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

complish this work and maintain its results. Henc
the diversion of the clear waters OF the upper Sacr1
mento river would have peculiarly bad effect upol
v the action in the channel below Your attention i
asked to portion g this report where this subjec
Of divert.ng Hood Sers is more fully considered
r (See appendix
As The case stands at present, this project is al
adyised one for it certainly would not relieve the
river below the country above. When it i:
4 known that the lower river clnno be brought 10
capacity sufficient to pass the waters Of ordinary
fio0cs, and when plan Is definitely settled upon
and IN operation for the prevention OF overflow III
the region above the mouth of Feather river, Their
the question OF relief at the point proposed may
come up under more favorable conditions, and with
necessities made more appal ent and definite. Now,
that time cannot arrive for some years in the future
pending a treatment of the natural drains hence
the subject does not worthy OF more extended
attention at this time.
THE DRAINAGE CANAL.
| 1t has been proposed to drain the waters which
now collect in the Yolo basn through deep cut in
the Montezuma Hills taking the water direct from
the bottom Of the basin, after it has there collected.
This is feature of the second phase of the gen.
| eral problem OF preventing overflow in the lower
food region, heretofore explained; but, reported
upon by the Engineer of the Drainage Commission,
it not il contemplation to make the work a
means Of relief to the river above, but only to carry
away the waters of Cache, Putah and other streams
which drain into the basin from the Coast Range.
As already above shown, these creek waters can
probably be taken through high grade canal by
tapping the channels where they come ont of the
mountains. But the very essence OF this proposition
Is to keep steep gradient so that the velocity OF
current attained would insure the performance Of
the work required; namely the transportation of
Its material and excavation OF its channel.
Such arrangement would keep the waters of the
Coast Range streams from entering the basin alto
gether. Then if, as the engineer to the Drainage
! Commission assumes must be the case. the waters
are kept out OF the upper portion OF the basin from
! the river by OF leVees. and II the water IL
kept out of the lower end of the basin by means of
levees and embanknents across Cache slough, ETC.,
there would not be any water in the basin to drain
| out except that which would rain down upon 1t or
| percOate through the swamp soil from the river,
and, consequently, the deep cut would not be neces
| sary.
| Suppose, however, that it necessary to
leve the river of part OF its flood waters, either
by diverting frem some points at the mouths
| OF Feather or American rivers, or permitting the
back water to come into the basin at its lower end
| from the river, through Cache slough, Were the
high-grade canal constructed for the Coast Range
waters it would not be possible to make use of the
same cut in which to conduct the water from the
basin through the hills, because in lowering the cut
| to an Elevation that would accomplish the drain
age of waters from the basin, its necessary grade
through the hills would be destroyed, and the creek
waters coming in on great slope, as they must at
the commencement of the cut, will simply back up
the waters in the basin and prevent its drainage, for
the lands in the basin proper four feet below the
high tide at the point of outfal furthermore, the
creek waters would no longer have tb grade and
velocity upon which TO carry their sediments for
ward to the bay, and wou deposit them In the
cut.
THE BOTTOM OF THE BASIN CANNOT BE
DRAINED BY DEEP CUT.
Then again, surprising for moment that this diff
Guilty were overcome and the waters of the creeks
were disposed 50 that they could not interfere with
drainage of the basin through deep cat if it
made; still this cou not eectually drain the basin
th0uph the Watprs of The ypra kpnt
at the mouth of Cache slough, for the reason that
the surface of the ground over large area of this
basin is only four feet above low tide in Montezuma
slough, into which the waters could CO. and the tide
raises eight feet in that Slough four feet above
the level of the lands Of the basin. Or in other
words the land to be drained is at the hight of
tide at the outfall-seven miles distant.
By keeping the waters of the river out from the |
lower e. d OF the basn and by diversion as hereto
fore suggested, of the creek waters through
a high grade canal, it would seem that |
the only use OF the deep cut would be |
to afford rapid drainage for food-waters
which might be diverted from or escape from |
the Sacramento river into the upper portion of the
basin. Admitting for the moment the necessity for
diverting water from the river above, either into
this basin into canal therein, the efficiency of
the cut for this purpose the possible efficiency
of the river channel itself from the mouth OF Cache
slough to the bay, may well be questioned aud
herein lies the mGst important fact with respect to
the whole matter.
1t may be supposed that this cut would end at a
point Of free outfall into the bay. Such is not the
case. At best, it could only be carried to Monte
yuma slough at about middle point on its course
Now this slough extends from the mouth of the |
river, at Coliinsye, in great arc, around north of
Suisun bay, distance of Is miles, and joins the
open water again near the lower end of the bay |
The land thus inclosed is know as Grizzly Island |
with some small islets at the southern end)
Montezuma Slough is generally very shallow chan
nell at points almost dry at low tide, and quite |
narrow one-not more than 800 to 500 feet in |
width for considerable distance of its length, |
with low marshy banks. Grizzly Island is for the |
most part surrounded by embankments which are
sufficiently high above high tide level to effect
its reclamation.
In order to put any such volume of food water
through Montezuma Slough would afford ma
teria relief to the basin above the hills it would be
necessary raise the water at the junction Of the
canal cut to afford fall through the slough channel
sufficient to carry away the waters into the bay.
When this is done we of course diminish the eff
cheney of the canal to draw down the waters of the
basin; the whole water plane would be held at |
higher level throughout the basin, the and the
slough than would be if the lower end of the
were at point of free outfall. The result might |
well be an inundaton of Grizzly Island and other
land already embarked and safe from overflow I'M
der present circumstances.
THE MOUTHS OF MoNTEZUMA SLOUGH.
Then too, where would this water go? As before
said, the slough has mouth which joi 8 the river
Immediately at its mouth, or point OF junction with
the San Joaquin river The waters taken through
the hills from the basin would then, in part at least,
return to the river by this roundabout channel and
check the free outflow past Colinsvle into the bay
This might be more unfavorable condition of af- I
fairs for the low island property below the mouth of
Cache slough than to have the water from the basin
come into the river through Cache slough.
For the same the deep cut through the hills
would not act as relief to the river, if the
ncation left open between it, the river and the
basin at the mouth of Cache slough. The waters
would not find point OF free outflow by going
through the cut on the contrary the distance
to such a point of free outfall would be
longer than by way Of the main river channel.
Montezuna slough would not carry any such great
volume of water would be put into it from the
deep cut, without a considerable elevation of Its
water plane at the point of junction OF the cut with
it and portion Of these waters would find their
way back into the river at Collinsylle to the detri
ment of the carrying capacity of the main channel
for the entire distance below Grand Island. These
points are all so simple that it is not deemed
sary to incumber this report with any further eu-
cdation OF them.
Hence it appears that there is much of fallacy in |
the idea that such a cut would relieve any consd- |
cradle portion of the lands of the basin from
flow, or lessen the danger of inundation to the |
islands below Grand Island
Further than this, the creation of this new mouth
as it were for the river is measure OF extremely
doubtful policy for the future welfare OF the whole
delta plain and safety OF the commercial interests OF
the State
Ii we are to have any faith whatever in the result
of scientific and practical observation and efReri-
ence the fewer mouths there are to SEDIMENT bear
ing river the better. The greater the volume of
water the lower the grade it can be carried on is
the accepted rule derived from engineering expert
ence in such matters As the pDsctcal object to be
attained with respect to the FLYER, is to lower its
elevation at the foot of Grand Island the working of
this rule in the flow of the food volume would de-
feat this end if We divide such flow between two
channels instead of keeping it in one TO point of
free outfa and even if it had entirely independ
ent outlet and did not pour portion OF its waters
back into the river in the face of its outward flow
at Colinsyile.
Then. too, the diversion OF these waters from the
river at the foot OF Grand Island as in ali cases of
diversion where the water is heavily charged with
sediment is a matter Of doubtful policy another
score.
DIVERSION OF THE TIDAL scoUR.
By this diversion very strong influence, which
now acts in keeping the comparatively fine and
commodious channel below Grand Island open,
would be lost Not only would the securing power
of the full winter flow be diminished, but the con
servative action of the tides, elsewhere explained,
would be divided between two channels instead OF
confined to one and as the tidal basin would not be
materially increased, the tendency would be to
make the two channels combined only as com