OPERATION OF HYDRAULIC STRUCTURES IN CANALS TO UTILIZE IN-CHANNEL STORAGE FOR TEMPORALLY VARIABLE WATER DEMAND

Abstract

 The authors evaluated a method using check gates to utilize in-channel storage in open-channel systems to absorb temporal mismatches between water supply and demand. The authors studied a paddy irrigation district that has had water shortage problems in its downstream area along a main irrigation canal. Field observations suggest that irrigation water is withdrawn preferentially into the upstream area, especially at peak hours for water demand. This is a possible reason for the water shortages downstream. To manage this problem, the authors present a method automating multiple check gates along the main canal so that a canal pool between an upstream control gate and a downstream control gate is used for storage. With this method, water can be stored in the pool during off-peak hours for water demand and released during peak hours. The authors tested the proposed method using numerical simulations. The simulations show that the method can moderate the decline in flow rates at canalside turnouts and the downstream end of the main canal during hours of peak water demand. With additional freeboard, the in-channel storage capacitiy can meet the simulated water demand without using reservoirs.