IRRIGATION WORKS - 1906 - PREFACE - WHEN the original College text-book on Engineering went out of print, it was decided that it should be re-written in the form of several manuals. Tlic firet to be undertaken was one on EIydraulics which was published in 1887. A Alanual of Building Materials and Construction was issued in 1894. The want of a Manual on Irrigation Works was felt by the College, and in 1396 a small work, adapted for the most part from Mullins Irrigation Manual by permission of the Government, and with the late General Mullins consent, was published. Experience showed, however, that this work required revision and amplification to fit it for College requirements, and it has accordingly been re-writIten. The present publication does not aim at being a conlpreiiensive treatise on irrigation, it is merely a manual compiled for the use of students. I have to acknowledge the courtesy of Mr. R. B. Buckley in granting permission to make use of his book Irrigation Works in India and Egypt, to Xr. Herbert M. Wilson in regard to extracts from his Manual of Irrigation Engineering, t, o Mr. James D. Schuyler for leave to reproduce several illustrations from his book on Reservoirs for Irrigat, ion, Water Power and Domestic Supply, and to Nessrs. Ransomes and Rapier for the notes on Stoneys sluices. I also express my gratitnde to His Excellency Lord Ampthill, Governor of Madras, for graciously accepting the dedication of this work. CONTENTS. CHAPTER I . ART . 1 . Xeaning of irrigation . . . . . . . . . . . . 2 . Necessity for irrigation . . . . . . . . . . . . 3 . Value of irrigation . . . . . . . . . . . . . . . 4 . Different modes of irrigation . . . . . . . . . 5 . Sourites of irrigation water . . . . . . . . . . . . 6 . Water for irrigation drawn from rivers . . . . . . 7 . Inundation and perennial canals . . . . . . . . . 8 . Parts of a canal system . . . . . . . . . . . . 9 . Tanks collecting rainfall for irrigation . . . . . . 10 . Reservoir dams for storing up irrigation water ... 11 . Masonry Reservoir dam with flood discharge sluices 12 . Preparation of irrigation projects . . . . . . . . . CHAPTER I1 . RAINFALRLU. N. OFFF. LOOD ISCHARG F F L S. O O L D E VEL A S N D THFIR REGISTRATIOEVNA. PORATIOABNS. ORPTIOSNIL. TIS . G 15. Rainfall . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . l 1 5 4 .. GRaauingfianlgl rreaginisftaelrls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 . Rnn. off . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 . Catchment bauin . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 . Maximum discharge of catchment basin . . . . . . . . . . . . . . . . . . 19 . Formulm for maximum run-off . . . . . . . . . . . . . . . . . . . . . 20 . Tables for representative areas . . . . . . . . . . . . . . . . . . . . 21 . Flood diacharges . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 . Flood lerels and their registration . . . . . . . . . . . . . . . . . . 23 . River embankments . . . . . . . . . . . . . . . . . . . . . . . . . . . E4 . Gauging river discharges . . . . . . . . . . . . . . . . . . . . . . . . 25 . Evaporation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 . Leakage and absorption . . . . . . . . . . . . . . . . . . . . . . . 27 . Amo notf losses in reservoirs and cnnals . . . . . . . . . . . . . . . 28 . Prevention of percolation . . . . . . . . . . . . . . . . . . . . . . . . 29 . Silt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...