Field measurement and analysis of water losses at the main and tertiary levels of irrigation canals: Varamin Irrigation Scheme, Iran

Abstract

Irrigation canals waste some of the water during the conveyance and distribution process. Due to the effect of water losses on distribution planning and operation process, it is necessary to estimate the conveyance efficiency and water losses. The purpose of this research is to evaluate the performance of water conveyance in all level of canals and to carry out an in-depth analysis of the water losses problem in the irrigation schemes through a case study. Therefore, the recorded data in more than 40 selected points of the main, secondary and tertiary canals were analyzed. The use of ultrasonic flowmeter in this study provided an appropriate precision for determining seepage losses and water conveyance efficiency. Results show that conveyance efficiency for main, secondary, and tertiary canals in the 1000 m reaches are 95%, 91.5%, and 89.3% respectively. In addition, the amount of seepage losses per unit of seepage surface for main, secondary, and tertiary canals is equal to 1.22, 1.18, and 0.63 m3/day respectively. Regarding the length of the canals, the total amount of seepage losses in a certain time and in an irrigation interval, in tertiary canals is more than secondary and in secondary canals is more than the main canal. In order to decrease the seepage losses, it is recommended to consider the serious preventive and corrective maintenance programs.