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(A) Statutory authorization.
(B) This floodplain ordinance is adopted pursuant to the authorization and policies contained in M.S. Chapter 103F; Minn. Rules, Parts 6120.5000 – 6120.6200; the rules and regulations of the National Flood Insurance Program codified as 44 Code of Federal Regulations Parts 59 - 78; and the planning and zoning enabling legislation in M.S. Chapter 462.
(C) Purpose.
(1) This part regulates development in the flood hazard areas of the city. The flood hazard areas of the city are subject to periodic inundation that results in potential loss of life, loss of property, health and safety hazards, disruption of commerce and governmental services, extraordinary public expenditures or flood protection and relief, and impairment of the tax base, all of which adversely affect the public health, safety and general welfare.
(2) This part is adopted to maintain the community's eligibility in the National Flood Insurance Program.
(3) This part is also intended to preserve the natural characteristics and functions of watercourses and floodplains in order to moderate flood and stormwater impacts, improve water quality, reduce soil erosion, protect aquatic and riparian habitat, provide recreational opportunities, provide aesthetic benefits, and enhance community and economic development.
(D) Lands to which this part applies. This part shall apply to all lands within the jurisdiction of the city shown on the official zoning map, and/or the attachments thereto, as being located within the boundaries of the Floodway, Flood Fringe, or General Floodplain Overlay Districts.
(E) Establishment of Official Zoning Map.
(1) The Official Zoning Map, together with all materials attached thereto, is hereby adopted by reference and declared to be a part of this part.
(2) The attached material shall include the Flood Insurance Study, Chisago County, Minnesota and Incorporated Areas dated 4/17/12, Flood Insurance Rate Map panels therein numbered 27025C0275D, 27025C0288D, 27025C0289D, 27025C0290D and 27025C0380D, all dated April 17, 2012, and prepared by the Federal Emergency Management Agency.
(3) The official zoning map shall be on file in the Office of the County Auditor and the Zoning Administrator.
(F) Regulatory flood protection elevation. The regulatory flood protection elevation shall be an elevation no lower than one foot above the elevation of the regional flood, plus any increases in flood elevation caused by encroachments on the floodplain that result from designation of a floodway.
(G) Interpretation.
(1) The Floodway, Flood Fringe, and General Floodplain Overlay Districts are overlay districts superimposed over existing zoning districts. The standards imposed in the overlay districts are in addition to any other requirements in this chapter. In case of a conflict, the more restrictive standards shall apply.
(2) Where a conflict exists between the floodplain limits illustrated on the official floodplain maps and actual field conditions, the regional flood elevations shall be the governing factor in locating the outer boundaries of the regional flood floodplain.
(3) The regulatory limits of the district boundaries shall be further extended outward based on the horizontal extension of the regulatory flood protection elevation.
(4) Persons contesting the location of the district boundaries shall be given a reasonable opportunity to present their case to the City Council and to submit technical evidence.
(H) Abrogation and greater restrictions. It is not intended by this part to repeal, abrogate or impair any existing easements, covenants or deed restrictions. However, where this part imposes greater restrictions, the provisions of this part shall prevail. All other ordinances inconsistent with this part are hereby repealed to the extent of the inconsistency only.
(I) Warning and disclaimer of liability. This part does not imply that areas outside the Floodplain Overlay Districts or land uses permitted within the districts will be free from flooding or flood damages. This part shall not create liability on the part of the city, or any officer or employee thereof, for any flood damages that result from reliance on this part or any administrative decision lawfully made thereunder.
(J) Severability. If any section, clause, provision, or portion of this part is adjudged unconstitutional or invalid by a court of competent jurisdiction, the remainder of this part shall not be affected thereby.
(L) Annexations. The flood insurance rate map panels adopted by reference may include floodplain areas that lie outside of the corporate boundaries of the city at the time of adoption of this part. If any of these floodplain land areas are annexed into the city after the date of adoption of this part, the newly annexed floodplain lands shall be subject to the provisions of this part immediately upon the date of annexation into the city.
(M) Establishment of districts.
(1) Districts.
(a) Floodway Overlay District. Those areas within Zone AE delineated within floodway areas as shown on the flood insurance rate maps and flood boundary and floodway maps adopted in this section that were determined to be located in the floodway based on delineation methods outlined in § 151.03.34(B).
(b) Flood Fringe Overlay District. Those areas within Zone AE as shown on the flood insurance rate map and flood boundary and floodway maps adopted in this section, but located outside of the floodway based on the delineation methods outlined in § 151.03.34(B). This district also includes any additional area encompassed by the horizontal extension of the regulatory flood protection elevation, as specified in subsection (G)(3) of this section.
(c) General Floodplain Overlay District. Those areas within Zone AE that do not have a floodway delineated as shown on the flood insurance rate maps adopted in this section. This district also includes any additional area encompassed by the horizontal extension of the regulatory flood protection elevation, as specified in subsection (G)(3) of this section.
(2) General requirements.
(a) A permit shall be obtained from the Zoning Administrator to verify if a development meets all applicable standards outlined in this part prior to conducting the following activities:
1. The erection, addition, modification, rehabilitation, or alteration of any building, structure, or portion thereof. Normal maintenance and repair also requires a permit if such work, separately or in conjunction with other planned work, constitutes a substantial improvement as defined in Chapter 154 Definitions.
2. The construction of a dam, on-site septic system, or any fence not meeting the definition of an agricultural fence defined in Chapter 154 Definitions.
3. The change or extension of a nonconforming use.
4. The repair of a structure that has been damaged by flood, fire, tornado, or any other source.
5. The placement of fill, excavation of materials, or the storage of materials or equipment within the floodplain.
6. Relocation or alteration of a watercourse (including stabilization projects or the construction of new or replacement culverts and bridges), unless a public waters work permit has been obtained by the Department of Natural Resources.
7. Any other type of “development” as defined in this chapter.
(b) Minimum development standards. All new development must be:
1. Designed or modified and adequately anchored to prevent flotation, collapse, or lateral movement of the structure resulting from hydrodynamic and hydrostatic loads, including the effects of buoyancy;
2. Constructed with materials and equipment resistant to flood damage;
3. Constructed by methods and practices that minimize flood damage;
4. Constructed with electrical, heating, ventilation, ductwork, plumbing, and air conditioning equipment and other service facilities that are designed and/or located so as to prevent water from entering or accumulating within the components during conditions of flooding;
5. Reasonably safe from flooding and consistent with the need to minimize flood damage within the flood-prone area; and
6. Assured to provide adequate drainage to reduce exposure to flood hazards, and not be detrimental to uses in adjoining areas.
7. Floodplain developments shall not adversely affect the hydraulic capacity of the channel and adjoining floodplain of any tributary watercourse or drainage system where a floodway or other encroachment limit has not been specified on the official zoning map.
(c) Floodplain developments shall not adversely affect the hydraulic capacity of the channel and adjoining floodplain of any tributary watercourse or drainage system.
(d) Materials that, in time of flooding, are buoyant, flammable, explosive, or could be injurious to human, animal, or plant life shall be stored at or above the flood protection elevation, floodproofed, or protected by structural measures consistent with the standards set forth herein. Furthermore, storage of materials likely to cause pollution of the waters, as defined in M.S. § 115.01, if subject to flooding are prohibited unless adequate safeguards approved by the state water pollution control agency are provided.
(e) Critical facilities, as defined in Chapter 154 Definitions, are to be located so that the lowest floor is not less than two feet above the regional flood elevation, or the 0.2% annual chance flood elevation, whichever is higher.
(Ord. 20220120-01, passed 1-20-22)
(A) Permitted uses. The permitted uses listed below are only allowable in the floodway if not prohibited by any other underlying zoning district classifications of the city, and if not prohibited by any applicable state or federal law:
(1) General farming, pasture, grazing, farm fences, outdoor plant nurseries, horticulture, forestry, sod farming, and wild crop harvesting;
(2) Loading areas, parking areas, streets, trails, airport landing strips, railroads, bridges, culverts, utility transmission lines and pipelines;
(3) Open space uses including but not limited to private and public golf courses, tennis courts, driving ranges, archery ranges, picnic grounds, boat-launching ramps, swimming areas, parks, wildlife and nature preserves, game farms, fish hatcheries, shooting preserves, hunting and fishing areas, and recreational trails;
(4) Residential yards, lawns, gardens, parking areas, and play areas, provided these uses do not include associated accessory structures; and
(5) Grading or land alterations associated with stabilization projects.
(6) Accessory structures.
(B) Standards for permitted uses.
(1) The use shall have a low flood damage potential.
(2) The use shall be permissible in the underlying zoning district if one exists.
(3) The use shall not obstruct flood flows or increase flood velocities, stages, or flood damages, as certified by a registered professional engineer.
(4) The use shall not involve structures.
(5) Development that will change the course, current, or cross section of protected wetlands or public waters is required to obtain a public waters work permit in accordance with M.S. § 103G.245 or a utility crossing license in accordance with M.S. § 84.415 from the Department of Natural Resources, or demonstrate that no permit is required, before applying for a local permit.
(6) Any facility that will be used by employees or the general public must be designed with a flood warning system that provides adequate time for evacuation if the area is inundated to a depth and velocity such that the depth (in feet) multiplied by the velocity (in feet per second) would exceed a product of four upon occurrence of the regional flood.
(7) Accessory structure standards:
(a) Structures are not intended for human habitation;
(b) Structures will have a low flood damage potential;
(c) Structures will be constructed and placed so as to offer a minimal obstruction to the flow of flood waters;
(d) Structures must be elevated on fill or structurally dry floodproofed and watertight to the regulatory flood protection elevation. Certifications consistent with § 151.03.39 shall be required.
(e) As an alternative, an accessory structure may be floodproofed in a water to accommodate internal flooding. To allow for the equalization of hydrostatic pressure, there shall be a minimum of two openings on at least two sides of the structure and the bottom of all openings shall be no higher than one foot above grade. The openings shall have a minimum net area of not less than one square inch for every square foot of enclosed area subject to flooding, have a net area of not less than one square inch for every square foot of enclosed area subject to flooding, and shall allow automatic entry and exit of floodwaters without human intervention. A floodproofing certification consistent with § 151.03.39 shall be required.
(C) Conditional uses. The conditional uses listed below are only allowable in the floodway if not prohibited by any other underlying zoning district classifications of the city, and if not prohibited by any applicable state or federal law.
(1) Grading, extraction, fill, and storage of sand, gravel and other materials for purposes other than stabilization projects;
(2) Marinas, boat rentals, permanent docks, piers, wharves, navigational facilities, and water-control structures;
(3) Railroads, streets, bridges, utility transmission lines and pipelines;
(4) Storage yards for equipment, machinery, or materials; and
(5) Fences that have the potential to obstruct flood flows.
(D) Standards for conditional uses.
(1) All uses. No fill (including fill for roads and levees), deposit, obstruction or other use may be allowed as a conditional use that will cause any increase in the stage of the regional flood, or cause an increase in flood damages in the reach or reaches affected.
(2) All floodway conditional uses shall be subject to the procedures and standards contained in § 151.06.14.
(3) The conditional use shall be permissible in the underlying zoning district if one exists.
(4) Fill; storage of materials and equipment.
(a) Fill, dredge, spoil and all other similar materials deposited or stored in the floodplain shall be protected from erosion by vegetative cover, mulching, riprap or other acceptable method.
(b) Dredge spoil sites and sand and gravel operations shall not be allowed in the floodway unless a long-term site development plan is submitted which includes an erosion/sedimentation prevention element to the plan.
(c)
As an alternative, and consistent with subsection (D)(2) of this section, dredge spoil disposal and sand and gravel operations may allow temporary, on-site storage of fill or other materials that would have caused an increase to the stage of the regional flood, but only after the city has received an appropriate plan that assures the removal of the materials from the floodway, based upon the flood-warning time available.
(d) Storage of other materials or equipment may be allowed if readily removable from the area within the time available after a flood warning, and in accordance with a plan approved by the governing body. The storage or processing of materials that are, in time of flooding, flammable, explosive or potentially injurious to human, animal or plant life is prohibited.
(5) The conditional use permit must be title-registered with the property in the Office of the County Recorder.
(Ord. 20220120-01, passed 1-20-22)
(A) Permitted uses.
(1) Permitted uses shall be those uses of land or structures listed as permitted uses in the underlying zoning district(s). If no preexisting, underlying zoning districts exist, then any residential or nonresidential structure or use of a structure or land shall be a permitted use in the Flood Fringe District, provided the use does not constitute a public nuisance.
(2)
All permitted uses shall comply with the standards for flood fringe permitted uses listed in subsection (B) of this section and the standards for all flood fringe uses listed in subsection (E) of this section.
(B) Standards for flood fringe permitted uses.
(1)
All structures, including accessory structures, must be elevated on fill so that the lowest floor, including the basement floor, is at or above the regulatory flood protection elevation or must adhere to the alternative listed in subsection (B)(2) of this section.
(a) The finished fill elevation for structures shall be no lower than one foot below the regulatory flood protection elevation. The fill for residential structures shall extend at the same elevation at least 15 feet beyond the outside limits of the structure erected thereon.
(2) As an alternative to elevation on fill, enclosed accessory structures that constitute a minimal investment and that do not exceed 576 square feet in size may be floodproofed in accordance with the following standards:
(a) Accessory structures shall only be used for parking and storage.
(b) Accessory structures must allow for the equalization of hydrostatic pressure by accommodating for the inundation of floodwaters. There must be a minimum of two openings in the outside walls of the structure, having a total net area of not less than one square inch for every square foot of enclosed area subject to flooding. There must be openings on at least two sides of the structure, and the bottom of all openings must be no higher than one foot above the lowest adjacent grade to the structure. The openings shall allow automatic entry and exit of floodwaters without human intervention.
(3)
The cumulative placement of fill where at any one time in excess of 1,000 cubic yards of fill is located on the parcel shall be allowable only as a conditional use, unless the fill is specifically intended to elevate a structure in accordance with subsection (B)(1) of this section.
(4) All fill must be properly compacted and the slopes must be properly protected by the use of riprap, vegetative cover, or other acceptable method.
(5) All new principal structures must have vehicular access at or above an elevation no more than two feet below the regulatory flood protection elevation, or must have a flood warning/emergency evacuation plan acceptable to the city.
(6) Accessory uses such as yards, railroad tracks, and parking lots may be at an elevation lower than the regulatory flood protection elevation. However, any facilities used by employees or the general public must be designed with a flood warning system that provides adequate time for evacuation if the area is inundated to a depth and velocity such that the depth multiplied by the velocity would exceed a product of four upon occurrence of the regional flood.
(7)
The provisions of subsection (E) of this section shall apply.
(C) Conditional uses.
(1) The placement of floodproofed nonresidential basements below the regulatory flood protection elevation.
(2) The cumulative placement of more than 1,000 cubic yards of fill when the fill is not being used to elevate a structure in accordance with subsection (B)(1) of this section.
(3) The use of methods other than the fill standards in subsection (B)(1) of this section to elevate the lowest floor above the regulatory flood protection elevation.
(D) Standards for flood fringe conditional uses.
(1) Alternative elevation methods. Alternative elevation methods other than the use of fill may be utilized to elevate a structure’s lowest floor above the regulatory flood protection elevation. These alternative methods may include the use of stilts, pilings, filled stem walls, parallel walls and the like, or internally-flooded, enclosed areas such as crawl spaces, attached garages, or tuck-under garages. The base or floor of an enclosed area shall be considered above-grade, and not a structure’s basement or lowest floor, if:
(a) The enclosed area is above-grade on at least one side of the structure;
(b) It is designed to internally flood; and
(c) It is used solely for parking of vehicles, building access or storage. The above-noted alternative elevation methods are subject to the following additional standards:
1. Internally-flooded, fully enclosed areas, such as crawl spaces or tuck-under garages, must be designed to internally flood and include a minimum of two openings on at least two sides of the structure. The bottom of all openings shall be no higher than one foot above grade, and have a minimum net area of not less than one square inch for every square foot of enclosed area subject to flooding unless a registered professional engineer or architect certifies that a smaller net area would suffice.
2. Floodproofing certifications consistent with § 151.03.39 shall be required. The structure shall be subject to a deed-restricted nonconversion agreement with the issuance of any permit.
(a) Residential basement construction shall not be allowed below the regulatory flood protection elevation.
(b) Nonresidential basements may be allowed below the regulatory flood protection elevation, provided the basement is structurally dry floodproofed in accordance with this part.
(3) Dry floodproofing. All areas of nonresidential structures, including basements, to be placed below the regulatory flood protection elevation shall be floodproofed in accordance with the structurally dry floodproofing classifications in the State Building Code. Structurally dry floodproofing must meet the FP-1 or FP-2 floodproofing classification in the State Building Code, and this shall require making the structure watertight, with the walls substantially impermeable to the passage of water, and with structural components having the capability of resisting hydrostatic and hydrodynamic loads and the effects of buoyancy. Structures floodproofed to the FP-3 or FP-4 classification shall not be permitted.
(4) Erosion/sedimentation control plan. When at any one time more than 1,000 cubic yards of fill or other similar material is located on a parcel for the activities as on-site storage, landscaping, sand and gravel operations, landfills, roads, dredge spoil disposal or construction of flood control works, an erosion/sedimentation control plan must be submitted unless the community is enforcing a state-approved shoreland management ordinance.
(5) Storage of materials and equipment.
(a) The storage or processing of materials that are, in time of flooding, flammable, explosive, or potentially injurious to human, animal or plant life is prohibited.
(b) Storage of other materials or equipment may be allowed if readily removable from the area within the time available after a flood warning and in accordance with a plan approved by the governing body.
(6)
The provisions of subsection (E) of this section shall also apply.
(E) Standards for all flood fringe uses.
(1) Vehicular access. All new principal structures must have vehicular access at or above an elevation not more than two feet below the regulatory flood protection elevation. If a variance to this requirement is granted, the Planning Commission must specify limitations on the period of use or occupancy of the structure for times of flooding, and only after determining that adequate flood warning time and local flood emergency response procedures exist.
(2) Commercial uses. Accessory land uses, such as yards, railroad tracks and parking lots, may be at elevations lower than the regulatory flood protection elevation. However, a permit for the facilities to be used by the employees or the general public shall not be granted in the absence of a flood warning system that provides adequate time for evacuation if the area would be inundated to a depth and velocity such that, when multiplying the depth (in feet) times velocity (in feet per second), the product number exceeds four upon occurrence of the regional flood.
(3) Manufacturing and industrial uses. Measures shall be taken to minimize interference with normal plant operations, especially along streams having protracted flood durations. Certain accessory land uses, such as yards and parking lots, may be at lower elevations subject to requirements set out in subsection (B) of this section. In considering permit applications, due consideration shall be given to needs of an industry whose business requires that it be located in floodplain areas.
(4) Fill compaction and side slope protection standards. Fill shall be properly compacted and the slopes shall be properly protected by the use of riprap, vegetative cover or other acceptable method. The Federal Emergency Agency (FEMA) has established criteria for removing the special flood hazard area designation for certain structures properly elevated on fill above the regional flood elevation. FEMA’s requirements incorporate specific fill compaction and side slope protection standards for multi-structure or multi-lot developments. These standards should be investigated prior to the initiation of site preparation if a change of special flood hazard area designation will be requested.
(Ord. 20220120-01, passed 1-20-22)
(A) Permitted uses.
(1) The uses listed in § 151.03.32 Floodway Overlay District are allowed with a permit.
(B) Procedures for determining floodway boundaries and base flood elevations.
(1) Requirements for detailed studies. Developments greater than 50 lots or five acres, or as requested by the Zoning Administrator, shall be subject to a detailed study to determine the regulatory flood protection elevation and the limits of the Floodway District. The determination of the floodway and flood fringe must be consistent with accepted hydrological and hydraulic engineering standards, and must include the following components, as applicable:
(a) Estimate the peak discharge of the regional flood.
(b) Calculate the water surface profile of the regional flood based upon a hydraulic analysis of the stream channel and overbank areas.
(c) Compute the floodway necessary to convey or store the base flood without increasing flood stages more than one-half foot. A lesser stage increase than one-half foot is required if, as a result of the stage increase, increased flood damages would result. An equal degree of encroachment on both sides of the stream within the reach must be assumed in computing floodway boundaries, unless development or geographic features warrant other analysis, as approved by the Department of Natural Resources.
(2) Alternative methods. For areas where a detailed study is not available or required, the regional flood elevation must be determined using best available data. Until a floodway determination can be completed, the entire floodplain must be treated as floodway, with allowable activities restricted to those identified in § 151.03.32.
(a) Development allowed in floodways (e.g. bridges, culverts, grading, filling, stabilization projects) must not cumulatively increase flood stages more than one-half foot during a base flood event, as determined by a professional engineer or by using accepted engineering practices approved by the Department of Natural Resources. A stage increase less than one-half foot must be used if increased flood damages would result.
(b) Development prohibited in floodways (e.g. buildings) require a floodway/flood fringe determination to verify the development is within the flood fringe. The floodway/flood fringe determination must be done by a professional engineer or utilize other accepted engineering practices approved by the Department of Natural Resources. Any such proposal must assume a one-half foot stage increase for the purposes of determining the regulatory flood protection elevation to accommodate for future cumulative impacts.
(3)
For areas in and along lakes, wetlands, and other basins that are not affected by velocities, where the floodway has not been determined, an alternative to subsections (B)(1) and (B)(2) of this section is:
(a) All areas that are at or below the ordinary high water level (OHW) will be considered floodway, and all areas below the base flood elevation but above the OHW will be considered flood fringe, provided that within 25 feet of the OHW, or within the Shore Impact Zone as identified in the community’s shoreland ordinance, whichever distance is greater, land alterations shall be restricted to:
1. The minimum required to accommodate beach and access areas, and accessory structures as permitted, not to exceed a volume greater than ten cubic yards; projects involving volumes exceeding ten cubic yards require engineering analysis as provided in subsections (B)(1) and (B)(2) of this section, whichever is applicable; and
2. The minimum required to accommodate shoreline stabilization projects to correct an identified erosion problem as identified by the Chisago Soil & Water Conservation District.
(C) The Zoning Administrator will review the submitted information and assess the technical evaluation and the recommended Floodway and/or Flood Fringe District boundary. The assessment must include the cumulative effects of previous floodway encroachments. The Zoning Administrator may seek technical assistance from an engineer or other expert person, or agency, including the Department of Natural Resources.
(D) Once the Floodway and Flood Fringe District boundaries have been determined, the Zoning Administrator must process the permit application consistent with the applicable provisions of this chapter.
(Ord. 20220120-01, passed 1-20-22)
No land shall be subdivided that is unsuitable for the reason of flooding, inadequate drainage, water supply, or sewage treatment facilities. Manufactured home parks and recreational vehicle parks or campgrounds are considered subdivisions under this division.
(A) All lots within the Floodplain Overlay Districts shall be able to contain a building site outside of the Floodway District at or above the regulatory flood protection elevation.
(B) All subdivisions shall have water and sewage treatment facilities that comply with the provisions of this part and have road access, both to the subdivision and to the individual building sites, no lower than two feet below the regulatory flood protection elevation unless a flood warning emergency plan for the safe evacuation of all vehicles and people during the regional flood prepared by a registered engineer or other qualified individual has been approved by the city.
(C) For all subdivisions in the floodplain, the Floodway and Flood Fringe District boundaries, the regulatory flood protection elevation and the required elevation of all access roads shall be clearly labeled on all required subdivision drawings and platting documents.
(Ord. 20220120-01, passed 1-20-22)
(A) Utilities. All utilities and facilities, such as gas, electrical, sewer and water supply systems, to be located in the floodplain shall be elevated to above the regulatory flood protection elevation or located and constructed to minimize or eliminate flood damage.
(B) Public transportation facilities. Railroad tracks, roads, and bridges to be located within the floodplain shall comply with this part. These facilities must be elevated to the regulatory flood protection elevation where failure or interruption of these transportation facilities would result in danger to the public health or safety, or where the facilities are essential to the orderly functioning of the area. Minor or auxiliary roads or railroads may be constructed at a lower elevation where failure or interruption of transportation services would not endanger the public health or safety.
(C) On-site sewage treatment and water supply systems. Where public utilities are not provided:
(1) On-site water supply systems must be designed to minimize or eliminate infiltration of flood waters into the systems and are subject to the provisions in Minn. Rules, Part 4725.4350, as amended; and
(2) New or replacement on-site sewage treatment systems must be designed to minimize or eliminate infiltration of flood waters into the systems, and discharges from the systems into flood waters, and shall not be subject to impairment or contamination during times of flooding, and are subject to the provisions in Minn. Rules, Part 7080.2270, as amended.
(Ord. 20220120-01, passed 1-20-22)
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