1907.] 



Water Supply for Villages. 



525 



WATER SUPPLY FOR VILLAGES. 



The scarcity of water from which many villages have suffered 

 during the past few years can hardly have been unanticipated 

 by careful observers of the meteorological conditions which pre- 

 vailed in the affected districts during the periods preceding the 

 scarcity. The summer of 1906 was particularly fine and dry, 

 and the rainfall for the whole year below the average ; but the 

 significant fact as regards the water-beds was that the winter 

 of 1905-06 crowned a succession of winters of remarkable 

 dryness. 



Whilst scarcity is usually most pronounced towards the end 

 of a dry summer, and is, indeed, popularly ascribed to summer 

 dryness, the real cause is to be sought in scanty rainfalls 

 during the preceding winter, for the winter rains, little needed 

 as they are for the nutrition of vegetation at the time of their 

 appearance, and fairly secure from evaporation by the sun's 

 rays, are largely absorbed by the earth and thus constitute 

 the means of replenishment of the vast underground water- 

 beds upon which well users depend for their supplies during 

 the drier months which follow. The summer rains, on the 

 contrary, are either taken up by growing crops or evaporated 

 from the surface by the heat of the sun almost as soon as they 

 fall. 



Computations by careful observers go to show that the degree 

 of infiltration of the rainfall during the period from December 

 to March inclusive is as high as 85 per cent., whilst that for the 

 months of June, July and August is less than 2 per cent. 



So great, in fact, are the needs of some forms of vegetable 

 life during the warmer months of the year that an oak tree 

 having about three-quarters of a million leaves will (according 

 to Pettenkofer) take up out of the earth and evaporate through 

 its leaves about eight and a-half times the amount of rain 

 falling during a whole year upon the ground which it covers. 



It will thus be seen that, even though the summer rains may 

 suffice for superficial seasonal needs, they are ordinarily in- 

 sufficient to restore to the subsoil the large volumes of water 

 annually drained upwards by the roots and fibrous " suckers " 

 of trees both large and small. 



