Buried pipe systems for irrigation in Bangladesh
conference contributionposted on 12.02.2018, 15:08 by Md. Harun-ur-Rashid, Mohammed A.K. Mridha, Ian K. Smout, Robert J. van Bentum
A study of eight cement concrete buried pipe schemes in Bangladesh was carried out during 1989-91 to evaluate both technical and management performance. Leakage through joints and pipe walls, averaged 0.9 leaks per 100m of pipeline, while 42% of outlet valves were observed to leak. Conveyance losses within the pipelines averaged 0.33 lps/100m by the tank test method and 0.69 lps/100m by inflow-outflow method, with earth channel losses averaging 7.69 lps/100m by the inflow-outflow method. Machine spun pipes performed better and "plain end pipe jointing" was found appropriate. Measured head losses for different pipe sizes and pump discharges were found compatible with theoretical values when using the ColebrookWhite Equation with Ks = 0.6 mm. Low pump discharge (60% of design), low periods of pump operation (12% of advised), small command areas (42% of intended) and low yields of irrigated crops were commonly observed. Seasonal repair and maintenance expenditure on pipeline systems varied from Tk 4.64/ha to Tk. 127.19/ha, with the average of Tk. 54.06/ha being only 18% of expenditure in earthen channels. Poor farming as well as water management practices contributed to poor levels of irrigation performance. Farmers' cooperatives were found either not to be functioning or operating only very poorly, and many institutional problems existed. Pipe systems are more economical than channel systems when the initial cost is affordable. There is however considerable potential to increase the net returns from buried pipe schemes through more efficient utilisation.
- Architecture, Building and Civil Engineering
- Water, Engineering and Development Centre (WEDC)