Sacramento daily record-union. [volume] (Sacramento [Calif.]) 1875-1891, 1880-02-04

raising its level at any given point on Nv
us now up the river, is so much gained in the
general interest. eN ~ 'ne
CHANNEL IMPROVEMENT = LOWER RIVER
SECURING ACTION OF THE CURRENT.
In the Improvements OF the Sacramento river chan.
mel, the most potent influence for general good Ins+
ever oe the Transporting power of the current in the
sire m itself, produced by the outflow of the land
drainage waters. For the beneficial effect of the
tides Will be confined to the lower divisions of the
rlver while this securing force of the DRAINAGE
waters graEiatnS to the sea is present throughout
the length OF the river, and only needs to be guided
and concentrated to work industrously for the de-
| sired results.
Without entering here upon any discussion of the
Transporting power OF running water, which is very
generally recognized, but very little understood Il
Is well to say that the observations made by the de-
partment On the transportation OF sediment and
SANDS by the waters OF the Feather and Sacramento
rivers, snow conclusively that-though at the lower
stages OF the streams, with the presence of
small mean velocity of current there
may be greater percentage of solid matter
| hed IN suspension, yet when the streams are high
tine sediments carried are OF a heavier character
| more sandy in their nature And furthermore Il
has been observed that during the full stages of the
streams the bottom is one moving mass of sand.
| At Freeport, II miles below Sacra nento. where
the river was sounded aud resounded IA times in one
cross section carefully over the same spots DURING
the highest freshet of the season. changes in mean
depth of l5 feet in "a hours frequent and the
| rule; while on one occasion the mean depth in one
cross section varied "a feet with n ma yimun, ,a
ration for about 100 feet Of the width of G. feet in
| depth And from the cross-sectional measurement
OF the stream, it has been found that where the
! waters which are now confined below the month Of
! the American and above Grand Island in one chan
mel, pass between banks abour $50 feet apart
their mean depth is Il feet below
| the low water line of 1878 as against
depth OF 4.s feet in widths of 300 feet; and that
uring floods the tendency is to raise the bottom in
the wider reaches and scour it out in those of
average width and in the narrow places when scour
ing is going at all. Here is evidence of the ability
OF the current to restore the channel and make it
better than ever, if it had the oppertunity-were
freed from the load of sands constantly coming from
above and had its channel bars removed by proper
treatment IL useless to prolong this report
by the citation ofmany facts to the nature and ex
tent of this class of phenomena observed during the
past season. Suffice it to say that certain primary
practical conclusions Of fact are had az follows:
Where the channel is at width duly proper
toned to the amount of water il now habituaIly
carries, we find depths of water which produce a
well formed cross section and furthermore at such
places the sands are carried up in the body of the
current more than in the wider reaches where they
are rolled along the bottom.
These facts appear to show that continuing the wa
ter to channel of width bearing such proportion
to its volume as to cause a scour to the greatest
depth possible, produces conditions IN the faments
OF the current favorable to the transportation of the
heavier sediment.
Now, if these observations are not in error, and
II the deductions sound then we have a kew
TO the measure OF securing power may expect
should the river be run as full could be carried
between entertainments of safe hight.
GENERAL TREATMENT OF THE RIVER CHANNEL,
1t were idle at this time, however to enter upon
discussion Of just whst this effect would be, even
II the observations had extended over sufficient
length OF time to be certain of results (Which
they have noD for so long as there remains the
constant supply Of sand from above the increase of
scour in the lower river would only accelerate the
advance of this injurious silt from the upper source
OF this we may be certain, however, that if the sup
ply of sand could be stopped, these river channels
could be very much improved within a few years,
chiefly through the agency just discussed.
The process would be somewhat as follows for
the river below the mouth of Feather: We must
suppose the water delivered at this point through
channels from the upper Sacramento and from the
Feather, and not from the great Suffer basin, as
much OF it now comes Why this must be, and
how it may be accomplished, will be sooken of later
With the corrections in The channel below, here
tofore noticed, and a similar treatment for several
other shoals at points above the head Of Grand
Island, the stream would be of irly good regimen;
it would be in condition to evee, and by raising
the water surface force the securing action without
danger OF washing out the material at one place in
the channel onyt deposit at another and thereby
making worse obstruction than there would be if
it had been deposited more evenly down the bed.
Thus were the levees of even disposition uniform
hight, properly adjusted width apart, according to
channel balanced in all its parts.
With these embankments feet above the flood
plane of 1872 3.3 feet above that of 1873, from
Feather river to the head OF Grand Island, on the
average, their mean elevation would be 7 feet, or
feet higher than the average of the lsvee
existing on the east side of the Sacramento below
that city to the lower point named.
During the first years Of the flushing Of the chan.
mel, such levee would be liable to overflow by the
waters of ordinary floods, but this must not be per-
mited, neither should considerable volumes of wa
ter be diverted at one point, as eief; for the
conditions in the current favorable to the trans
portation of sediment would thereby be disturbed
and deposit would occur. But at many points, say
every four miles along the way, located according
to circumstances to be studied attentively, there
should be an escape weir, capable OF passing maxi
mum volume of 1000 to 5000 cubic feet per second,
each opening into channel between entertainments
leading back into Yolo basin.
Now, so long the river channel could pass all
the water presented for transmission during any
freshet none should be allowed to escape, but the
securing power should be preserved at maximum
degree for the greatest period possible; but when
there came danger of rupture overthrow OF any
portion of the levee the foed gates should be per-
mitted to act sufficiently to ward off the evil.
1t cannot be doubted that the result would be
made manifest in great increase in the capacity Of
the stream. The narrowest places would be wijened
the bottom all along taken out. And if perchanee
hard bar should be exposed that would not yield to
the securing action, it must be dredged out; if
bank to endanger the levee, it must be
protected, and promptly, too.
Such is outline Of what is thought to be
proper treatment for the lower Sacramento. Fur
Their details at this time would add nothing to the
practical value OF this report The principle involved
is broad River mprovement-the promotion of
rapid drainage, the reclamation of the swamp and
overiowed lands of this vslley-requres organiza-
ton, government of works. subseryience of indivd-
ual interest to public good.
TO PROMOTE RAPID DRAINAGE-LowER FLOOD
CONGRATULATIONS.
With the lights before at it
that much good be effected and great harm pre-
vented by
First-Turning Putah and Cache creeks over the
Montezuma hills, to new outfall through the Mon
tezuma slough.
second-Removing the channel bars below Grand
Island and widening the channel in the Horseshoe
bend. 5sp
Third-Openng new head to Steamboat slough,
and making it the main food-carrying channel OF
the river
Notwithstanding an uniform system Of leyees,
higher than those now existing, with waste or flood
escape weirs at short intervals Of space leading into
the Yolo basin.
Always provided however, that the sandfow
from the upper streams be checked, that the whole
drainage system is properly managed after the works
are built and that the upper valley drainage is reg
ulated as hereinafter described.
With this accomplished very much OF the Yolo
basin would be exempt from flooding in ordinary
winters for a comparatively narrow strip through
the upper part would lead away all the flood that
would gel into it after very few years to the great
sink at its lower end and as the floods would al
ways run down much sooner than they do now, such
lands would dry out earlier in the season, for there
would not be any escape upon them except at the
top Of the flood flow.
The American basin would be exempt from over
flow from the river but would still the drain
age waters brought down by Auburn ravine and
other creeks from the east In the course Of time
this could be remedied, by conducting these waters
to the river, some around the head of the
basin into the Feather Sacramento, and
some into the American at the lower end.
Grand Island, and others below it, would be
longer endangered by sudden eruptions OF water
from the Yolo basin upon them; for unless there
should come such a great inundatioR pre-
scented in 1862, there would never be enough water
got into the basin to produce anything more than
gentle flow from Cache slough
The river bank property, including the city Of
Sacramento would be much more secure than it
could be otherwise for the river, though kept at
high stage, would have regulator 50 TO speak, upon
it, and with judicious management the danger OF
overflow would be reduced to minimum,
1t will be seen that the project involves the diver
sion of water from the river channel at time OF food
but it should be distinctly understood that the
ner of diversion is entirely different from that where
H1r ~ IN l.-E - IL -