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.