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seepage level on the downstream slope is below El. 3690. Seepage above this elevation has <br />not been observed. <br />2.3 Dam 2 <br />Dam 2 is approximately 1,700 feet long and is tallest of the Julesburg,Reservbir embankments <br />with a maximum height of 65 feet and a crest width of approximately-,,W feet. The upstream <br />face of the dam is paved with a concrete for slope protection, and, includes a 3 foot high <br />concrete parapet wall for wave runup protection. The upstream slope of the -dam varies from <br />1.5 to 1.7:1. The downstream slope of the dam is non uniform, varying in slope from 1.5:1 <br />at the abutments to approximately 2.5:1 at the ma— ArnU'm Jsection. A stabilizing berm <br />constructed at the base of the downstream slope in 1.992 is.20 feet wide at the top and has <br />a slope of 3:1. <br />Dam 2 failed on March 11, 1910. Investigation of the�cause f failure was performed by Mr. <br />George Prince. He concluded that thoicause of failure was mashing out (piping) of fines within <br />the bedrock upper stratification land development of `hydrostatic pressure of sufficient <br />magnitude to lift the overlying mass of rock-an' d eartWM the downstream toe of the dam. The <br />report documents large blocks of bedrock being carried by flood water for considerable <br />distances downstream of the dam <br />The breach of.the dam was approxirately 300 feet wide at the base and 400 feet at the top. <br />Reconstruction of the 'breach -included construction of two concrete cutoff walls extending <br />approximately 4 feet into bedrock. <br />In 1978, a series of _t °oe drain systems were recommended by Chen & Associates due to <br />excessive seepage and other concerns expressed by the State Engineer. A downstream toe <br />drain system"vvas installed in two sections, the western section being approximately 750 feet <br />long and the eastern section being 350 feet long. <br />2\re0orts \97- 1 - 500.nk <br />,® <br />