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DAM EMBANKMENT <br />The dam is jurisdictional and rated as small Class II. The "Rules <br />and Regulations for Dam Safety and Dam Construction" prepared by <br />the Colorado State Engineer, Division of Water Resources state the <br />following criteria should be met: <br />* a minimum of 5 feet of freeboard, <br />* an outlet pipe capable of draining the top 5 feet of storage <br />in 5 days, suggested but not required, <br />* a crest width equal to the vertical height divided by 5 plus <br />10 feet, <br />* a spillway capable of passing 50~ PMP, <br />* upstream rip rap to protect the embankment, <br />* and soils investigation and analysis. <br />Plans and specifications must be prepared and approved by the State <br />Engineer prior to beginning construction. Soils tests and material <br />evaluations will be required to prepare the plans and <br />specifications. The reconnaissance designs described herein are <br />based upon a site inspection and review of available data; more <br />detailed engineering work may result in a different design. <br />EMBANKMENT: The Big Battlement dam is listed as 23 feet high by <br />the State Engineer but the survey performed by the City indicates <br />the dam is 24 feet high, a small difference. The dam is restricted <br />because of excessive seepage through the embankment and foundation, <br />as shown by several seepage holes on the upstream slope. Major <br />modifications are necessary to correct the problems so <br />reconstruction appears to be the best long term solution. <br />The existing dam has the following dimensions: <br />* 24 feet high, <br />* crest length of about 350 feet, <br />* crest width of 10 feet, <br />* 3.OH:1.OV upstream and 2.OH:1.OV downstream slopes <br />* 12 inch diameter outlet pipe, <br />* 15 foot wide spillway. <br />The shape and type of design for the reconstructed dam embankment <br />is difficult to estimate until foundation testing and the access <br />issue are resolved. For purposes of this report the embankment is <br />assumed to be an earth embankment constructed with materials in the <br />reservoir area and with the following the dimensions: <br />* 24 feet high, <br />* crest length of about 350 feet, <br />* crest width of 16 feet, <br />* 3.75H:1.OV upstream and 3.OH:1.OV downstream slopes <br />* 24 inch diameter outlet pipe, <br />* 15 foot wide spillway. <br />Big Battlement Dam 7 <br />