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<br />;r · <br /> <br />~; , <br /> <br />IJli 1055 <br /> <br />CROSS <br /> <br />TASK MEMORANDUM_ <br />PHASE III <br /> <br />Analysis of the Bear Report Blaney.Criddle Crop Coefficients <br /> <br />.1& ~ <br /> <br />In several of the high elevation river sub.baslna of the Colorado River drainage. for example the <br />Vampa and White River basins, many Irrig810rs do not Irrigate Ifter mid to late July. The SCS. <br />Blaney Criddle method ISCS.BC) estimates crop evapotranspiration blsed on the Issumption that <br />irrigation continues throughout the growing 88ason. In a report titled, DUTY OF WA TER UNDER <br />THE BEAR RIVER COMPACT: FIELD VERIFICA TION OF EMPIRICAL METHODS FOR ESTIMA TING <br />DEPLETION. Hili. et al. present a set of monthly crop coefficients for alfalfa and Irrigated meadows <br />(hereinafter relerred to as the Hill coefficients). The Hili coefficients were locally calibrated and <br />are applicable for Irrigated meadows whiCh are not Irrigated after July 15 and are assumed to have <br />a full loil moilture reservoir on July 15. The objective of this study I, to determine if the Hill <br />coefficients are more suitable than SCS-BC coefficients in determining ditch diversion demands <br />for CROSS modeling. <br /> <br />2.Jl. DISCUSSIONI ANALYSIS <br /> <br />Table 1 lists the monthly SCS-BC crop coefficIents for Irrigated meadows from Table 12 of Hill. <br />et al. Also listed In Table 1 are the SCS.BC coefficients for pasture grass as listed In Figure 15 <br />of SCS TR-21. <br /> <br /> TAW 1 <br /> SCS BLANEY CRIDDLE CROP COEFFICIENTS <br /> IRRlClATED MEADOW COEFFICIENT' FADM HILL. IT AL. <br />LOCATION, MAY JUN JUL Aua SEP OCT <br />Montpeliet 1.28 1.47 1.2S .74 .64 .28 <br />Illndolph /' 1.40 1.80 1.4S .85 .81 .41 <br />HiIIi,rd 1.20 1.71 .1..42 .77 .&11 .30 <br />f) PAITUAE ClIlA8ll FROM SCS "".at <br />AM i I 0.80 I 0.82 I 0.82 I 0.'1 I 0.87 I 0.&7 <br />UTlO OF ICI.Be GRAn COEFFICIENTS TO HILL" ICS.Be COEFFICIENT' <br />Monlpell... 0.70 0.13 0.7& 1.21 1.el 2.1' <br />Illndolph 0.84 0.&1 0.e2 1.07 1.43 1.31 <br />Hilliard 0.71 0.64 0.8& 1.11 1.&a 1.80 <br /> <br />-/ 0 <br />J <br /> <br />133S.I\MEMO _ . '.211.81 <br /> <br />1 <br /> <br />A .111 WALTEII <br /> <br />~O'd ~OO'ON 8v:~1 <br /> <br />S6 S~ 6nl;l <br /> <br />~08~-19L-~0~-1:l31 <br /> <br />JOSSI;l ~ Jalaa4~ .~.~ <br />