A. Site Conditions: Site conditions shall be such that the peak rate of runoff that can be expected to occur once in one hundred (100) years, pursuant to ascertainable standards, can be safely passed through: (1977 Code § 4-6-5; amd. 2004 Code)
1. A natural or constructed spillway; or
2. A combination of principal and emergency spillways.
B. Drainage Area:
1. The drainage area above the pond must be protected against erosion to the extent that expected normal sedimentation will not shorten the planned effective life of the structure.
2. The drainage area shall be large enough that surface runoff, together with ground water flow, will maintain an adequate supply of water in the pond. In determination of an "adequate" supply, consideration shall be given to seepage and evaporation losses, and possible future needs of additional water during the effective life of the pond. Multiple uses of the pond must be considered, and maximum practical use of good sites should be encouraged. The possibility of an extended drought for at least six (6) months shall be considered in the determination of storage requirements.
C. Depth:
1. Embankment Ponds: Embankment ponds shall be at least ten feet (10') deep over an area of approximately one thousand (1,000) square feet unless underlying material limits the depth, in which case, the pond shall be at least eight feet (8') deep over an area of one thousand five hundred (1,500) square feet.
2. Excavated Ponds: Excavated ponds must be at least eight feet (8') deep over an area of one thousand (1,000) square feet unless underlying material limits the depth, in which case, the pond shall be at least six feet (6') deep over an area of one thousand five hundred (1,500) square feet. In all cases, the pond shall be designed to store a dependable supply considering beneficial use, sedimentation, runoff from drainage area, season of use and evaporation and seepage losses. Maximum depth of the pond shall be posed in legible letters not less than three inches (3") in height. (1977 Code § 4-6-5)
D. Foundation: The area on which an embankment is to be placed shall consist of material that has sufficient bearing strength to support the embankment without excessive consolidation. The foundation must consist of, or be underlaid by impervious material, which will prevent excess passage of water. Lines or sealing materials should be specified where site conditions require extra precautions against leakage.
E. Safety Shelf: There shall be a safety shelf with an area of zero percent slope a minimum of five feet (5') in width extending into a pond at a depth of three feet (3') below the ordinary normal water level of the pond. (1977 Code § 4-6-5; amd. 2004 Code)