Your search found 1 records
1 Ahmad, Ch. B.; Ali, A.; Raza, A. 1993. Pattern of flow variations in distributaries and reachwise supply to outlets. In Government of Pakistan-USAID Irrigation Systems Management Research Project; IIMI, Proceedings: Irrigation Systems Management Research Symposium, Lahore, 11-13 April 1993. Vol.1. - Integrated watercourse management. pp.49-62.
(Location: IWMI-HQ Call no: IIMI 631.7.8 IIMI Record No: H012883)
Discharge measurements were undertaken on eight selected distributaries, each located on a major canal to evaluate the pattern of flow variations, the reachwise supply to outlets and the apparent reasons for such variations. The results based on monthly measurements from June 1990 to May 1992 show 122%, 98%, 95%, 89%, 87%, 85%, 74% and 68% of the designed discharge for Josar 8-R, Dhudian, Nall, Nasirpur, Kiddi, Sheikh Yousaf, Renala 1 RB and Madan distributaries respectively. Excess supply to Josar is probably to compensate for 33% closure period as it is run on rotation. Silt clearance from the distributaries during January 1992 increased water supply to all distributaries particularly four of them which also improved reachwise equity. The head reach outlets on each distributary were drawing more than design discharge (101-134%)at the expense of lower reaches, particularly tail reach (38-97%). During deficit supplies, tail reach watercourses suffer a greater loss, and at Dhudian supply to tail watercourses was totally cut off when supply dropped below 77% of the design discharge. On Nall distributary alone, reachwise supplies to outlets appear to be somewhat equitable because of recently completed rehabilitation work including lining of tail section. Apparent reasons for variations in outlet discharge, apart from variations in the feeding channel, were laxity in enforcement of outlet design parameters, reduced capacities, degraded sections and poor maintenance of the distributaries. In the cases of Dhudian and Nasirpur distributaries low discharge and greater length also appear to be major constraints.
Powered by DB/Text WebPublisher, from
