Abstract:
Chandpur Irrigation Project (CIP) is one of the successful irrigation projects' of
Bangladesh Water Development Board. Although the project has abundant sources of
irrigation water, the desired benefit of irrigation has not been achieved, possibly due to
absence of improved management and technology, lack of farmer's awareness and
inadequate infrastructure facilities. This study has been performed to estimate demand
and compare it with the irrigation water supply and to evaluate the system performance
in terms of water balance parameters. Water balance study and performance evaluation
was performed for irrigation seasons of 1996 and 1998. The inputs (Irrigation water
supply and rainfall), outputs (Crop water use and percolation losses) and storage change
were calculated for each 10-day period.
Irrigation water supply was calculated from the combined discharge and the operating
hours as recorded in the logbook. Seepage and percolation from rice field and canal
network was considered for this study. The former was taken as 2.5 mm/day and later
one was calculated by an assumed value based on global average value of conveyance
loss. Crop water requirement was computed using CROPW AT software developed by
FAO. Required crop data and climatic data were collected from Department of
Agriculture Extension and Bangladesh Meteorological Department respectively.
Effective rainfall was calculated by USDA soil conservation service method.
The results show that water deficiency occurred in 3 decades out of 10 in 1996 and in 2
decades out of 11. Irrigation water supply situation was more adequate in the irrigation
season of 1998 compared to 1996. Seasonal average value of Relative Water Supply was
found to be 1.21 in 1996 and 1.08 in 1998. Seasonal Project Efficiency was computed as
62.0 % in 1996 and 64.0 % in 1998. On the other hand Water delivery Performance was
computed as 60.9 % in 1996 and 48.0% in 1998.
In the irrigation season of 1998 substantial improvement of project performance in terms
of water adequacy and efficiency was observed which might be due to the rehabilitation
works carried out by the project authority of CIP in 1997.
