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<br />....... <br /> <br />Service Creek <br />Green Creek <br />Harrison Creek <br /> <br />Creeks flowing into the Yampa in the study area include: <br /> <br />Walton Creek <br />Burgess Creek (via Casey's Pond) <br />Fish Creek <br />Spring Creek <br />Butcherknife Creek <br />Soda Creek <br /> <br />Geomorphology <br />The Yampa River consists of both an active river channel and a surrounding floodplain. A natural erosion <br />and deposition cycle associated with flooding is imponant to the health of fisheries and riparian ecosystems, <br />including cottonwood regeneration. An examination of the floodplain and the location of cottonwoods within <br />the study area indicate that the river has been altered, and much of the original floodplain has been lost to <br />development. <br /> <br />The character of the river differs from upstream to downstream. Upper portions of the river are only slightly <br />entrenched, have an intact and largely undeveloped floodplain, and contain meander patterns commonly found <br />in a U-shaped glacial valley. These areas include point bars on the inside of the bends and deep pools along <br />the outside, providing high quality fish habitat. The lower portion of the river, beginning in about the center of <br />the study area, has a significantly different character. The channel in these areas is highly entrenched and less <br />sinuous, with slopes about four times greater than upstream areas, Reaches of the river further downstream <br />(below the Stockbridge) return to a more natural state, with river morphology characteristics similar to both <br />the central and upstream portions of the study area. <br /> <br />A number of habitat improvements have been made to the river. Riparian enhancements and the addition of <br />in-channel rock structures and v-dams have improved both the recreational environment and aquatic habitat. <br /> <br />Water Flow <br />The hydrologic regime (timing and amounts of flow over the year) of many rivers in the west has been <br />modified. These changes are typically caused by damming and diversion projects. The Yampa River and <br />its major tributaries have relatively few dams and diversions from the headwaters to its confluence with the <br />Green River. Reservoirs upstream of Steamboat Springs along the Yampa River include Yamcolo Reservoir, <br />Stagecoach Reservoir and Lake Catamount, none of which are major storage facilities. <br /> <br />~~'_".io. t~~~_r .~_.~~_"~..~._.__J..~ <br />1\ J'.~' F ("J i\"! :) I' ~( I \J C \ C. \.\ L \ " :\ ,:... U I) <br /> <br />~ <br /> <br />Based on a review of historic flows of the Yampa River at the Steamboat Springs U.S. Geological Survey <br />(USGS) gauge station, the flow regime seen in the early 1900's appears to be relatively similar to those <br />seen in the present day. Therefore, many of the physical forces of the river that influence plant and animal <br />communities in the past continue today, Figure 2-4 compares recent versus historic hydrographs, showing <br />that the flow regimes are very similar. During both periods, peak spring flows tended to range from 2000 to <br />3000 cfs. <br /> <br />Hydrograph for the Vampa River at Steamboat Springs, Colorado <br /> <br /> r191'019_21l_ 1991-200~ t <br /> 1---- <br />~ a. ~ ~ W ~ ~ \.e..J ~ ~ <br /> <br />iJOOO <br /> <br />i 2500 <br />! <br />Wi 2000 <br /> <br />i 1500 <br />. <br />i <br />i "00 <br /> <br />500 <br /> <br />. ~ . <br />~ ~ ~ I ~ I I 8 <br />~ g ~ ~ S <br />. <br /> <br />Figure 2-4. Comparisons of hydrographs for the Yampa River at Steamboat Springs, Colorado, for the period <br />between January 1911 through December of 1920 and January 1991 through December 2000. <br /> <br />o <br />~ <br />o <br />w <br />en <br />~ <br /> <br />CH/\['TFR <br /> <br />x <br /> <br /><) <br />" <br /> <br />P L /\ \J ~I I \J C, <br /> <br />c: C, 'I <br />