Laserfiche WebLink
• Section 4.6.1 (Hydrologic Balance Control Plan, Sedimentation Control Summary) of the <br />Edna Mine permit; and <br />• Appendix 4.6 -M, West Ridge Hydrologic Reconstruction Plan. <br />Moffat Area Down Drain #1 <br />This down drain is on the west side of the main access road and has received Phase I bond <br />release. There are two 36" culverts, ten feet apart with little sediment at the outlet. The area <br />above the culverts (beneath the road) was steeply sloped but well vegetated with no erosion <br />present. The channel rip rap averaged 9" in diameter and includes some scoria. The vegetation <br />was well - established with no erosion. The slope design is 15 degrees. The entire length of the <br />drainage appeared to be stable and is functioning as designed. <br />Moffat Area Down Drain #2 <br />This down drain is located on the east side of the main access road and has received Phase I bond <br />release. Down Drain #2 connects to #11 via 36" culverts (Photo 8789). The drainage was wider <br />than Down Drain #1 with more basalt and scoria present (Photo 8790). The channel rip rap <br />averaged 6 inched in diameter and contains more scoria. The well established vegetation in this <br />area consisted mainly of rabbit brush and big sage brush, which are very effective in controlling <br />erosion because of their well established root systems. The slope design for this Down Drain is <br />15 degrees. The entire length of the drainage appeared to be stable and is functioning as <br />designed. <br />Moffat Area Down Drain #3 <br />This drainage contained medium -sized rip rap that averaged 6 inches in diameter and has <br />received Phase I bond release. The well established vegetation in this area consisted mainly of <br />rabbit brush and big sage brush, which are very effective in controlling erosion because of their <br />well established root systems. The slope design is 22 degrees. The entire length of the drainage <br />appeared to be stable and is functioning as designed. <br />Moffat Area Down Drain #4 <br />The rip rap increases in size towards the bottom of this drainage near Moffat Pond (Photo 879 1) <br />which has also received Phase I bond release. Nearly half way up the drainage, the channel <br />diverts, resulting in a fork in the drainage. The cause appears to be a high spot in the channel. <br />The water is rerouting itself to the north of this blockage. There are two constructed drop <br />structures near the top of the drainage channel, where the slope is steeper than the 14 degree <br />average (Photo 8792). These drop structures appear effective in dissipating the energy of water <br />flow. <br />Immediately adjacent to the drainage is an area that appears to be a heavily traveled corridor to <br />Moffat Pond, which serves as a water source for sheep that graze in the vicinity. There is a lack <br />of shrubs and grasses here and minor rilling has occurred (Photo 8793). The landowner should <br />not concentrate grazing in this location so that vegetation has an opportunity to establish itself. <br />