Abstract:
Irrigation is among the oldest applied arts, practised by humanity from the dawnof its history. Until late in the Nineteenth Century, irrigation was still considered an ad-vanced form of agriculture. The concept of irrigation as a branch of Engineering Science, Is, therefore, relatively recent.. The necessity of abstracting water from its natural source to convey to the fields for irrigation, led to the necessity for the design and construction of irrigation works, such as weirs, barrages and dams &c.
Consequent to the failures of a number of diversion works, in the early 20th Century, the necessity for a rational approach for the design of these structures, assumed great importance. with the advancement of hydraulic science, seve-ral theories have been evolved for a safe and satisfactory function of such structures.
The direct object of any diversion structure is the• control of the water flow in a river or in a canal, and, there-fore, the first step in its design is the hydraulic analysis of the conditions under which it is supposed to work. The quan-tities dealt with in this analysis are discharge, velocities, water slopes, water levels, silt charge &c. The general arrange-ment of the proposed work, and its main dimensions, will be based on the result of this analysis
