HiliUkndork. — Artesian Wells in the Christchurch Area. 



153 



was constantly higher on Sundays than on Saturdays and Mondays, and 

 that even a public holiday was accompanied by a decisive rise in the 

 well under observation. Mr. Dobson. Christchurch City Engineer, has 

 informed me that the installation of a city water-supply has been 

 followed by the breaking-out of springs in numerous places about the 

 city, and he explains this as follows : In the early days of the city's 

 life wells sunk on some of the higher ground had a static level of 1 ft 

 or 2 ft. above the ground. As more and more wells were sunk to the 

 same stratum, the static level was lowered ; those on ground a foot or 

 two lower continued to flow, but those on higher ground had their 

 static level reduced to below that of the ground, ceased to flow, were 

 abandoned and forgotten, and their mouths covered up. On the installa- 

 tion of the city supply many users of artesian water stopped their 

 flowing wells, the static level recovered itself, and the old abandoned 

 wells recommenced their flow, sometimes in such inconvenient places as 

 cellars, public parks, and important streets. The explanation seems 

 very probable, and emphasizes the interdependence of wells sunk to the 

 same stratum. Mr. Dobson further informs me that he on one occasion 

 fitted a pump to a particular flowing well, and started to work the 

 pump with a steam-engine, with the result that as long as the pump 

 was at work all the wells in the neighbourhood ceased to flow. It was 

 primarily to escape this interference of one well with others in its neighbour- 

 hood that I commenced observations on the comparatively isolated well at 

 Lincoln, and it was the evening rise that was the original object of the in- 

 quiry. As stated before, there are only four other wells of the same depth 

 as the College well within a radius of two miles ; the nearest of these is 

 three-quarters of a mile away, and I felt that I could secure from the owners 

 of all these wells any co-operation necessary for my observations. 



The object for which the investigation was undertaken has, however, not 

 been accomplished, since no light has been thrown on the evening rise, except 

 that it does exist, and that it is not caused by the shutting-off of neigh- 

 bouring wells. Out of the fifty-one weeks during which the observations 

 have been made, the weekly averages of the evening readings have been 

 higher than those of the morning readings on thirty-six weeks, equal on 

 four weeks, and lower on eleven weeks. The following tabic shows the 

 averages of all the readings of each month, with the evening rise : — 



