The record-union., 1898-04-10

/ ity of such dredger, or dredgers, to con-
struct levee thirty feet in hight above
/ the surface at the place OF operation
and equal in frmness to the best clam
/ shell. or any sother dredger embank-
ment, at the rate Of 1000 cubic yards
| per hour without detriment to any
/ lands, except those upon which the
yevee may be located, or those within
| the basin to which a like amount in
liquid material may be conducted.
! And further, we agree that our
plant shall in all particulars be free
from legal or technical entanglements
or entertainments on valid patents in
use in similar machines and shall dem
onstrate by actual test in the opera
ton of leyee building superior ability
to do such excavation at 20 per cent.
less cost Of construction and operation,
maintenance and repair, then any
dredger now in use or heretofore used.
The said test work to be done on
the Sacramento River at such point
as may be determined. Very respect
fully, fSigned9. WILLIAM MUIR,
President Hydraulic Ejector Dredging
Company"
ENGINEERS DREDGING REPORT.
Engineer NJ. A Nurse presented a re-
port drafted Jointly by himself and
Major Heuer. relative to the advisable
ity of dredgers being used on the river.
The report, which was ordered placed
on file, is as follows:
Department Public Works, Sacra-
mento, Cal.-Gentlemen: Complying
with your inquiry Of January 20, 1898.
concerning dredging machines, asking
at what points on the Sacramento and
San JOAQUIN Rivers. if any, hydraulic
dredger could be used to advantage;
what make of dredger we would rec
|onmend as the best; its cost. capacity
and cost to operate; what disposition
we would recommend to make Of the
material taken out of the rivers. ana
whether or not the work that could
be done with q dredger would justify
the expenditure for purchase OF sucn
a machine. we have the honor TO sub
nit the following report:
! BY a hydraulic dredger we mean a
machine which generally by suction
aided by other mechanical devices, re
moves material from the bed OF river,
and bv the aid of water conveys
through pipes such material ashore or
deposits it in other places in the bed
of the stream. All machines of this
i character are protected by various pat
ents. and their unauthorized use might
! lead to vexatious litigation. Some ny
draulic dredgers use buckets or con-
vevOrs for hosting the eXcavated ma
terial into a pipe or hopper, and then
bv the application of pumps force the
spoil ashore.
For economical purposes hydraulic
dredgers use centrifugal pumps either
for lifting the material or for forcing
it ashore. generally for both purposes
Where the material to be removed has
to be deposited on q bank or leVee eK-
ceeding about fifteen feet in hight
above the surface of the water, the ex-
pense of handling is greatly increased,
and for this reason for the purposes
as of levee building they are not con-
sidered as economical machines.
For purposes of rapidly cutting a
channel through or over a bar, pro-
vided the material can be redeposited
in the river or on a low bank, even
though the place Of deposit be several
| thousand feet distant, a hydraulic
ldredger is eminently the economical one
to use.
"On material such as is found in the
San Joaquin River, where cut-offs have
heretofore been made, such machines
have not been tried, though the OppOr-
tunity has been given and machines
were available The work was open
to competition, but the hydraulic ma
Lchines failed to get the award, either
because their owners failed to bid or
because the owners of other types OF
machines underbid them.
For ordinary channel-making, where
the excavated material can be placed
on the bank or laid up in the form of
a levee at a convenient distance along
side the cut, the clamshell and bucket
dredgers seem to have an advantage
over the hydraulic machines. More
over when any hydraulic machine
places the spoil ashore it is done by
the aid of water, and the volume of
water required to convey the solid mat
ter ashore varies from three to ten
times that of the solid matter.
I'm a country where crops are under
cultivation this type of apparatus can
not we'll be used. Bars only interfere
with navigation at and during low
water periods; it is at such times that
they can be most easily and economic
ally cut through, but at such periods
the river banks themselves are far
above the water surface, and if as has
been stated, the banks are fifteen feet
or more in hight, the cost of pumping
the material to this hight again be-
comes excessive and ceases to be econ
omical
For purposes of bar removal in
streams like the San Joaquin and Sac
ramento Rivers it is doubtful if the
United States Government would per-
nit the material excavated from any
one bar to be redeposited in the bed of
the stream, for the reason that much
Of it would, through the action of cur
rents, fail to remain where deposited,
and would find lodgment on other
shoals, to the detriment of navigation.
The largest hydraulic dredgers yet
built are in use on the Mississippi
River. One, known as the Alpha, was
built in 1891 The tests, which we're
published throughout the country, were
phenomenal; generally such tests rare
ly exceeded one minute in duration
Such results have not been maintained
in actual working operations. The Mis-
sissippi River Commission, however
has reported the work done by this
. machine during eightyfour days in
1890, based on FIVE separate tests.
These tests showed a capacity of 33f
cubic yards of sand per hour dis
charged through 1,0025 feet of floating
pipe. In these eighty-four days a rec
ord of the performances of the machine
was kept from which the following ex-
tract is taken:
Per cent. of
total time.