Terms defined by SDCL 46-1 to 46-7, inclusive, have the same meaning when used in this chapter. In addition, terms used in this chapter mean:
(1) "Area capacity curves," graphic curves which show the relationship between reservoir surface area and the storage capacity of the reservoir at given elevations;(2) "Breach analysis," a simulated dam failure performed to determine the outflow hydrograph and to route the resulting flood wave;(3) "Category 1 dam," a high hazard dam whose failure may cause loss of life;(4) "Category 2 dam," a significant hazard dam whose failure may cause damage to buildings, highways, railroads, bridges, or public utilities; loss of a water supply reservoir for a water distribution system; other extensive economic loss; or the reservoir is the only source of water for a water distribution system;(5) "Category 3 dam," a low hazard dam whose failure may cause limited damage to agricultural lands or county and township roads or minimum economic loss;(6) "Conservation storage capacity," the volume in acre-feet in the reservoir at the crest of the primary spillway;(7) "Dam," for the purpose of this chapter an artificial barrier, including appurtenant works, which impounds or diverts water and which is 25 feet or more in height from the natural bed of the stream or watercourse measured at the downstream toe of the barrier or from the lowest elevation of the outside limit of the barrier, if it is not across a stream channel or watercourse, to the maximum water storage elevation or has an impounding capacity at maximum water storage elevation of 50 acre-feet or more. A barrier is not considered a dam for the purpose of this chapter if the height does not exceed 6 feet regardless of storage capacity or if the storage capacity at maximum water storage elevation does not exceed 15 acre-feet regardless of height;(8) "Effective height," the difference in elevation in feet between the lowest point in the cross section taken along the centerline of the dam and the crest of the emergency spillway. If there is no emergency spillway, the top of the dam is the upper limit;(9) "Emergency preparedness plan," "EPP," a predetermined plan of action to be taken to reduce the potential for property damage and loss of lives in an area that may be affected by a dam break;(10) "Engineer," a person who is registered as a professional engineer pursuant to SDCL 36-18, or a person who is employed by a federal or state agency and who designs or inspects dams as part of the person's employment, acting under the supervision of a professional engineer registered pursuant to SDCL 36-18;(11) "Freeboard," the vertical distance between the top of the dam and the estimated maximum water level;(12) "Height," the difference in the elevation of either the natural bed of the stream or watercourse or the lowest point on the toe of the dam, whichever is lower, and the crest elevation of the dam;(13) "Inspection," a visual or mechanical check by measuring, boring, or any method necessary to determine the adequacy of construction techniques and the safety and operating performance of a dam;(14) "Intermediate storage capacity," the volume in acre-feet in the reservoir at the crest of the emergency spillway;(15) "Maximum storage capacity," the volume in acre-feet in the reservoir at the crest of the dam;(16) "Owner," "dam owner," a person as defined by SDCL 46-1-6(1) who owns, controls, operates, maintains, manages, or proposes to construct a dam or reservoir;(17) "Preliminary risk assessment," as applied to dam safety, the process of identifying the downstream hazard potential for the purpose of classifying a dam;(18) "Probable maximum flood," "PMF," the flood that may be expected from the most severe combination of critical meteorologic and hydrologic conditions that are possible in the region;(19) "Probable maximum precipitation," "PMP," the precipitation that may be expected from the most severe combination of critical meteorologic conditions that are reasonably possible in an area as found in the National Weather Service Hydrometeorological Report No. 51, "Probable Maximum Precipitation Estimates, United States East of the 105th Meridian"; or Hydrometeorological Report No. 55, "Probable Maximum Precipitation Estimates, United States Between the Continental Divide and the 103rd Meridian";(20) "Process water," water that may have chemicals, sewage, metals, or any other material added to it during the use of the water in an operation;(21) "Risk assessment," as applied to dam safety, the process of identifying the likelihood and consequences of dam failure to provide the basis for informed decisions on a course of action;(22) "Spillway," an open or closed channel, conduit, or drop structure used to convey water from a reservoir.(23) "Spillway design flood," the flood that the spillway of a given project is designated to pass safely without overtopping the structure;(24) "25-year, 24-hour duration flood," the flood magnitude expected to be equaled or exceeded on the average of once in 25 years, with a four percent chance of being exceeded in any given year, determined by using the 25-year, 24-hour storm unless gauging data is available and proved to be accurate;(25) "50-year, 24-hour duration flood," the flood magnitude expected to be equaled or exceeded on the average of once in 50 years, with a two percent chance of being exceeded in any given year, determined by using the 50-year, 24-hour storm unless gauging data is available and proved to be accurate;(26) "100-year flood," the flood magnitude expected to be equaled or exceeded on the average of once in 100 years, with a one percent chance of being exceeded in any given year, determined by using the 100-year, 24-hour storm unless gauging data is available and proved to be accurate.S.D. Admin. R. 74:02:08:01
13 SDR 49, effective 10/27/1986; 13 SDR 129, 13 SDR 141, effective 7/1/1987; 13 SDR 197, effective 7/2/1987; 14 SDR 67, effective 11/8/1987; 15 SDR 158, effective 4/23/1989.General Authority: SDCL 46-2-5, 46-7-3.
Law Implemented: SDCL 46-1-6, 46-1-15, 46-5-10, 46-5-11, 46-5-47, 46-7-3, 46-7-5.
Hydrometeorological Report No. 51, "Probable Maximum Precipitation Estimates, United States East of the 105th Meridian," June 1978, Reprinted August 1986; Hydrometeorological Report No. 55, "Probable Maximum Precipitation Estimates, United States Between the Continental Divide and the 103rd Meridian," March 1984, prepared by the Office of Hydrology, National Weather Service, National Oceanic and Atmospheric Administration, U. S. Department of Commerce. Copies may be obtained from the Division of Water Rights, Joe Foss Building, 523 East Capitol Avenue, at no cost.