Evaluation of hydraulics characteristics and management strategies of subsurface drainage system in Indira Gandhi Canal Command
Keywords:subsurface drainage, unsteady drain spacing equations, evaluation hydraulic characteristics, management strategies
The present study revealed the performance of subsurface drainage systems for long-term sustainability of irrigated agriculture. The performance of subsurface drainage systems was evaluated on the basis of drain spacing equations for disposal of effluent and hydraulic characteristics of envelop materials, like entrance resistance created by envelop and hydraulic conductivity. Three important synthetic envelopes, HG 22, SAPP 240 and CAN 2 were tested in laboratory using sand tank model and permeability apparatus to compare their performances in terms of entrance resistance and hydraulic conductivity of soil envelope system. The hydraulic conductivity for SAPP 240 filter was found the highest and entrance resistance the lowest. Performance of four unsteady state drain spacing equations viz. Glover-Dumm, Van Schilfgaarde, Integrated Hooghoudt and Modified Glover equations were also tested to evaluate disposal efficiency of excess water. The percentage deviation between predicted drain spacing and actual spacing was -33.31% to -31.55%, 9.40% to 17.07%, 11.84% to 20.83% and 6.10% to 14.62% for Glover-Dumm, Van Schilfgaarde, Integrated Hooghoudt and Modified Glover equations, respectively. Modified Glover equation showed minimum deviation from actual drain spacing due to its versatile applicability. Therefore, the Modified Glover equation with SAPP 240 filter was recommended for subsurface drainage system in sandy soil texture areas.
Keywords: subsurface drainage, unsteady drain spacing equations, evaluation hydraulic characteristics, management strategies