Laserfiche WebLink
Woodward-Cly� . � _ . . <br />The reservoir water is used for irrigation of alfalfa crop and orchazds. For the last three <br />or faur years, the dam has been maintained essentialiy full. In 1993, however, the <br />growing season was dry and ca11s were made on the reservoir for water releases. <br />Between mid-June and mid-August, the reservoir was drawn down, with the rate of <br />drawdown �between about mid-July and mid-August exceeding 1 foot per day. In the <br />middle to tatter part of August, the owner began hauiing riprap to the dam to place on <br />the upstream slape to fill in some of the overly steep areas. As the rock was being <br />hauled in, the owner noted a crack on the downstream edge af the crest of the dam. <br />Approximately 1bQ tons of rock were hauled in and placed at six or seven places across <br />the dam before the work was stopped. The reservoir drawdown was also stopped at this <br />time. <br />The downstream slope of the dam is covered by scattered brush and some grass with <br />substantial azeas that are not ve r, there is very littie, if aay, erosian <br />evident on the downstream sla . ownstream siope is somewhat irregular; <br />however, this is apparently e t c and subsequent placement of <br />some earth berms to ' e awnstaream slope of the dam. The <br />crest is generally cleaz of vegetation in the center 8 feet, with tall weeds growing on the <br />shoulders. There is no appazent differential settlement, however, there is cracking on <br />the downstream slope of the dam. The cracking begins about 20Q feet from the right <br />abutment o£ the dam. Cracks were noted about 18 inches and about 30 to 36 inches <br />below the crest of the dam. These two cracks generally occur over a total distance of <br />about 400 feet. A third crack, located about 6 feet below the crest of the dam, was <br />noted at 380 feet from the right abutment. The cra.cking becomes difficult to trace near <br />the cxest control building. Mr. Graber (Colorado State Engineer's Office) indicated that <br />the cracking could extend over a total length of up to 600 feet. Mr. Graber has placed <br />stakes across the cracks and monitors movement periodically. The reservoir is currently <br />being maintained at a constant, Iow level with all iaflow (approximately 20 cfs) being <br />diverted into the irrigation system. <br />The upstream slope is fully covered with riprap, and there were no obvious signs that <br />would indicate receat movement, although observation is very di�cult because of the <br />rock cover. At the extreme right abutment, the riprap appears to be in excellent shape <br />and consists of a very planar surface of hand-placed rock. If the entire dam was <br />Woodwatd-Clyde Consultants <br />23360/PR0.1 l2-0&93(l:52am)/RPT 1-2 <br />