Abstract:
The Hydraulic performance of structures provided for regulation in irrigation canals is influenced by
many parameters such as type of flow control, type and frequency of adjustments, and topographical features of
sub-systems that they are installed. The irrigation systems in Sri Lanka mostly designed for up-stream discharge
control operation, with manually/mechanically adjusted gated structures, under steady state flow conditions.
Further, topographical features of many gravity irrigation systems are varying at sub-system level due to presence
of single and double bank reaches, inclusion of in-lined storage tanks. However, irrigation systems are operated
under varying flow regime due to scheduled or unscheduled flows in water delivery. The adjustments of gates in
structures in such situations are done by manually/mechanically by operators at different frequencies.
Therefore these situations are analyzed by hydraulic simulations using SIC hydraulic model for three different
topographical sub-systems under different frequency of adjustments. The actual performance in water delivery is
evaluated by effective volume of water delivered, timeliness in water delivery, at the final delivery location while
maintaining on-line water adequacy through delivery points along the canal. The results will provide guidance for
operation of regulation structures for effective conveyance of water under varying flow conditions.
