DOWNSTREAM CONTROL OF MULTIREACH CANAL SYSTEMS

A downstream control algorithm was developed for the control of multir each canal systems. The objective of the control is to maintain a targ et water level at the downstream end of each pool by adjusting the con trol gate at the upstream end of the pool. If the measured water level differs from its target value, the gate is adjusted, aiming to elimin ate the deviation as soon as possible. The method is based on an expli cit solution procedure of the St. Venant equations. Adjustments of eac h control gate are calculated according to water levels and flow rates at the information nodes downstream of the gate and the water level i mmediately upstream of it. Unless the pool is extremely long, an effec tive control can be obtained with only two information nodes in each p ool (at the most upstream and downstream ends of the pool). If flow ra tes at information nodes are estimated using the slope stage method, f our water levels are measured in each pool.