Land leveling and watercourse improvements for Pakistan

Abstract

Despite the intensified efforts and the technological advancement in agriculture over the past three decades, Pakistan is still faced with the challenge to produce enough food to feed her people. The problems posed by this challenge are further compounded by the fact that often there are both economic and trained manpower constraints on irrigated agricultural development. An extensive irrigation network was built in Pakistan to provide an increased water supply. While the network brought more areas under cultivation and increased crop production, it later created the twin menace of waterlogging and salinity. At this stage a viable, effective, and economical alternative which should be considered is the improved on-farm water management for efficient use of water. Better on-farm water management provides improved delivery and application efficiencies and minimizes the dangers of waterlogging, salinity, and short water supplies. In this study, the research was conducted on the benefits of land leveling and watercourse improvements. For this purpose the Kanjra watercourse command area, near Lahore, was selected. Necessary surveys were made to collect the required information. About 20 percent of the area was precisely leveled to determine the seasonal impact of land leveling on application efficiencies. The average seasonal application efficiencies were found to range from 81-90 percent on leveled fields to 49-50 percent on unleveled fields. The cost data for precision land leveling was collected from the watercourse command area as well as from the other parts of the country. The average operational cost was Rs. 2.5 per cubic yard. The benefit cost ratios always exceeded unity against three selected rates of return. For better on-farm water management, economical "Katcha" watercourse improvement alternatives were also undertaken. Water measurements were made with cutthroat flumes to determine the differences in delivery efficiency before and after improvement. The average delivery efficiency of a four branch watercourse system at the before and after stages were 70 and 90 percent, respectively. The benefit cost analysis, with alternatives consisting of renovation of branches A and D, essential improvement of branch B, and cleaning of branch C, gave highly acceptable ratios. Had the improvement activity stopped at intermediate stage of branches A and B, the cost per unit of water saved would have been more attractive. The average improvement cost per linear ft for the four branch watercourse was a little more than Rs. 0.50. The role of water user associations for implementation and efficient use of water was discussed. At the end, recommendations were made for a package of land leveling and watercourse improvements for Pakistan.