Consideration of the project in different phases for upland field irrigation: -a case study of the upland field by using pump-

摘要

The upland field improvement projects, mainly integrated upland field improvement projects, have been carried out to secure crop production and to enlarge the degree of freedom of crop selection. The rate of upland irrigation improvement reached 16% at the end of FY 1995 while the fourth long-term plan of land improvement aims at increasing the rate to 30%. As it becomes more difficult to secure satisfactory water resources, many projects would adopt water conveyance system by using pump. A case study of T irrigation project has shown that establishment of irrigation farming needs considerable time in projects with water conveyance system by using pump. It is important that the irrigation project in different phases should be adopted to reduce the difference between plan and actual condition of water utilization, and to establish water utilization suitable to area condition. This paper discusses favorable design condition of the project in different phases with diameter of pipe and actual pump head, in view of reducing total cost of construction and maintenance in projects with water conveyance system by using pump. The result shows that introduction of the project in different phases suitable to area condition including project implementation system is necessary in high pump head area (actual pump head is above 80m).