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Minnesota Legislature

Office of the Revisor of Statutes

6120.5000 DEFINITIONS.

Subpart 1.

Scope of terms.

For the purposes of these rules, certain terms or words used herein shall be interpreted as follows.

Subp. 2.

Building code.

"Building code" means a collection of regulations adopted by a local governing body setting forth standards for the construction, addition, modification, and repair of buildings and other structures for the purpose of protecting the public health, safety, and general welfare.

Subp. 3.


"Channel" means a natural or artificial depression of perceptible extent, with definite bed and banks to confine and conduct flowing water either continuously or periodically.

Subp. 4.


"Commissioner" means the commissioner of natural resources.

Subp. 5.

Encroachment lines.

"Encroachment lines" means the lateral limits or lines drawn along each side and generally parallel to a stream or another body of water, which delineates the floodway and within which the flood-carrying capacity of the stream or other body of water is to be preserved. Their location, if along a stream, should be such that the floodway between them will effectively carry and discharge a flood not less than the regional flood.

Subp. 6.

Equal degree of encroachment.

"Equal degree of encroachment" means a method of determining the location of encroachment lines so that floodplain lands on both sides of a stream are capable of conveying a proportionate share of flood flows. This is determined by considering the effect of encroachment on the hydraulic efficiency of the floodplain along both sides of a stream for a significant reach.

Subp. 7.


"Flood" means a temporary rise in stream flow or stage which results in inundation of the areas adjacent to the channel.

Subp. 8.

Flood frequency.

"Flood frequency" means the average frequency, statistically determined, for which it is expected that a specific flood stage or discharge may be equalled or exceeded. By strict definition, such estimates are designated "exceedence frequency," but in practice the term "frequency" is used. The frequency of a particular stage or discharge is usually expressed as having a probability of occurring once within a specified number of years. See also recurrence interval in subpart 20.

Subp. 9.

Flood fringe.

"Flood fringe" means that portion of the floodplain outside of the floodway.

Subp. 10.

Flood peak.

"Flood peak" means the highest value of stage or discharge attained during a flood event; thus peak stage or peak discharge.

Subp. 11.


"Floodplain" means the areas adjoining a watercourse which has been or hereafter may be covered by the regional flood.

Subp. 12.

Floodplain management.

"Floodplain management" means the full range of public policy and action for ensuring wise use of the floodplains. It includes everything from collection and dissemination of flood control information to actual acquisition of floodplain lands, construction of flood control measures, and enactment and administration of codes, ordinances, and statutes regarding floodplain land use.

Subp. 13.

Floodplain regulations.

"Floodplain regulations" means the full range of codes, ordinances, and other regulations relating to the use of land and construction within floodplain limits. The term encompasses zoning ordinances, subdivision regulations, and sanitary and building codes.

Subp. 14.

Flood profile.

"Flood profile" means a graph or a longitudinal plot of water surface elevations of a flood event along a reach of a stream or river.

Subp. 15.


"Floodproofing" means a combination of structural provisions, changes or adjustments to properties and structures subject to flooding primarily for the reduction or elimination of flood damages to properties, water and sanitary facilities, structures, and contents of buildings in a flood hazard area.

Subp. 16.

Flood stage.

"Flood stage" means, as commonly used by the U.S. Weather Bureau and others, that stage, at a particular river gauge, where overflow of the natural banks of the stream results in significant flood damage in any portion of the reach for which the gauge is a representative index.

Subp. 17.


"Floodway" means the channel of the watercourse and those portions of the adjoining floodplains which are reasonably required to carry and discharge the regional flood.

Subp. 18.

Local governmental unit.

"Local governmental unit" means a county, city, village, or borough.

Subp. 19.


"Reach" means the hydraulic engineering term used to describe longitudinal segments of a stream or river influenced by a natural or human-made obstruction. In an urban area, the segment of a stream or river between two consecutive bridge crossings would typically constitute a reach.

Subp. 20.

Recurrence interval.

"Recurrence interval" means the average interval of time, based on a statistical analysis of actual or representative stream flow records, which can be expected to elapse between floods equal to or greater than a specified stage or discharge. The recurrence interval is generally expressed in years. See also flood frequency in subpart 8.

Subp. 21.

Regional flood.

"Regional flood" means a flood which is representative of large floods known to have occurred generally in Minnesota and reasonably characteristic of what can be expected to occur on an average frequency in the magnitude of the 100-year recurrence interval.

Subp. 22.

Rural areas.

"Rural areas" means all areas not included under urban areas, such as agricultural, forest, and undeveloped areas.

Subp. 23.

Standard project flood.

"Standard project flood" means the flood that may be expected from the most severe combination of meteorological and hydrological conditions that is considered reasonably characteristic of the geographical area in which the drainage basin is located, excluding extremely rare combinations. Such floods are intended as practicable expressions of the degree of protection that should be sought in the design of flood control works, the failure of which might be disastrous.

Subp. 24.

Subdivision regulations.

"Subdivision regulations" means regulations and standards established by a local unit of government with authority granted under a state enabling law, for the subdivision of land in order to secure coordinated land development.

Subp. 25.

Urban areas.

"Urban areas" means the area within the present corporate limits plus the adjoining areas that are or could be under the statutory extraterritorial zoning jurisdiction of any city, village, or borough.

Subp. 26.


"Watercourse" means a channel in which a flow of water occurs either continuously or intermittently in a definite direction. The term applies to either natural or artificially constructed channels.

Subp. 27.

Zoning ordinance.

"Zoning ordinance" means an ordinance adopted by a local unit of government, with authority from state enabling legislation, which under the police power divides local governmental areas into districts and, within each district, regulates the use of land.

Statutory Authority:

MS s 104.05


17 SR 1279

Published Electronically:

June 11, 2008