Irrigation efficiency and water users' performance in water management: a case study on the Heran distributary Sanghar, Sindh, Pakistan
Lashari, Bakhshal, author
Siddiqui, Rubina, author
U.S. Committee on Irrigation and Drainage, publisher
This study focuses on water use efficiency and water user's role in maintenance of the system for sustainable irrigated agriculture. The parameters assessed were water delivery to water users, water distribution, water use efficiency and farmers' role. The relevant data were collected in the field and through a literature survey. Analyses of data indicate that DPR during the season varied from 1.0 to 1.60. The middle reach received slightly more than the head reach, and in the tail reach it varied from 0.6 to 1.80. Furthermore, water distribution among watercourses was also variable. The 7L- head watercourse received 30 to 82 percent more water than its design discharge (Qd). The downstream watercourses (16R and 18AT) also received up to 183 percent more discharge than Qd. However, the mid-reach watercourses (9AR and 13R) received the design share or less, though the flow of water was greater. In spite of unfair distribution there were no complaints from the water users about unequal distribution because there was enough water for everyone. Furthermore, result indicated that total water supply was 6.62 mm/day and the crop water requirement was between 2.54 and 3.56 mm/day in the Rabi (winter) crop season. Thus, the total loss of water was estimated as 46 percent. This was also verified by estimating seepage losses in watercourses and the distributary, which were 4.5 percent and 26 percent, respectively. However, the role of the Water Users Associations (WUA) in the maintenance of the distributary was significant. They collectively desilted the channel at a cost of about US$ 0.25 (Pak Rs. 21) per acre of land, which improved the head-tail water delivery performance ratio from 3.53 to 2.55 (Lashari and Murray-Rust 2002). But the maturity index has indicated that only 12.5 percent of the WUAs were at a sustainable level (Lashari et al. 2009).
Presented at Meeting irrigation demands in a water-challenged environment: SCADA and technology: tools to improve production: a USCID water management conference held on September 28 - October 1, 2010 in Fort Collins, Colorado.