Laserfiche WebLink
water supply that use sprinklers, and to meet any remaining requirement on lands that <br />flood irrigate and also have ground water supply. For the Rio Grande Basin historic <br />consumptive use analysis, the "maximize supply" option was chosen for all structures. <br />Two BASIC language pre-processor programs, developed under this subtask, were used <br />to create the Crop Distribution and Annual Time Series input files (sprink.bas and <br />wellproc.bas). The data management interface StateDMI will be used to create future <br />input files for the Rio Grande Basin historic consumptive use analysis scenario. <br />Approach and Results <br />Generate Irrigated Acreage Time Series <br />The crop distribution file (rg2004.cds) contains acreage and associated crop percentages <br />for each key, aggregated, and ground water only structures for every year in the analysis <br />period (1950 through 2002). The 1998 acreage and crop types were determined during <br />the Irrigated Acreage Assessment performed by Agro Engineering, Inc. as part of the <br />Consumptive Use and Water Budget component of RGDSS. Irrigated acreage was <br />assigned to a ditch system structure identifier based on service area locations, as <br />described in the 1998 Irrigated Lands Assessment Using Satellite Imagery in the Rio <br />Grande Basin of Colorado, Agro Engineering Inc., July 2000. Parcels without a surface <br />water source were assigned to ground water only aggregates, as described in the Task 8.1 <br />Review Wells and Lands Served by Ground Water Only memorandum, developed by the <br />Surface Water Contractor. Acreage for aggregated diversion structures was determined <br />by adding the acreage of the individual structures making up the aggregate, as described <br />in the Task 7.1 A~~re~ated Water Rights/Irrigated Lands Not Explicitly Modeled <br />memorandum, developed by the Surface Water Contractor. <br />The 1998 irrigated acreage assessment focused on defining acreage in the floor of the San <br />Luis Valley. Acreage outside the valley floor was defined where possible, but in some <br />areas it was difficult to distinguish irrigated acreage from forested areas, or acreage could <br />not be defined due to cloud cover. There are 108 structures with current diversions for <br />irrigation where acreage could not be defined, 14 of these structures have been defined as <br />"key" and the remaining are included in aggregates. For these structures, user-defined <br />acreage reported in the diversion record database for 1998 was used. Table 1 summarizes <br />the 1998 acreage used as a basis for historic consumptive use estimates by source. Table <br />2 summarizes the 1998 acreage by crop type. <br />Table 1 <br />1998 Irri ated Acrea e b Source <br />Acreage Source Acreage % of Total <br />1998 Irri ated Acrea e Assessment 615,092 99 <br />1998 User Defined 7,776 1 <br />Total Basin 622,868 100 <br />C:\Projects\rgdss\finemos_2004\appendA_cropcu_6-2004.doc A-2 of A-10 June 2004 <br />