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<br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br /> <br />porti on of the seepage appears to be passi ng through the dam itself, but a <br />large amount may also be transmitted along the dam-bedrock contact. <br /> <br />1.3 Outlet Works <br /> <br />The primary reason for the zero storage restri cti on imposed on Twi n Lakes <br />Reservoir by the State Engineer is the condition of the outlet works. The <br />outl et works consists of a 22-inch di ameter cast-i n-pl ace concrete condui t <br />apparently founded on bedrock along the right abutment. The inlet is flush <br />with the bottom of the reservoi rand is protected by a trash rack. Flow of <br />water through the conduit is controlled by a leaf valve located in the center <br />of the dam. The valve is operated manually from the crest. The valve stem is <br />located in a three-foot di ameter bri ck masonry dry well accessi bl e at the <br />upstream edge of the crest. <br /> <br />Due to the diameter of the conduit, it was impossible to physically inspect <br />the interior; however, the City recorded the conduit conditions in August of <br />1985, by taki ng a vi deo camera through the conduit. MKE vi ewed thi s vi deo <br />tape. A log of that video tape is included in Appendix A. The tape showed <br />the downstream section of the conduit to be in fairly good shape except for <br />the porti on immedi ately downstream of the val ve. At thi s poi nt the metal <br />conduit lining was partially ripped away and hanging into the opening. The <br />upstream part of the conduit was in poor condition with concrete spalls up to <br />a few inches deep in several locations, especially at contraction joints in <br />the conduit. The leaf and seat of the valve itself appeared to be corroded <br />and partially worn away, rendering the valve unable to properly seat and stop <br />the flow of water completely. <br /> <br /> <br />The i nl et structure appeared to be in sati sfactory condi ti on. The outl et <br />structure consi sts of a masonry stone headwall with wingwall s. The concrete <br />training wall at the left side of the outlet structure was cracked and fallen <br />to one side, thus allowing flows to discharge along the bedrock abutment- <br />embankment contact. The top of the concrete condui tis exposed over the <br />downstream ten feet. <br /> <br />-44- <br />