SEEPAGE LOSSES IN WARSAK GRAVITY CANAL PESHAWAR

Afield study was undertaken between RD.11890and RD.17256 of Warsak Gravity Canal near Peshawar during 1995-96. The objective of the study was to determine canal seepage losses from the bed and sides of the canal and how well the system is performing and to pinpoint the sections where improvement could be made by reducing the losses of water by seepage through the canal. For this purpose the distance between RD.11890 and RD.17256 was divided into four sub-sections. Discharge at the head and tail of each sub-section was measured and by comparing the inflows and outflows from a sub-section, seepage losses were determined. Discharges in themain Canaland outletswere measured by current meter and cut-throat flume respectively, (Table-1 & 2). A total of 16 % seepage losses were observed between RD.11890 and RD.17256. This includes 11.24% losses in the unlined portion, 0.447 c losses in the concrete-lined section and 3.18% in the damaged concrete-lined section. The field study indicates that Concrete lining is more useful, economical and less liable to cracks rather than other lining. Improvements can easily be made by regular maintenance and proper operation of the canal irrigation system. Thus the loss of water due to seepage from the bed and sides of the canal as well as poor management can either be controlled or minimized to greater extent