2014-04-16_INSPECTION - C1981010

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Apri19, 2014 C- 1981 - 010 /Trapper Mine JLE No Name reconstructed channel was observed. We walked up the channel (south) beginning near NNE 44 stock tank. The channel above the tank has been phase III bond released. The purpose of observing this portion of the channel was to assess the long term stability of the reclaimed channel where Trappers current channel construction, stabilization and maintenance plan has been implemented. According to the 2013 annual reclamation report maps, the Phase III bond released parcels in which the channel was constructed was seeded in 1998 and 1999. Overall, this portion of the channel is wide and not as steep as the lower reaches of the channel that have not been Phase III bond released. Thick grassy vegetation has established throughout the channel. Check dams were constructed throughout this portion of the channel at varying intervals based on the steepness of the slope. According to Mr. Roberts, Trapper currently determines the placement of the check dams visually. When a lower check dam is installed, the Operator views the constructed dam from below at a certain distance. While looking upslope the approximate location of the tow of the next check dam is placed at about the level of the crest of the constructed dam. By using this method, check dams are constructed at shorter intervals on steeper slopes. In general, a small center channel forms at the bottom of each reconstructed drainage. In the Phase III released portion of No Name drainage, the center channel varies in depth from a few inches to deep 6 foot cuts with steep or vertical side slopes. At several locations check dam failures have occurred causing deep cuts below the check dam. In places the center channel of the drainage cuts around the check dam. It appears that brush piles were placed in several locations throughout the channel to repair deep cuts. The center channel generally cuts around the brush piles or blows through it. The maj ority of the channel area within the Phase III release area is heavily vegetated and stable. The main erosional feature is the center channel which generally stops at the toe of each check dam but forms again above the crest of the dam. It is unclear if this center channel has reached an equilibrium and will not get significantly deeper or if the channel will continue to erode. The channel below NNE 44 stock tank was walked down slope (north) to about NNE #6 stock tank. This portion of the channel is adjacent to Phase III bond release land and within parcels that have been seeded in 2004. This portion of the channel is steep and has more sinuosity. At the observation point NN3, it was observed that sediment builds up behind the check dam and water flows over and at times under the rocks used to construct the dam. Likely during lower flow events, water continually flows through the check dam rocks causing them to undercut and the center channel below a check dam becomes incised. At observation point NN4, a check dam failure occurred and a large six foot cut has occurred above and below the check dam. Large rocks used to construct the check dams have rolled down the channel. According to Mr. Roberts at the NN5 observation point, backfilled spoil was pushed against undisturbed portions of the site and the channel was constructed at the base of this point. The channel bends above this point to the west, and the flow has cut the eastern side of the channel to a near vertical wall about six feet in height. Repairs to the channel that run through parcels D -B -04 and D -C -04 need to occur. Check dams need repair and possible side slope armoring may need to occur. Portions of the Middle Pyeatt drainage were walked. We walked the reconstructed channel the run through parcel A -B -10. Also an upper branch of the channel that runs through Phase III bond release area to the east of Parcel A- Number of Partial Inspection this Fiscal Year: 7 Number of Complete Inspections this Fiscal Year: 3 Page 3 of 22