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GUNSUL'1'AlV 1'J llVU <br />Tfie structure can pass a flood 'resulting from an event equivalent to <br />40 percent of the "Hydro-I~eteoroloyical Report No. 49" Probably t+,aximuri <br />Thunderstorm witi~out overtoppiny the embankment. <br />It is recommended that a detailed study be performed evaluating the <br />options for increasing the spillway capacity such as raising the darts and/or <br />widening the spillway. However, it is our judgement, based upon the con- <br />dition and history of the dam, that the best approach would be to regrade <br />the crest to a consistent elevation and widen the spillway sufficient]y to <br />enable the dam and reservoir to handle the PMGS and PMTS storm runoff <br />without overtopping the dam embankment. <br />8. STRUCTURAL AND GEOTECNNICAL EVALUATION. <br />a. General. The evaluation of structural stability for Monument <br />Dam is based on discussions with Mr. Simineo and the visual inspection. <br />b. Embankment. The sloughs along the downstream face are judged to <br />be indicative of adverse embankment conditions. Tlie association of seepage <br />with the: sloughing is indicative of a higher than desirab]e phreatic sur- <br />face through tl~e dam at that point. The dam does not appear to suffer unu- <br />sual quantity of seepage. <br />Apparently, no stability analyses were performed in connection with or <br />subsequent to original design. If stability analyses were to be performed, <br />based on existing conditions in fire embankment and foundation, it is <br />believed unlikely that the resulting factors of safety would be comparable <br />to the requirements of paragraph 4.4 of the "Recommended Guidelines for the <br />Safety Inspection of Darns" (Reference 3). The sloughs along the dovrnstream <br />• face are believed to be a clear indication of toss of strength 6y <br />saturation. It is concluded that the existing factor of safety against a <br />deeper seated failure of the dovrnstream face with steady state seepage is <br />unacceptab]y low. <br />9. ASSESSMENT AND RECOMMENDATIONS. <br />a. General. In order for Monument Dam and Reservoir to be main- <br />tained in good structural and operating condition, the following steps <br />should be, taken to improve its structural integrity. <br />b. Embankment. <br />{I) The sloughs and surface slides alony the dovrnstream face <br />sfiould be repaired and their locations marked to permit observation during <br />future inspections. <br />(2) The dam should be surveyed and accurate sketches prepared <br />shovring all major features and locating the existing sloughs. <br />face. <br />(3) Piezometers should be installed to monitor the phreatic sur- <br /> <br />-~- <br />