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<br />.- <br />-.J <br />CD <br />CD <br /> <br />Aspen Trees <br />Save Water? <br /> <br />The loss of aspen to conifer t~ In natures <br />successional trend IS signlhcantlY re<:lUCmg <br />water yl€lds within the CoIoraao River Basm, <br />water that could be used to dilute san <br />downstream. This suggestion IS addressed In <br />a report prepared by the Utah Water <br />Research laboratory entitled. A Prellmmary <br />Quanrlflcatlon of rhe Impacts 01 Asp9n to <br />Conder Succession on Warer Ylflld Within <br />the Colorado RIVer Basm (A Procoss <br />Aggravating me Salt Pollution PrOblem), <br />published at Utah Stale University. logan. <br />Utah 84322. In January 1983 (Hydraulics and <br />HydrOlOgy Senes UWRLiH-83':Ol) <br />Mature aspen forests are replaced Q','ef <br />lime by e'Vefgreen conifers unless some lorm <br />of major disturbance (fire. disease. <br />clearcuttlng) occurs When such disturbance <br />destroys the overstory canopy of an aspen <br />forest, aspen sprOUl from the fOOts and grow <br />faster ltlan the other vegetation. and the <br />aspen stand IS thus able to perpetuate itself <br />WithOut man's InlervefltlOn. many areas <br />once dOminated by aspen have become <br />coniferous forests The Impact 01 thIS shift In <br />dominant lores! cover on streamflow from <br />SUbalpine mountain zones IS DQOny <br />underStood Available literature and <br />preliminary modeling eHortS, ~. <br />strongly suggest that the asperl to cof'lIfer <br />succession significantly reduces water yl€'ld <br />ana dilution potenllal <br />The effect IS already being fell SU''lCE' the <br />aspen to conder successiOn IS presently well <br />advanced on many former aspen acreages <br />Besides decreasmg natural water Yields, the <br />Increasing conifer acreage may also <br />stgnlflcantly reduce tne ga.n In watN Yields <br />achlt'Vab~ througn snov. augmentation Oy <br />cloud seeding <br />Results of tne I'TlOOellng SlucMs IndICate <br />7.3 Inches per year 1"etloss of mQlsturewnen <br />spnx:e repjaceaspen. aM a loss of 2 8 Inches <br />when fir forests CO'vef the watersheC <br />Considering all 33 milllQl"l acrBS Of aspen <br />wltrlln the Colorado Rrver Basm, thiS <br />translates Into 20and 08 millIOn acre-teet of <br />waler per year, respecll'o'ely that IS currently <br />diluting sail downstream from the h'9h <br />water-y~ldlng watersneds that may be <br />decreasea as the conlf€( replace tne aspen <br /> <br />, <br /> <br /> <br />..,. <br /> <br />& <br /> <br />...;;. <br />. <br /> <br />USGS Studies Salinity Loads <br /> <br />conSISt€(lt and accurate mettlOds of <br />estlmalmg dlssolved-sohds concerltratlOOS <br />and loads <br />Tr;e pnmary Dbtoctrve at lhe present study <br />IS to develop computer onented estimatIOn <br />lechnlClues based 0f1 hydrolOgIC. hydraulic. <br />and statlstlC8.l pnnclples 10 estimate monthly <br />and annual diSSOlved sollCis load data sets for <br />tne penod 1941-1983, at 120t the 20 stations <br />In l/1e ColoradO RI\I8I' Basin whICh have <br />varying Denods of mISSing recore:!, <br />A SImilar effort will be undertak€(l by the <br />AnZDna Dlstnct of USGS to develop a saliMy <br />load data base at selected locatIOns below <br />Laguna Darn-from Impenal Dam to the <br />Southefty International Border The data <br />oase would be de'velopec:J tor the calendar <br />year penOO 1935 10 current year. or as <br />appropnate They will develop the montnty <br />sail loads. monthly flow data, ancl OOCUmef1t <br />the procedures used In the develOpmerll <br /> <br />USGS IS evaluating the natural anc:l man- <br />made sallMy lOads In the ColoradO RIVet" <br />basin The eJ<.lstlng Memorandum of <br />Ull(!efstandlng betWeen !he Bureau 01 <br />ReclamatIOn and the U 5 GeoloJlCal 5ufVt>y <br />nas bt>en amended to allOw- tor additIonal <br />....on. elements In tile ColoradO Dlstnct to <br />facilitate compleliOfl of present proteCt <br />Object.." <br />ThiS study plan IS to estimate diSSOlved <br />solids load for penods at mISSIng record In <br />tt'le ColOrado Rrver Basin <br />In me past, Reclamation has used vaflOuS <br />methOOs to estimate salt loads at d!ff8fcot <br />statIOnS and In different yea~ Ba..<>tld on the <br />need to have a sta1"ldard method of <br />calculatmg the salinity bOl!1ln the past and In <br />the future, three computer programs were <br />prevIOUSly developed 10 proVIde more <br />