Application of DRAINMOD under semi-arid conditions

Abstract

The water table management model, DRAINMOD, was evaluated for possible applications under semi-arid climatic conditions by comparing the predicted midspan water table heights with the measured ones in four subsurface-drained test plots in Kota, India under the RAJAD (RAJasthan Agricultural Drainage) Research project. Though the measurements were also made on the subsurface drain outflows, however, they could not be considered in this study due to the submerged outlets during most part of this study. In general, a good agreement was found between the measured data and the predicted values. The average absolute deviations between the measured and predicted midspan water table heights ranged from 14 to 24 cm for the four test plots. The corresponding standard errors of estimate ranged from 15 to 30 cm. The above range of values compares favourably with the other validation studies that have been conducted to evaluate DRAINMOD and other mathematical models for the humid regions of North America. Based on our investigations, it appears that DRAINMOD can be used to design or evaluate subsurface drainage systems under the semi-arid climatic conditions. However, further evaluations are warranted before any concrete conclusions could be drawn.