of 10-in. pipe
were taken out of the 16-in. line. On the contrary, it took the position
of the grade line, _ABE_.
During the interval between March, 1908, and May, 1909, the water came
to overflow from the stand-pipe at _B_, when the line was running under
full pressure, indicating an increase of capacity in the 10-in. pipe
greater than a corresponding increase in the 16-in. The alignment of the
10-in. line, vertically and horizontally, is more regular and uniform
than the 16-in. line. The latter has many abrupt curves and bends,
vertically and horizontally. It crosses nine sharp ridges and dips under
as many deep arroyos. This introduces a fixed element of frictional
resistance which does not decrease with the increasing smoothness of
the interior surface of wood pipe, and probably accounts for the higher
resistance of the 16-in. line.
From Fig. 2 it appears that, while the 10-in. line had an initial
coefficient of roughness slightly greater than 0.009 and now equal to
it, the 16-in. line had one equal at first but now slightly less than
0.01.
The line from Bonito Creek to Nogal Reservoir was to have a capacity of
5 sec-ft. Referring to the profile, it was determined that for the
hydraulic grade of 33-1/3 ft. per 1000 ft., a 10-in. pipe was necessary,
and that a 16-in.
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