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

about 4.3 miles Of its course, below which II IL
ample width, and only needs securing out. and sem
dredging perhaps a. the Hog's-back bar
Studies for this correction Of the river are bein
made IN this Office, on the detailed maps which hav
Just been completed, and tits hoped that opportunt
VIII be had, To observe the flood phenomens sti
furtber in order that the results thus far obtaine
may be checked, Indeed it is anticipated that flu,
the Observable ns Will give this matter even a NOR
favorable aspect. now come to a consideration Z
the means whereby the general condition of tn
stream may be improved.
CHANNEL IMPRovEMENT-LowER RIyER-IN
FLUENcE OF THE TIDES.
The cross section of the upper rivel-meanlng b
this term the portion above the mouth of Feather
has for ages past, perhaps, been determined by tn
flow OF the waters OF land drainage only, togethe
with local physical conditions whose mode of actio
Is not so apparent.
quantity and kind of material transported by tn
waters, the presence or absence of reservoirs-re
heving the hight or prolonging the duration O
high water-are clements helping to determine tn,
normal section of the channel.
Leaving out what is merely local and which ma,
change from one part to another the great genera
fact which governs the size of the river is tn,
quantity of water it is called upon to carry mo-
systematically in great waves of flood of short dura
ton, but habtualy for great portions of the year
~ SD0SiNS bOtH III lSSptCt 70 btlc qu1il
tlty OF water carried and the sources from which
lnls water is derived that there is eharacterisl
uHefehce between the lower and the uppel
iiVer' The latter derives its waters exclusively
from lana drainage The former carries moi
only the land drainage, but also receive;
from and returns to the sea daily two
very considerable waves OF tidal water. While the
iau vi aiaSe Is spaslnodlc IN its features sending
down Tor a month or two in the winter great con
.rlou.ioh' ana then Stacking down first to a
an ILeh 70 small How, the tidal supply
teinaiis Subsidy UNIFORM throughout the year
Duilhg the very nigh st ges OF the river the tidal
action upon the waters above the divisions nearest
me pay becomes relatively insignificant but during
,he low stages OF the river, when the flow of low
lanu urainaSe Is reduced TO hive or six thousand
cuolc leet per second, the tidal supply becomes
nuen the more important, and this is the condition
OF the river Tor some entire years, and Tor great
part oil every year.
San Josonin which ;s u5a 49, an ~ ;,e ioWer
stream That it is so is due almost entirely to the
daily ebb and flow OF considerable tide In its lower
divisions. Ii this tide were absent or even
if it were inconsiderable- rising only foot
as it does at the mouth of the Mississippi
the section OF the lower San JOAQUIN would be de-
terminei mainly by its land drainage alone, and IL
must be plain that, under these circumstances the
river would be entirely diff rent in Character and
quite insignificant in dimensions
1t is then not ouly the daily regularity of the tide
goes so far to determine its channel section Now
the quantity of tidal water 1bich ebhs and flows
through any given section, during the tidal period
Of or hours must DEPEND upon the storage vol
ume above and it must also be said that the Volume
that can pass up river il as much denendent on a
section and slope of channel as it is mon
the rise of the tide itself
These two elements are in a sense eomnlements Of
each other IL Won can by straipbtenin1 a channel
or by guiding the greater veocitv of tidal nro,ayo ;
=
same water on its return being concantrated in ;ts
action. will not only conserve INIT will act 10 in
crease the depth Of the ehanrel Tho valoc;tv NJ
of the tidaway s unconditional 10 the
square root of the mean dentb If therefore the
mean depth is reduced by anv cause the velocity ia
essened. the rise above becomes less the onantitv
Of water passing is reduced the conservative action
IS lesseped and the useful Qualities az the channel
are in every way IMPAIRED
80
'ohMhh TIDAL AoIloN IN The SACRAMENTO.
1t is understood to be true that thirty years ago
the effect Of the tide was noticeable at the mouth of
the Feather, and as much as two feet at Sacra-
mento. To-day, owing to the increase of slope, the
tidal action is not felt above Haycoek shoal which
is about 81 miles below the mouth of the Feather
river. The increase of slope during the
asst thirty years below Sacramento is illus
trated by the following facts The low water OF
ls49 at Sacramento city was 385 feet above low
water at New York Landing The high-tide mark
ow stage OF the river at Sacramento. Now the av-
erage owwater stage of the river at Sacramento Is
more than feet above low water at New York
Landing, showing an increase of slope of than
feet in 80 miles during 80 Years.
While the IN nimum depth OF channel below Sac.
nento has not greatly changed except through
steamboat slough and the Newton shoal, it is
Known that the mean depth has been much reduced
The deep pools have been greatly filed In these
acts have the explanation of the reduction of
jda1 iufuepcp within Tra tha
liver
If, then, we admit the conservative ac ion of the
de, and of this there be no doubt we must next
INQUIRE whether is possible to extend the range of
scent of the tide to points higher on the river and
Increase its hight all along the range From what
las been said it will be understood that this oues
ion is only another form of inuuirinc whether the
mean depth of the lower river can be increased and
is slope diminished
The fl st answer to this question must. / think
now, under present circumstances, be in
.he negative For the reason that the
volume of sand coming down the streams is as great
IS ever The causes which have produced the in
creased slope and have incumbered the channels
are still in existence Not only are the channels
now more or less incumbered with sand, but there
re mains an unmeasured reserve of great extent i'm
the rverbeds above and in the CANYONS of the hills
10 add influence to these unfavorable tendencies
If these bad influences cannot be restrained or
substantially modified and mitigated. we must con-
tinue to give negative swer to this question
The opinion has been expressed in this report that
such modification is possible If this hope should
by proper action become positive fact the charac
icter OF the engineering problem would be entirely
hanged
The Sacramento would then become what we
night term a natural river. subject to such in
luences only for good or evil as natural processes
produce
oncer such condltlons the proDem OF extending
.verv conf;Jenca Of srccess It haconnes tben nn
onper an Inrried experiment II Is merely a rene,
ition of operations that have been successful in
many European rivers. notably the CLYDE and the
thames
II can hardly he necessary to do moro here than
ketcb a general outline of the means of accom-
,lishipg these results. This has been really indi
ated in what precedes but it NAV be well to point
mt here how it will be possible to detect the places
vbere special constructions will be necessary in
rider tn nromote the objects in view
A defective condition OF a ida, channel NAV be
in one or both of two wayg Either by
he abnormal shape of the diurnal tidal curve which
; recorded bv an ordinary clockwork tide gauge. or
NAV be shown by a sudden change in the slope OF
he eotidal inc ne shown on the prefe of the water
1lrface in the channel
The defect being evidenced in this way. the cause
souoht for in the local section or local slope the
ection NAV be too wide. or too narrow or ILL.,
haned an adjacent bar NAV exercise an injurious
influence or the slope NAV be too great or a second.
nv channel NAV interfere. In some such way-the
ause being clearly established and the case dag
remedy is usually not difficult.
In river treatment the diagnosis of the case is
.aallv the essence of the matter the facts are so