2014-04-09_REVISION - M1980110 - Laserfiche WebLink

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During construction of the concrete box culvert, erosion control best management practices will be implemented to protect surface and groundwater quality. There are no known subsurface openings (mine shafts, adits etc.) in the subject area that would create or compromise the integrity of surface, subsurface or ground water. 2. Final Grading Contractor shall return the landscape to the approximate original contour and consistent with the reclamation plan shown on sheet 5 in the amendment application. Contractor shall minimize erosion on or adjacent to reclaimed area. Contractor shall control sources of contamination and implement best management practices to protect the integrity of surface and groundwater quality. Contractor shall fill the lake using earthwork equipment normally used for this environment. Contractor shall complete operations at a schedule that does not impact vegetated areas around the lake. Dewatering of the lake is not anticipated in order for the Contractor to fill the lake. The water in the lake is expected to dissipate into the adjacent ground as the filling process proceeds. The rate of filling the lake shall not exceed a rate which would create a flooding situation or damage to surrounding vegetation. The Contractor shall provide a means of monitoring the water level throughout the filling operation to ensure that the surrounding property is not adversely affected. The material in the lake will be compacted by front end loader wheel to minimize any voids or settling of fill material. In place compaction or material density will not be measured. The material is expected to be adequately compacted during the placement process. Contractor shall fill the lake to the contours shown on the plans. Variation from the finished grade shall not be more than 0.25 foot. The estimated volume of complete in place fill required to be transported from the borrow area into the lake to complete the project is 732,734 cubic yards. This is based on a pre- construction survey of the lake bed and using the finished grades on the plans. To allow for some variation in the lake bed survey, the Authority has increased the estimate of fill required to 760,000 cubic yards. The Authority will survey the finished grades once the lake is filled and then calculate the volume of material used. No slopes steeper than 3 (horiz.) to 1 (vert.) are planned. Night work is prohibited on this project. Work hours within the borrow pit area will be dictated by Brannan Sand and Gravel. The final grades and contours shall return the area to a drainage pattern similar to that before mining operations. See URS drainage letter dated January 2, 2014 (below).