Ord 556 Amend Code Concerning Floodway DistrictsCITY OF MENDOTA HEIGHTS
DAKOTA COUNTY, MINNESOTA
ORDINANCE NO. 556
AN ORDINANCE AMENDING TITLE 12, CHAPTER 7, SECTION 4 AND 5 OF THE
CITY CODE OF THE CITY OF MENDOTA HEIGHTS, MINNESOTA, DAKOTA
COUNTY, CONCERNING FLOODWAY DISTRICTS
The City Council of the City of Mendota Heights, Minnesota, does hereby ordain:
Title 12-7 is hereby amended as follows:
12-7-4: FLOODWAY DISTRICT (FW):
A. Permitted Uses, Standards For Floodway and Flood Fringe Permitted Uses:
1. Permitted uses shall be any use of land which does not involve a structure, a fence, an addition to
the outside dimensions to an existing structure (including a fence) or an obstruction to flood flows
such as fill, excavation, or storage of materials or equipment.
2. The use shall not obstruct flood flows or increase flood elevations and shall not involve structures,
fill, obstructions, excavations or storage of materials or equipment.
B. Conditional Uses:
1. Conditional uses shall be permissible in the underlying zoning district and shall have low flood
damage potential.
2. Structures accessory to the uses listed in subsections A and B3 through B8 of this section.
3. Extraction and storage of sand, gravel, and other materials.
4. Marinas, boat rentals, docks, piers, wharves, and water control structures.
5. Railroads, streets, bridges, utility transmission lines, and pipelines.
6. Storage yards for equipment, machinery, or materials.
7. Placement of fill or construction of fences.
8. Structural works for flood control such as levees, dikes, and floodwalls constructed to any height
where the intent is to protect individual structures.
C. Standards for Floodway and Flood Fringe Conditional Uses:
1. All Uses: No structure (temporary or permanent), fill (including fill.for roads and levees), deposit,
obstruction, storage of materials or equipment, or other uses may be allowed as a conditional use
that will cause any increase in the stage of the 100 -year or regional flood or cause an increase in
flood damages in the reach or reaches affected.
2. Procedures And Standards: All floodway and Flood Fringe conditional uses shall be subject to the
procedures and standards contained in subsection 12-7-10D of this chapter.
3. Fill:
Fill, dredge spoil and all other similar materials deposited or stored in the floodplain shah be
preteGted from erosion by vegetative Gover, mulGhing, Fiprap er other acceptable . and Flood
Fringe shall not cause a net decrease in storage capacity without providing compensatory storage.
This shall be determined by a professional engineer, or satisfied through a no -rise certification. If
compensatory storage is needed creation of determined adequate storage shall be created before
the proposed fill is placed unless it is demonstrated that doing so is impractical and that placement
of fill and creation of compensatory storage can be achieved concurrently.
b. Fill, dredge spoil and all other similar materials deposited or stored in the floodplain and Flood Fringe
shall be protected from erosion by vegetative cover, mulching, riprap or other acceptable method.
c. Dredge spoil sites and sand and gravel operations shall not be allowed in the floodway and Flood
Fringe unless a long term site development plan is submitted which includes an
erosion/sedimentation prevention element to the plan.
d. As an alternative and consistent with subsection C3b of this section, dredge spoil disposal and sand
and gravel operations may allow temporary, on site storage of fill or other materials which would
have caused an increase to the stage of the 100 -year or regional flood but only after the governing
body has received an appropriate plan which assures the removal of the materials from the floodway
and Flood Fringe based upon the flood warning time available. The conditional use permit must be
title registered with the property in the office of the county recorder.
4. Accessory Structures:
a. Accessory structures shall not be designed for human habitation.
b. Accessory structures, if permitted, shall be constructed and placed on the building site so as to offer
the minimum obstruction to the flow of floodwaters:
(1) Whenever possible, structures shall be constructed with the longitudinal axis parallel to the direction
of flood flow; and
(2) So far as practicable, structures shall be placed approximately on the same flood flow lines as those
of adjoining structures.
c. Accessory structures shall be elevated on fill or structurally dry floodproofed in accordance with the
FP -1 or FP -2 floodproofing classifications in the state building code. As an alternative, an accessory
structure may be floodproofed to the FP -3 or FP -4 floodproofing classification in the state building
code provided the accessory structure constitutes a minimal investment, does not exceed five
hundred (500) square feet in size at its largest projection, and for a detached garage, the detached
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garage must be used solely for parking of vehicles and limited storage. All floodproofed accessory
structures must meet the following additional standards:
(1) The structure must be adequately anchored to prevent flotation, collapse or lateral movement of the
structure and shall be designed to equalize hydrostatic flood forces on exterior walls;
(2) Any mechanical and utility equipment in a structure must be elevated to or above the regulatory
flood protection elevation or properly floodproofed; and
(3) To allow for the equalization of hydrostatic pressure, there must be a minimum of two (2)
"automatic" 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 (2) sides of the structure and the bottom of all openings must be no higher than one foot
(1') above the lowest adjacent grade to the structure. Using human intervention to open a garage
door prior to flooding will not satisfy this requirement for automatic openings.
12-7-5: FLOOD FRINGE DISTRICT (FF):
A. Permitted Uses: Permitted uses shall be those uses of land or structures listed as permitted uses
in the underlying zoning use district(s).
B. Standards For Flood Fringe Permitted Uses:
1. All structures, including accessory structures, must be elevated on fill so that the lowest floor
including basement floor is at or above the regulatory flood protection elevation. The finished fill
elevation for structures shall be no lower than one feet (1') two feet (2') below the regulatory flood
protection elevation, unless protection via floodproofing is provided, and the fill shall extend at such
elevation at least fifteen feet (15') beyond the outside limits of the structure erected thereon.
2. As an alternative to elevation on fill, accessory structures that constitute a minimal investment and
that do not exceed five hundred (500) square feet at its largest projection may be internally
floodproofed in accordance with subsection 12-7-4C4 of this chapter.
3. The storage of any materials or equipment shall be elevated on fill to the regulatory flood protection
elevation.
This Ordinance shall be in effect from and after the date of its passage and publication.
Adopted and ordained into an Ordinance this twenty first day of April, 2020.
CITY COUNCIL
CITY OF MENDOTA HEIGHTS
Neil Garlock, Mayor
Lorri Smith, City Clerk
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