k found on
one joint was at the rate of 17[,?]280 gal. per day. Leakage between or
through the staves is not measurable, as it is not fast enough to come
away in drops unless there is some imperfection in the wood.

The insignificant leakage of 120 gal., stated above, is from the 11-in.
pipe in the pumping main between Coyote and Corona. The present maximum
working pressure on it is 100 lb. per sq. in. All the figures given
above include visible and invisible leakage, the latter being such as
does not appear on the surface. The visible leakage is but a small part
of the total.

_Stopping the Leaks_.--Generally, any ordinary leak is readily stopped
by pine wedges. Sometimes a loose joint requires individual bands bolted
around it. Bran or saw-dust is effective in stopping the small leaks
which cannot be reached by the wedges. The good effect of the latter is
likely to be destroyed by a rapid emptying of the pipe. If the water is
drawn out faster than the air can enter through the air-valves, heavy
vacuums are formed down long slopes, and the air forces its way in
through the joints and between the staves. The result is that the pipe
will frequently leak badly for some time after it is refilled, although
it may have been tight previously.

A full pipe and a steady pressure are highly desirable. This doubtless
accounts to some extent for the extreme tightness of the wood pipe in
the pumping main.

_Grade Lines_.--The hydraulic grade lines, shown on Plate V, were laid
as best fitting the controlling elevations. The various diameters of
pipe were determined by Darcy's general formula, with _C_ = 0.00033 for
wood and = 0.00066 for iron pipe, checking by Kutter's formula, with _n_
= 0.01 for wood and = 0.012 for iron. These coefficients were taken as
conservative and on the safe side, and such they proved to be. It was
desired that the line should carry not less than 5 sec-ft. to Nogal and
half as much beyond.

_Velocities_.--The pipe line from Bonito Creek to the Nogal Reservoir
affords excellent conditions for velocity and capacity measurements,
there being no distribution service from it. Beginning at the creek, it
consists of 12,700 ft. of 10-in. wood pipe, with a hydraulic grade of
0.03338, followed by 48,000 ft. of 16-in. wood pipe, with a hydraulic
grade of 0.0030625, ending on the south rim of the Nogal Reservoir.
There is an open stand-pipe where the two pipes and grades join.

When this section of the line was