117 



TABLE OF CONTENTS. 



Page. 



INTRODUCTION 3 



I. SELECTION OF AN IRRIGATED 'FARM AND SETTING OUT 



ORCHARDS: 



Selection of an Orchard or Farm Under Irrigation 4 



1. Climatic conditions 4 



2. Chemical composition of the soil 5 



3. Texture of soil and subsoil 5 



4. Location and site of orchard 5 



Preparation of Land for Orchard 6 



1. Clearing the surface 6 



2. Growing crops to improve condition of the soil 8 



3. Locating the tree rows . ." 9 



II. UNITS OF MEASUREMENT OF WATER AND METHODS OF 

 MEASURING WATER: 



Necessity for Knowledge of Measurement of Water 10 



Units of Measurement 10 



1. The cubic foot per second or second foot 10 



2. The British Columbia miners' inch 11 



3. Acre foot 11 



4. Relation between cubic foot per second, miners' inch and 



acre foot 11 



Methods of Measurement 12 



1. Volumetric measurements 12 



2. Weirs 13 



Measurement of discharge. . . . . . 14 



Weir board on a ditch 17 



Weir box 17 



3. Miners' inch board or box 20 



Miners' inch box placed in canal or ditch 21 



Miners' inch box and take out from pipe line under no 



pressure 23 



Miners' inch box and take out from pressure pipe line. ... 24 



Miners' inch box with overflow wall for canals or flumes. . 24 



4. Special measuring devices 25 



The Grant-Michell meter 25 



5. Measurement of discharge by obtaining velocity of flow and 



cross section of flume or canal 25 



Current meter . 27 



Rating station and rating flume 27 



Automatic registers . . . 27 



III. CONVEYANCE OF WATER FOR THE IRRIGATION SYSTEMS OF 

 BRITISH COLUMBIA: 



Types of Irrigation Systems ; . t , V; 29 



Permanent Construction 31 



Conveyance Losses of Water in Canals 32 



1. Extent of seepage losses in canals -,. ;>.^. 32 



2. Evaporation loss from water surface of canals 33 



Prevention of Seepage Losses in Canals 33 



1. Concrete linings 35 



Form of cross section and thickness of lining 35 



Shrinkage and expansion 36 



Effect of frost 36 



Method of construction of concrete linings 36 



