J. P. SinghPoonam Kiran2017-01-062017-01-062009http://krishikosh.egranth.ac.in/handle/1/94827The water management simulation model DRAINMOD-S was calibrated and validated using 3 years (1995-1997) experimental field data from the installed subsurface drainage system at 1.8 m drain depth with 40, 60 and 80 m drain spacing at Golewala watershed, Fridkot. The parameters that were determined to be most effective in changing the model output were lateral saturated hydraulic conductivity, drain depth and drain spacing. The reliability of model has been evaluated by comparing observed and simulated values. The calibrated and validated model was used to predict the salt concentration for five consecutive years (1998-2003). The average soil salinity of root zone decreased from 1417 to 1083, 1523 to 1097 and 1167 to 789 ppm, at the end of five year (2003) for 40, 60 and 80 m drain spacing respectively. The Root mean square error, model efficiency and correlation coefficient between observed and simulated salt concentration ranged from 6.49 to 38.43 ppm, 0.647 to 0.834 and 0.957 to 0.999 for three mentioned drain spacing respectively. These values are quite comparable to values reported by others in similar model validation studies. The overall performance of DRAINMOD-S was satisfactory and can be applied for design and evaluation of subsurface drainage system at Punjab and other parts of country in similar conditions.enfruitsThesis