IRRIGATION AND DRAINAGE 



INTRODUCTION 



GENERAL REMARKS ON THE IMPORTANCE OF WATER 



THE watering of land, which is irrigation, and the 

 withdrawal of such part of that water as does not 

 evaporate, which is land drainage, are two methods, 

 one the opposite of the other ; but, looked at in the 

 broadest sense, both are natural, and each is as old 

 as the time when the rains descended upon the first 

 lands which rose above the ocean's level. The periodic 

 watering and draining of the earliest rock fragments 

 which covered the earliest lands, and which came to 

 be the earliest soils, constituted at once the most 

 primitive, the most profound, and the most persis- 

 tent environment to which all forms of land -life 

 have been forced to adapt themselves. 



Since the very earliest forms of life probably came 

 into being in the water, and were composed in large 

 measure of it, it is not strange that we yet know of 

 no forms which can live without water, and to which, 

 indeed, water is not the most fundamentally important 

 substance and food. It is so. not more because it 

 makes up so large a part by weight of all living and 



A (1) 



