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Task 4 <br />Drainage Repair and Construction: <br />A large gully has formed on the lower end of the steep rip rap channel where the drainage <br />transitions between rock and an earth lined channel. Approximately 250 feet of rip rap channel <br />will need to be constructed or repaired as indicated on Drawing 1, Slope Drainage Course Cross <br />Section and Plan View The rock will be collected by the CONTRACTOR at a location specified f <br />by the PROJECT MANAGER. , <br />Drainage Dimensions A channel with side slopes no steeper than 3H:1 V, eight (8) foot bottom ' <br />width will be constructed from the end of the existing rip rap channel to the bottom portion of the , <br />slope as located by the PROJECT MANAGER. <br />Drainage Rock Sizing The bottom of the drainage channel will be lined to a minimum 30" depth <br />of riprap. Using on site materials, the rip rap will consist of a combination of 20% minimum 4' <br />diameter rock, 40% minimum 2' to 3' diameter rock and 40% 12" to 18" diameter rock. <br />Drainage Rock Placement The 4' diameter rock will be keyed into the bottom of the constructed <br />3H:1V channel through excavation placement so that no rock extends more than 30" above <br />ground level. These rocks will be placed every 20' of slope length. The 12" to 18" diameter rock <br />Pr l I will be placed and compacted into the bottom of the excavated channel. The 2' to 3' diameter <br />P t S .i, rock will then be placed over the smaller rock to fulfill the 30" minimum rip rap depth <br />A l"ri requirement. Placement will be such that voids will be eliminated to the extent possible with rock <br />contacting rock. Side slopes of the constructed channel will be at a maximum 3H:1V slope. Side <br />slope rip rap will extend up the sides of the constructed channel to a minimum 4' height. <br />Material excavated as a result of drainage course construction may be excavated and hauled to <br />or graded against the excavated bench cuts as noted on the drawing. Prior to depositing or <br />grading excavated material against the excavated bench cuts, existing vegetation and soils to a <br />24" depth will be graded off and stockpiled. Stockpiled vegetation and soils will be evenly <br />redistributed over the deposited material from drainage course construction upon completion of <br />earthmoving procedures. <br />If any trash is encountered during excavation for channel construction, trash will be collected <br />and hauled to the nearest County approved landfill site. <br />Measurement and Payment <br />The constructed channel will be measured to the nearest linear foot. Measurement for payment <br />will consist of physically measuring the length of the channel. Payment for this task will be paid <br />for at the prices established in Item 4 of the Bid Schedule per linear foot installed. Such <br />payment shall be considered full compensation for all labor, materials, equipment and all other <br />items necessary and incidental to the construction of the channels to the specifications, <br />including excavation and furnishing and placing the specified rock materials directed and <br />described in the specifications. Payment will be as this task is completed and approved by the <br />PROJECT MANAGER. <br />7 <br />