Sacramento daily record-union. [volume] (Sacramento [Calif.]) 1875-1891, 1889-01-14
A DAM NUISANCE.
Engineers Grunsky and Bassett Make
Their RcpOrta.

a
Engineers Grunsky and Bassett Make
Their Reports.
The Board of Supervisors of Sacramento
county are looking out for the rivers. On
Saturday, City Engineer Bassett, who had
been sent out on accommodating expedi-
ton, made his report to the Board, in
which he said: Pursuant to the instruc-
tons of the Chairman of your Board, in
company with c. E. Grunsky. C. E., on the
10Th of last month / made an examination
of the dam built in Bear river, near to and
about opposite the town of Dutch Flat,
Placer county, by the Liberty Hill Consoli-
dated Mining and Water Company, in the
latter part of the year 1885, for the purpose
of restraining the mining debris discharged
from said mine.
+" l found the dam to be substantially in
tact, and about in the same condition as
described in an affidavit in relation thereto
by me CD the 9th of January, 1886, copy
of which is hereto attached. The dam has
been raised perhaps foot in hight mot to
exceed one FOOT in some places, and COW
cred with layer of large cobble stones and
small powders on top. This work, how
ever, has not appreciably increased the
strength of the dam or lessened its liabil-
ity to destruction in the ways indicated in
the affidavit hereto appended.
The utility of the dam. as a work for
restraining the flow of mining debris,
found to be practically at an end, as the
reservoir, caused by the construction of the
dam, is filled with mining debris to a level
with the outlet or bottom of the waste way.
In fact, very coarse sand could be seen roll
ing along in the bottom of the water fiow-
ing through the waste way and being dis
charged into the river below the dam, and
this notwithstanding the fact that the vol
ume of water flowing at the time was
small-in fact, minimum winter dis
charge. During time of storms, with a
large volume of water flowing through the
waste way, there must necessarily be a
large discharge of the old mining tailings
lodged in the canyon above the dam.
through the waste way.
At the time this dam was constructed it
was represented that the reservoir capacity
created thereby would be sufficient to hold
the tailings from the Liberty Hill mine for
long perlOd-one engineer estimating the
time at eight years continuous running of
the mine, and another at twenty wears.
The mine was operated only few weeks
after the dam was constructed; but three
years has elapsed since that time, and vet
the dam is already filled to overhowing-
the washing down of the old tailings lodged
in the canyons during the operating of the
mine in the years preceding the construc-
ton of the dam, having alone been suffi-
cient to effect that result. Had the mine
continued in operation the complete filling
of the reservoir would undoubtedly have
resulted in few months, as the tendency
for tho fiIliy1O 10 tO fol 10 hal
dam nearly on a level, after which only the
coarser portions of the mining debris is re-
strained"
GRUNsKY's OPINION.
Q. E. Grunsky, who made the examina-
ton with Mr. Bassett in the capacity of an
engineer expert, says: The dam referred to
is in the main structure built of broken
rock, cobbles, gravel and sand matted
together with branches. 1t appears to rest
on cobble and gravel bed and abuts on
the right bank against solid ledge or point
OF rock through which the waste-way has
been cut. On the west bank 1t rests against
the dump of the Polar Bear mine. A large
part OF the material used in the construc-
ton of the dam was taken from the DUNN.
The dam is "a feet in height above the
river bed.
The waste-way in the right bank of the
river around the end of the dam is cut
through narrow, rocky point to a depth
OF 10 to IL feet below the crest height of
the dam. 1t has a width of about 40 feet
and its length on the bottom about 100
feet. The beds and sides of this waste-way
are the natural rock
The bottom of the waste-way at its lower
end showed signs of some erosion pre-
ceding the time of my visit in 1886, and
very little from that time to this.
At The time of my last examination. but
little over week ago, the condition of the
dam was practically unchanged, but to the
hight OF the bottom of the wasteway its
capacity for the storage of debris is already
exhausted; very little water was percu.
lating through the dam. The water an.
preaching it flowed in channel near the
right bank of the river, is cut slightly into
the Shiny ooze and sand forming the most
recent and uppermost layers of the deposit
above the dam. Sand was being carried
through the wasteway by the water of the
river. The river was flowing about so to
100 cubic feet OF water per second
. row OF alder trees had been planted in
the upper face of the dam from bank to
bank. at about the hight of the top of the
deposit They have grown thrifty, some
OF the largest having diameters OF about
two inches at the ground
BY reason of the deposit of material
above the dam and the decrease of the vol
ume OF water flowing through it. the
structure now appears more permanent
than when L frst saw it. nearly three wears
ago. 1t cannot, however be regarded as
structure which, for all time, will prevent
the material now restrained by it from be-
ing washed down the river. Injury to it
by the water flowing through the tunnel of
the Polar Star mine is possible. If at any
time it be overtopped by a rise of the river,
which in my judgment is possible, it may
be swept out completely"
The reports, which are sworn to, were
placed on file, and certified copies of each
will be forwarded to the United States
Debris Commission now sitting IN San
Francisco
The steYena Manument