Evaluation of DRAINMOD‐S for simulating water table management under semi‐arid conditions

Abstract

AbstractThe water table management simulation model, DRAINMOD‐S, was evaluated under semi‐arid conditions using field data from the Maruit experimental field in the western delta of Egypt for three cropping seasons; maize 1999, wheat 1999/2000 and maize 2000. Two water table management systems (conventional drainage (FD) and controlled drainage (CD)) were applied in the study area. The recorded data included daily ground water table depths, drain outflows during flow events, soil salinity to depth of 1.20 m from the soil surface (0.30 m interval), and relative crop yield. DRAINMOD‐S was run to simulate the applied water table management systems for the same study periods. The reliability of the model was evaluated by comparing measured and predicted values of the daily ground water table depth, cumulative outflow based on total monthly outflow, soil salinity during each season, and relative crop yield. Good agreement was found between the measured and predicted values. DRAINMOD‐S predicted values within an absolute deviation ranged from 11.0 to 16.0 cm for ground water table depth, from 18 to 75 mm for drain outflows, from 0.22 to 1.08 dS m−1 for soil salinity, and from 4.62 to 4.86% for relative crop yield. The model showed the potential for long‐term simulation and planning of ground water table management systems under semi‐arid conditions of the western delta of Egypt. Copyright © 2002 John Wiley & Sons, Ltd.