Laserfiche WebLink
<br />relate the index peak discharge of a selected exceedence risk to other foods <br /> <br />with various exceedence probabilities. <br /> <br /> <br />In Colorado there have been four hydrologic regions defined; South <br /> <br /> <br />Platte River, Arkansas River, Rio Grande and Colorado. Regional flood- <br /> <br /> <br />frequency analysis have been performed by Patterson (1964; 1965), Patterson <br />and Somers (1966), Matthai (196B), McCain and Jarrett (1976), Lichty and <br />Liscum (1978), Livingston (1970, 1981), Kircher and others (1985), Livingston <br />and Minges (1987), Jarrett and Costa (1988) and Lichty and Karlinger (1989). <br />Within each of these regions there are distinct areas such as plains, <br />mountai nOLIS areas, pI ateaus and the foothi 11 s regi on. The foothi 11 s regi ons <br /> <br /> <br />is defined as that area between the high mountainous areas and plains. As <br /> <br /> <br />early as 1960, Jenkins (1960) suggested that flood originating on streams that <br /> <br /> <br />have drainage area in the mountainous, foothills and plains area could be of <br /> <br /> <br />two types, those caused by snowmelt or by rainfall. Jenkins went on to say <br /> <br /> <br />that meteorologic data notwithstanding, there were indications that "intense <br /> <br /> <br />(rainfall) storms rarely, if ever, occur at the high elevations of the <br /> <br /> <br />headwaters of Boulder Creek" (Jenkins, 1960, p. 6) but that the intense <br /> <br /> <br />rainstorms have been confined mostly to the lower elevations. This is an <br /> <br /> <br />early indication that flood flow magnitudes may in fact be influenced by <br /> <br /> <br />elevation. In Design of Small Dams <U.S. Bureau of Reclamation, 1973) it was <br /> <br /> <br />recognized that flood potential depends on geology, topography and moisture <br /> <br /> <br />source and that depending on location flood flows originate from rainfall, <br /> <br /> <br />from snowmelt or from a combination of varying amounts of rainfall and <br /> <br />snowmelt. The U.S. weather Bureau has been studying meteorology since 1937 to <br /> <br />provide storm potential data for many parts of the United States. The <br /> <br />Hydrometeorological Branch, National Weather Service has published generalized <br /> <br />8 <br />