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( ',- ( \, 1 L , . '. APPENDJX E the period 1928-1951 when reliable records of diversions betrreen Del Norte and Alamosa are available. The recorded innow betvreen Alamosa ani Lobato~ excluding the Conejos River flows, was adjusted to reflect the change in return flows from the area served by the Monte. Vista and EmpireCamls, resulting from a regulated water supply. This adjusted inncnr between Alamosa lIDi Lobatos was subtracted from the Rio Grame Division's scheduled Rio Grande Compact delivery. To estimate the allowable depletion from Del Norte to Alamosa, the amount of water necessary at Alamosa to meet the scheduled delivery was subtracted from the recorded flow of the Rio GraIde at Del Norte. This allowable depletion averaged 502,000 acre-feet for the period 1928 through 1951 as shown in Table E-7. To estimate the allowable " depletion between Del Narte ani Alamosafor the years trior to 1928 when reliable records of diversions are not aVailable, a correlation was derived, as shown on Figure E-6; between the now of the Rio GraIJie at Del Narte ani the allowable- depletion between Del Narte am Alamos80 Enteri~ this correlation with the annual flows of the R10GraIJie at Del Norte. . shown in Table ];-1, the average annue~ allowable depletion between Del Norte am Alamosa for the period 1890 through 1951 was estimated to average about 547,000 acre-feet per year. Historically, the depletion between Del Norte am Allllliosa averaged about 88 percent of the total diversions in this reaCh, including the re-diverted return flow, as shown in Table E-7. With regulation of the Rio GraIJie nows by Wagon Wheel Gap Reservoir, the depletion is expected to be a slightly higher percentage of the diversions and an average annual value of approximately 90 percent was adopted for this analysis. TheaverSfW annual diversions betvreen Del Norte ani Alamosa urder project conditions for the long-time period" 1890 through 1951, would be the average annual allowable depleti.on of about 547,000 acre-feet divided by the relationship of annual diversions to annual depletion of approxi- mately 90 percent, or about 60El,000 acre-feet. The obligation of Colorado to deliver water at Lobatos each calendar year is 10,000 acre-feet less than the sum of the scheduled deliveries of the Comjos ani Rio Grande Divisions. Deperding upon the determination of the division of the 10,000 acre-feet between the Comjoll ani Rio Grande Div1sions~ which bas not yet been made, the allClVlllbJ.e diversions between Del Norte ani Alamosa might be slight1;\r greater than estimated :for azv period by tIus )IlE!thod of amlysis. The monthly distribution of the average annual diversion demard . shoom in Table E-8 is based upon PI'lst. studies, eXllllIinat.ion of d1.versions ::bj.ditc"hes"i(ith'senior righf;s,. ar.d.consul:taMon,with l.'Ocal Vl6ter" Users-". .... and. offici-als of. the" State of. Golorado. .' /'~ ..., ...~ il (~ E-32.