Laserfiche WebLink
-23- <br />This effect would be temporary, and would cease when sediment ponds are <br />removed. <br />Following reclamation, the disturbed sites will, for a short period of <br />time, be susceptible to erosion, and will temporarily increase runoff <br />rates. These problems are rectified with time as the reseeded areas <br />develop with plant root yrowth and the fresh topsoil becomes settled and <br />stabilized. <br />Contour furrowing and plowing will be used to retain water from <br />precipitation as much as possible within seeded areas during <br />reclamation, and will also reduce erosion. During the early years <br />following reclamation, all of the runoff should be retained by the <br />contour furrows. <br />At the end of the bonding period, vegetative cover will be established <br />and the topsoil will be stabilized, and contour furrows and sediment <br />ponds will no longer be needed to retain runoff. At this point, the <br />runoff from the reclaimed surface will drain unrestricted into the <br />receiving streams. <br />The estimated increase of flow in receiving streams is presented below <br />and is based upon a 35% increase in runoff from disturbed sites. <br />Receiving Streams <br />Bolton Uraw <br />Bush Draw <br />Williams Draw <br />Sudduth Draw <br />I~lann Uraw <br />Canadian River <br />Percent Yield Increases <br />6.5% <br />0.3% <br />1.2% <br />0.4% <br />4.8% <br />O.Ug% <br />These represent a worst case conaition. Any actual increase would <br />probably be less. <br />The sediment pond effluent limitation on total suspended solids is <br />set at 30 mg/1 by WPDES standards. This effluent limitation will <br />have the effect of requiring the three mining operations to release <br />water which is actually lower in sediment load than national <br />baseline levels. <br />This condition may, in turn, have the effect of causing erosion <br />downstream from the mines to regain the natural level of sediment <br />load. This effect has been suggested on a theoretical basis at <br />several mine sites. However, it has yet to be documented either by <br />the Division's inspectors or by the companies. Should the erosion <br />occur, it would begin immediately downstream from the ponds <br />discharge points. Given the infrequent nature of stream flow in <br />this area, it would not spread rapidly, and could be mitigated if <br />it occurs. <br />