1997-06-18_GENERAL DOCUMENTS - C1981017

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most sediment pond located south of Road A. Segment Two of channel B shall be lined to minimize erosion and to help maintain channel integrity during flow events. Stockpile B channel will be approximately 1,150 feet in length, but will be constructed in two segments (Figure 6, Typical Surface Channel Cross Sections). Segment one is approximately five hundred fifty feet (550') in length. It will be trapezoidal in shape with a base of two feet (2'), and a minimum depth of eighteen inches (18") as measured from the base to the crest of the channel. Side slopes shall not exceed 2.5H:IV. Segment two is approximately three hundred fifty feet (350') in length, and will traverse down the previously graded Stockpile B slope, across Road A and down the eastern most slope of Stockpile M area. After installation of the liner described below, segment two shall be trapezoidal in shape with a minimum bottom width of two feet (2') and a minimum depth of two feet (2'), as measured from the base of the channel to the crest of the channel. Side slopes shall not exceed 2.5H:1V. Segment two will be lined with a double layer liner system. The lower liner shall consist of Permamat 200f or approved equivalent. The lower mat shall be installed as per manufacturers specifications. Upon completion of installation of the lower liner, two inches (2") of soil shall be placed within the channel over the lower liner. The soil will be fertilized at a rate of two tons per acre commercial fertilizer as specified in Task 10, Revegetation, and then broadcast seeded with the Diversion Mixture at a rate of sixty pounds (60#) per acre. The seed will be provided by the PROJECT MANAGER. After the initial liner is installed and the soil placed, fertilized and seeded, a second liner shall be installed through the lined portion of Segment two. The upper liner shall consist of a natural material such as coconut fiber sown between two ultra-violet stabilized nets (North American Green C125 flexible channel liner or approved equivalent). The fabric shall be installed as per manufacturers specifications. Although within the upper three hundred fifty feet (350') of Segment two, no liner need be installed where the channel crosses Road A. A low water crossing (Figure 7, Low Water Crossing) measuring ten feet (10') in length (parallel to the channel axis) will be constructed at the point where the channel crosses Road A. The exact location will be marked in the field by the PROJECT MANAGER prior to construction. The base of the channel will be widened to five feet (5'), and the side slopes will be constructed so that they are no steeper than 5H:1V. The channel depth will be at least two feet (2') after placement of rip rap. Angular rip rap averaging four to six inches (4" to 6"), as measured across the long axis of any single rock, will be placed within the channel at this location. The rip rap will extend from side to side of the channel (side slopes and base) for the ten feet (10') width of the low water crossing. Rip rap shall consist of angular durable rock only. Unaltered shale, friable sandstone and rounded rock are not acceptable materials. Segment three of the Stockpile B channel will traverse approximately two hundred fifty feet from the end of Segment two to the northern most sediment pond located south of Road A. Segment three shall be trapezoidal in shape with a minimum bottom width of two feet (2') and a minimum depth of two feet (2'), as measured from the base of the channel to the crest of the channel. Side slopes shall not exceed 2.5H:IV. Stockpile M Channel Two channels will be constructed in this area. The longer central channel will be approximately seven hundred feet (700') in length; six hundred feet (600') of which will be constructed west of the confluence with the northern channel and one hundred feet (100') to be constructed east of the confluence. This 15