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<br />e <br /> <br />DAM EMBANKMENT <br /> <br />The Red Mesa Dam, is jurisdictional and is an intermediate Class <br />II. The "Rules and Regulations for Dam Safety and Dam <br />Construction" prepared by the Colorado State Engineer, Division of <br />Water Resources state the following criteria should be met: <br /> <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, <br />* a crest width equal to the vertical height divided by 5 plus <br />10 feet, with a maximum of 25 feetr <br />* a spillway capable of passing 50% of the PMP, <br />* upstream rip rap to protect the embankment, <br />* and soils investigation and analysis. <br /> <br />e <br /> <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 /> <br />EMBANKMENT: The existing Red Mesa Dam is about 50 feet high with <br />slopes of 3.2: 1 upstream and 2.4: 1 downstream (based on field <br />survey of the maximum section for this report), a 10 foot crest <br />width, and a 4 ft by 2 ft horseshoe outlet tunnel. The dam is in <br />relatively good condition and is not restricted. The main <br />embankment concern is the crest elevation that is not consistent, <br />the center of the dam is about 3 feet lower than the outside crest <br />elevations. There is also an embankment groin leak which should be <br />addressed in designs for an enlargement. <br /> <br />Enlargement of the dam will involve ra~s~ng the crest from <br />elevation 6903 feet (lowest point on the crest) to 6932 feet <br />elevation (MSL elevations are plus or minus 5 feet) an increase of <br />29 feet. The upstream slope of 3.2H:1.0V will be extended and the <br />downstream slope will be 2.5H:1.0V. <br /> <br />The enlarged dam will be an earth embankment with following the <br />dimensions: <br /> <br />* 82 feet high, <br />* 7 feet of freeboard, <br />* crest length of about 720 feet (including spillway), <br />* crest width of 25 feet, <br />* 3.2H:1.0V upstream and 2.5H:l.0V downstream slopes <br />* extension of existing 2 ft by 4 ft horseshoe tunnel, <br />* a spillway width of 200 feet. <br /> <br />Red Mesa Dam <br /> <br />7 <br />