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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 />I <br />I <br />I <br />I <br /> <br />Hydrometeorological Report Number 55 and routed through the reservoir <br />utilizing the HEC-l computer program. It was found that the existing <br />spillways could, in fact, safely pass the PMF with one foot of freeboard on <br />the embankment dam. Duri ng the course of the study, the SED's cri teri a for <br />computing the design flood for high hazard dams was modified to 75 percent of <br />the probable maximum precipitation (PMP). The local storm hydrographs were <br />recomputed and resulted in a peak discharge of 9571 cubic feet per second with <br />a volume of 1,022 acre-feet. <br /> <br />The hydraul ics of the existing outlet works were evaluated based on three <br />performance criteria: (1) the capability to release the maximum five feet of <br />reservoi r storage at a rate of one foot per day, (2) the abi 1 i ty to ma i ntai n <br />water levels to comply with the current operating restriction, and (3) the <br />capabil ity to safely pass normal flows. The rel ease capabil i ty of the outl et <br />works was found to be adequate to meet these criteria. <br /> <br />Fi el d work commenced wi th a si te i nspecti on by representati ves of MKE, the <br />City, and the U.S. Forest Service in July 1987. The inspection included an <br />internal examination of the outlet works conduit. At that time, a Phase I <br />inspection checklist was prepared, similar to the form used by the SED. <br /> <br />The site inspections showed the dam crest to have several low areas and a lack <br />of cross slope drainage. The upstream slope was in fair condition with <br />several areas of spotty riprap protection. The downstream slope appeared <br />stable, but numerous erosion rivulets had formed in the sparse grass slope <br />protection. All seepage flow was being satisfactorily collected by the toe <br />drain. The embankment dam appeared to be stable. <br /> <br />The recently rebuil t outl et works di scharge structure was in good condi ti on. <br />The internal inspection of the outlet conduit revealed that recent repairs <br />were only partially successful. Many iron-stained seeps occurred over the <br />entire length of the original concrete arch conduit usually associated with <br />cracks, constructi on joi nts, and porous concrete. Many of the seeps emerged <br />from areas patched and/or grouted duri ng the 1 atest repai rs. It was only <br />possible to inspect the inside of the intake structure, which appeared to be <br />in good condition except for a small leak from the upper gate. <br /> <br />E-3 <br /> <br />1151c <br /> <br />- <br />