of
these dams arise from the present condition of the beds of the streams,
the accumulations of past years, and the current mining operations. The
channels in their present state contain large quantities of such
detritus. In the Yuba alone above Smartsville over 80,000,000 cubic
yards are estimated to be deposited in the canons, and between
Smartsville and the mouth of the Yuba some 700,-000,000 cubic yards are
said to be in the bed of the stream. According to the testimony given
in the case of Keyes vs Little York Gold Washing and
Water Company, 86,000,-000 cubic yards were estimated in 1878 to have
been deposited in the bed of Bear River above the plains, and
36,-000,000 cubic yards below the foot-hills to its mouth, a total of
122,000,000 cubic yards.
Without
entering further into details of numerous other streams in which debris
is or has been deposited for the past thirty-five years, suffice it to
say that, mining or no mining, it is only a question of time as to when
a large part of this mass will move down into the lowlands, unless
measures are taken to prevent the continuous eroding action of the
waters and also to impound the material, which can be done only by the
construction of a system of permanent dams. Such structures would
prevent the streams from eroding the deposits to their original beds,
which otherwise, under certain conditions, must sooner or later occur.
They would hold in check the accumulations of sand and debris now
stored in the canons, and would permit the continuation of mining
without detriment to the interests of others.
"
It may be asked," says Col. Mendell, "whether the protection afforded
in this way will be complete and include all grades of mining tailings.
This cannot be claimed. The suspensory matter of fine sands and clay
cannot be restrained in this way or by any other method which does not
provide a settling basin in which the water can be maintained in a
quiescent state for some time.
"
It may also be expected that during the flood stages in the early
period of development a certain portion of material of every grade may
be suspended, and thus pass the crest of the barrier; but it is to be remarked
