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Postmine herbaceous canopy cover, herbaceous production, and woody stem density were evaluated in reconstructed drainage areas in 1988, 1989, 1990, and 1991, and compared to sample data from undisturbed premine drainage areas. (Sampling was conducted on drainageways rewnstructed in 1987.) Various post- mine drainage treatments were incorporated to evaluate vegetation response on topsoiled, non-topsoiled, 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 recon- structed 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. A list of plant species encountered in reclaimed drainages and in undisturbed drainages is provided in Tables 2 and 3 respectively. Vegetation response was the best on topsoiled and irrigated treatments and was significanty 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 recon- structed drainages and decreased on undisturbed drainage segments to 69% cover. Herbaceous canopy cover within postmine drainageways and in undisturbed drainages was equal al 65% in 1990. In 1991, herbaceous canopy cover measured 71%within undisturbed drainages and 66% in reclaimed drainages. Herbaceous primary production averaged 876 Ibs/acre in reconstructed drainages and 1943 lbs/acre on undisturbed sites in 1988. In 1989, herbaceous primary production decreased to 420 Ibs/acre 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 primary production averaged 1712 pounds/acre in postmine drainages and 1629 pounds/acre in undisturbed drainages in 1990. In 1991, herbaceous production was 1,802 pounds/acre in undisturbed drainages and • 2,545 pounds/acre in reclaimed channels. Woody stem densities on undisturbed drainage areas averaged 4888 stems/acre (or all three years compared to 471 stems/acre in 1988, 897 stems/acre in 1989, and 104 stems/acre in 1990 and 1,945 stems/acre (stems/acre are planted densities, not actual survival) on reconstructed drainage areas. Flow rates have been significantly reduced following the installation of stock tanks and dozer basins on reclaim and spoil areas, respectively. Discharge readings were recorded from a 10-year, 24-hour parshall Flume (with Stevens Water Level Recorder) located in the north end of the Coyote Gulch reconswcted drainage channel. The peak flow in 1987 (22.24 cfs) occurred as a result of a high intensity thunderstorm in June (.74" ppt) and caused severe erosion within the newly regraded drainage channel In 1988, following drainage reconstruction and water retention strategies, the peak flow rate associated with a .53" precipita- tionevent (June) registered .04 cfs of discharge water. Similarly, a high intensity thunderstorm in July 1989 (.75" ppt) resulted in a discharge of 1.23 cfs. The peak flow in 1990 and 1991 was 1.78 cfs and 1.38 cfs respectively and occurred during March. In addition to assisting in runoff control, the proper frequency and distribution of livestock ponds has aided in evenly spreading big game animal and livestock use over the entire reclaimed area, thus reducing their impact on vegetation establishment. Gully formation and sediment loss was significantly reduced in postmine drainageways when compared to pre-drainage reconstruction. In Coyote Gulch, for example, an estimated 99,400 cubic yards of sediment was lost to gutty erosion and sheet and rill erosion from 1984-1987. Following treatment an estimated 1,360 cu yds of sediment is lost annualty to sheet, rill and gully erosion. This is a reduction in the annual erosion rate of 24 times the pre-treatment erosion rates. Much of the success for the reduction in erosion rates must be attributed to the wide variety of erosion wntrol materials, methods and sediment reducing measures that were used in reconstructing drafnageways and adjacent reclaimed sideslopes. As a result of appropriate erosion control treatment in reestablished postmine drainageways, Trapper Mine has not needed to clean a single sediment pond in tour years. A net savings to Trapper Mine of $270,000 has been realized since drainage reconstruction was initiated and sedimentation pond cleaning ceased.