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<br />ODZi377 <br /> <br />. <br /> <br />B. <br /> <br />Potential Consumptive Use by Phreatophytes Based on Analysis of Aerial <br />Photographs. <br /> <br />Aerial photographs of the Mancos River were analyzed to estimate the <br /> <br /> <br />area of phreatophytes and water surface area throughout the reach between <br /> <br /> <br />the town of Mancos and the confluence with Aztec Wash near the Colorado- <br /> <br /> <br />New Mexico state line. The aerial photographs used in the analysis were <br /> <br /> <br />at a scale of about one inch to 600 feet. Estimated phreatophyte and <br /> <br /> <br />open water areas are summarized below: <br /> <br /> Reach Average Water Surface <br /> Length Width and Phreatophyte <br /> Reach (miles) (feet) Area (acres) <br /> West, Middle & East Mancos <br /> Rivers to Weber Canyon 14.6 160 280 <br /> Weber Canyon to Navajo Canyon 15.2 280 520 <br />. Navajo Canyon to Highway 666 12.5 390 590 <br /> Highway 666 to Aztec Wash 11.4 500 ~ <br /> Totals 53.7 2,080 <br /> Johnson Canyon to Highway 666 20.2 330 800 <br /> <br />Phreatophytes along the Mancos River predominately consist of salt cedar, <br /> <br /> <br />willows, cottonwoods, rushes, and grasses. The amount of water consumed <br /> <br /> <br />by phreatophytes is dependent on several factors including the density <br /> <br /> <br />and health of the vegetation. Analysis of aerial photographs provides <br /> <br /> <br />an estimate of the overall areal extent of phreatophytes, but does not <br /> <br /> <br />provide accurate information concerning the vegetation density and health. <br /> <br />The potential consumptive use of water by dense willows, salt cedars, <br /> <br /> <br />and small cottonwoods was calculated through use of the Blaney-Criddle <br /> <br /> <br />method, based on experimental data published in "Consumptive Use and <br /> <br />. <br /> <br />-31- <br /> <br />. <br />