproofed to prevent flotation of storage containers, or damage to storage containers which could result in the escape of toxic materials into floodwaters.
7. Location of building pads or envelopes.
8. Installation and maintenance of new landscaping and preservation of existing riparian vegetation.
9. Issuance of all required and necessary federal and state permits (e.g., 404 permits).
10. Any other condition reasonably related to the issuance of a flood hazard development permit. [Ord. 230, 2016.]
18.80.080 Stream alteration permit.
No person may excavate in, disturb, fill, build in, upon or across, deposit in, or change the channel of any nonintermittent stream within the flood hazard district without a stream alteration permit issued by the planning and zoning commission.
A. Application. Applications shall be made for a stream alteration permit upon a form furnished by the flood hazard ordinance administrator. Information to be provided by the applicant for any stream alteration permit issued hereunder shall include, but not necessarily be limited to, the following:
1. Applicant’s name, address and phone number.
2. Name of engineer, if any, who prepared the application.
3. Property location and legal description.
4. Name and reach of stream and area of proposed work.
5. Length of the stream section to be worked on.
6. Type of work to be done.
7. Type of equipment to be used.
8. Starting and completion dates of work.
9. Vicinity map of the area.
10. Names and addresses of property owners on both sides of the stream 300 feet upstream and 1,000 feet downstream from the proposed work site, typed on mailing labels.
11. Plans and information at a one-quarter-inch scale, accurately and legibly showing:
a. Location and dimension of lot or property.
b. Location of existing or proposed structures and location of previous stream alterations.
c. Typical cross-section of the proposed work.
d. Location of the lot or property in relation to the stream channel, floodway, and floodplain.
e. A valley cross-section of the area to be altered, if requested by the city engineer, showing the stream channel, floodway limit lines, elevations of land area adjacent to the stream, and the base flood elevation. The city engineer, and FEMA officials, if requested by the city engineer, shall review and approve or disapprove the cross-section.
f. Location of any drainage ways or overflow channel through the property affected.
12. A statement addressing potential beneficial and adverse impacts in the immediate project area (upstream, downstream and across the stream).
13. A fee which shall be established by city council resolution.
14. Eight copies of the above information. The administrator may request additional copies.
B. Public Hearing. Each application shall be reviewed at public hearings before the planning and zoning commission following adequate public notice.
1. Notice shall be given by United States mail insofar as practicable to each property owner whose name appears on the list accompanying the application, giving the date, time and place of the hearing, the action sought, and the identification of the property under consideration. When notice is required to 200 or more property owners or purchasers of record, alternate forms of notice may be provided in lieu of mailed notice. Sufficient notice shall be deemed to have been provided if the city provides notice through a display advertisement at least four inches by two columns in size in the official newspaper of the city at least 15 days prior to the hearing date, in addition to site posting on all external boundaries of the site.
2. The Idaho Department of Water Resources shall be notified by the applicant prior to any alteration or relocation of a watercourse, and the flood hazard ordinance administrator shall submit evidence of such notification to the Federal Insurance Administration.
3. In any public hearing on a stream alteration permit application, the presiding officer may order the hearing to be continued up to 30 days without further notice.
C. Commission Evaluation. A completed application will be heard by the commission at a public hearing within a maximum of 30 days following its receipt. The commission shall review the particular facts and circumstances of each proposed stream alteration and make its determination.
1. Standards. No stream alteration permit shall be issued unless the commission finds adequate evidence that the following mandatory requirements have been met:
a. The applicant has been granted all necessary permits from the Army Corps of Engineers and from the Idaho Department of Water Resources, if applicable.
b. The stream alteration desired will not involve placing an encroachment, structure, fill, deposit, obstruction, storage of materials, or storage of equipment in the floodway unless certification by a registered engineer is provided demonstrating that such alteration will not result in any increase in flood levels during the occurrence of a 100-year flood.
c. The stream alteration desired will not materially increase the boundaries of the floodplain subdistrict.
d. No property of another person will be adversely affected by the proposed stream alteration, whether such property is adjacent to, upstream or downstream from the proposed stream alteration.
D. Conditions. The commission may attach conditions to any stream alteration permit, including, but not limited to, the following:
1. Requiring work to be done at times of lowest water.
2. Requiring work to be done by appropriate construction equipment.
3. Requiring the project to be built to Idaho Department of Water Resources, Army Corps of Engineers or city of Donnelly specifications and standards.
4. Requiring that a registered engineer certify, in writing, that the work has been completed according to the city requirements and stipulations.
5. Requiring any modification in the extent or design of the proposed work in order to meet the mandatory conditions imposed by this chapter.
6. Requiring preservation of existing vegetation, revegetation or placement of fish or wildlife enhancement features.
7. Posting of sufficient security to insure the completion of the work.
8. Requiring review or approval of the application by other agencies or governmental units.
9. Requiring the work to be done at a certain height or location.
10. Reclamation of eroded stream banks in the floodway.
11. Requiring overflow channels to remain open.
12. Restricting the future location of building envelopes.
13. Requiring modifications of the project so as not to raise the level of the base flood elevation and not to encroach upon the floodway.
14. Requiring maintenance within the altered or relocated portion of said watercourse so that the flood carrying capacity is not diminished.
15. Issuance of all required and necessary federal and state permits (e.g., 404 permits).
16. Any other condition reasonably related to the issuance of a stream alteration permit. [Ord. 230, 2016.]
18.80.090 Violation – Penalty.
Any person, entity, or organization which performs or causes or permits to be performed any work or activity in violation of this chapter or who performs any work in excess of the authority granted by the issuance of a flood hazard development permit or a stream alteration permit hereunder or who violates any condition or stipulation placed upon the issuance of a flood hazard development permit or a stream alteration permit shall be guilty of a misdemeanor and upon conviction thereof may be sentenced to serve six months in jail or pay a fine of $300.00 or both. Each day or portion thereof during which any work performed in violation of this chapter continues in existence shall constitute a separate and distinct violation of these provisions. All enforcement provisions of DCC 18.20.060 shall be applicable to any violation of this chapter. [Ord. 230, 2016.]