CONSERVATION OF GROUND WATERS 
193 
population and the rapid growth of large cities there have come not 
proportional increases in the demand for water but a demand 
which has grown by leaps and bounds, in geometric ratio. Appli- 
cation of water to sanitary purposes in the home, public sewage 
systems, enormous manufacturing industries, all these call for 
usage of amounts of water which to our forefathers would 
have seemed unbelievable. The ordinary shallow well in the 
back yard is not only insufficient, it is inefficient, incapable and 
unsanitary. The great system of galleries, the battery of large 
wells, the deep bores piercing the aquifers far underground, these 
have taken its place. The shallow well of our fathers, the 
clear sparkling streams and ponds of our childhood are gone or, 
what is worse, are polluted beyond use or are in danger of con- 
tamination. 
The Effect of Agriculture . — Paralleling this enlarged demand 
for water there has come a change in surface conditions which has 
diminished the supply or at least has tended to interfere with its 
replenishment. Agriculture, either by carelessness or by wrong 
methods or in part perhaps by necessity, has caused an increase 
in the run-off, thus lessening the amount which should seep into 
the ground, while at the same time filling the stream channels with 
the richest of the surface soil. The breaking up of the sod which 
held back the rain as it fell so that it might be absorbed instead 
of washing gullies in the soil ; the cutting away of the forests 
from the steep slopes, permitting the gullying and gashing of the 
hillsides; all of these have acted counter to the needs of the 
state — they have wasted and lessened its available water-supply 
when it should have been conserved and increased. 
Doctor Beyer stated in his Presidential address before the Iowa 
Academy of Science that ‘The records show that the average 
lowering (of the water table) for the entire country is about nine 
feet and for Iowa some twelve and a half feet during the fifty 
years preceding 1910.” Happily he stated further that “The rate 
of lowering was highest during the early stages but appears to 
be proceeding at a diminished rate.” I firmly believe that this 
lowering is due to the practical loss of so much rainfall because 
of the increased run-off mentioned above as much as to the in- 
crease in the use of water. If some means can be found to check 
what is practically a waste of water an important step will have 
been taken in the conservation of the ground water supply. 
Most of the water that is used by plants is returned to the atmos- 
phere and is useful in maintaining atmospheric humidity and rain- 
