11 Miss. Code. R. 7-3.1
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.
11 Miss. Code. R. 7-3.1