In addition to the minimum spillway design flood requirements of § 74:02:08:07, all new category 1 and 2 dams must have low-level drawdown facilities. If an existing category 1 or 2 dam undergoes extensive repairs which require complete drawing down of the reservoir or is being repaired after the dam has failed, a low-level drawdown facility must be installed. A low-level drawdown facility may be either a gated pipe through the embankment that would allow the release of water below the primary spillway or sufficient available pumping capacity to draw down the reservoir. A breach analysis report must be completed by the owner for the proposed dam if a preliminary risk assessment indicates that the dam is a category 1 or 2 dam and must be submitted to the chief engineer with the plans and specifications required by § 74:02:08:09. A breach analysis, if required, must be performed with a simulated water surface at or above the top of the dam.

Source: 13 SDR 49, effective October 27, 1986; 13 SDR 129, 13 SDR 141, effective July 1, 1987; 13 SDR 197, effective July 2, 1987; 15 SDR 158, effective April 23, 1989.

General Authority: SDCL 46-2-5 , 46-7-3.

Law Implemented: SDCL 46-5-8 to 46-5-11 , 46-5-47 , 46-7-3 , 46-7-5.