PRODIGIOUS STREAM RESTORATION, REHABILITATION AND RECLAMATION NEEDS IN THE APPALACHIAN COAL FIELDS

Although the 1977 Surface Mine Control and Reclamation Act (SMCRA), requires surface coal mines be returned to Approximate Original Contour (AOC), reclaimed landscapes are far removed from natural form and function. Drainage design focuses on storm-water runoff and slope stability, but sediment transport and ecological function are ignored. Acid mine drainage is the foremost stream issue associated with high-sulfur coal, especially in northern coalfields, but hydraulic geometry and stream function are ecologically limiting at many sites with good water quality.

Pre-SMCRA strip mines present both great hazards and extreme restoration challenges. The typical setting is fine-grained, side-cast overburden on over-steepened slopes. Drainage may be haphazard, incising unarmored spoil or colluvium and producing sediment loads fare exceeding those in unmined streams. The Abandoned Mine Lands (AML) program is gradually reclaiming dangerous pre-SMCRA sites, but completed AML sites may yield excessive sediment loads if drainage is not well designed.

The best potential for use of natural stream principles may occur in valley fills, exceptions to AOC provisions where 1st and 2nd order streams are buried under 10 to 300 m of unconsolidated overburden. Large fills are common only in the steep southern coalfields and present opportunities to design and construct new streams from scratch. Streams impacted by valley fill may have little in common with nearby natural streams, but reference reaches reclaimed in the last 30 years may provide useful hydraulic geometry analogs for stable design.

Contour strip mines reclaimed to AOC, provide less dramatic, but more pervasive, departures from natural conditions. Drainage density may be greatly reduced compared to pre-mining networks. Many reclamation sites lack small streams, relying entirely on subsurface and overland flow to convey water downstream. Hundreds of small unmined upland streams are severed from trunk streams by reclaimed slopes lacking designed surface drainage. Moderate- to high-magnitude runoff may create significant gullies soon after reclamation, indicating where functioning channels should be constructed.