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etc, and man-made obatrl1ctions sucn .~" bridges, buildings, and roadl.'ays. These obatructiona have the tendency of increaaing flood elevations upatream of the obstructions and velocities downstream of the obstruc- tion. In aomeinatancea, debris piled against a structure does prl!sent n potential ~hreat to the safety of the structure. During the fall of 1970 and summer of 1971, the U.S. Bureau of Reclamation, in cooperation with the Army Corps of Engineers, completed ~ clearing and snag removal program. This program was primarily confined to the area above the high water level of Blue Mesa Reservoir and downstream of the study reach. An earth levee waa hurriedly constructed aear the aoutheastern part of the Dos Rios Island. Characteristics of Different Reaches The study reaches for Gunnison RiVer and Tomichi Creek are shown on tne Index ~ap, (Plate 2). The Gunnison Rlv;,r reach extends fro~ the bridge across Gunnison River on Colorado Highway 135 to McCabe Bridge located approximately 1.6 miles do~~stredrn from TomiChi Creek confluence with Gunnison River. The Tomich 1 Creek reach extends from the point of its confluence with Gunnison River to its upper limits represented by a point approximately 500 feet downstream from N~'W ~exico Principal Meridian. The lengths of the two reaches ate approximately 7.6 and 4.9 miles for Gunnison River and Tomichi Creek, respectively. The str;,am valleys in the study rench are generally charac- terized by broad plains extending between hills. Theae plains vary in width, and are In excess of 2 miles wide at certaIn locations. Alluvial lands on the flood plains along streams consist primarily of material recently deposited by streams. The texture is widely variable and commonly has very cobbly or stony areas interspersed throu~hout. These lands are subject to ero~ion from floods and changes in stream channels. The streams have the tendency to meander. especially Tomichi Creek. Future floods are likely to shift the river channel us it nag in the past. The construction of the Taylor Park Reservoir ncnr Taylor Park (completed in September 1937) has reduced peak flows of Taylor River at Almont atreamflow measuring station and in turn reduced the peak flo~s in the st~dy reach. Approximately 28% of the decrease in flo~s (218 cfs) of Taylor Riv~r at Almont ~lnce 1938 can bc attributed to the construc- tion of Taylor Park Rescrvoir and the remainder to natural decre"~e in runoff. Generally speaking, Taylor Park Reservoir cannot be depended upon to reduce peak flows in the study reach, since its primary function is to provide water aupply for irrigation purposes. The historicsl use of the flood plain has becn for ran~e and wildlife with limited improvements confined to dwellin~s and other structures supporting ranching activities. Irrigated pastures on rhes", plains h"ve good plant cover and support meadow vegetntion, wBlows and ""rrowleaf cottonwood. S....ll area~ withi" the floodplain are flooded annually and support little or no ve~etattio". The ~rowth of Gunnison in recent years has forced gU.at..r development in the flood plain par- tlc~l~rly ~long C~nnison Rivor in the ~cstcrn pnrt cf thc cit~ nnd In rhe vicinity of Dos Rlos Island. With lhis InCrl",sed e"cw..chment uf development in the floodplain, the flood hazard to theCO"""-unity h increased and w111 continue in the> fnture unl"",,s .~d"qllat" me"~llre8 .~re adopted to k~~p t.he ~evelorment o\ltsid.. th~ fInO<! n"~"rd areas. Obnructions to floodflo\ols\o/ithin rhe study reach incl~eboth n..tural ohstruc.tions sucn ..", v"getat!.--m Rro,",th, fallen tre..s, lee Jam~, 12 13