DITCHES AND FLUMES. DITCHES.
The
demand for water throughout the mining districts has caused the
construction of thousands of miles of ditches. The cost of these has
been immense, but the returns on legitimate enterprises have well
repaid the capital invested. On account of the rugged character of the
country traversed by the ditch lines, in order to lessen the cost and
expedite the work, steep grades were used, high trestles were built (in
some instances supporting large flumes at elevations of two hundred to
two hundred and fifty feet), and wrought-iron pipes were introduced for
conveying the water across the valleys and canons. The boldness with
which these works were undertaken was characteristic of their
originators.
Location and Construction Principles.—In locating and constructing ditches the following rules should be observed:
(1)
The source of supply should be at sufficient elevation to cover the
greatest range of mining ground at the smallest expense, great
hydrostatic pressure being always desirable.
(2) An abundant and permanent supply of water during the summer months should be secured.
(3)
The snow line, when possible, should be avoided, and the ditch,
especially in snow regions, located so as to have a southern exposure.
(4)
All water-courses on the line of the ditch should be secured ; their
supply partially counteracts the loss by evaporation, leakage, and
absorption, and frequently fur-
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