Sacramento daily record-union. [volume] (Sacramento [Calif.]) 1875-1891, 1880-11-20
HORSESHOE BEND CORRECTION.

| HORSESHOE BEND CORRECTION.
The general idea of this correction has
been conversed in former mention of it.
A point bar has grown rapidly and become
covered with swamp growth of vegetation
The high-water currents are thrown torcibiy
against the opposite bank, which is but the
narrow rim of bank land forming the north
ern border of Sherman Island. This rim is
being rapidly eroded 1t is proposed to di-
vert the current from its present point of at
tack and cause it to cut away the opposite
bar again.
The means of accomplishing this may be
briefly designated as a series of spur dykes
thrown out from the concave shore, COM
mencing well above the present point OF
caving and extending down to and over it.
These spurs will be for the NEST part per-
meable, constructed of piles and brush-wood,
and designed to check the force of the cur
rent all along the south or Sherman Island
shore, and defect it to the opposite bank.
1t is believed that as the result of the exc
cution of the foregoing works, the river
throughout its lower or tidal compartment
will be brought to good regimen, the tidal
flow will be facilitated, the volume of tidal
water will be augmented and the whole
channel viii be rendered more efficient as a
line of food escape through this cempart.
ment And, furthermore, it is maintained
sential to the successful treatment of the
river above the enlargement of its capacity.
IMPROVEMENT COMPARTMENT.
In this compartment we have the tidal &C.
ton in diminished degree. and the flow OF
land drainage on sufficiently inclined slopes
to induce great securing power, as our agent
for the improvement of the channel.
As already remarked, our first object is to
secure channel of good regimen. In this
compartment of the river exists the most Sc
rious defect in the regimen of the river In
any portion of its course-the division of its
waters into two channels, which occurs at
| Grand Island.
CORRECTION AT GRAND ISLAND.
It is proposed to correct this defect by
making Steamboat slough the channel of the
river and closing Old River channel at its
head. This proposition is discussed at page
Sc to SO of the report heretofore mentioned.
Steamboat slough is to be preferred to Old
River as the main channel for the following
reasons:
First-It is SO much the shortest that
material lowering of the food. line would be
| effected on this account at the head of Grand
| island and above, by its successful improve
ment.
Second-It is the most direct and can be
| developed so as to have less bend resistance
| than can Old River channel.
Third-It is equally as good a channel for
the lower two-thirds of its length and bet
| ter channel at its lower end than Old River.
Fourth-It is only leveed on one side and
the land is regarded as in a measure reclaimed
] only on that side, so there is room for widen
| ing it and setting the levee on the other side
| far enough back to afford the necessary water
way. Whereas Old River is already leveed
on both sides and the entertainments
not affording sufficient waterway be-
tween them for the floods. so that the
improvement of this channel would
necessitate large outlay for property dam
age, and the destruction of at least one of
the existing levees.
Fifth-The Old River is already tolerably
clear channel, with a connection through to
the Mokelumne and San Joaquin rivers by
way of Georgiana Slough, which would ad-
| nit of tidal circulation, and hence if it were
closed at its upper end and the sands thus
prevented from entering there, it would re-
main open as navigable stream, affording
boating facilities for the traffic from its bank
lands to the bay; whereas the closure of
Steamboat Slough at its head, in its present
condition, and there not being a circulation of
tidal water through it, would result in its
complete destruction as q navigable channel,
to the detriment of lands along its borders.
! Sixth-Cache creek, which, as before
pointed out, is an important tributary, as
draining the Yolo basin, enters Steamboat
Slough channel, AID materially aids in clear
ing it at its lower end, while it has just the
reverse effect upon the Old River channel, as
our studies of the tides and soundings reveal.
1t is proposed to close the head of Old
river gradually by means of brush mattress
stills laid in during successive seasons, one on
top of the other, until a dam is formed, the
whole to be held in position by piles and
weighted down with stone.
In the mean time Steamboat slough must
be improved by opening a new head to it,
and dredging through deep channel to start
the securing action, training its currents to
cut off the points, straighten it and to wash
out its bars.
The material obtained by the dredging
operations to be used in raising and strength
ening the existing levee and constructing one
to correspond with it on the north bank.
AS the forcing of Steamboat slough chan
mel will cause temporary super elevation Of
the food line of the river above, all levees
must be raised and strengthened to meet this
as far as Sacramento, at least before the work
is commenced.
CLOSURE OF SUFFER- SLOUGH.
For the same reasons as we have given in
the case of closing Old river, Suffer slough
should be closed at its upper end; and the
process will be similar to that just described
for the former channel, only the time re-
quired need not be more than one season, see
ing that this small opening.
NEUTRALITY-SUSPICIOUS. COMPARTMENT ABOVE
GRAND ISLAND, AND THE UPPER CoMPART-
MENT,
All works necessary above Grand Island,
throughout that portion of the river affected
by the tides, and that above it also, may be
generally classified together, as follows:
l. Removal of channel bars.
g Protection and alignment of banks.
8. Strengthening the channel.
4. Closure of crevasses and other outlets.
5. Leveeing.
6. Provision of high-hood overflow chan
nels.
REMOVAL OF CHANNEL BARS.
I Between Grand Island and the mouth of
Feather river there are two notable chan
mel bars and one other shoal, but little less
marked in its development. Haycock shoal
and Six-mile shoal-the one about nine miles
below Sacramento and the other about FIVE
miles above-being the first two of the three
in Importance, while the bar just above
the old Russian crossing, known as
Ten-mile shoal is to be ranked next.
Two other shallow reaches exist in this
portion of the river, but it is to be hoped
the works mentioned would result IN the es-
Establishment and maintenance at those points
of channel even in width and depth with
that above and below, which would admit
free transit of the sands forward, and of the
general deepening of the whole stream.
Above the junction of the Feather and the
Sacramento, on the Sacramento particularly
above Colusa, there are number of points
where this treatment must ultimately be ap-
piled, but none SO necessary as those before
mentioned, or SO prominent as to deserve
special mention above others at this time.
PROTECTION AND ALIGNMENT OF BANKS.
Where the river banks are being rapidly
worn away locally, the action must be ar.
rested, unless it be where widening of the
stream or a change of alignment is desirable
in the direction towards which the change
tends; and in cases where the trend of the
banks Is such as to cause notable eddies and
point bars, the cause of these should be re-
! H. Ill.