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Erosion control and revegetation ma« ing protects newty-reseeded surfaces until permanent vegetation is <br />established. The blankets reduce rainfall impact and runoff velocity, and also enhance plant growth by <br />moderating soil temperatures and reducing evaporative moisture losses. Blankets are commonly made of <br />coconut fiber and a synthetic netting material and are sewn together with nylon thread. The natural fibers <br />degrade over time, but nondegradable synthetic matting materials made of bonded, plastic fdaments are <br />used for more permanent applications. <br />Moldable erosion control fibers are bundles of polypropylene f1Uers that can be stuffed into rills or gullies <br />and anchored with stakes or staples. The bundle slows the velocity of runoff and causes upstream sedimen- <br />tation,allowing the channel to heal itself and revegetate. <br />Erosion control strand (roving) is a relativety thick, spaghetti-like yarn that is blown onto an erosion trouble <br />spot or newly-reseeded area. The fiberglass or polypropylene yarn is tacked to the ground with an asphalt <br />emulsion or similar substance. The mass of fibers slows runoff flow and catches sediment in the spaces <br />between strands. <br />Soil confinement systems generally consist of a series of honeycomb-like cells formed into a spreadable <br />sheet or blanket Sheets of the material are anchored and filled with soil, creating a solid, pavement-like <br />surface in areas of poor soil stability. <br />3.4 Improvements and Repairs <br />Drainages improvements and repairs were performed to provide benefiu to all drainages treated in 1987-91, <br />as well as portions of undisturbed drainage segments. Drainage improvements included the installation of <br />. several thousand shrub seedlings in 1987-90 treatment areas, the rock armoring of a few hay bale swctures <br />in 1987 treated drainageways, and dozer basin construction in newly stripped topsoil areas and on regraded <br />spoils. Drainage repairs and enhancement were conducted in all previous reconstructed drainageways (87- <br />90) with a minimum of effort required to complete this task. Essentially no downcutting in drainage bottoms <br />occurred, therefore efforts were directed at reinforcing potential problem areas. <br />Rock structures were installed a[ an average frequenry of 40-150' throughout the reconswcted Johnson <br />Gulch and East Buzzard drainages in 1991. <br />3.5 Reconstructed Drainages Profiles (As-Built) <br />As agreed with the Division in Trapper's 1989 Annual Report (D.A. Berry Corres 6/8190) Trapper is no <br />longer required to provide as-built drainage profiles as part of the annual report <br />3.6 Permanent Diversion Establishment <br />As mentioned in a previous section, livestock watering tanks are often constructed on water harvesting <br />diversions to trap water on reclaimed sideslopes and make available reliable water for wildlife/livestock use. <br />To increase the amount of water available to livestock tanks, appropriate water harvesting diversions may be <br />removed immedia[ety above the target diversion. The remaining diversion and stock tank would be perma- <br />nent landscape features. Permanent water harvcsting diversions are shown on the "Drainages Reconstruc- <br />tion" map and was approved by the Division in Trapper's 1989 Annual Rcport <br />3.7 Results <br />Vegetation response, decreased ^ow rates and reduced gully formation wcre the primary factors in assessing <br />the success of drainage reconstruction projects at Trapper Mine. <br />