Laserfiche WebLink
CRDSS <br />TASK MEMORANDUM 1.14-1 <br />Consumptive Use Model <br />Summary of Consumptive Use Model Recommendation <br />1.0 ISSUE <br />The purpose of this task memorandum is to describe the recommendations for estimating consumptive <br />use and to summarize the recommended changes to the U. S. Bureau of Reclamation (USBR) Methods <br />Manual for preparing the Colorado River System Consumptive Uses and Losses Report . <br />2.0 DISCUSSION/ANALYSIS <br />The USBR Methods Manual for preparing the Colorado River Consumptive Uses and Losses Report <br />suggests basic categories for estimating consumptive use. This task memorandum describes agricultural <br />consumptive use and consumptive use for other categories using the same categories adopted by the <br />USBR. <br />Estimating Agricultural Consumptive Use <br />Although there are many categories for consumptive use, the agricultural category is probably the most <br />important. This is because 64 to 69 percent of consumptive use on upper basin tributaries of the <br />Colorado River is agricultural (according to the USBR Consumptive Uses an d Losses Report for 1981- <br />1985). Agricultural consumptive use is composed of the irrigated acreage, livestock, and stock pond <br />categories. <br />Irrigated Acreage <br />The use of water by crops on irrigated acreage is difficult to determine and requires complex modeling <br />techniques and multiple data layers. The CRDSS consumptive use model will use a geographic <br />information system (GIS) as a tool to estimate crop consumptive use. This will allow the user to <br />consider the types of crops grown on irrigated lands, the types of soil in the region, and the elevation, and <br />will allow the user to evaluate different weather station locations. ARC/INFO will be used in the <br />development of any data required for the consumptive use model. After the data are developed, the data <br />will be transferred to GRASS for use in the modeling environment. <br />One of the objectives of this task is to evaluate appropriate evapotranspiration models for the CRDSS. A <br />review of the Project Feasibility Study, information from the consumptive use technical subcommittee, <br />and an investigation of possible models helped to identify the initial evapotranspiration models <br />considered for use with CRDSS. In order to reasonably reproduce the work being done by the USBR, <br />the Soil Conservation Service's (SCS?s) modified Blaney-Criddle (SCS Blaney-Criddle) method will be <br />used during Phase II(a). <br />1 <br />A275 01.09.95 1.14-1 CSU IDS <br />