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<br />~ <br /> <br />e <br /> <br />e <br /> <br />e <br /> <br />MEMORANDIJM OF INSPECTION <br /> <br />Dam Name: Davis No. I Dam <br /> <br />Division: I <br /> <br />District: 6 <br /> <br />DAMID: 060 III <br /> <br />Hazard Class: 2 <br /> <br />Date ofInspection: November 22, 1996 <br /> <br />Inspector: Dennis G, Miller V G#1 <br /> <br />Purpose of Inspection: Internal inspection of outlet conduit <br /> <br />Weather Conditions: Cloudy, cool, dry <br /> <br />Ground Conditions: Damp <br /> <br />Reservoir Water Level: G. H. 6.4 <br /> <br />Inspection Participants: Lee Forsyth, Boulder &: Lefthand Ditch Co, <br />John Brunner, Boulder & Lefthand Ditch Co. <br /> <br />Ob!lervations: <br /> <br />An internal inspection of the outlet conduit at this dam was performed on 11/22/96, as a <br />follow-up to the previous internal inspection of 3/20/96. At the time of the March inspection, <br />the Sled could not be inserted the full length of the pipe, due to a rock blocking the Sled's <br />progress at about 25 feet in from the downstream end. At that time. I told Lee that I would like <br />to return later, after the rock was removed. to complete the job. <br /> <br />The outlet conduit is a 30-inch diameter CMP, about 62 feet in length along a straight <br />alignment, with an upstream vertical slide gate. The Dams Database indicates that the dam was <br />constrUcted in 1948, and the outlet pipe is probably of that vintage. Gate leakage during this <br />inspection was somewhat greater than for the March inspection, estimated this time at about 50 <br />gpm. This was providing a measured depth of water in the conduit, at the downstream invert, of <br />3 inches. <br /> <br />Prior to inserting the Sled into the pipe, it was necessary to cut a large growth of moss off <br />of the left (looking upstream) pipe wall at the waterline, in the same place it was observed <br />growing last March. After using a shovel to cut off the moss. it was noted on the opposite side <br />wall. at springline, that the pipe wall was showing some severe corrosion. Probing by hand and <br />with the point of the shovel revealed perforation of the pipe wall and general through-corrosion, * <br />such that several small pieces of metal from the pipe wall were easily removed. This exposed a <br />stiff clay soil with root growth on the outside of the pipe. The area of metal removal and <br />exposed soil was about I foot upstream of the end of the pipe, and obvious corrosion exists a <br />good foot upstream of that. It appears that the concrete headwall at the downstream end of the <br />