[HISTORY: Adopted by the City Commission of the City of Royal Oak 10-10-1977 by Ord. No. 77-17. Amendments noted where applicable.]
In order to accomplish its purposes, this chapter includes methods and provisions for:
Restricting or prohibiting uses which are dangerous to health, safety, and property due to water or erosion hazards, or which result in damaging increases in erosion or in flood heights or velocities;
Requiring that uses vulnerable to floods, including facilities which serve such uses, be protected against flood damage at the time of initial construction;
Controlling the alteration of natural floodplains, stream channels, and natural protective barriers, which help accommodate or channel floodwaters;
Controlling filling, grading, dredging and other development which may increase flood damage; and
Preventing or regulating the construction of flood barriers which will unnaturally divert floodwaters or which may increase flood hazards in other areas.
Unless specifically defined below, words or phrases used in this chapter shall be interpreted so as to give them the meanings they have in common usage and to give this chapter its most reasonable application:
- AREA OF SPECIAL FLOOD HAZARD
- The land in the floodplain within a community subject to a one-percent or greater chance of flooding in any given year.
- BASE FLOOD
- The flood having a one-percent chance of being equaled or exceeded in any given year.
- Any man-made change to improved or unimproved real estate, including but not limited to buildings or other structures, mining, dredging, filling, grading, paving, excavation or drilling operations located within the area of special flood hazard.
- FLOOD or FLOODING
- A general and temporary condition of partial or complete inundation of normally dry land areas from:
- FLOOD HAZARD BOUNDARY MAP (FHBM)
- The official map issued by the Federal Insurance Administration where the areas of special flood hazard have been designated Zone A.
- HABITABLE FLOOR
- Any floor usable for living purposes, which includes working, sleeping, eating, cooking or recreation, or a combination thereof. A floor used only for storage purposes is not a "habitable floor."
- MOBILE HOME
- A structure that is transportable in one or more sections, built on a permanent chassis, and designed to be used with or without a permanent foundation when connected to the required utilities. It does not include recreational vehicles or travel trailers.
- A walled and roofed building or mobile home that is principally above ground.
- SUBSTANTIAL IMPROVEMENT
- Any repair, reconstruction, or improvement of a structure, the cost of which equals or exceed 50% of the market value of the structure either before the improvement or repair is started, or, if the structure has been damaged and is being restored, before the damage occurred. For the purposes of this definition, "substantial improvement" is considered to occur when the first alteration of any wall, ceiling, floor, or other structural part of the building commences, whether or not that alteration affects the external dimensions of the structure. The term does not, however, include either:
- A. Any project for improvement of a structure to comply with existing state or local health, sanitary, or safety code specifications which are solely necessary to assure safe living conditions; or
- B. Any alteration of a structure listed on the National Register of Historic Places or a State Inventory of Historic Places.
For the purpose of this chapter only, the following rules shall apply:
This chapter shall apply to all areas of special flood hazard within the jurisdiction of Royal Oak.
The areas of special flood hazard identified by the Federal Insurance Administration in its Flood Hazard Boundary Map (FHBM), #03, dated June 4, 1976, are adopted by reference and declared to be a part of this chapter. The FHBM is on file at 211 Williams Street, Royal Oak, Michigan.
No structure or land shall hereafter be constructed, located, extended, converted, or altered without full compliance with the terms of this chapter and other applicable regulations.
This chapter is not intended to repeal, abrogate, or impair any existing easements, covenants, or deed restrictions. However, where this chapter and another ordinance, easement, covenant, or deed restriction conflict or overlap, whichever imposes the more stringent restriction shall prevail.
The degree of flood protection required by this chapter is considered reasonable for regulatory purposes and is based on scientific and engineering considerations. Larger floods can and will occur on rare occasions. Flood heights may be increased by man-made or natural causes. This chapter does not imply that land outside the areas of special flood hazard or uses permitted within such areas will be free from flooding or flood damages. This chapter shall not create liability on the part of the City of Royal Oak, any officer or employee thereof, or the Federal Insurance Administration, for any flood damages that result from reliance on this chapter or any administrative decision lawfully made thereunder.
Establishment of development permit. A development permit shall be obtained before construction or development begins within any area of special flood hazard established in § 351-3B. Application for a development permit shall be made on forms furnished by the Director of Community Development and may include, but not be limited to, plans, in duplicate, drawn to scale showing the nature, location, dimensions and elevations of the area in question, existing or proposed structures, fill, storage of materials, drainage facilities and the location of the foregoing. Specifically, the following information is required:
Elevation, in relation to mean sea level, of the lowest floor (including basement) of all structures;
Elevation in relation to mean sea level to which any structure has been floodproofed;
Certification by a registered professional engineer or architect that the floodproofing methods for any nonresidential structure meet the floodproofing criteria in § 351-6B; and
Description of the extent to which any watercourse will be altered or relocated as a result of proposed development.
Designation of the Director of Community Development. The Director of Community Development is hereby appointed to administer and implement this chapter by granting or denying development permit applications in accordance with its provisions.
Duties and responsibilities of the Director of Community Development. The duties of the Director of Community Development shall include, but not be limited to:
Permit review. The Director of Community Development shall:
Review all development permits to determine that the permit requirements of this chapter have been satisfied.
Review all development permits to determine that all necessary permits have been obtained from those federal, state or local governmental agencies from which prior approval is required.
Review all development permits to determine if the proposed development adversely affects the flood-carrying capacity of the area of special flood hazard. For the purposes of this chapter, "adversely affects" means damage to adjacent properties because of rises in flood stages attributed to physical changes of the channel and the adjacent overbank areas.
If it is determined that there is no adverse effect and the development is not a building, then the permit shall be granted without further consideration.
If it is determined that there is an adverse effect, then technical justification (i.e., a registered professional engineer) for the proposed development shall be required.
If the proposed development is a building, then the provisions of this chapter shall apply.
Use of other base flood data. When base flood elevation data has not been provided in accordance with § 351-3B, the Director of Community Development shall obtain, review and reasonably utilize any base flood elevation data available from a federal, state or other source, in order to administer § 351-6, Specific standards for flood hazard reduction.
Information to be obtained and maintained. The Director of Community Development shall:
Obtain and record the actual elevation (in relation to mean sea level) of the lowest habitable floor (including basement) of all new or substantially improved structures, and whether or not the structure contains a basement.
Maintain for public inspection all records pertaining to the provisions of this chapter.
Alteration of watercourses. The Director of Community Development shall:
Notify adjacent communities and the Department of Natural Resources prior to any alteration or relocation of a watercourse and submit evidence of such notification to the Federal Insurance Administration.
Require that maintenance is provided within the altered or relocated portion of said watercourse so that the flood-carrying capacity is not diminished.
Interpretation of FHBM boundaries. The Director of Community Development shall make interpretations, where needed, as to the exact location of the boundaries of the areas of special flood hazard (for example, where there appears to be a conflict between a mapped boundary and actual field conditions).
In all areas of special flood hazard, the following standards are required:
All new construction and substantial improvements shall be anchored to prevent flotation, collapse, or lateral movement of the structure.
All mobile homes shall be anchored to resist flotation, collapse, or lateral movement by providing over-the-top and frame ties to ground anchors. Specific requirements shall be that:
Over-the-top ties be provided at each of the four corners of the mobile home, with two additional ties per side at intermediate locations, with mobile homes less than 50 feet long requiring one additional tie per side;
Frame ties be provided at each corner of the home with five additional ties per side at intermediate points, with mobile homes less than 50 feet long requiring four additional ties per side;
All components of the anchoring system be capable of carrying a force of 4,800 pounds; and
Any additions to the mobile home be similarly anchored.
Construction materials and methods.
All new and replacement water supply systems shall be designed to minimize or eliminate infiltration of floodwaters into the system;
New and replacement sanitary sewage systems shall be designed to minimize or eliminate infiltration of floodwaters into the systems and discharge from the systems into floodwaters; and
On-site waste disposal systems shall be located to avoid impairment to them or contamination from them during flooding.
All subdivision proposals shall be consistent with the need to minimize flood damage;
All subdivision proposals shall have public utilities and facilities such as sewer, gas, electrical, and water systems located and constructed to minimize flood damage;
All subdivision proposals shall have adequate drainage provided to reduce exposure to flood damage; and
Base flood elevation data shall be provided for subdivision proposals and other proposed development which contain at least 50 lots or five acres (whichever is less).
In all areas of special flood hazard where base flood elevation data has been provided as set forth in § 351-4C(2), Use of other base flood data, the following standards are required:
Residential construction. New construction and substantial improvement of any residential structure shall have the lowest floor, including basement, elevated to or above base flood elevation.
Nonresidential construction. New construction and substantial improvement of any commercial, industrial or other nonresidential structure shall either have the lowest floor, including basement, elevated to the level of the base flood elevation or, together with attendant utility and sanitary facilities, shall:
Be floodproofed so that below the base flood level the structure is watertight with walls substantially impermeable to the passage of water;
Have structural components capable of resisting hydrostatic and hydrodynamic loads and effects of buoyancy; and
This chapter shall be known and may be cited as the "Flood Damage Prevention Ordinance."