WATERS OP WESTERN INDIA. 161 



still respectable — and all four flow for a great part of their course 

 in wide sandy channels between high alluvial banks, as much resem- 

 bling in appearance the great river-beds of the Deccan as their local 

 tributaries and lesser neighbours do those of the Konkan. 



All four are subject to violent floods ; and once they top their 

 banks, the fiat nature of the country lays it a good deal at their 

 mercy. 



The gi-eat characteristic of the waters of Gujarat, however, is 

 that its plain is, especially to the northward, a country of tanks. 

 The rainfall (which in the hills is high, reaching 100 inches, and 

 probably much exceeding that on some hill tops) is here moderate, 

 and the great thickness of the alluvial soil often makes it impos- 

 sible to get water in a well of reasonable depth. 



The natural remedy is found in tanks, and it will make my later 

 remarks clearer if I describe a typical Gujarat tank. Where the 

 ground slopes sufficiently for the water to know which way to run 

 (which is not always the case), a great crescent-shaped ditch is 

 dug with its horns, of course, pointing against the stream and 

 the convex side downwards. The earth out of this is thrown out 

 on the outer or convex side, and forms an embankment of which 

 the crest ought to be perfectly level tapering in thickness towards 

 each horn ; and if the measurements are true, meeting the natural 

 slope of the ground at the points*. As the greatest pressure is 

 expected on the centre of the crescent, this is naturally the most 

 massive part of the dam ; and that part of the trench which is its 

 ballast-pit will naturally be widest and deepest. But, besides this, 

 ambitious engineers in old days went on digging on theinside of their 

 trench long after the dam was big enough, throwing up the spoil 

 into hills, often into islands, some of them quite high enough to be 

 conspicuous from afar in so flat a country. Such mounds are apt to 

 be crowned with a Hindu temple or Musalman tomb, having 

 usually a few trees around it, and,' when isolated, are naturally very 

 favourite spots with waterfowl and crocodiles on account of their 

 safety from disturbance. I have here described a large first-class 

 tank, which would have 30 acres or upwards of water when full. 

 There are many such, and more modest ponds are innumerable in 

 the northern plains. These are so liable to inundation that, in 

 practice, at least once a year, a fish can change his quarters in almost 

 any direction he pleases, following drainage channels which, in the 

 dry season, can only be detected by careful survey, 



