(1) Reclaimed drainage basins, including valleys, channels, and floodplains must be constructed to:

(a) comply with the postmining topography map required by ARM 17.24.313(1)(d)(iv) and approved by the department;

(b) approximate original contour;

(c) an appropriate geomorphic habit or characteristic pattern consistent with 82-4-231(10)(k), MCA;

(d) allow the drainage channel to remain in dynamic equilibrium with the drainage basin system without the use of artificial structural controls unless approved by the department;

(e) provide separation of flow between adjacent drainages and safely pass the runoff from a six-hour precipitation event with a 100-year recurrence interval, or larger event as specified by the department;

(f) provide for the long-term relative stability of the landscape. The term "relative" refers to a condition comparable to an unmined landscape with similar climate, topography, vegetation and land use;

(g) provide an average channel gradient that exhibits a concave longitudinal profile;

(h) establish or restore a diversity of habitats that are consistent with the approved postmining land use, and restore, enhance where practicable, or maintain natural riparian vegetation as necessary to comply with ARM subchapter 7; and

(i) exhibit dimensions and characteristics that will blend with the undisturbed drainage system above and below the area to be reclaimed and that will accommodate the approved revegetation and postmining land use requirements.

(2) Any permanent structure placed or constructed within a perennial or intermittent stream must be certified by a qualified licensed professional engineer as meeting the performance standards and any design criteria specified by the department.


History: 82-4-205, MCA; IMP, 82-4-231, MCA; NEW, 1980 MAR p. 725, Eff. 4/1/80; AMD, 1989 MAR p. 30, Eff. 1/13/89; AMD, 1994 MAR p. 2957, Eff. 11/11/94; TRANS, from DSL, 1996 MAR p. 2852; AMD, 1999 MAR p. 811, Eff. 4/23/99; AMD, 2004 MAR p. 2548, Eff. 10/22/04; AMD, 2024 MAR p. 258, Eff. 2/10/24.