Laserfiche WebLink
' <br />' South Gray <br />The main area of concern for South Gray is the excessive seepage along the middle portion of the <br />' dam from Station 3+00 to Station 17+OOe There is seepage at the dam toe and a concentrated <br />seepage source located at Station 4+00. To control the seepage a toe drain will be installed <br />consisting of a perforated PVC pipe surrounded by a filter layer of C33 sand as shown on Drawing <br />' S. The drain will be placed about 6 feet below grade at the locations shown on Drawings 1 and 2. <br />Seepage also exists along the south dam on South Gray. Toe drains are planned for to be installed <br />, starting at the spillway and extending approximately 450 feet to the east along the dam. The details <br />of the toe drains are expected to be the same as shown on Drawing 5. <br />' There is no vehicle access to the downstream end of the outlet conduit at South Gray. Due to the 3:1 <br />breach for Gray No. 3, the access road will be routed along the downstream toe of both dams as can <br />' be seen on Drawing 1 and Drawing 2. <br />Alternative #2 <br />' Gray No. 3 <br />' This alternative is similar to Alternative No. 1. The difference is the breach through Gray No. 3 will <br />be made at an 8:1 slope which will allow routing the access road through the breach and across the <br />dam crest rather than at the dam toe. Due to this, the access to the outlet of South Gray will require <br />, a ramp constructed along the downstream face of South Gray as shown on Drawings 3 and 4. <br />South Gray <br />' The toe drains for South Gray will be the same as described for Alternative #1. The toe drains are <br />shown on Drawings 3, 4, and 5. <br />' Alternative #3 <br />' Gray No. 3 <br />This alternative consists of a complete rehabilitation of Gray No. 3 dam and its appurtenant <br />' structures. The complete rehabilitation will include the following work. <br />' 1. Breaching the dam and removal and replacement of the existing outlet works. <br />2. Providing a liner on the upstream side of the dam to reduce seepage losses. <br />3. Provide an adequate spillway and raise the dam crest to provide adequate freeboard. <br />, 4. Place riprap slope protection on the upstream face of the dam to provide erosion protection. <br />5. Install a toe drain to control potential seepage. <br />' <br />Gray Reservoirs-Feasibility Study <br />, <br />Page 6 <br />1 <br />