The record-union., 1896-11-27

feet per second.
What, therefore, would have been the
actual condition of the river at the
point of measurement. had the river
been improved as herein suggested?
Let us assume that the water surface
should rise no higher than 10 feet above
low tide at the point above cited, as the
point Of observation.
We will have cross-sectional area
of not less than 4O,376 square feet. 1t
is fair to presume that, with uniform
river as here proposed, we would have
a uniform velocity of feet per second,
which would discharge 161 ,5O4 cubic
feet per second, or nearly as much
water as passed this point on February
i, 1896, but at an elevation 3 feet lower
than at that time-at least 10000 cubic
feet per second more than was passing
into Yolo Basin and the Sacramento
River at the confluence of the Sacra-
mento and Feather
Again, we find, according to the gauge
records, that the difference in elevation
between the high water at Collinsville
and at Toland's Landing during the
flood of 1896 was seven-tenths of one
foot or on a grade of 100000 for each
running foot, and that at high tide.
Let this same grade be continued on
UP the river to the point at the foot of
Grand Island, where our observations
were taken, and we have distance of
10000 feet, which would give gradient
elevation of 16 feet, or the surface of
the water would be 10.1 feet above low
tide in Suisun Bay, instead of 13.1, as we
found it. In other words, for the same
volume of water we may, by the i'm
provement proposed, lower the flood
hight of water feet and dispose of all
the water presented for disposal on
February l, 1896.
1t has been estimated by the Chief
Engineer of the Board of Commissioners
OF Sacramento River Drainage District,
dated November %, 1879, that the Yolo
Basin, during high water in 1878, was
practically a reservoir holding 10000
coo, 900 cubic feet of water.
1t would take the river, thus i'm
proved. running 161 900 cubic feet of
water per second, about three and one
half days to empty the basin.
If the river discharged 236, 900 cubic
feet per second, as would have been the
case had the Improvement been made
and the water as high as found last
February, the basin could have been
emptied in two and two-fifth days of
twentyfour hours each.
But this condition never would have
existed if the river had been improved
as suggested Th outlet would have
been far greater in capacity at lower
stage of the flood than the inflow or
supply. The result would have been
that safety valve would have been put
upon the flood stage and the danger that
menaced the islands of the lower river
| would never have come.
Let us ask the property-owners Of
Ryer Island and the Egbert District
what would have been the result on
Cache Slough if the flood line of 1896
had been three feet lower than it was
in February, 1896? If the outlet of
Cache Slough should be properly i'm
proved, it is safe to say the flood hight
at Main Prairie would have been at least
four feet lower than it was in Febru-
ary, 1896.
What would have been the result Of
this single Improvement on Old River
and Steamboat Slough? The distance
from the mouth of Old River to Walnut
Grove is by river %, $50 feet. Assuming
that the flood waters should reach the
same elevation at this point as they
did in February last, then with this
| Improvement perfected we would have
had fall of the surface of the flood
limo Of = IN ha icfo Of
| instead of fall of 2.S feet, which we
had last February.
The cross section at low water, 1896,
| at the foot of Ida Island, on Old River,
was 500 square feet. If we assume
the elevation of high water to be eleven
| feet as it would be if the river was i'm
proved as proposed, then would the
| cross sectional area at this point be
$3.50 square feet, and, with the fall
| above indicated, would give us a veloc-
ity of 3.1S feet per second. The actual
velocity observed by US on February
| 1st last was j 50 feet per second, with
| a cross sectional area of 1892 square
| feet, which signified that 10, sos cubic
| feet Of water was flowing down Old
! River at that time
|
| ond, Old River would have discharged
| at this point 2S,079 cubic feet per sec
one at an elevation three feet lower
| than it was during the food of Febru-
airy, 1906; gain of S,571 cubic feet per
| second.
STEAMBOAT SLOUGH
! Similar conditions would obtain in
| Steamboat Slough. In fact, Steamboat
! Slough, being the shorter Of the two
| branches of the Sacramento River by
| six miles. we could reasonably expect
| * to have greater velocity than Old
| River. The fall or slope of the high
| water line from the head of Grand
/ Island to the foot of the same on Steam
| boat Slough, when the river is i'm
proved as suggested. could be FIVE feet
instead of little over two feet. The
| velocity Of the stream would be 3. 4
| feet per second, and with a cross sec
tional area the same as Old River would
! discharge 30,00 cubic feet per second.
Therefore. Immediately upon the
opening of the river over the Newtown
Shoals. We may expect discharge Of
/ 5S,00o cubic feet per second on a lower
elevation Of food plane by three feet
While 1t is evident the last flood periol
/ for these rivers discharged but 10000
cubic feet per second.
We have now gained an increase in
+ the discharge of Old River and steam
/ boat Slough of $1,000 cubic feet pel
! second, Or nearly one-third more water
! at an elevation Of three feet below the
/ food plane of last February
We do not presume that any person
! familiar with the action of water viii
| question the results that may be antic-
! ipated from this one step of improve
/ mont. Ii Is not unrea e.nna hIe tn OK.