2003-11-07_REVISION - M1984041 - Laserfiche WebLink

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e , ~ .- STATE OF COLORADO DNISION OF WATER RESOURCES OFFICE OF STATE ENGINEER SPECIFICATIONS TO GOVERN THE CONSIRUCITON OF AN EROSION CONTROL DAM Preparatiost of Folmdation for Dam-All vegetable matter of every destxiptkm, iocludittg toots ro a depth of two feet, shall be removed from the entire area upon which the dam will test, together with boggy or unstable materials and deposited outside the toes of the dam. The baala of the scram chattrtel shall be dressed ro a slope of about 11:1. A cutoff ttmcl4 with alopiag riders and a bottom width of cot lea than 5 fat and depth of 4 feet, shall then be ezravated beneath the curter lice of the dam the full ktlgtlt thereof which ttmch shall be refilled with the twat impervious materials available. The foundation of the dam shall thm be lightly plowed lengthwise of the dam, ro Provide proper matact between the foundation and the dam embanl®att PLt®g of Dam Emb®1®mt The materials shall be planed is the atroff ttmeh and in the emban!®eat of the dam is layers cot etrcceding 6 inches in tludmess. after which each layer shall 6e thorot;gltly mmpac[cd by a Leanly loaded disc cultivator, a mrtttgated or sheep's foot tulle, the reads of a ntetpillar or trudq or by livestock used in the construction. Dttriag the eoastrltctioa period, the top of the embanlm®t shall be maintained as a horizontal plane the full width cad length themof and no side dumping of materials shall be permitted. The materials shall at aB times contain suffidmt moisture ro provide proper campac[ion. Poddliag of maasial with wad shall not be permuted. No ftaren material or large clods or stones shag be incorporated is the dam. The upstream face of the dam shall be mnstrtlcaed with a slope cot steeper than 21:1, and the downstream faoe oa a slope not steeper than 2:1. The oast or top of the finiehwl dam shall be cot lea than 8 feet is width The upstream two-thirds of the dam shall be cotlstntcted of the moat impervious mataiaLs, such as clay loam, or ~a m;.n,.. of clay and sand, and the dowttstrram oae-third of tnom pervious material, such as sand or gravel. The upstream face of the dam shall be adequately Pcotacted against wave action by stone riprap, or other suitable materials when tegtdred. Oatlet 7Lete shall be located beneath the dam an uagatrd outlet pipe not lea than 12 i~hes is diameoer and large enough to drain within thirty-six bouts any impotmdalmt in eoreess of two acre-fat Sneh outlet pipe shall be provided with cutoff collets. The pipe shall be plaecd is a trench botrottxd in stable formation, and shall be mmpktely surnouaded with well rompaeted impervious materials. Splbray-For the protx-tiaa of the dam, as adoquate sptlway shall be eonatrttcted around one or both ends of the dam, of suffidmt width m provide a capadty ro carry the more discharge from the drainage basic above the dam doting periods of vausilal runoff. The spillway shag be kleated instable tOrmatioas not easily eroded, and shall lStPad ro a point well downstream from the dam. The following table shall be used ro determine the rleoeaary width of spillway ro tnat the above requirementi. The top of the dam at all points shall be cot lea than 4 feet above the botrom of the spillway. The following table shows the widths of spillways for eotzesponding draitrage axes with as alklwame of a +~;++;+~,^* &aboatd between the matdntum high ware line cad top of dam, of 2.3 feet, and marimum vekldties of 3S feet per setbad of time. MFRS OF LOW RAINFALL IMEMS/lY AREAS OF H/GF/ RAINFALL WlFA15l1Y AtFAffotwNenetttcsu tcausmreomaFauwAr ArFwaFrnewa;EttAwt tea~wtomoF AiF/16QY1N11rtEatSN ttt~a®wvmoF AaWEaIlYNl16® SIN AT WeiDwFSf PONtN Aila0E d1Y NAO® auwAr l-ATNI1fiOWf$r At)nVE al101NALSOH ~alItA7Sr ATNMNa1N@,7 FgT IWrNrffr fCNf NiffT e e tl 0 tl 0 450 M tl 11 tl 1f 000 00 tl u m to aeo os too to too a coo 1aa 1tl zt tzo zs Too m 100 2a /tl aD 000 iTD ~ z9 too x coo ttl 100 y 100 0T lOW 100 10o ere 1m u ttao ten ono ere za tl tap ~ too tlo .z 1tl so taco to tlo .~ ap m too to sao b ap s7 taro tsa coo ~ et ~ our eo taoo ap too ss am m troo zu coo z atl ee ttoo 2te son ez oeo To teoo zrs taco ea am n lam w ALL AREAS EAST OF THE CONTINENTAL DIVIDE BELOW AN ELEVATION OF 7000 FEET, ARE CONSIDERED AS BEING IN THE HIGH RAINFALL BJTENSITY ZONE. The above spillway widths maybe reduced at a point 50 fat below iatakS, by 25 per curt, whex the spillway is located the full length theaot in hard clay or shale, and by 50 per curt when located is hard tack formatiotu, if the slope or grade of the botromts inaeasad aooordingiy. 13e grade for clay and shale formations should be 0.30 foot per 100 feet, and for rock formations 0.90 toot per 100 feet The width of the eneranoe ro the sptVtNay must in all roses be one-third wider than shown is the table, and the bottom should slope from the lower cad of the funnel sectio4 toward the teserwir 1.0 foot is the distance of 50 feet, and the slope downstream should be 0?S foot in a distance of 100 fat Borrow Pim-Pits, from which materials ax taken ro build the dam, shall be cleared of aB vrgemble matter, and tw mataial shall be boaowed within a distance of 50 feet of airy part of the dam without apprtrral. Materials excavated hour the sptLway, when suitable, may be used is building the dam.