NONCONSTRICTING RECTANGULAR CHANNELS FOR MEASURING FARM WATER DELIVERIES

摘要

There is frequent need to measure farm water deliveries, but often farmers object to constricting the flow and raising upstream water levels. This study is an effort to correlate velocity at the center of a rectangular channel with the overall average velocity of water in the channel. Rectangular channels were tested where the width nearly corresponds with the farm watercourse and the length is the width × 9/4. Current meter readings at 5 depths and 4 locations along the length of the channel were tested. It is best to place the current meter at the middle of a rectangular channel at half of the water depth of the mid-length flow cross-section. A Velocity Multiplication Factor was developed for various sizes of channels. The details of fabrication of the rectangular channel are also provided