Sacramento daily record-union. [volume] (Sacramento [Calif.]) 1875-1891, 1880-11-17
DAILY n C0RD.BST0y aypyss.
ValUnE XlE-Hy8aRRa 80.

terial in its bed aud 1t continues this process from
the outlet down to the sea- until 1t is So steep that
restored velocity prevents further deposition IN it
RESULT OF AN INSUFFICIENT cURREEZ
The current being insufficient 70 sustain the IN
tire burden Of sediment after 1t passes the outlet
the excess falls Immediately below it. and BY shoal
ing the channel there restores the velocity tb,
shoal but not below it the result Is tn the sboeJ
| is extended on down, II the outlet remains perma
nently open, until repeated floods reduce the size Of
the entire river from the outlet to tide level But
1t does not stop when this is done for the reason
that the ratio OF friction to volume has been In.
creased, and greater slope than the original ono
must be produced to create the velocity necessary
to prevent further shoaling. Therefore. although
the first effect of crevasse natural outlet Is to
lower the hight Of the foods, the final and perma-
nent one is to increase 1t in proportion to the mag
nitude OF the outlet because the slope OF tho river
must De increased In proportion as the volume is
diminished
The proof that such change will occur In tho
rivers slope is shown by the fact, that the slopes OF
| silt. bearing streams flowing through alluviai de-
posifs all over the world in an inverse ratio to
their volumes that Is to say, where the volume Is
small, the slope is great and conversely.
What has been said Of outlets thus far relates to
those from which the do not again return 70
| the river. Whether they return or not, hewever
| an island Is formed by the division of the water
II returns the increase Of slope win extend only
from the outlet TO the point where the wnssr again
| enters the river. The same phenomena occur
In Island channels. II two channels incsosnr an
island be OF equal size and length, they will be per
manent, unless one or the other becomes obstrcted
BY some accidental cause but II one be much long
er than the other, the river cannot narease tho
slope OF the longer, because 1t would be controlled
by the shorter one, and ultimately the latter, be-
cause Of Its greater slope and current would become
the man river while the former would be separated
from by deposits formed in the sluggish waters
both ends OF it. The longer one would thus become
| a lake of the character frequently tho
main river In allu, ial districts.
BUTTE SIDUCH AND THE RYrRR
the alluval deposits through which Butte slough
fs formed were less firm the enlargement Of that
outlet would be RAJ i'd that the main river would
probably soon flow through it, forsaking entirely the
tor uous channel between Butte slough and Feather
river. In any event, II Butte slough be left open
the sedim mt which enters this basin must In time
| reduce its width and form well defined channel
through it, to the still greater injury II the main
river. The route through the basin TO the mouth Of
the Feather being but about half as long and there
fore twice steep, the tendency OF the river TO at
take that route is only checked by the capacity
Of the sloagb and the fretiona RESISTANCE 70 the
flow Of the water the wide bed Of the basin.
Its early closure and the STRENGTHENING Of the river
bv cut-os between the slough and the mouth cf the
Feather, proposed by the State Engineer, cannot
fail to improve the navigation of the river and lower
the hight of the Hoods.
RESULTS or LOSS OF voLUMH.
As a shoang OF the channel, an increase OF siopo
and higher floods the inevitable results Of loss
of volume, 1t Is apparent that these phenomena
the expansion of the riverbed into excessive widtSs
its subdivision into numerous channels, increases
the resistance, thereby causing shoaine, sleeper
slopes and higher floods il Is equally apparent that,
BIZ narrowing the wide places and compelling the
water TO flow in fut channel, shoals will disap
pear, the slope be lowered and flood lines be re-
dueed. An increase OF resistance is equivalent TO 8
loss OF force, far velocity is nes and 1t
follows, therefore, that the same evils will result
from increase of frictional those reulting
from a loss of volume. These causes have both
ornhT nod hast he. ipit tn NJ
the Sacramento and its tributaries Their beds being
raised by sedimentarv deposits, the friciosi resist
ance has increased with the diminished nc OF the
channel and at the time, the loss OF volume,
by the oveifow of the bauks has been greater and
greater with the elevation OF the food nights. This
fact is Of value for 1t shows that beneficial results
will in like manner speedily follow the proper man
agement OF the two great elernents-force and re-
sistance.
DESIGN OF THE CHANNEL WORKS.
The channel works proposed by Ar. Hall de-
signed to lessen the resistance by gradually narrow
ing the wide places, closing Old River channel at
Grand Isiard, and lessenug the bend resistance
knights Landing, by making certain cut-offs 10
straighten the channel in that 1eighborhood, and
other less important improvements. These correc
lions would enable the channel, without over
flowing, to receive more heod water, and this would
be an Increase Of force
Any correction which would compel oil Of the ~a-
ters to flow into their proper channel within any
very brief period, is not TO be thought of. This
would have to be the work OF probably fifteen or
twenty years. Bat by pushing the channel works
and strengthening and elevating the levees little
at certain localities, the closing OF the present out
let's in the gradual manner proposed by Mr.. Hall.
may be done with ut increasing the danger OF over
iow provided the works for arrestiDg the mining
detritus be then constructed.
CAPACITY OF THE SACRAMENTO TO CARRY
FLOOD WATERS.
Great doubt has been expressed by many intelil-
gent persons to the possibility of giving such
capacity of channel to the Sacramento all enable
it TO discharge the entire food waters of the valley.
In considering this we must remember that tire
capacity Of the river to discharge Moods viii be
greatly improved, without any enlargement of It,
so soon as il is brought to approximate uni.
formity OF width and depth, and its most tnItuous
parts are siraightened. 1t is difficult if not npos
sible to estimate accurately how mitch more wrter
il viii then be capable of discharging. because the
quantities Of some Of the clements Of the problem
are difficult to aScertaiu ; but we may safely as
slirle that with greater frod elevations, Il VIII
when thus improved discharge fully fifty per cent.
more than at present The effect Of st:ch an in
creased volume will be to deepen the bed after the
rectifcation of the channel is effected and this pro-
cess will continue until lower surface slope reduces
the velocity much that 1t will be only capable OF
carving the sediment poured into il by its ibuta-
ries without taking up any additional quantity from
it's own bed. II suppose that this much deepen
ing of the bed and reduction of slope have occurred
under the impulse of fifty per eentum edded TO ita
food discharge. and the deepening to have then
ceased the surface slope will then have been
greatly lowered that much mo than fifty per cent
um may then he added to that increased volume
without raising the foods beyond their former hight
CARRYING POWER DISCUSSED.
Each Increment added to the food volume produces
increased velocity which in turn gives the water in
creased power to carry sediment, ard the extra
amount Of this is picked up from he bed by the
rapid current, until the bed Is so much deepcned
that lower slope Of surface ensues This gradually
reduces the carry ing capacity OF the water 10 that
velocity which is unable to produce further deep
ening Of the bed When this is done, condition Of
stable equilibrium is again established between the
several inpelling and resisting forces In this
ner streams lower their surisce slopes throughout
alIuvIa dis rcts In proportion their volumes
increased. The South Pass of the Mississippi is
twelve miles long. and the Southwest Pass Is
eighteen. They separate at poin. where the river,
IN food Is about three feet higher than the mean
Level of the Gulf; consequently the shorter one has
slope of three inches per mile, while the longer
one has but inches This difference OF slope is
because the sleeper one discharges but quarter
az much water the other. Ii the volume Of the
larger were discharged through the smaller channel
1t would rapidly deepen and enlarge 1t, and take
lower slope OF surface.
SLOPE OF TIRE MAIN RIVER.
The main river, which is nearly three times
as large as the larger pass, has, owing TO
its immense vslume, only about one inch
and one third fall per mile In this vicinity Al,era-
tions in the slope Of the Mississippi have been OBJ
served by the exact measurements Of the Mississippi
River Commission and those Of the United States
Engineers, which leave room TO doubt these
changes and they are known TO result front such
causes as have explained. 1t FOL ows then, that
as the slope IL gradually lowered by each addition
to the volume which the channel is compelled to re-
ceive and carry, the capacity Of the sacramento
like that Of all other streams flowing through their
Own deposits viii be only limited by the volume IL
Is compelled to carry; and, the lowering OF the
slope brings the food surface at first below the ton
Of the levees and finally below tho tops of the banks
the volume is increased and 50 ON ttili lower IL
the volume be still more increased il follows that
when the channel is once tcted the volume can
be more rapidly arAment each tucceediny wear
and thus what may first see;n paradox becomes
reality-nan ely, Sle larger the volume of the
floods carried in the river the less Will be the need
OF levees ii is however, only in proyort;on as va
ascend the that the benefits Of the reduced
slope Will become apparent because one end Of the
fpodline Is at the sea, tide lovel where the pro
posed works cannot alter IT, But the lowering OF
the river floods at SACRAMENTO city below the rat
raj surface OF the land there after proper correo
ton Of the chanrel shall have been made viii be a
question Of the volume OF discharge through 4. if
this be sufficiently il creased the Hood line can be
permanently kept belos the lands IN the vicinity of
the clty, without levees.
MUST THE RIVER BE wIpEsYp?
Fears have bcen expressed that thu width os the
river will have TO be greatly increased e the atternpt
is made to discharge alLof the food waters thro,,p
It, and hence mech valuable land will be lost on cal cb
side OF 1t by the enlargement cf the river
Here, aaaia, the lessons which are drawn from OBJ
serving the capacity OF different sized pinas 10 dis.
charg; water can be ed 10 advantage 10 enable us
to form correct Judgment Ipon tfts ,,,reti,,, 20,