BACK STREAM TYPE Fixed Rate Division Work

Abstract

Since division works as well as water measurement faclities in an irrigation canal system are important in order to maintain and control irrigation water, there are many reports on water division and water measurement to make best use of irrigation water.
On the other hand, a variety of division works has been devised from ancient times, and some of them are fulfilling their function even today at various parts of the world. But it can be said that there are no division works which satisfy all conditions required.
Especially in case the main canal discharge fluctuates in a wide range, and floating trashes such as shrubs and weeds are blown or flown in water-course to cause sediment particles to flow down along the canal, the function of division works will be lowered and both maintenance and control of irrigation water will become difficult.
This paper discusses the characteristics and practical applicability of BACK STREAM TYPE fixed rate division works which will be established at a step of about 1 m in height in a main canal as shown in Fig. 5.
The structure of this type division work is exceedingly simpler than others.
Morecver, it keeps the designed fixed rate division with a high accuracy by providing a given incident angle of nappe against the sloped floor set under certain conditions, without influence of up or down stream.
And there are little functional disorder with floating trushes or sediment particles, because these particles are flushed away towards downstream along the nappe guide board.
Therefore, it is no doubt that this type division work is one of the most effectual facities for dividing irrigation water.