Evaluation of a gravity-fed drip irrigation system under varying hydraulic head and land slope for hilly terrain

Evaluation of a gravity-fed drip irrigation system

Abstract

This study examined the performance of gravity-fed drip irrigation system under the varying hydraulic head and sub main line placed on varying field slope for hilly terrain of Sikkim, India. The coefficient of uniformity (CU) and emission uniformity (EU) of gravity fed drip irrigation system were evaluated for different combinations of hydraulic head and field slope. From the findings of the study, emission uniformity found to be 91.03%, 84.50%, 75.20% and 70.84% at 3.0 m hydraulic head for 0%, 5%, 10% and 15% land slope respectively. The coefficient of uniformity (CU) and the emission uniformity (EU) decreased with lowering the hydraulic head (tank height and increasing the sub main line slope. The coefficient of uniformity and the emission uniformity decreased significantly at sub main slope steeper than 10%. The coefficient of uniformity and emission uniformity follows a linear relationship with either hydraulic head or slope. At the 3.0 m head at all slopes, the performance of the gravity system was optimum as compared to less than 3.0 m head. Developed regression models for the coefficient of uniformity at varying head and slope may be used for predicting water distribution uniformity and standardization of gravity drip irrigation system in the region.