Laserfiche WebLink
<br />genora I storm cond itions wi'thout sp!>c I f ic relere"~e to Lef't-f<and <br />Creck. An improved storm warning service Should be available in <br />about two years since Boulder County is in tho effective range of the <br />planned weatMr radar at limon, Colorado. Even though this will pro- <br />videa better method of locatlrl9 individual stormcells,ground <br />observers arc needed to indicate the progress and magnitude of flooding. <br />Consideration should be given to a local flash flood network Which <br />can bo effective with proper procedures and responsibilities. NormalLy, <br />the basic forecast procedure is established by tho Weather Bureau as <br />part of their radar program. Local officials can then use these <br />tecMniqueswithsupplemental information froo the Weather BUreilU ilS <br />the basis for local warnings. <br /> <br />GENERAL CONDITIONS <br /> <br />This section presants the general basin description and <br />a more detai led description ot the study reilCh. <br /> <br />Stream and Valley Characteristics <br />lelt-Hilnd Creek, a right bank tributary to St. Vrain <br />Creek, lies innorth-central Colorado. The basin extends about <br />JOmileSflastwardfrom its headwaters in the Roosevelt National <br />Forest to its junction with St. Vraln Creek at Longmont. Most of <br />thebasln,57.Ssquaremiles, lies In the Rocky Mountains and varies <br />in ele~atlon from 11,000 to 5,600 feet. The relTlill nder of the basin <br />lies In the high plains and conhlns an additional 14.5 square Miles <br />between the mountains and the mouth. This lower basin, with a strea~ <br />lengthofaboutl4miles, Is the reach studied in this report and the <br />remaining discussion refers only totnls part. ThvLeft-HandCre(lk <br />flood plain ~arles from SOO to 1,000 feet wide excopt for the lower <br />TWO Oliles where it widans and merges with the St. Vrain flood plain . <br />The cnannel bed slopes range from 15 feet per mi Ie at the mouth to <br />120 feet per mile at tne upper end of the study reach. The lower <br />tnree miles 01 the stream nave been straigntened and confined to a <br />"U"snapodcnannol,withfarroingextonolngtotnebankline. The <br />next mIle of channel snows evidence of straightening but is more <br />typically characterized by tno unimproved channel. The uni~oroved <br />reaches have a low flow Channel approximately is fflet wide, with the <br />remainder of the active channel sloping up to merge with the flood <br />pL~i n, often with an ind I stinct bank Ii na. Tne followi ng pictures <br />ty p j 1 Y tile Channa I tl1 roug ho" t the s ~ud y r<ldG h . <br /> <br />, <br /> <br />, <br />