Study of water flow velocities in irrigation canals in Iraq and their mathematical analysis

摘要

Water velocity is an important physical factor in the conditioning of streams and canals as habitats for the intermediate snail host of bilharziasis. Ecologists in most of the bilharziasis endemic areas have studied the resistance of these molluscs to the disturbing action of water motion. However, the complex nature of water flow through natural and man-made courses makes it very difficult to determine accurately the limiting range of water velocity that allows the settlement and development of snail colonies in a watercourse, and results are therefore still inconclusive.This paper describes the procedure employed in and the results obtained from a study designed to elucidate the water flow phenomenon through analysis of the relative variations of water velocity at any point of the cross-section of the canal. From this study it was possible to derive a simplified method for measuring the rate of water flow in earth canals that may be of wide application in snail control by the use of molluscicides.