For the purpose of these rules and regulations, the term: “Abutment” means the bordering area of the dam site which functions as a support for the ends of the dam structure. “Act” means "The Safe Dams Act of 1973", T.C.A. § 69-11-101 et seq., as amended. “Alterations” means any repair, change to the structure, removal or change in use of a dam that may affect the safety of that dam. “Applicant” means any owner of an existing or new dam who applies to the Division for a "Certificate" under the provisions of the Act. “Appurtenant Works” means such structures as spillways, either in the dam or separate therefrom; the reservoir and its rims; water level outlet works; access bridges; and water conduits such as tunnels, pipelines or penstocks, either through the dam or its abutments. “Certificate” means a "Certificate" as required by the Act for the construction, alteration, or operation of a dam. “Commence Construction” means the actual start of on-site building but does not include preliminary surveying work or engineering plans preparation. “Commissioner” means the Commissioner of the Department of Environment and Conservation, his duly authorized representatives and in the event of his absence or a vacancy in the office of Commissioner, the Deputy Commissioner. “Conduit” means any closed waterway including but not limited to, a cast-in-place cut-and- cover culvert, a precast or prefabricated pipe embedded in the dam or foundation or a tunnel bored through the dam. “Dam” means any artificial barrier, together with appurtenant works, which does or may impound or divert water, and which either (1) is or will be twenty (20) feet or more in height from the natural bed of the stream or watercourse at the downstream toe of the barrier, as determined by the Commissioner, or (2) has or will have an impounding capacity at maximum water storage elevation of thirty (30) acre-feet or more. Provided, however, that any such barrier which is or will be less than six (6) feet in height, regardless of storage capacity, or which has or will have a maximum storage capacity not in excess of fifteen (15) acre-feet, regardless of height, shall not be considered a dam, nor shall any barrier, regardless of size, be considered a dam, if, in the judgment of the Commissioner, such barrier creates an impoundment used only as a farm pond. Diversion weirs, roadbeds, water tanks, and wastewater impoundment barriers as defined in this section are not dams. “Days” means calendar days, including Sundays and holidays. “Division” means the Division of Water Resources of the Tennessee Department of Environment and Conservation. “Director” means the Director of the Division of Water Resources of the Department of Environment and Conservation of the State of Tennessee. “Diversion Weir” means a structure substantially within the bed of a stream, designed to impound water only during low flow conditions, that would not cause substantial overflow of water onto the downstream floodplain in the event of failure, and meets the definition of a Category 3 dam in part (2)(b)3 of Rule 0400-45-07-.05. “Easily Erodible” means any soil with a plasticity index of less than ten (10) or greater than forty (40). “Emergency Spillway” means the spillway which conveys out of the reservoir any runoff in excess of that conveyed by the principal spillway. “Engineer” means a professional engineer registered by the State of Tennessee. “Erosion Resistant” means any soil not easily erodible. “Existing Dam” means any dam complete and capable of impounding water prior to October 3, 1987. “Enlargement” means any change in, or addition to, an existing dam or reservoir, which does or may raise the water storage elevation of the dam. “Factor of Safety” means the ratio of the forces or moments resisting mass movement to the forces or moments tending to produce mass movement. “Farm Pond” means any impoundment used only for providing water for agricultural and domestic purposes such as livestock and poultry watering, irrigation of crops, recreation, and conservation, for the owner or occupant of the farm, his family, and invited guests, but does not include any impoundment for which the water, or privileges or products of the water, are available to the general public.

1. (a) General Public as used above means patrons, members, and customers of institutions and/or clubs such as but not limited to summer camps, schools, retirement facilities, churches, private clubs, communes, hunting clubs, and health care facilities.
2. (b) The following are some examples of impoundments which are not farm ponds: Lakes owned or operated by a city, county, or the state, lakes that lie on three or more property parcels, residential subdivision lakes, industrial waste impoundments, industrial water supply impoundments, impoundments owned or used by hunting clubs, public water supply impoundments, commercial land development impoundments, and watershed district impoundments.

3. (c) The following are some examples of impoundments which are farm ponds:

   1. 1. Impoundments directly used in support of farming operations.
   2. 2. Impoundments used for agriculture, livestock watering, recreation or conservation solely by the owner and not available to the general public. “Foundation” means the earth or rock on which the dam rests. “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. “Impoundment” means the water or liquid substance that is or will be stored by a dam. “Maximum Water Storage Elevation” means the elevation of the lowest point on the top of the dam, excluding any spillway structures. “Maximum Storage Capacity” means the volume of water stored at the maximum water storage elevation. “New Dam” means any dam that is not an existing dam. “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. “Owner” means any person who owns an interest in, controls, or operates a dam. “Person” means any individual, firm, association, organization, partnership, business trust, corporation, company, county, municipal or quasi-municipal corporation, public utility, utility or other district, the State of Tennessee and its departments, divisions, institutions, and agencies, and the duly authorized officers, agents, and representatives thereof, or any combination of any of the above. Person does not include the United States government nor any agency owned by the United States or any agency thereof, nor those who own a dam or reservoir leased to or operated by the United States or any agency thereof, nor those dams licensed by the Federal Energy Regulatory Commission (previously the Federal Power Commission). “Principal Spillway” means the spillway which conveys normal runoff out of the reservoir. “Probable Maximum Precipitation” “(PMP)” means the greatest amount of rainfall of a six- hour duration which would be expected for a given drainage basin as determined by National Weather Service meteorological estimates. The PMP for 10 square miles shall be used for watersheds smaller than 10 square miles. “Probable Maximum Flood” “(PMF)” means the flood that may be expected from the most severe combination of critical meteorologic and hydrologic conditions that are reasonably possible in the region. The PMF is derived from the probable maximum precipitation (PMP). “Removal” means altering a dam such that it is no longer a dam as defined in these rules. “Reservoir” means any basin which contains or will contain the water impounded by a dam. “Roadbed” means the earth support work of a road prepared for surfacing which is not intended to impound water and which does not impound water continuously. “Spillway” means the feature of a storage or detention dam which is designed to release surplus water, and at diversion dams is a means to bypass flows exceeding those which are turned into the diversion system. “Structural Height” means the height of the dam measured from the natural bed of the stream or watercourse at the downstream toe of the barrier to the low point in the top of the dam. “Wastewater Impoundment Barrier” means an artificial barrier impounding a body of wastewater for the purpose of treatment and designed so that no surface runoff from areas adjacent to the barrier is introduced into the impoundment. “Water Tank” means a vessel designed and used to hold water.

Authority: T.C.A. §§ 69-11-101 et seq., and 4-5-201 et seq. Administrative History: Original rule filed October 16, 2012; effective January 14, 2013. Rule renumbered from 1200-05-07.