The development of a model for water harvesting systems

Abstract

CRDP76, Cluff (1977), is a computer program which models the processes of a water harvesting reservoir system. GROP76 utilizes the computer program RAMDD1, which is a rainfall/runoff model. The objective of the research is to develop an improved calibrated version of the program which will be of practical use to non-research oriented technicians in developing countries. The new versions are called CRDP84 and RAMD1084. The development of CRDP84 involved improving the user interactive statements, installing a reservoir seepage routine, developing an alternative water yeild routine based on the U.S.S.C.S. runoff equation, and a partial calibration of the soil moisture routine. The calibration involved a comparison between the actual and the simulated values of seasonal irrigation and consumptive use of four crops: wheat, sorghum, cotton, and grapes. Improvements were made in the program equations that calculated the rate of root growth, the soil moisture depletion fraction and actual evapotranspiration. In the final simulation, the percentage difference for crop consumptive use calculated from the actual data and the simulation was +2.6 % for sorghum, -2.4 % for grapes, +2.0 % for Meat, and -8.8 % for cotton.