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Basin <br />Basin was developed by the USBR, Nebraska and K ansas projects office, Grand Island, Nebraska; the <br />technical contact is L. Mylter. The model was written in FORTRAN on a UNIX workstation. This <br />model uses SCS Blaney-Criddle and the Jensen Haise methods to estimate monthly ET. <br />The primary design purpose for this model is to estimate farm and project delivery water requirements <br />and ground water table recharge. The estimated monthly CIR for a specified area is calculated by <br />considering the infiltration, the soil moisture budget, deep percolation, and monthly rainfall. Infiltration <br />soil curves should be developed using rainfall versus runoff data for the specified area. <br />The program was recently converted from an IBM-compatible PC-based FORTRAN version to a UNIX <br />workstation version. Because of this recent conversion, the documentation is poor. Since the model only <br />contains the SCS Blaney-Criddle method (Jensen-Haise is not being considered for this project), it was <br />determined that XCONS2 provided this capability. Also, the model contains additional components that <br />are not required for this project (e.g., ground water recharge). Therefore, Basin was excluded from the <br />short list. <br />CRPSM and CROPWAT <br />CRPSM and CROPWAT were developed at Utah State University by Dr. Robert Hill; the models are not <br />in the public domain. These models were written in FORTRAN and can be run on an IBM-compatible <br />PC. These models use five methods to estimate daily ET. These methods are the 1982 Kimberly- <br />Penman, FAO-24 Blaney-Criddle, Jensen-Haise, Hargraves, and Pan Evaporation methods. The models <br />estimate CIR by including changes in the soil moisture content, and they treat any rainfall as effective <br />rainfall in the calculation of the CIR estimate. <br />The difference between CRPSM and CROPWAT is the method of calculating the crop coefficients. The <br />CRPSM model estimates crop yield as a function of plant ET during the growing season. For that <br />reason, a separate function is required to calculate each soil evaporation coefficient and crop <br />transpiration coefficient in CIR estimation. In the CROPWAT model, the FAO crop coefficients are <br />used for CIR estimation. Neither model provides a method for calculating effective precipitation. <br />The testing of these programs took some time because of problems in developing and understanding the <br />format of the input files. The model CRPSM has a user manual, but the documentation for the <br />CROPWAT model is very limited. Dr. Hill was available to discuss questions regarding the input data <br />and model capabilities. The source code for the models was not available during testing because the <br />models are not in the public domain. Dr. Hill, however, is willing to sell the source code for a few <br />hundred dollars (~$350-$400) and would require a license agreement. The license agreement in <br />preliminary discussions seemed to be flexible, although Dr. Hill would like to be involved to some <br />degree in the modifications to the code or at least be notified of the changes to the code. These models <br />proved to be good choices for the short list; however, the fact that the models are not in the public <br />domain was considered a disadvantage. If, at some point, a combination equation is desired, the fact that <br />SMB and its developer (Ivan Walter) is a member of the CRDSS team makes the selection of SMB a <br />better choice for CRDSS. <br />2 <br />A275 01.09.95 1.14-5 CSU IDS <br />