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Transactions . 



manner and to the same degree as in the Lincoln well, but there is a much 

 less decline in its static level during a similar period" of almost similar rain. 

 (3.) There is no sign of floods in the Waimakariri influencing the well. 

 (4.) There is no sign of agreement between the graph of the well and that 

 of the barometer, however the latter is manipulated. (5.) There is an 

 evening rise. Points (2) and (3) are illustrated by the following graph 

 (fig. 8), which is comparable to fig. 2, both graphs being on the same scale. 



Fig. 8. — Weekly Averages of Height of Museum Well and Weekly Totals of 



Rainfall at Lincoln (18W-95). 



The want of agreement between the graph of the well and that of the 

 barometer may be explained either as the result of the Waimakariri assist- 

 ing the rainfall to supply the well, or as the result of the interference of 

 neighbouring wells. That such interference does take place has been shown 

 in a previous section. 



The lack of pronounced decline during a comparatively rainless period, 

 and the smallness of the annual variation (10^ in.), opens up seriously 

 the question as to whether the Waimakariri does assist the supply of the 

 flowing wells in Christchurch. In favour of the rainfall being the sole 

 source of supply are the following facts : (1) The rise of the well after 

 rain ; (2) the absence of effect of even the greatest floods on the river 

 (see fig. 8 , 1st December) ; (3) the diminution of the static level of the 

 wells as each additional well is put down. The Museum well has fallen 

 4| ft. in fifteen years, and there is a generally expressed opinion that 

 all the wells in the town are similarly affected. This would be the 

 natural effect if there were a restricted supply of water, such as a rainfall 

 of 25 in. affords. If the lowering of the static level of the wells is an 

 indication of the lowering of the water in the water-table at the outcrop 

 (and it is difficult to suppose otherwise), then the wells in the town are 

 robbing the crops in the country of the supply of water that they should 

 receive by capillary rise, a matter of some importance on light shingly ground. 



