2010-10-21_REVISION - C1982057 - Laserfiche WebLink

Home Browse Search

7556.5 4468825.3 309612.1 40.620 7597.124 7600 2.876 7605 10+31 7645.9 4468850.1 309726.8 40.620 7686.543 7692 5.457 7696 14+16 - PM-lA is a channel in the southern portion of the disturbed area and is the upper portion of channel PM-1, above the intercept point with channel PM-1B. This channel also runs basically east to west, with an as-built length of 1,504 feet and a designed of 1,616 feet. The channel design specifies a bottom width of 3 feet, an overall depth of 0.8 feet and a lining of vegetation. The observed channel bottom width was between 5 and 8 feet, its depth was between 2 and 4 feet and its lining was a combination of 9 inch riprap and vegetation. The as-built channel PM-lA basically follows the path of the designed channel with the exception that the as-built channel is approximately 100 feet shorter than the designed channel (it does not go up the slope as far). There was some side- cutting along the north edge of the channel for its entire length and minor erosion in the channel itself. Seneca has constructed a surge pond in the channel at approximately station 12+10 on the Division's channel profile. There was some erosion at the inlet of the surge pond and at the outfall of the surge pond, continuing to the end of the channel, where it becomes PM-1. The as-built channel profile is approximately 10 feet higher in elevation than the designed channel for the lower 1,200 feet of the channel. The following chart shows the GPS data for post-mining channel PM-IA. GPS Height Northing Easting Z Corr. Correct Z Exh D Elev. Z Diff. Exh 20- 5.9 Station 7661.3 4468856.9 309756.4 40.620 7701.879 7700 -1.879 7696 0+00 7781.6 4468890.6 309907.6 40.620 7822.220 7824 1.780 7810 5+08 7855.1 4468912.1 309998.1 40.620 7895.736 7896 0.264 7885 8+13 7889.6 4468924.8 310041.3 40.620 7930.216 7930 -0.216 7918 9+61 7934.5 4468948.4 310113.2 40.620 7975.161 7978 2.839 7969 12+10 7960.8 4468973.6 310156.3 40.620 8001.454 8014 12.546 7998 13+73 7983.1 4468984.9 310194.6 40.620 8023.751 8022 -1.751 8020 15+04 - Channel PM-1B flows on the south side of channels PM-1 and PM-lA in a southwest direction, turning northwest to intercept PM-1 and PM-IA. The channel has an as-built length of approximately 1,656 feet long and a design length of approximately 1,931 feet long. The channel design specifies a bottom width of 3 feet, an overall depth of 0.9 feet and a lining of either vegetation or TRM. The observed channel bottom width was between 2 and 7 feet, its depth was between 2 and 5 feet and its lining was TRM. The upper portion of the as-built channel follows the designed location, with the exception of the fact that the as-built channel is approximately 275 feet shorter than the designed channel. The lower portion of the as-built channel is moved approximately 75 feet west of its designed location and intercepts channel PM-1/PM-lA approximately 75 feet lower than designed. There was some side-cutting along the north side of channel PM-1B and some erosion in the channel itself. There was also some under-cutting of the TRM in places, which has resulted in the channel not having vegetative cover in those locations. The as-built channel profile is basically identical to the designed profile with the exception of the lower approximately 285 feet. This area is up to 10 feet lower in