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<br />SECTION VII <br /> <br />THE PRELIMINARY DESIGN <br /> <br />The pr.lmary purpose of this Section Is to dl!;cuss pertinent details <br />of the overall design. There are numerous Items of a generalizad nature <br />that occur throughout the entire reach of Big Dry Creek. These Items will <br />be discussed first, and that wIll be followe,d by" discussion In datall of <br />the drawings In Volume Two, proceeding gener'ally from County Line Road <br />southwest towards Standley Lake. <br /> <br />In concurrence with both Adams County and We!;tmlnster, this report <br />does not cover any of the details surrounding the Intended lIse of the <br />flood plain as parks and open space. These detal Is will be worked out <br />with Individual developers by the local entities liS de',alopment occurs. <br />However, In most Instances specific provisi,e.ns ha",e belen made In the pre- <br />lIminary design for pedestrian passage ,:ontlnuously along the length of <br />Big Dry Creek. One of the most Important feature!; of the des Ign is to <br />ut Illze the clear water releases from Standley Lake and Great Western Reser- <br />voir as aesthetic features In that there Is a unique Ol)portunlty for the <br />Denver Metropolitan Region to establish a "1 I veil Jrtaandoerlng stream through <br />the heart of an urban I zing area. Prov i s Ions, have been made throughout to <br />provide erosion controls both of concrete or' of rock ('gabions) In order to <br />stab 111 ze the present downward-cutt I ng trend of the chianne 1 and to ease the <br />maIntenance burden on the local entities. In many Instances the concrete <br />checks are ra I sed above the ex is t I ng chi3nne I bottom In order to create a <br />flatter water surface slope and lower the low flol,' ve),)cltTes. As a result, <br />the water surface area for low flows wiT I be, s lightly Increased and there <br />wilT be a slight Increase In evaporatTO]1 of Irrlgal: Ion releases. However, <br />the effect will hardly be noticeable, and as the l,rea I,lrbanlzes retllrn flows <br />from lawn Irrigation will more than makl! up for the in,:reasfl in evaporation <br />losses. <br /> <br />Sheet 7, as well as Sheet 22. show,'; recotm18ndo.d d..talls for the con- <br />struction of the concrete and gablon i01~ flow erolilon control. The gablon <br />low flow erosion controls are used where the, norll1lll velocIty of low flow <br />up to 250 cfs Is less than 3 feet per second (fps). The primary purpose <br />Is to protect the channel from eros Ion from commonly oo:currlng storms whlch <br />occur frequently throughout the year. The fJexlbll ity and permanence of <br />of the gablons are Ideally suited to this purpose.. <br /> <br />The concrete low flow eros Ion contJ'oJ shown on Sheet 7 Is used to Im- <br />pose a flatter water surface slope than would nor,~.1 Jy occur' In order that <br />the velocIty of 250 cfs be less than 3 fps. As opposed to the concrete <br />erosion control shown on Sheet 22 and the gab Ion :'ow flow eras Ion centrol, <br />this structure Is to be bul It with the ,;oncrete 1 'Ip above the channel <br />bottom In an attempt to stop the eras 1011 currently occlJrrinSI. The eros Ion <br />controi shown on Sheet 22 Is to be constructlld flu:>h wIth the existIng <br /> <br />VII-I <br />