Compilation of Rules and Regulations of the State of Georgia
Department 391 - RULES OF GEORGIA DEPARTMENT OF NATURAL RESOURCES
Chapter 391-3 - ENVIRONMENTAL PROTECTION
Subject 391-3-8 - RULES FOR DAM SAFETY
Rule 391-3-8-.02 - Definitions

Universal Citation: GA Rules and Regs r 391-3-8-.02

Current through Rules and Regulations filed through December 18, 2024

For the purpose of these rules and regulations, the term:

(a) "abutment" means the bordering area of the dam site which functions as a support for the ends of the dam structure.

(b) "Act" means the "Georgia Safe Dams Act of 1978" as amended (O.C.G.A. 12-5-370 through 12-5-385).

(c) "appurtenant works" means such structures as spillways, either in the dam or separate therefrom; the reservoir and its rims; low level outlet works; access bridges; and water conduits such as tunnels, pipelines or penstock, either through the dam or its abutments.

(d) "Category I" means the classification where improper operation or dam failure would result in probable loss of human life. Situations constituting "probable loss of life" are those situations involving frequently occupied structures or facilities, including, but not limited to, residences, commercial and manufacturing facilities, schools and churches.

(e) "Category II" means the classification where improper operation or dam failure would not be expected to result in probable loss of human life.

(f) "conduit" means any closed waterway such as a cast-in-place cut-and-cover culvert, a precast or prefabricated pipe imbedded in the dam or foundation or a tunnel bored through the abutment used for the purpose of regulating or releasing water impounded by a dam.

(g) "construct" or "construction" means the building, removal or modification of any artificial barrier, together with appurtenant works for the impoundment or diversion of water or liquid substances and shall include any activity which, other than routinely as part of an approved maintenance program, repairs, removes, or restores such artificial barrier, or alters its design, shape or structural characteristics, and shall also include any enlargement of such artificial barrier.

(h) "dam" means with the exception of the exemptions outlined in Rule 391-3-8-.04 herein, the following:

1. Any artificial barrier, including appurtenant works, which impounds or diverts water and which the improper operation or failure of such would result in probable loss of human life as determined pursuant to the Act, and which
(i) is twenty-five (25) feet or more in height from the natural bed of the stream or water course measured at the downstream toe or the lowest elevation of the outside limit of the barrier (whichever is lower) to the maximum water storage elevation; or

(ii) has an impounding capacity at maximum water storage elevation of one hundred (100) acre-feet or more.

2. Any artificial barrier, including appurtenant works, constructed in conjunction with the reclamation of surface mined land, and meeting the requirements of subsection 1. above, and when improper operation or failure would result in probable loss of human life.

(i) "small dam" means any artificial barrier meeting the requirements of subsection (h) above with a storage capacity not exceeding 500 acre-feet and a height not exceeding 25 feet.

(j) "medium dam" means any artificial barrier meeting the requirements of subsection (h) above with a storage capacity exceeding 500 acre-feet but not exceeding 1000 acre-feet or a height exceeding 25 feet but not exceeding 35 feet.

(k) "large dam" means any artificial barrier meeting the requirements of subsection (h) above and with a storage capacity exceeding 1000 acre-feet but not exceeding 50,000 acre-feet or a height exceeding 35 feet but not exceeding 100 feet.

(l) "very large dam" means any artificial barrier meeting the requirements of subsection (h) above and with a storage capacity exceeding 50,000 acre-feet or a height exceeding 100 feet.

(m) "engineer" means the State Conservation Engineer of the Natural Resources Conservation Service or the engineer of record.

(n) "engineer of record" - means an individual who:

1. Is a licensed engineer registered with the State of Georgia; and

2. Is competent and has relevant experience in areas related to dam investigation, inspection, design, and construction for the type of dam being investigated, inspected, designed, or constructed; and

3. Understands adverse dam incidents, failures and the potential causes and consequences of dam failures; and

4. Will have responsible charge for the design of a new Category I dam or repair of an existing Category I dam; and

5. Has substantiated their qualifications to the Georgia Safe Dams Program prior to their engagement by an Owner/Operator of an existing or proposed Category I Dam.

(o) "flood control pool" means the storage volume of the entire reservoir at the crest of the emergency spillway.

(p) "flood control zone" means the storage volume available between the normal pool and the flood control pool.

(q) "foundation" means the earth or rock which the dams rests.

(r) "freeboard" means the difference in elevation between the top of the dam and the maximum reservoir water surface that would result should the inflow design flood occur and should the outlet works function as planned.

(s) "hydrometeorological gauges" means any of a variety of measuring devices used in determining data concerning rainfall, snow, fog, dew, etc.

(t) "impoundment" means the water or liquid substance that is or will be stored by a dam--commonly referred to as the reservoir.

(u) "maximum water storage elevation" means the elevation of the lowest point of the top of the impoundment structure independent of low points caused by partial failure or collapse.

(v) "normal pool" means the reservoir storage volume at normal storage elevation.

(w) "normal water storage elevation" means the normal elevation of water surface which is obtained by the reservoir when the intake and outlet works are operating as planned during periods of normal precipitation and runoff and not during periods of drought or flood.

(x) "principal spillway" means the spillway which conveys normal runoff out of the reservoir.

(y) "probable maximum precipitation (PMP)" means the greatest amount of rainfall of a six-hour duration which would be excepted for a given drainage basin as determined by Hydrometeorological Report No. 52 published by the U.S. Weather Bureau.

(z) "spillway" means the feature of a storage or detention dam which is designed to released surplus water which cannot be contained in the allotted storage space, and at diversion dams is a means to bypass flows exceeding those which are turned into the diversion system.

(aa) "structural height" means the height of the dam measured from the lowest point of the dam's foundation to the highest point on the top of the dam.

(bb) "surcharge zone" means the reservoir of the storage volume located between the crest of the emergency spillway (flood control pool) and the maximum water storage elevation.

(cc) "surface mining" means any activity constituting all part of a process for the removal of minerals ores and the solid matter for sale or for processing or for consumption in the regular operations of a business. However the removal of mineral ores and other solid matter by tunnels, shafts, and dimension stone quarries shall not be considered surface mining.

O.C.G.A. §§ 12-5-370 through 12-5-385.

Disclaimer: These regulations may not be the most recent version. Georgia may have more current or accurate information. We make no warranties or guarantees about the accuracy, completeness, or adequacy of the information contained on this site or the information linked to on the state site. Please check official sources.
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