Irrigation Engineering

Irrigation is an ancient art. Irrigation has been practised from time immemorial and so has been the construction of irrigation canals. There are constructions dating back to many centuries in India, Egypt and other countries. In earlier periods irrigation was restricted to comparatively smaller areas close to the rivers by means of inundation canals. Later with the taking up of large irrigation schemes, perennial irrigation came into being and with that the subject of design of irrigation canals, economical in first cost and maintenance with minimum liability to silting and scouring engaged the attention of engineers. However, formulation of laws governing the flow of water and sediment transport has been done in recent times.
It is only in the nineteenth century that canals have been designed on a more or less scientific basis. The formula of Chezy with coefficients derived from Kutter’s and Bazin’s formulae is currently in use in India and many other counthes. Manning’s formula is equally widely used. Kennedy’s formulae and the rational empirical Lacey’s regime theory, although originated in India, are used in many countries too. The tractive force theory, though not developed for general and practical adoption on a wider scale, is currently mainly used as a check over the parameters calculated by one or other empirical formula. Thus both empirical and analytical concepts are increasingly being used.