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1 • • <br />1 sedimentation. Moderately sized channels typically carry 10 to 250 cfs. In larger channels <br />where peak flows are expected to exceed 250 cfs, check dams may be placed to control channel <br />' gradienu and cross sections, and prevent excessive erosion. These check dams may be <br />constructed using various materials depending upon the anticipated operational life of the <br />structure and the estimated peak flow. <br />1 Water bars may be used to collect and divert storm water runoff across and away from well <br />pads, access roads, and solution collector pipelines during the operational life of a mining <br />panel. Their successful use depends upon adequate construction at frequent intervals <br />detemtined by slope (Table 4). <br />After development disturbance is completed, silt fencing will be systematically replaced with <br />1 more permanent, lower maintenance erosion and sediment control methods and structures. Cut <br />and fill slopes may have therr surfaces roughened using plowing, ripping, land imprinting or <br />contour furrowing operations. Roughening will provide erosion and sediment controls while <br />longer-term measures, such as the establishment of interim revegetation and vegetative filters, <br />1 are rmplemented. Interim vegetation may be established on disturbed areas outside of normal <br />traffic ways. Mulch and surface amendmenu may be applied to promote vegetation <br />establishment and growth. On disturbed slopes steeper than 2h:ly, geotextile fabrics may be <br />1 used in conjunction with the establishment of interim revegetation seed mixtures to control <br />erosion and sedimentation, while helping to promote vegetation growth and establishment. <br />Interseedings to establish or enhance vegetative filters at the bottoms of disturbed ouulopes <br />1 may also be performed. <br />4.6 SURFACE FACILITIES <br />1 Development, operation and reclamation of the facilities areas will proceed in the same general <br />sequence described above for the well field. There will be differences between the Piceance <br />and Parachute facility locations due to differing amounu of past disturbance. The Parachute <br />' facility has very little if any soil materials available for salvage. Soil was previously salvaged <br />and stockpiled at the site during previous development activities performed by UNOCAL. [f <br />additional aria is disturbed that wntains suitable topdressing materials, it will be placed in these <br />1 existing stockpiles. Development of new disturbance area at the Parachute Site will begin with <br />the establishment of erosion and sediment controls. Since Gtde or no additional disturbance is <br />initially expected, establishing erosion and sediment controls will primarily involve <br />maintenance or repair of existing structures and practices. Some replacement or new structures <br />1 may be required, but overall the amount of erosion and sediment control work expected for this <br />site is minimal. Once operational, the site is expected to remain static, with little or no <br />additional future disturbance. During the life of the facilities routine inspection and <br />1 maintenance or replacement of erosion and sediment controls will be performed. <br />A site-specific reclamation plan for ffie Parachute Site facility will be developed well in advance <br />of final closure. However, preparing such a plan at this time is premature. For instance, <br />1 future disturbance may create opportunities to salvage additional soil materials for topdressing <br />previously disturbed areas where soil was not stockpiled. Also, since the minimum Yankee <br />Gulch Project life is estimated to be thirty years, it is impossible to determine what the adjacent <br />1 postmining land uses will be and how best to reclaim the facilities area to enhance adjacent <br />property values and compliment their uses. When the final reclamation plan is prepared it will <br />follow the general sequence detailed above. <br />1 The principal BMPs that will be used to control erosion and sedimentation for the two <br />operating facility locations include channels and diversions, level spreaders, check dams, <br />1 Amaicm soda. I I D. 4-6 <br />Soil Cottxrvauoo, Plosion and Seditoeot <br />Control, Reclamation, and Revegcution Ran <br />1 October 18, 1998 <br />