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Oul4i3 -7- . 6. Upper Basin - Present Development (Cont'dh NOTE (8)1 In the Colorado River Basin in Western Colorado. the 1940 U. S. Census reported 844.~4 acres irrigated in the season of 1939. and for the same year the District Water Commissioners reported 887.476 acres of irrigated land. Land Classification surveys heretofore submitted to this office by the Bureau of Rec lamation oovered 767.060 acres of irrigated land. For purposes of estimating pres- ent depletions. the Bureau adopts the period 1931-1940. and this may account for the figure of 733.670' acres used in the Report. Since small differences in assumed consumptive use rates could off- set oomparatively large differences in acreage data. the adequacy of the allowances for depletions cannot be determined without fur- ther detailed cheQking which is prohibited at this time by the dates set for review and revision of the Report. Present exportations of water from the Oolorado Hi ver basin. for use in other valleys of the Upper Basin States. are based an 1931-1940 aver- ages. and as shown in the Report are as follows. Average 1931-1940 Exportations (Acre Feet) Division Oolorado Utah Total - Green 0 98.COO* 98.000 Grand 358.000** 0 358.000 San Juan 4.000 0 4.000 Total 362.000 (9) 98.020 460.000 * Includes 32.000 for Provo project. under construction. ** Includes 260.000 for Colorado-Big Thompson project. un- der construction. No exportations in Wyoming. New Mexico or Arizona. -, NOTE (9). The allowance of 260.000 acre feet for Colorado-Big Thompson ex- portations duri ng drouth cyc les such as 1931-1940. should any such ever again occur. may be adequate. Similarly. an allowance of 102,000 acre feet for all other projects in Cclorado may be adequate. as the same are now constructed. (In a normal climatic year they are estimated to yield 135.700 AF). However. some pro- jects under construction are not now comp lete. such as Denver's systems at Moffat and Jones Pass tunnels. Since the Bureau makes allowances for future diversions by projects under construction by that agency. it might properly make similar allowanees for pro- jects under construction by others. , Estimated present depletions in the Upper Basin. including irriga- tion consumption and export diversions. are s~~arized fram the Report. as follows. - units 1.000 acre feet - averages 1931-1940. "-.'>.