HYDRO20111 - Laserfiche WebLink

Home Browse Search

of the mine for the state or assists other agencies of the state that have jurisdiction over other aspects of the mine (such as dischazge permits) as needed. We started by looking at Pond F (Photograph No. 1), which Joe indicates the state also has some concerns with as faz as design of the pond is concerned. The drawing submitted for the design of the pond does not match what was constructed. It was also noted that flows that used to come from drainage above the spoil pile above Pond F aze now diverted azound both sides of the spoil pile and into Pond F. Before construction of the pond and the spoil pile, the flows from this drainage crossed over the Deer Trail Ditch (DTD) and then under the FMC via a 4' diameter concrete culvert. With the current design of the pond and spoil pile drainage, this flow is diverted (Photograph No. 3) and will now enter Pond F. Any flows greater than 10 year frequency storms will now drain into the FMC (Photograph No. 2) with a minor amount going into the DTD. This additional inflow could potentially endanger and possible fail the FMC. It was also mentioned to Joe that the FMC has been lined with concrete over the yeazs to reduce seepage. This seepage can cause instability of the canal foundation as well as seepage problems in fields, etc. downhill of the FMC. The FMC below Pond F was lined during early construction for these reasons and now with an unlined Pond F situated above the FMC, instability and seepage problems may occur again. On previous trips we had looked at Ponds B, C and D with mine personnel and, since Joe was quite familiaz with those ponds, we concentrated on showing Jce the DTD and the various issues and concerns dealing with the limited capacity and maintenance of the DTD, We did note the location of the discharge pipe from Pond D (Photograph No. 4). This discharge pipe is located along the "old" Highway 133 and water from it.crosses under the highway in a corrugated metal pipe (cmp), along with flows from the emergency spillways on both Ponds C and D, drainage flows, etc. that go to the DTD and the FMC west or d/s of where the Bowie Mine pump house takes water from the DTD (Photograph No. 5). A small pipe (approx 8" diameter) crosses the FMC (Photograph No. 6) downhill from the pump house and the DTD and below where runoff from Ponds C and D cross under the "old" Highway 133 is directed to the DTD. Some water from this runoff also seems to be channeled towards this small pipe, but a cmp manhole with a small turnout gate was also found on the DTD (Photograph No.7) which has been piped in this section. Originally, this pipe was probably installed to convey DTD irrigation water across the FMC but now may have more flows from runoff than from the DTD. West of the pump house the DTD has significant amounts of vegetation growing in the ditch (Photograph No. 8), and one short piped section in the initial stretch a short distance west (d/s) of the pump house had water backed up which inundated the pipe inlet (Photograph No. 9). The pipe size seems to be similar to the pipe used upstream so it would appear that this pazticulaz pipe is partially blocked or plugged. A pipe crossing further downstream was discharging water into the FMC (Photograph No. 10). This pipe crossing was also noted in the October 15, 2004 site visit. This pipe has a "Y" on the right (north) berm of the FMC with a valve that can be opened to allow DTD water into the FMC. The inlet end of this pipe was underwater as was the inlet to the pipe section of the DTD that continues downstream towards Pond B (Photograph No. 11). The piped section going westerly had a screen over the opening that was partially plugged with debris but it is not known if that is the sole reason for the water backed up in this azea. Whatever the situation, the capacity of the DTD is restricted in this azea. The last turnout on the DTD is to provide water the Terror Creek Co. This pipe crossing over the FMC is located downhill of Pond 2