16-19 Section 1638
1638 -1 DESCRIPTION Construct, maintain and remove earth embankments used to trap sediment from dewatering construction sites during construction of drilled piers, footing excavation or culvert construction. Work includes providing permeable stone drain, cleaning out, mainta ining, removing and disposing of the stilling basins and all components and reshaping the area. The actual conditions that occur during the construction of the project will determine the quantity of stilling basins constructed. The quantity of stilling ba sins may be increased, decreased or eliminated entirely as directed by the Engineer . Such variations in quantity will not be considered as alterations in the details of construction or a change in the character of the work. 1638 -2 MATERIALS Use suitable excavated materials, as specified in Sections 225, 230 and 240, in the construction of earth embankments for stilling basins, except where otherwise specified by the Engineer . Refer to Division 10. Item Section Coir Fiber Mat 1060 -14 Sediment Control Stone, Standard Size No. 5 or 57 1005 Stone for Erosion Control, Class B 1042 1638 -3 CONSTRUCTION METHODS Construct stilling basins at the locations shown in the plan s and at other locations as directed by the Engineer . Construct earth embankment with a permeable stone drain in a rectangular form adjacent to the stream and culvert following the applicable requirements of Section 235. The maximum height allowed for earth dikes is 5 feet. Excavate below the natural ground for greater depths of basins. Install coir fiber baffles in accordance with Section 1640 or as directed by the Engineer . 1638 -4 MAINTENANCE AND REMOVAL Maintain the stilling basins, coir fiber baffles and remove and dispose of silt accumulations at the stilling basins in accordance with Section 1630. Remove the stilling basins as the project nears completion, or at such time the Engineer deems the device to be no longer useful. Prepare a seed bed and seed and mulch the area after removal of the stilling basin in accordance with Section 1660. 1638 -5 MEASUREMENT AND PAYMENT Stilling Basin quantities will be measured and paid in cubic yards, in place and computed by the average -end-method for the actual number of cubic yards of basin capacity. The measurements will be the internal measurements of the basin measured up to the top of the permeable stone drain. Materials used to construct the basin that originates from another payment item ( i.e., unclassified excavation, borrow excavation) will not be deducted from the volume of that original pay item. Stone for Erosion Control, Class ____ will be measured and paid in accordance with
Article 1610 — 4.
Sediment Control Stone will be measured and paid in accordance with Article 1610- 4.