The outside slopes and terraces of an impoundment shall be designed, constructed, operated and maintained as follows:

1. (1) The outside slopes of the dike may not exceed 25% unless the following requirements are met:

   1. (i) A horizontal terrace with a minimum width of 10 feet is constructed at each 20-foot vertical rise of the slope, or the Department approves in the permit a terrace with different dimensions.
   2. (ii) Surface water on the terrace is collected and discharged so that it does not erode or otherwise adversely affect the stability of the dike.
   3. (iii) The final slope does not exceed 50%.
2. (2) The outside slope and terraces of the dike shall be stabilized with permanent vegetation, rock rip-rap or other nonerodable material to prevent wind and water erosion and preserve the structural integrity of the dike.

Cross References

This section cited in 25 Pa. Code § 287.114 (relating to interim operational requirements for unpermitted processing or disposal facilities); 25 Pa. Code § 287.115 (relating to filing by permitted facilities); 25 Pa. Code § 287.116 (relating to interim operational requirements); 25 Pa. Code § 289.161 (relating to impoundment plan); and 25 Pa. Code § 299.144 (relating to operating requirements).