Current through Register Vol. 54, No.43, October 26, 2024
Section 90.104 - 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 ditches.(b) Diversions shall be designed, constructed and maintained using current engineering practices to pass safely the peak runoff from a precipitation event within a 2-year occurrence interval for temporary diversions or a 10-year recurrence interval for permanent diversions. 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) Diversions shall be vegetated or otherwise stabilized to prevent erosion and 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, nontoxic-forming rock that will not slake in water 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 coal refuse 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 § 90.151 (relating to revegetation: general requirements).(h) Diversions may not be constructed or operated to divert water into underground mines without the approval of the Department. The discharges must meet the requirements of Chapter 89 (relating to underground mining of coal and coal preparation facilities).The provisions of this §90.104 adopted December 19, 1980, 10 Pa.B. 4789, effective 7/31/1982, 12 Pa.B. 2382; amended July 30, 1982, 12 Pa.B. 2473, effective 7/31/1982, 12 Pa.B. 2382. This section cited in 25 Pa. Code § 90.38 (relating to diversions); 25 Pa. Code § 90.113 (relating to hydrologic balance: coal processing waste dams and embankments); 25 Pa. Code § 90.302 (relating to definitions); and 25 Pa. Code § 90.307 (relating to treatment of discharges).