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'nn!: ~Q -14- gated 8.Oreage in the Project. Because of the faot that Water Commissioner s report acreage by I;ater Districts, and the Census Bureau by stream basins and counties, it \'as necessary to me.ke segregations of Census data to correspond to Hater District values. The entire Unoompahgre Drainagft area lies in Water Dis- tricts 41 and 68. Water District 68 is made up of Ouray County e.lC5lnlh Thus, whenever the Census Bureau reports figures for the Basin and for the counties also, a value for Water Distriot 41 oan be obtained by sub- traoting Oure.y County from the Basin total. comparison of the Projeot aoreage with total aoreage in Dis- trict 41 establishes the differential between the two, ~ioh is the amount of irrigated land under private control in District 41. l:Uring the oourse of the 19313-41 investigations a land use sur- vey \'I8.S made to determine the extent and charaoter of the water using area then be ing studied. This survey together with the U. S. Bureau of Reclamation land classifioation surveys afforded a reliable check against Project and Hater District areas, and permitted a further break down of the area of Water District 41 into the area being studied and the acre- age outside the study area. (For details see Part II). It should prob- ably be explained here that the survey shows an area of normal cropped land amounting to 72,345 acres ~ich has been considered as the irrigated area. In addition to this acreage there was 14.180 acres classified as "cropped land-seeped". This is land to which irrigation water is not de- livered but whioh reoeives enough water indirectly to be used for agri- oultural purposes. In the study of irri~ted areas the latter olassifi- oation is not oonsidered. (apparently not being reported by any agenoy as irrigated). but will necessarily be oonsidered in the analysis of water consuming arens. The aocompanying table (No.6) and graph (Plate III) illus- trate the growth of aoreage from approxiJ.lately 30,000 ..cres prior to 1901, up to about 75,000 aores at present, (extent and location of pre- sent aoreage sho'Ml on Plate IV). The extreme variations in Water Com- missioner's figures were definitely determined to be gross inacouracies.. A study of the yearly reports, wherein the acreasa is broken oown by di t- ches clearly indioates this. The most evident errors betv.een 1921 and 1930 (see graph) lire due in part to the COIIlIllissioner making his own esti- mates of Projeot area instead of obtaining the Bureau of Reolamation re~ ports. in part to the practice of reporting exoessive aoreage under pri- vate ditohes, and in part to reporting acrenEe for unknown ditohes. The modified figures for Distriot 41 are made. up of a composite of the best sources of information and is believed to be a reasonably aoourate pic- ture of the growth and fluotuation of irrigated acreage in District 41. In the years when modified values are not shom, the Water Commissioners values are aooepted.