WATER SUPPLY 233
fallen to 15 feet per mile, and many wells have ceased to ow.
The discharge of the water is attributed to the compression
of the sandstone by the weight of the over-lying material,
whereby the district around Ellendale has subsided 43%
inches. North Dakota in 1921 passed a law (Meinzer and
Levels in feet
500
00 -
300 ~
200 -
00 -
Sex level
“(ON
~ 1000
=1500 -—
Fie. 60.—THE Kynuna TowN WzLL, QUEENSLAND,
The ascent of water in flowing wells by the influence of rock-pressure,
The well passed through 22 water-bearing layers; the rise of water
from each layer increases with the depth, until the water from the
depth of 1800 feet discharges at the surface, The water from the
lowest beds would rise in a pipe 67 feet above the mouth of the well.
Hard, U.S.G.S. Wat. Sup., Pap. 520, 1925, p. 76) prohibiting
waste of water from the flowing wells; this Act has reduced
the loss of head and will, it is hoped, limit the discharge
to the amount renewed by subterranean inflow from the
western intake.
Gas-PressurE—Many flowing wells are due to the pressure
of their included gases or water vapour, which force the