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these specifications. <br /> Task 3 <br /> Rock Check Dam Construction: <br /> Rock Check Dams are required in three areas; along the access road, on the portal bench and <br /> the outslope of the fill. See drawing for locations. Rock check dams shall be installed as <br /> follows: <br /> • Access Road- Small erosion features extend down the slope approximately 200 feet. <br /> Install a rock check dam every 20 feet as directed by the Project Manager. Rock check <br /> dams shall consist of 18" to 24" of rock using on site material. Rock check dam <br /> dimensions will be 3' long by 3' wide by 2' deep and be keyed into a depth of 2'. <br /> Placement will be such that voids will be eliminated to the best extent possible with rock <br /> contacting rock and smaller rock used to fill any voids. <br /> • Portal Bench- One large erosion feature extends down the graded portal slope <br /> approximately 50 feet in length. Rock check dams will be installed every 10 feet as <br /> directed by the project manager. Rock check dam rip rap, available on-site will consist of <br /> an evenly distributed combination of 60% minimum 4' diameter rock rip rap, 20% 2' to 3' <br /> foot diameter rip-rap and 20% 12" to 18" rock. The 4' diameter rock will be keyed into the <br /> bottom of the constructed 3H:1V channel through excavation placement not to extend <br /> more than 30" high. The check dam will be constructed in a V-shape with the middle of <br /> the V situated 4' in slope length, up slope in elevation. Rip-rap will extend a minimum 4' <br /> up the side slopes. Side slopes to the constructed channel will be at a maximum 2H:1V <br /> slope. Positive drainage will be maintained from the bench cut to into the drainage <br /> channel. <br /> • Fill Outslope- Small erosion features extend down the sloe approximately 100 feet. <br /> Install a rock check dam every 20 feet as directed by the Project Manager. Rock check <br /> dams shall consist of 18" to 24" using on site material. Rock check dams will be 3' long <br /> by 3' wide by 2' deep and be keyed into a depth of 2'. Placement will be such that voids <br /> will be eliminated to the best extent possible with rock contacting rock and smaller rock <br /> used to fill any voids. <br /> Measurement and Payment <br /> There will be no measurement for payment of Task 3, Rock Check Dams. Payment for this <br /> Task will be reflected in a lump sum bid under Item 3 on the Bid Schedule. This lump sum bid <br /> will cover all costs for excavating, hauling, placing and placing the rip-rap material as described <br /> in these specifications. <br /> Task 4 <br /> Drainage Repair and Construction: <br /> A large gully has formed on the lower end of the steep riprap 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. <br /> - 8 - <br />