Figure 9-7.Use of bucket on end of surface intake.
Figure 9-8.Float-type surface intake.
of the float. If support lines are used to secure
the float to the banks, the position of the float
can be altered to correspond to changes in depth
by manipulation of the lines. The chief advantage
of a float intake is the ease with which the screen
can be adjusted vertically (fig. 9-8).
Water from muddy streams can be improved
in quality by digging intake galleries along the
bank. A trench is dug along the bank deep enough
so that water from the stream percolates into it so
it intercepts ground water flowing toward the
stream. The trench is filled with gravel to prevent
the sides from collapsing. The intake strainer is
placed in the gravel below the water table (fig.
9-9). The amount of work required to produce
Figure 9-9.Gravel-filled gallery intake.