Dams and Reservoirs Definitions

Alteration - any change to a dam or reservoir which affects the physical parameters and safety of the dam or reservoir which may include but is not limited to changing the height of a dam, increasing the normal pool or principal spillway elevation or changing the elevation or physical dimensions of an emergency spillway.

Appurtenant works - include but are not limited to such structures as spillways, either in the dam or separate therefrom, low level outlet works and water conduits.

Board - the Board of Health and Environmental Control.

Classification inspection - visual examination of an existing dam or proposed dam site to determine the physical dimensions of the dam and reservoir and the hazard potential of the structure, irrespective of the structural safety of the dam itself.

Dam - any artificial barrier, together with appurtenant works, including but not limited to dams, levees, dikes or floodwalls for the impoundment or diversion of water or other fluids where failure may cause danger to life or property.

Department - the South Carolina Department of Health and Environmental Control or its staff or agents.

Detailed inspection - all studies, investigations and analyses necessary to evaluate conclusively the structural safety and hydraulic capacity of a dam or reservoir and appurtenant works. This inspection may include but is not limited to soil analysis, concrete or earth stability analysis, materials testing, foundation explorations, hydrologic analysis, including basin studies and flood potential. This inspection shall be performed by a qualified registered professional engineer.

Engineer - a registered professional engineer licensed to practice in the State or an individual employed by the USDA-Natural Resources Conservation Service with the title of engineer who is qualified and authorized to sign documents prepared and submitted by USDA-Natural Resources Conservation Service.

Hazard Potential - the potential for causing property damage or loss of human life in the event of failure or improper operation of a dam or reservoir.

Height of a dam is measured in feet from the top of the dam to the natural bed of the stream or water course at the downstream toe of the barrier; if the barrier is not across a stream or water course, height is measured from the top of the dam to the lowest elevation of the outside limit of the barrier.

Operate a dam or reservoir - to perform functions intended to preserve or protect the dam or reservoir (or the area potentially impacted by the dam or reservoir). Examples of operator functions include removal or replacement of flashboards, opening or closing of gates, removal of accumulated trash at the spillway, and maintenance functions such as mowing grass on the dam, etc

Order - a written document prepared and issued by the Department which mandates specific actions to be accomplished by a dam owner within a specified time frame.

Owner - those who own, control, operate, maintain, manage or propose to construct a dam or reservoir. In cases where a dam has been abandoned by its owner (either intentionally or unintentionally), and it is necessary to reestablish ownership, the Department shall look first to those entities who hold title to the property on which the dam is constructed and those entities who have acquired some legal responsibility for the dam through covenants or other legal agreements, and secondarily to the other entities who fall under the definition of owner.

Preliminary inspection - a visual but technical evaluation of the structural integrity and physical stability of a dam and may include an analysis of the dam's ability to pass flood waters. The term preliminary inspection - also the recurring routine reinspections that the Department may schedule for certain dams.

Probable Maximum Flood (PMF) - the largest flood that theoretically could occur at a given site during our present geological and climatic era. The initiating event in a PMF determination is the PMP.

Probable Maximum Precipitation (PMP) - the theoretically greatest-depth of precipitation for a given duration that is physically possible over a given area at a given time of year; these projected maximum precipitation numbers are arrived at by the National Weather Service by studying actual storm events that have occurred in similar climatic areas. Information on PMP is available in publications from the National Weather Service NOAA.

Removal - the destruction or breaching of a dam or reservoir to the extent that no water or fluid can be impounded by the dam or reservoir.

Repairs - any work done on a dam which may affect the safety of the dam. This includes but is not limited to work requiring excavation into the embankment fill or foundation of a dam or work requiring removal or replacement of major structural components of a dam.

Reservoir - an area which contains or will contain the water or fluid impounded by a dam.

Storage capacity or impoundment storage of a reservoir is defined to be the volume of water (normally measured in acre-feet) contained in the impoundment at maximum storage elevation (i.e., when water is at the top of the dam.)​​​​​​​


Dams & Reservoirs Environment