SARKI A., MEMON S.Q., LEGHARI M.
Abstract
Study was conducted on an earthen water course 1R Qaiser minor near Tando Jam. Aim of study was to compare
two different methods of estimation seepage one was inflow–outflow and second was ponding method. Before study
soil texture of bed of watercourse was analyzed which was varying from sandy soil to sandy loam, and bed slope
was calculated with Autolevel which was 0.0002. Experiment was conducted on a straight reach of water course of
600 m length. This reach was divided into five sections of 120 m each. For inflow-out flow test reach inflow and
reach outflow was measured by cut-throat flume. Ponding test was conducted over short sections of 30 m each in
inflow-outflow sections of 120 m. Seepage loss was calculated 0.0016 m3 per sec (LPS)/100 m by inflow-outflow test
and 0.00123 m3/100 m by ponding test. Ponding test measured water losses 23% less than inflow-outflow test. Reason
of this difference may be over estimation of discharge through cut throat flume and under estimation of seepage
loss through ponding test due to silt deposition in the water course, and actual seepage loss could be expected some
where between these two.
Key words:
seepage, inflow–outflow, cut-throat flume, Ponding