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<br />. <br /> <br />r :" I"" <br />OOltl'J~) <br /> <br />. <br /> <br />the site. Estimated short-term runoff in McElmo Creek above the confluence <br /> <br /> <br />with Alkali Canyon and at the "McElmo Creek below Cortez" gaging station <br /> <br /> <br />are summarized in Tables 6 and 7, respectively. <br /> <br />. <br /> <br />. <br /> <br />Stream Losses <br /> <br /> <br />The virgin runoff estimates for McElmo Creek have not been reduced <br /> <br /> <br />to account for evaporation losses (consumptive use) associated with riparian <br /> <br /> <br />vegetation along the stream channel. Such consumptive use results in a signifi- <br /> <br /> <br />cant stream loss during the growing season. Evaporation from the water surface <br /> <br /> <br />in the stream also contributes to the stream loss. Monthly losses were estimated <br /> <br /> <br />on the basis of an analysis of potential use by phreatophtes. Aerial photographs <br /> <br /> <br />of McElmo Creek were examined to estimate the areal extent of phreatophytes <br /> <br /> <br />and water surface area downstream of Alkali Canyon. The aerial photographs <br /> <br /> <br />used in the analysis were at a scale of about one inch to 600 feet. Estimated <br /> <br /> <br />phreatophyte and open water areas are summarized below: <br /> <br />. <br /> <br />. <br /> <br />. <br /> <br />Reach <br /> <br />A I kali Canyon to site of <br />"McElmo Creek below Cortez" <br />gage <br /> <br />Reach <br />Length <br />(miles) <br /> <br />8.8 <br /> <br />Average <br />Width <br />(feet) <br /> <br />420 <br /> <br />Water Surface <br />& Phreatophyte <br />Area (acres) <br /> <br />450 <br /> <br />"McElmo Creek below Cortez" <br />gage to state line gage <br /> <br />11.8 <br /> <br />350 <br /> <br />500 <br /> <br />. <br /> <br />Totals <br /> <br />20.6 <br /> <br />950 <br /> <br />. <br /> <br />Phreatophytes exist along McElmo Crek and its tributaries upstream of Alkali <br /> <br /> <br />Canyon, but no estimates were made of their areal extent. <br /> <br />. <br /> <br />Riparian vegetation along McElmo Creek consists predominantly of cotton- <br /> <br /> <br />woods, box elders, willows, rushes, salt cedar, and grasses. The amount of water <br /> <br />consumed by these phreatophytes is dependent on several factors including <br /> <br /> <br />the density and health of the vegetation. Analysis of aerial photographs provides <br /> <br />-18- <br /> <br />. <br /> <br />;l1o,i;l;'! <br />