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Award Nomination for Excellence in Surface Coal Mining and Reclamation - USDI, OSMRE - 1990 September, 1990 Erosion control fabric provide a ground armor that dissipates the energy generated by water movement from run-off or rainfall. Soil retention is a secondary function. Fabrics offering high strength and abra- sion resistance and are used under rip rap. Erosion control and revegetation matting protects newly-reseeded surfaces until permanent vegetation is established. The blankets reduce rainfall impact and run-off velocity, and also enhance plant growth by moderating soil temperatures and reducing evaporative moisture losses. Blankets are commonly made of coconut fiber and a synthetic netting material and are sewn together with nylon thread. The natural fibers degrade over time, but non-degradable synthetic matting materials made of bonded, plastic filaments are used for more permanent applications. Moldable erosion control fibers are bundles of polypropylene fibers that can be stuffed into rills or gullies and anchored with stakes or staples. The bundle slows the velocity of run-off and causes upstream sedi- mentation,allowing the channel to heal itself and revegetate. Erosion control strand is a relatively thick, spaghetti-like yarn that is blown onto an erosion trouble spot or newly-reseeded area. The fiberglass yarn is tacked to [he ground with an asphalt emulsion or similar substance. The mass of fibers slows run-off Oow and catches sediment in the spaces between strands. Soil confinement systems generally consist of a series of honeycomb-like cells formed into a spreadable sheet or blanket. Sheets of the material are anchored and filled with soil, creating a solid, pavement-like surface in areas of poor soil stability. Results Vegetation response, decreased Oow rates and reduced gully formation were the primary factors in assessing the success of drainage reconstruction projects at Trapper Mine. Postmine herbaceous canopy cover, herbaceous production, and woody stem density were evaluated in reconstructed drainage areas in 1988, 1989, and 1990, and wmpared to sample data from undisturbed premine drainage areas. (Sampling was conducted on drainageways reconstructed in 1987.) Various postmine drainage treatments were incorporated to evaluate vegetation response on topsoiled, non-top- soiled, irrigated, and non-irrigated drainage segments (Table 1). Treatments on undisturbed areas were irrigated and non-irrigated drainage segments (Table 1). Generally, vegetation measurements were lower in reconstructed drainageways than in undisturbed drainage sites in the initial growing season. However, by the end of the third growing season vegetation parameters on reclaimed drainage areas were equal to or exceeded those measured on undisturbed drainage areas. Vegetation response was the best on topsoiled and irrigated treatments and was significantly higher when comparing topsoiled versus non-topsoiled areas without irrigation. The overall herbaceous canopy cover for all reconstructed drainage treatments in 1988 (measure of initial growing season) was 39% compared to 71% on undisturbed drainage segments. In 1989, herbaceous canopy cover had increased to 60% in reconstructed drainages and decreased on undisturbed drainage segments to 69% cover. Herbaceous canopy wver within postmine drainageways and in undisturbed drainages was equal at 65% in 1990. Herbaceous primary production averaged 876 Ibs/acre in reconstructed drainages and 1943 Ibs/acre on undisturbed sites in 1988. In 1989, herbaceous primary production decreased to 420 Ibs/acres on recon- structed drainages and 521 Ibs/acre on undisturbed drainage segments. The reduction in production in 1989 compared to 1988 was a result of severe drought conditions in the area during 1989. Herbaceous pri- mary production averaged 1712 pounds/acre in postmine drainages and 1629 pounds/acre in undisturbed drainages in 1990.