MOVEMENTS OF UNDERGROUND WATER Ts 
TABLE II 
SHOWING THE INCREASE IN FLOW DUE TO INCREASE IN HEAD 
FLow IN GRAMS PER MINUTE 
WELLS 
rt Ft. Head 2 Ft. Head 3 Ft. Head 4 Ft. Head 
A oP) 
ook Increase in flow 
B 216 388 
sea Increase in flow | 172 or 71 % 
C 215 383 540 
aie Increase in flow | 168 or 78% | 157 or 73% 
oes \ 225 390 555 EO 
(| Increase in flow | 165 or 73% | 165 or 73% | 155 or 72% 
eee) 166 279 397 516 
gees Increase in flow | 113 or 68% | 118 or 71% | 119 or 71% 
Commissioners in 1903 the capacity of the Main Street well (No. 10) 
at Madison, Wis. (see Fig. 2), was found to be 599,000 gallons per 
day when the water stood 18 feet below the surface. On lowering 
the water to a depth of 72 feet below the surface the yield was increased 
to 1,500,000 gallons per day, the increase in flow being only 63 per 
cent. of the increase in head. 
Table I shows that the flow at any well was at a maximum when the 
well was first tapped or allowed to flow. The flow then gradually 
decreased and finally became constant. During this decrease in flow 
the water in the remaining wells gradually lowered and readjusted 
itself. The final position of the water in the wells after the flow 
became uniform in wells D and E is shown by the dotted lines in 
Fig. 1. The greater flow during the first stages is probably due to 
the fact that the water immediately adjacent to the well finds ready 
entrance into the well with comparatively little friction. As the water 
farther from the well is drawn upon, the friction becomes greater 
and greater as the distance the water moves through the sand 
particles increases, and the yield consequently less ahd less. Finally 
the well adjusts itself to its new conditions of head and friction, and 
the yield becomes fairly uniform. 
The point of interest here is that the wells farthest from the intake 
yield as strong a flow as those one-third or one-fourth the distance 
