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BEST MANAGEMENT PRACTICES OVERVIEW <br />Maintaining or establishing surface hydrologic stability is a critical component in the mining <br />and reclamation process. Adequately controlling erosion and minimising sediment transport <br />serves to prevent or minimize impacts to receiving waters, and supports and enhances the loag- <br />term stability of reclaimed areas. There are a variety BMPs that may be employed to <br />accornpiish these goals during development, operation and reclamation of the project. BMPs <br />may be used independently or in combination to accomplish erosion and sedrment control <br />objectives. While serving a common purpose there are distinct applications to which BMPs are <br />best suited. <br />Erosion and sediment control requires the use of specific BMPs that address different physical <br />conditions than those associated with channel reconstruction. Generally, surface sheet flow <br />control practices vary physically from those used to control concentrated surface flows because <br />of the differences in envrrorunental conditions and requirements. Selecting a single or <br />combination of BMPs for use on a site must take into consideration the variety of flow <br />conditions that may occur there. Often there isn't a correct solution, but rather a variety of <br />combinations that may accomplish erosion and sediment control objectives for a given location. <br />Typically, complex flows require more sophisticated structures and practices than less complex <br />flows. <br />BMPs have been grouped in these appendices based on Uteir primary uses or applications. <br />While the use of some of them may be limited to the category in which they ate placed, many <br />of them present useful applications in multiple categories. Typical installations for BMPs ate <br />provided for clarity. The practice of routinely prescribing controls for erosion and <br />sedimentation problems will be avoided. Each drainage srtuation will be treated creatively to <br />mmimi~r. COILStrllCtlon and treatinent costs, While St[IVIIIg to maximi~r the effectiveness of <br />BMPs. <br />WATER TREATMENT <br />A variety of water treatment stittctures may be used to finish water before it is discharged off <br />site. Vegetative filter; and silt fences will be used to treat overland and concentrated surface <br />flows from small watersheds. For watersheds that are moderate in size or smaller, flows can <br />be leafed using a variety of sediment traps either singly or in series. For lazge watersheds or <br />areas that require special water treatment, sedimentation ponds are expected to be used for <br />erosion and sediment control and for water treament. <br />Vegetative Filters <br />Vegetative filters ate dense strips of close-growing vegetation located to receive runoff from <br />diffuse sources, waterways, small drains or intertnitteut streams. The vegetative filter is used <br />to reduce flow velocities and to trap sediment before the runoff leaves a disturbed area. <br />Vegetative filters are normally composed of perennial fast growing rhizomatous grasses. <br />Filters ma be used where soils and moisture support the necessary growth to provide an <br />adequate filtering capability. Where water enters the vegetative filter rt should be spmad by <br />natural topography or by installation of a level spreader ditch. Existing vegetation often makes <br />excellent vegetative filter strips and should be used when available. The width of the strip <br />should be adequate to filter and allow settlement of sediments. Slope, type of vegetation and <br />quantity of anticipated runoff water will dictate the minimum width required for a vegetative . <br />filter to be effective. A minimum width of 10 feet is recommended on relatively level ground, <br />with additional width being planted as conditions dictate. <br />Sllt Fences <br />1} 1 <br />