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III IIIIIIIIII'II'll Doc Date:12/11/2001 <br />sss <br />A_ ~~ Fi <br />SECITON 3.0 Drainages Rernnstruction, Improvement and <br />Repairs at'IYapper Mine in 1991. <br />3.1 Drainage reconstruction 1987A1 <br />At Trapper Mine, all or portions of five major drainageways (Coyote, Johnson, E. Buzzard, E. No-Name <br />and W. No-Name) and their tnbutaries were regraded and appropriately vested to reduce the erosion rate <br />and assist in permanent channel stabilization in 1987, 1988, 1989, 1990, and 1991. At the conclusion of the <br />1991 field season, approximatety 44,4501inear feet (8.41 miles) of permanent drainages reconswction had <br />been completed at Trapper Mine (see attached "Drainage Reconswction" map). <br />3.Z Vegetation Sampling Methods <br />Herbaceous plant canopy cover, annual herbaceous primary production and woody stem densities were <br />measured on twelve postmine reclaimed drainage sites and on two undisturbed premise drainage locations <br />in 1991. Plant canopy cover was estimated in three 100-m vansecrs spaced 10-m apart at each site. Herba- <br />ceous plant canopy cover and percent mulch cover were estimated by species using the point-hit technique <br />(Optical Point Bar) (Viert 1985). Herbaceous production was estimated by clipping sbc 1/4-m plots (20.m <br />spacing) on each of the three line nansects at each site. Woody stem density on undisturbed drainage seg- <br />ments was calculated using the pointcenter~uarter (PCQ) method (Dix 1961). Five PCQ's were conducted <br />on each line nansect at 20.m spacing. Distances from the center of each PCQ to the nearest line stem is <br />each quarter was recorded. Woody stem densities in reconswcted drainage segments is an approximation <br />of the actual seedlings planted at each site. <br />3.3 Erosion Control Methods <br />A wide variety of erosion convol materials, methods and sediment reducing measures were used in recon- <br />snucted drainageways, on reclaim sideslopes and on regraded spoils. The following list of measures and/or <br />materials were applied in combination to decrease the likelihood of accelerated erosion, to reduce Oow <br />rates and to reduce the sediment loading m downsveam sedimentation structures. <br />Dozer basins (sediment basin) were constructed to nap and store sediment on newly snipped topsoil areas <br />and on regraded spoils to reduce or abate the sediment load. Basins are used to prevent the siltation of <br />diversions, waterways, livestock ponds, and sveanu; to nap sediment originating from the active mine site <br />and to prevent undesirable deposition on undisturbed bottomlands and reclaimed areas. The dozer basins <br />primary use is to nap sediment, reduce on-site erasion, reduce peak Slows at downsveam locations, and <br />reduce gutty erosion. <br />Livestock watering tanks (ponds) are used to trap water on reclaimed sideslopes, in drainageways, and to <br />reduce peak flows at downstream locations making available reliable water for wildlife use. The location of <br />livestock ponds is such that a minimal amount of sediment will be deposited. This was accomplished by <br />installation of ponds at headwater locations or on relatively gentle grades often within water harvesting <br />diversions on reclaim sideslopes. <br /> <br />