Loading...
HomeMy WebLinkAboutOrdinance 75- 952, Establishes flood hazard district. 346 ORDINANCE NO. 952 AN ORDINANCE OF TIlE CITY OF BOZEMAN, MONTANA, ESTABLISHING A FLOOD HAZARD DISTRICT, DEFINING ITS BOUNDARIES, PROVIDING FOR THE ISSUANCE OF SPECIAL PERMITS, PROHIBITING SPECIFIC USES, DESIGNATING FLOOD- PROOFING REQUIREMENTS, AND PROVIDING FOR APPEALS AND VARIANCES. Section 1 I BE IT ORDAINED BY THE CITY COMMISSION OF THE CITY OF BOZEMAN, MONTANA, AS FOLLOWS, TO WIT: Intent The Flood Hazard District is an area subject to periodic inundation from flood waters which may overflow from local streams and river. In order to avoid hazard to health, safety, and ~ublic and personal property, this section has been designed to restrict or prohibit uses which are vulner- able to flood damage or loss or which may cause increased flood heights or velocities. Section 2 Special Definitions 1. "Alteration" means an,. change or addition to an artificial obstruction that either increases the size of the artificial obstruction or increases its potential flood hazard. Mainte- nance of an artificial obstruction is not an alteration. However, the repair, reconstruction, or improvement of an artificial obstruction, the cost of which equals or exceeds fifty (50) percent of the actual cash value of the artificial obstruction either (a) before the improvement is started, or (b) if the artificial obstruction has been damaged and is being restored, before the damage occurred, is an alteration and not maintenance. 2. "Channelization project" means the excavation and construction of an artificial channel for the purpose of diverting the entire flow of a watercourse or drainway from its established course. 3. "Flood Fringe" means that portion of a designated floodplain outside the limits of a desi- gnated floodway. I 4. "Floodplain" means the area adjoining the watercourse or drainway which would be covered by the flood water of a flood of one hundred (100) year frequency. 5. "Floodway" means the channel of a watercourse or drainway and those portions of the flood- plain adjoining the channel which are reasonably required to carry and discharge the flood water of any watercourse or drainway. 6. "Riprap" means stone, rock, concrete block, or analogous material that is placed along the banks or bed of a watercourse or drainway for the p~rpose of alleviating erosion. Section 3 District Boundaries and Delineations 1. The area of the district shall be as designated on the flood Hazard Boundary Map for the City of Bozeman, as prepared by the Department of Housing and Urban Development and as delineated in the East Gallatin River and Upper Tributary Flood Hazard Analysis for the area outside of the City of Bozeman, as prepared by the United States Department of Agriculture, Soil Conservation Service. 2. The mapping of the Flood Hazard District does not delineate the boundary between the "Flood- way" and the "Flood fringe". Until such a delineation has been officially made, the requirements of this section shall be uniform for the entire floodplain. 3. The requirements of this section are to be applied as an overlying district in addition to those contained in the basic underlying zone. Section 4 Procedure In addition to the requirements of this zoning code for building and land use permits, the I following procedure shall be followed in the Flood Hazard District: I. Where a special permit to locate a use in the Flood Hazard District is required under the terms of this section, an application form may be obtained from the office of the City Building Inspector. 2. The application shall be filled out and attached to the building or land use permit when submitted to the Building Inspector's office for approval. 3. The Building Inspector shall issue the special permit if, in his opinion, the requirements of this section and of the underlying district have been met. I I I NOTE: for the purposes of enforcing these requirements, the Building Inspector may require a land survey with elevations be submitted by a land surveyor licensed by the state to practice as such. Section 5 Uses Not requiring A Special Permit A special permit is not required in the Flood Hazard District for the following uses, provided they do not require structures other than portable structures, fill, or permanent storage of mater- ials or equipment. 1. Agricultural uses; 2. Industrial-commercial uses, such as loading areas, parking areas, and emergency landing strips; 3. Private and public recreational uses, such as golf courses, driving ranges, archery ranges, picnic grounds, boat launching ramps, swimming areas, parks, wildlife management and natural areas, game farms, fish hatcheries, shooting preserves, target ranges, trap and skeet ranges, hunting and fishing areas, and hiking and horseback riding trails; 4. Forestry, including processing of forest products with portable equipment; and, 5. Residential uses, such as lawns, gardens, parking areas, and play areas. 6. Irrigation and livestock supply wells, provided that they are located at least five hundred (500) feet from domestic supply wells; and, 7. Fences, except permanent fences crossing channels. Section 6 Uses Requiring a Special Permit Uses other than those uses listed in Section 5 shall be allowed by special permit, subject to the following conditions: I. Residential structures and customary accessory buildings shall be constructed such that the lowest finished floor elevation (including basement) are two (2) feet or more above the ele- vation of the flood of one hundred (lOO) year frequency. Footings and foundations may be built by any method permitted by the current issue of the Uniform Building Code. The fill shall be at an elevation no lower than the elevation of the flood of one hundred (100) year frequency and shall extend for at least fifteen (IS) feet at that elevation beyond the structure in all directions, and shall meet the standards set forth in Chapter 70 of the Uniform Building Code. Where existing streets, utilities, or lot dimensions make strict compliance with this provision impossible, the City Building Inspector may authorize through the permit a lesser amount of fill or alternative floodproofing measures. The City Building Inspector shall notify the Department of Natural re- sources, State of Montana, and receive its approval prior to approving any lesser fill or alternative f100dproofing for residential structures; 2. New commercial and industrial structures shall be either constructed as specified in the preceding subparagraph or be adequately floodproofed up to an elevation no lower than two (2) feet above the elevation of the flood of one hundred (100) year frequency. Floodproofing shall be accom- plished in accordance with Section 21.8 and shall further include the following: (a) If the structure is designed to allow internal flooding of the lowest floor, use of the floor shall be limited to such uses as parking, loading areas, and storage of equipment or materials not appreciably affected by flood water. Further, the floors and walls shall be designed and con- structed of materials resistant to flooding up to an elevation of two (2) or more feet above the elevation of the flood of one hundred (100) year frequency; and, (b) Structures whose lowest floors are used for purposes other than parking, loading, or storage of materials resistant to flooding shall be waterproofed up to an elevation no lower than two (2) feet above the elevation of the flood of one hundred (100) year frequency. Waterproofing shall include impermeable membranes or materials for floors and walls, and watertight enclosures for all windows, doors, and other openings. These structures shall be designed to withstand the hydrostatic pres.sures resulting from a flood of one hundred (100) year frequency. 3. Roads, streets, highways, and rail lines shall be designed to minimize increases in flood heights. Where failure or interruption of transportation facilities would result in danger to the public health or safety, the facilities shall be located two (2) feet above the elevation of the flood of one hundred (100) year frequency; and, 4. Public or private structures and facilities for liquid or solid waste treatment and dis- posal must be floodproofed to insure that no pollutants enter flood waters. These facilities must 347 Section 8 Floodproofing Requirements l. All electrical service materials, equipment, and installation for uses permitted with or 348 be allowed and approved under laws and standards administered by the Department of Health and En- vironmental Sciences prior to any approval given by the City Building Inspector. 5. Agricultural structures that have a low flood damage potential, such as sheds, barns, shelters, and hay and grain storage structures, and which are not intended for human habitation are located insofar as possi~le on ground higher than the surrounding ground. 6. Flood control works including: (a) Flood control levees and floodwalls if they are designed and constructed to safely I convey a flood of one hundred (100} year frequency; the cumulative effect of the levees and flood- walls combined with allowable flood fringe encroachments shall not increase the unobstructed ele- vation of a flood of one hundred (100) year frequency more than five-tenths (0.5) foot at any point. The City Engineer may establish either a lower or higher permiss1ble increase in the elevation of the flood of one hundred (100) year frequency for individual levee projects, based on the following criteria: (i) the proposed levees and floodwa11s, except those to protect agricultural land use, areoonstructed at least three (3) feet higher than the elevation of a flood of one hundred (100) year frequency more than five-tenths (0.5) foot at any point; and, (ii) the estimated cumulative effect of other reasonably anticipated future permissible uses; and, (iii) the type and amount of existing flood prone development in the affected area. (b) Riprap, except that which is hand placed, if: (i) the riprap is designed to withstand a flood of one hundred (lOO) year frequency; (ii) the riprap does not increase the elevation of the flood of one hundred (100) year frequency; and, (iii) the riprap will not increase erosion upstream, downstream, or across stream from the riprap site. (c) Channelization projects if they do not significantly increase the magnitude, vel- ocity, or elevation of the flood of one hundred (100) year frequency downstream from such projects. I (d) Dams, provided that: (i) they are designed and constructed in accordance with approved safety standards; and, (ii) they will not increase flood hazards downstream, either through operational procedures or improper hydrologic design. 7. Proposed structures must be anchored to prevent flotation or collapse and must be located as far from stream channels as is practicable; and, 8. Where a proposed development within such designated floodplain may significantly increase flood velocities or depths, additional hydraulic and survey information may be required of the permit applicant before a permit application is acted upon. This information may include but not be limited to any of the following: (a) Valley cross sections of the watercourse and adjoining floodplain; (b) Certification by a qualified professional engineer that floodproofing measures are reasonably adequate to protect against major flood damages; or, (c) A hydrologic study documenting probable effect on upstream or downstream property owners. Section 7 Prohibited uses The following uses are prohibited in the Flood Hazard Distri~t: 1. Solid waste disposal and soil absorption sewage systems, except as allowed or approved under laws and standards administered by the Department of Health and Environmental Sciences; and I 2. Storage of highly toxic, flammable, or explosive materials. Storage of petroleum pro- ducts may beallowed by permit if buried in tightly sealed and constrained containers or if stored on compacted fill at least two (2) feet above the elevation of the flood of one hundred (100) year frequency. I I I without a permit in the Flood Hazard District shall conform to the following conditions: (a) All incoming power service equipment, including all metering equipment, control centers, transformers, distribution and lighting panels, and all other stationary equipment must be located at least two (2) feet above the elevation of the flood of one hundred (100) year frequency; (b) Portable or movable electrical equipment may be placed below the elevation of the flood of one hundred (100) year frequency, provided that the equipment can be disconnected by a single plug-and~socket assembly of the submersible type; (c) The main power service line shall have automatically operated electrical disconnect equipment or manually operated electrical disconnect equipment located at an accessible remote location outside the designated floodplain and above the elevation of the flood of one hundred (100) year frequency; and, (d) All electrical wiring systems installed below the elevation of the flood of one hundred (100) year frequency shall be suitable for continuous submergence and may not contain fibrous components. 2. Heating systems for allowed and permitted !lood Hazard District uses shall conform to the following conditions: (a) Float operated automatic control waives must be installed in supply lines to gas furnaces, so that the fuel supply is automatically shut off when flood waters reach the floor level where the furnaces are located; (b) Manually operated gate valves that can be operated from a location above the ele- vation of the flood of one hundred (100) year frequency shall also be provided in gas supply lines; and (c) Electric heating systems must be installed in accordance with item one (1) of this section. 3. Plumbing systems for allowed and permitted Flood Hazard Districts shall conform to the following conditions: (a) Sewer Lines, except those to buried and sealed vaults, must have check valves in- stalled to prevent sewage backup into permitted structures; and, (b) All toilet stools, sinks, urinals, and drains must be located such that the lowest point of possible water entry is at least two (2) feet above the elevation of the flood of one hundred (100) year frequency. Section 9 Additional Factors In addition to the other requirements of this section, the following additional factors shall be considered by the Building Inspector before a special permit is granted or denied: 1. The danger to life and property from backwater or diverted flow caused by the obstruction; 2. The danger that the obstruction will be swept downstream to the injury of others; 3. The availability of alternative locations; 4. The construction of alteration of the obstruction in such a manner as to lessen the danger; 5. The permanence of the obstruction; 6. The anticipated development in the foreseeable future of the area which may be affected by the obstruction; and 7. Such other factors as are in harmony with the purposes of the Act and these rules. Section 10 Appeals and Variance Requests Appeals and variance requests from the use requirements may be granted in accordance with the provision of Section 31, and only if: 1. The proposed use would not increase flood heights or flood hazard either upstream or downstream; 2. Refusal of a permit would, because of exceptional circumstances, cause a unique or undue hardship on the applicant or community involved; 3. The proposed use is adequately floodproofed; and, 4. Reasonable alternative locations outside the designated floodplain are not available. Appeals related to the boundary delineation of the Flood Hazard District must be made to the Department of Natural Resources and Conservation of the State of Montana; where an area originally designated as being included in the floodplain is officially deleted or the floodplain is otherwise 349 350 amended by the Department of Natural Resources and Conservation, the boundaries of the Flood Hazard District shall be automatically amended to reflect these changes. Section 11 Time Period for Approval A permit application is considered to have been automatically granted sixty (60) days after receipt of the application, unless the Building Inspector notifies the applicant before the six- tieth (60th) day that the permit is denied or granted. PASSED, ADOPTED, and APPROVED by the City Commission of the City of Bozeman this 19th day of March, 1975. EDMUND P. SEDIVY, Sr., Mayor ATTEST: ~) ~/ c~/ L 'A~7V~~ HA~tNC:<f~' . '7 Clerk of the City Commission State of Montana ) County of Gallatin ss City of Bozeman ) 1, Erna V. Harding, Clerk of the Commission of the City of Bozeman, do hereby certify, that the foregoing Ordinance No. 952 was published by Title and number in the Bozeman Daily Chronicle, a newspaper of general circulat- ion printed and published in Bozeman in the issue of the 23rd day of March 1975, and due proof of such publication is on file in my office. IN WITNESS WHEREOF 1 hereunto set my hand and affix the corporate seal of my office this 26th day of March 1975. c /O~ J::c:-?:?-c<.../ I, ;/~t: ... c ':/ ERNA V. HARDING, Clerk of the City Commission I I I