30 CFR 817.43 - How must I construct and maintain diversions?
(a)Classification. The term diversion applies to the following categories of channels that convey surface water flow:
(1)Diversion Ditches. Diversion ditches are channels constructed to convey surface water runoff or other flows from areas not disturbed by mining activities away from or around disturbed areas. Diversion ditches may be temporary or permanent.
(i) You must remove a temporary diversion ditch as soon as it is no longer needed. You must restore the land disturbed by the removal process in accordance with the approved permit and § 817.55 of this part. Before removing a temporary diversion ditch, you must modify or remove downstream water treatment facilities previously protected by the ditch to prevent overtopping or failure of the facilities. You must continue to maintain water treatment facilities until they are no longer needed.
(A) Be environmentally beneficial;
(A) Any surface runoff or other flows from mined areas abandoned before May 3, 1978.
(B) Any surface runoff or other flows from undisturbed areas.
(2)Stream diversions. Stream diversions are temporary or permanent relocations of perennial or intermittent streams. Diversions of perennial and intermittent streams must comply with the applicable requirements of this section, § 784.28 of this chapter, and § 817.57 of this part.
(i) You must remove temporary stream diversions after the original stream channel is reconstructed after mining. As set forth in § 784.28(f) of this chapter, different requirements apply to temporary stream diversions depending on whether they will be in existence for less or more than 3 years.
(ii)Permanent stream diversions remain in their locations following mining and reclamation.
(3)Conveyances and channels within the disturbed area. All other conveyances and channels that are constructed within the disturbed area to transport surface water are also diversions. During mining, these channels or conveyances must deliver all captured surface water flow to siltation structures.
(i) You must remove temporary conveyances or channels when they are no longer needed for their intended purpose.
(b)Design criteria. When the permit requires the use of siltation structures for sediment control, you must construct diversions designed to the standards of this section to convey runoff from the disturbed area to the siltation structures unless the topography will naturally direct all surface runoff or other flows to a siltation structure.
(1) You must design all diversions to -
(i) Ensure the safety of the public.
(2) You must design, locate, construct, maintain, and use each diversion and its appurtenant structures to -
(i) Be stable.
(ii) Provide and maintain the capacity to safely pass the peak flow of surface runoff from a 2-year, 6-hour precipitation event for a temporary diversion and a 10-year, 6-hour precipitation event for a permanent diversion. Flow capacity for stream diversions includes both the in-channel capacity and the flood-prone area overbank capacity. Flow capacity for diversion ditches and conveyances or channels includes only in-channel capacity, with adequate freeboard to prevent out-of-channel flow. You must use the appropriate regional Natural Resources Conservation Service synthetic storm distribution to determine peak flows.
(iv) Comply with all applicable federal, state, tribal, and local laws and regulations.
- 30 CFR 817.102 — How Must I Backfill Surface Excavations and Grade and Configure the Land Surface?
- 30 CFR 817.83 — What Special Requirements Apply to Coal Mine Waste Refuse Piles?
- 30 CFR 817.71 — How Must I Dispose of Excess Spoil?
- 30 CFR 784.29 — What Information Must I Include in the Surface-Water Runoff Control Plan?
- 30 CFR 817.84 — What Special Requirements Apply to Coal Mine Waste Impounding Structures?
- 30 CFR 942.817 — Performance Standards - Underground Mining Activities.