Mississippi Administrative Code › Title 11 - Mississippi Department of Environmental Quality › Part 7 - Surface Water and Groundwater Use and Protection, Licensing of Water Well Contractors and Dam Safety Regulations › Chapter 3 - Mississippi Commission on Environmental Quality Dam Safety Regulations › Rule 11-7-3.1 - Definitions

Current through June 25, 2024
The words and phrases used in this regulation shall have the
				  meanings set forth in this section:
Alter or Repair
- Any change in the
				  surface or cross-section of existing dams and/or appurtenant works or any
				  modification to appurtenant structures, other than minor grading and fill
				  associated with routine slope and turf maintenance activities. Examples of
				  alterations or repairs include such work as adding significant amounts of
				  material to, or removing material from, the cross-section of a dam; changing
				  the dimensions or elevations of an auxiliary (emergency) or overflow spillway;
				  replacing pipe or in any other way altering a principal spillway; making any
				  repairs of erosion or undermining associated with seepage through the dam;
				  building a roadway on or across any part of a dam; burying pipelines; or in any
				  way altering the approved operational features of a dam.
Appurtenant Works
- This term
				  includes, but is not limited to; spillways, either in the dam or separate there
				  from; the reservoir and its rim or shoreline; low level outlet works; and water
				  conduits such as tunnels, pipelines, or penstocks, either through the dam or
				  its abutments.
Breach
- Partial removal of a dam
				  by creating a channel through the dam to the original stream bed elevation, so
				  that no water is impounded by the breached structure.
Commission
- The Mississippi
				  Commission on Environmental Quality, or its designee.
Dam
- Any artificial barrier,
				  including appurtenant works, constructed to impound or divert water, waste
				  water, liquid borne materials, or solids that may flow if saturated. All
				  structures necessary to maintain the water level in an impoundment or to divert
				  a stream from its course will be considered one dam.
Days
- Calendar days including
				  Saturdays, Sundays, and Holidays; unless specifically indicated otherwise in
				  the body of this regulation.
Department or MDEQ
- The
				  Mississippi Department of Environmental Quality.
Emergency Action Plan
- A formal
				  written document identifying the area that would be inundated in the event of a
				  dam failure and setting forth the plans and procedures for notifying the
				  individuals, agencies, and public officials that would mobilize resources to
				  respond to the emergency.
Emergency
- This term includes, but
				  is not limited to, uncontrolled breach of a dam; or any conditions leading to,
				  or causing, a breach, overtopping, or any other condition in the dam and/or its
				  appurtenant works that may lead to failure of the dam or otherwise pose a
				  threat to life or property.
Enlarge
- Any change in, or
				  addition to, an existing dam or reservoir, which raises, or may raise the water
				  storage elevation or storage volume of the water, waste-water, or liquid- borne
				  material impounded by the dam.
High Hazard
- A class of dam in
				  which failure may cause loss of life, serious damage to residential,
				  industrial, or commercial buildings; or damage to, or disruption of, important
				  public utilities or transportation facilities such as major highways or
				  railroads. Dams which meet the statutory thresholds for regulation that are
				  proposed for construction in established or proposed residential, commercial,
				  or industrial areas will be assigned this classification, unless the applicant
				  provides convincing evidence to the contrary.
Impoundment or Reservoir
- A
				  man-made dammed, leveed, or diked area or basin designed to store water or
				  other liquids above surface levels that would occur under natural conditions.
Incremental Consequence Analysis
-
				  Incremental Consequence Analysis is an analysis to determine the flood above
				  which there is a negligible increase in downstream water surface elevation,
				  velocity, and/or consequences due to failure of the dam when compared to the
				  same flood without dam failure.
Inflow Design Flood
- the flood
				  event used to determine the design dimensions for the dam and spillways
Low Hazard
- A class of dam in
				  which failure would at the most result in damage to agricultural land, farm
				  buildings (excluding residences), or minor roads.
Permit
- Official written
				  authorization from the Board, or its designee, authorizing construction,
				  enlargement, repair, or alteration of a dam; including any specified conditions
				  or limitations under which the work is to be performed by the person to whom
				  the approval is granted.
Permit Board or Board
- The
				  Mississippi Environmental Quality Permit Board.
Person
- The state or other agency
				  or institution thereof, any municipality, political subdivision, public or
				  private corporation, individual, partnership, association or other entity, and
				  including any officer or governing or managing body of any municipality,
				  political subdivision, or public or private corporation, or the United States
				  or any officer or employee thereof.
Probable Maximum Precipitation
				  (PMP)
- The rainfall event used for hydraulic design of dams and
				  appurtenant spillways in Mississippi. The Probable Maximum Precipitation (PMP)
				  varies by location within the state and the event used in design shall be as
				  defined for the proposed construction location by Hydrometeorological Reports
				  published by the Office of Hydrology, National Weather Service.
Professional Engineer
- An engineer
				  with a minimum of 5 years' experience in the design and construction of dams
				  who is registered with the State of Mississippi Board of Registration for
				  Professional Engineers and Land Surveyors.
Professional Geologist
- A
				  geologist with experience in determining and analyzing geologic conditions
				  affecting the siting of dams who is registered with the Mississippi State Board
				  of Registered Professional Geologists.
Removal
- Complete elimination of
				  the dam embankment or structure to restore the approximate original topographic
				  contours of the area.
Significant Hazard
- A class of dam
				  in which failure poses no threat to life, but may cause significant damage to
				  main roads, minor railroads, or cause interruption of use or service of public
				  utilities.
Substantial Completion
-
				  Substantial completion means the dam is capable of impounding water
Sunny Day Top of Dam
- A condition
				  in which the water surface elevation in the lake is at the elevation of the low
				  point on the crest of the dam and the downstream channel is considered dry
				  prior to a failure of the dam.
Water Storage Elevation
- The
				  maximum surface elevation of water that can be maintained by a dam or
				  reservoir.
Miss. Code Ann.
				  §§
										51-3-1,
				  et seq., 49-2-1, et seq. and 49-17-1, et seq.