Section 87.105. Hydrologic balance: diversions

(a) Surface water and shallow groundwater flow from undisturbed areas which will drain into the affected area shall be intercepted and diverted away from the disturbed area by means of diversion.

(b) Diversions shall be designed, constructed and maintained using current engineering practices to pass safely the peak runoff from a precipitation event with a 2-year recurrence interval for temporary diversions and 10-year recurrence interval for permanent diversion. If necessary to protect public health and safety or prevent pollution, a larger event shall be used.

(c) All topsoil shall be removed, stored on a stable site, and protected against erosion and compaction until restoration of the diversion.

(d) Diversion shall be vegetated or otherwise stabilized to prevent erosion or contributions of sediment to stream or runoff outside the affected area. Asphalt, concrete or other similar lining shall only be used when approved by the Department. Riprap shall be nondegradable, nonacid-forming or toxic-forming rock that will not slake and will be free of coal, clay or shale.

(e) A diversion may not be located so as to increase the potential for landslides or other offsite damage.

(f) Excess material shall be placed in the backfilling, or at an excess spoil disposal area.

(g) When no longer needed, the diversion shall be regraded to blend with the natural contours and drainage pattern, and revegetated in accordance with § 87.147 (relating to revegetation: general requirements).

The provisions of this § 87.105 adopted December 19, 1980, 10 Pa.B. 4789, effective July 31, 1982, 12 Pa.B. 2382; amended July 30, 1982, 12 Pa.B. 2473, effective July 31, 1982, 12 Pa.B. 2382.

Notation

Cross References

This section cited in 25 Pa. Code § 87.72 (relating to diversions); 25 Pa. Code § 87.131 (relating to disposal of excess spoil); and 25 Pa. Code § 87.207 (relating to treatment of discharges).