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Figure 1 <br />Irrigated Acreage Estimate 1950 through 2002 <br />800000 <br />700000 <br />600000 <br />500000 <br />d <br />N 400000 <br />L <br />V <br />a <br />300000 <br />200000 <br />100000 <br />0 <br />1950 <br />r <br />_..~ • ,,, _ i -r ~ ~ <br />~ ~ <br />~^ ~ / ~ ~ ~ ~ <br />1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 <br />+CAS (w/out meadow) Estimated Historic Acreage (w/out meadow and vegetables) ~ Estimated Total Historic Acreage <br />Generate the Sprinkler Acreage Time Series <br />The annual irrigation parameter time series file (rg2004.ipy) contains the estimated <br />acreage irrigated by sprinklers for key, aggregated, and ground water only structures for <br />every year in the analysis period (1950 through 2004). The following steps were <br />performed to generate this time series. <br />1. Sprinkler extent maps for 14 years (1975,76,77,78,79,80,82,83,84,89,91,93,96 and <br />1998) were obtained from Alan Davey of Davis Engineering in paper format. These <br />maps, prepared for Rio Grande Water Conservancy District (RGWCD), were <br />digitized to create 14 different ArcView coverages. <br />2. The ArcView 1998 irrigated parcel coverage, prepared by Agro Engineering for the <br />Irrigated Acreage Assessment, had an irrigation methodology attribute assigned to <br />each parcel. Parcels identified as having a "sprinkler" method were selected from this <br />coverage using a query command in ArcView. The selected parcels were saved to a <br />new coverage named 98sprink. <br />3. Several parcels were identified by the 1998 RGWCD map, but not the 1998 Irrigated <br />Acreage Assessment, as having sprinklers. These parcels may represent side roll or <br />lateral sprinklers not easily identified from satellite imagery. These parcels were <br />added to the 98sprink coverage (and the 1998 Irrigated Acreage Assessment <br />C:\Projects\rgdss\finemos_2004\appendA_cropcu_6-2004.doc A-6 of A-10 June 2004 <br />