H. J. L. Beadnell — On Artesian Welh. 



23 



YI. — Thk Mutual Inxekfeeence of Aktesi.\n Wells. 

 By II. J. Llewellyx Beadnell, Assoc. Inst.M.M., F.G.S., F.R.G.S. 



IN the February and March issues of the Geological Magazine for 

 1908 I published a general account of the underground water- 

 supply of the oasis of Kharga, in the Libyan Desert, and briefly 

 referred to the influence of one bore on another. 



Although the mutual interference of wells, a question of the 

 highest importance in the development of artesian basins, has been 

 touched on by several writers, I have not come across any published 

 accounts of detailed experiments. It is indeed seldom that oppor- 

 tunities for such observations, on wells of which full boring records 

 are available, present themselves. The results of certain experiments 

 which I was recently able to carry out in the oasis of Kharga may 

 therefore be of some value to geologists and engineers interested in 

 water-supply. 



The first observations I propose to I'ecord were made on two wells 

 comparatively close together. Bore No. o being 570 metres W.S.W. 

 of ]iore No. 6, the outlet of the former being at 57-38 metres and 

 of the latter at 59-18 metres above sea-level, a difference of 1-8 

 metres. No. 5 has an internal diameter of 5^ inches, is 645 feet deep, 

 and 310 feet into the water-sandstones; No. 6 has a diameter of 

 8 inches, is 480 feet deep, and 200 feet into the sandstones. The two 

 wells had been flowing continuously for a considerable period, and 

 during the experiment neighbouring wells were kept shut down, so 

 that there is no reason to suppose that the observations were affected 

 by other bores. Eore No. 5, discharging 114 gallons per minute, was 

 closed at 7 p.m. on June 12, 1907, and reopened after twelve hours, 

 at 7 a.m. on June 13. The following hourly observations show the 

 effects produced on Bore No. 6 : — 



This experiment shows that the closing of a flowing or the opening 

 of a closed well, may produce a most marked effect on a neighbouring 

 well within the short space of 60 minutes, even when the intervening 

 distance is over 500 metres. In the above case the effect was most 

 noticeable at first, there being a gain of 7 gallons per minute, 



