تاثير شدت تخليه بر نيمرخ سطح ايستابي در زهكشي با لوله هاي زميني

Effect of discharge rate on water table profile in subsurface drainage using drain tube

The effect of discharge rate or drainage coefficient on water table build-up and its effect on crop production is important. A laboratory drainage model was used to investigate the effect of different discharge rates ranging from 4.617 to 42.12 cm3/s on 19 different water table profiles under steady state conditions. Soil used in the model was sandy loam with bulk density of 1.4 g/cm3 and saturated hydraulic conductivity of 0.53 m/day. The model had a drainage pipe and nine piezometers that were installed at 10 cm intervals inside the model. The results of statistical analysis showed that relationship between water table profile and discharge rate can be expressed by a polynomial of order 6 with coefficient of determination of more than 92 percent. The prediction of this polynomial function versus the measured data showed this function can predict the measured water table profile closely.