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. The [SSA Weather Burceu lo~eted at the Pueblo Meme- rial Airport supplies weather forecests four times daily for Pueblo, Colorado, eod vicinity. These forecasts are dissernioeted to local nOOlSOIedi<'ldirGctlybylimacdecGlIse telephone. A 51milar__but 5eperete-~in6telletion is weed for general public dissemination. In addition to the routine forecasts, special fore~este af Bevere storms or flood warnings ete issued as re- , qulred. A community flash flood reporting network of river and rein fall stations and e flood warning program developed end operated in connection with the 24-hcur Weather Bureau facili- ties could minimize lass of life e~d movable property in ths event of a major flood. Such en arrangement ~ould require that 10001 river and rainfall reports be oommunioated promptly by responsible looal offioials to the Weather Bureau Foreoest OfM fioe for evaluation and analysis. If available, this data and analysis would be usod by the Weather Bureau to mOre acourately forewarn community representatives of potential storm and flood oonditions. Thi~ typ~ of n€t~ork i~ presently in offect in por- tions of the Arkansas Rivor basin and, to an extremely limited degree, in other tributAry arAas. . The Strea~ and Its Valley The St. Charles Rher origil1"L,,;; ""'li- Sail ba['~l, Colorado, on the northoast faoe of the Wet Mou~tai~s. After following a 50 mile northeasterly couroo, its waters enter the Arkan'M River abOJt 6 ..iles "ast of Pueblo. In tho study reach, the river ha~ eroded into shale and limestone strata deposited during the Cretaceous age to form a narrow, entrenched valley within surrounding high plains. This valley is bordered by bluffs that seidom exceed 30 feet in height. Valley widths range from ebout 1,200 feet in the upper ctudy reach to 3,000 feet"earthorivar'smouth,withsomeieolatedce9ments , 10 narro~ing to os little as 600 feet. Approximately 67 square miles of the upper watershed is eboveg,OOOfeetinalavation. CreenhornMountainondSt.Charlas Peak at elevations of 12,349 and 11,138 feet, respectively, are in this locality. The stre"",bed elevation at the mouth h about 4,545 fect. Stream siopes are relatively steep, averaging about 20 feet per mile through thc study reach. The tot"l 462 square mile water- shed includes the 232 equare mile oontributing drainage area of the Greenhcrn River. Aa the principal tributary stream, the Greenhorn River joins the St. Charles River near the abandoned community of Lime about S milea aouth of Pueblo. The study reach lies primarily in the lower short-grass plain ZOne where native blue grema and gallata grasses with sOme rabbit brush are found. Cottonwood, willow, and tamarisk (salt cedar) ara the predominant trees growing along the channel banks. The upper watershed vegetation consists of mixed oonifers, such as pine, fir, and spruce, and typical mountain grasses including s!da- oats grama, needle, arizona fasque, and mountain muley. The river is a typical perennial mou~ta1n stream aus- t~ined by runoff From sno"'''clt end rainfall in the late hll, "'in- , ter, and early spring. Runoff increases end flooding ocours during the Summer "'onths in conjunction wi th increased thunderstorm activ~ it1es. The average annual precipitation varies from about 12 inchM es at the mouth of tho stream te 24 inches in the upper elevations of the watershed. Pertinent drainage areas of tha St. Charles River are given in Table 1. Develooments in the FlOOd Plain Plahs 4 through lOshelll the floodplains of the St. Charles River for ths reach covered by this report. In recent years, urbanization has gredually expanded into the lower valley to occupy some flood plain lands that were formerly uaad for 11