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SLIDES AND DAMAGE <br />During the inspection, I discussed with the operator's representative renovation work for the diversion <br />ditch and pipe (culvert CS) in the Revision 1 area. Also we discussed the need for erosion control <br />where gullies have formed in the East Pit area (see September 2004 inspection report for a description <br />of the gullies). The gullies aze approximately 1 foot deep by several tens of feet long. The headcuts of <br />the gullies are midway up the slope on the east and west sides of the East Pit area. In most locations <br />the headcuts appear to have resulted from runoff concentrating on a flat terrace and then downcutting <br />on the outer (downhill) edge of the terrace. Downslope from each headcut a gully has a channel <br />bottom of baze rock and walls of topsoil and rock. The gully channels extend to the ditches at the <br />bottom of the slope. Of the erosion control options available, rock check structures were discussed as <br />having the greatest probability of success. If properly designed and installed, it seems reasonable that <br />check structures at a few key headcut locations could reduce flow velocity enough to allow the gullies <br />to act as a permanent diversion (slope drain) system that reduces further headcut retreat and protects <br />inter-channel areas from further erosion. The operator's representative explained his plan to submit a <br />Technical Revision application proposing installation of rock check structures. We discussed the need <br />for proper selection of rock size and shape, proper anchoring of the rock into the slope (flush with the <br />surface), and the minimization of re-disturbance of sur•ounding land. <br />4 <br />