The record-union., 1899-06-13

SURVEYS were thereupon made near
low water stage with a view 70 deli
nitely fix suitable locations for Wing
dams. The surveys showed conclusive
ly that ait each Of these shoals, except
ing Heacock's, the depth of water ex-
ceeded that which was deemed sufficient
by both boards. Heacoch shoals was
improved by means Of wing dams in
1894, and have given no further trouble
since; neither have any of the otner
shoals, excepting those In the 1mme-
diate vicinity of Sacramento.
1t is for this reason that the board
hesitates to design and fix locations for
wing dams in separate reaches of the
river. or to recommend that contracts
be made for the construction of such
works, when Ut is possible that before
works could be completed in any one
reach. the necessity for those below
might no longer exist, and other local
tiles which now have a sufficient depth
might deteriorate and require treat
ment which had not been provided for.
In the absence of information where
future shoals will be when the reach
near Sacramento shall have been inn
proved, or of even an approximation of
be required to build contraction works
elsewhere, the board recommends at
present that no work below Sacram ento
other than in the reach herein referred
to be done, for which it believes $780,
600 is sufficient. 1t also recommends
that this portion of the work, for eco
nomical reasons. be done by contract
based upon unit prices OF material in
place.
The wing dams will consist of two
parallel rows of piles about six feet
apart, the piles in each row being about
ten feet between centers. On these,
longitudinal stringers of ks plank will
be spiked, as nearly as practicable at
low water level the spaces between the
rows of piles to be filled with bundled
brush or faScineS, the top of same to
be from one to three feet above low
water level, tie pieces of ks plank to
be spiked to the top Of the piles to
keep the rows from spreading. On
the top of the brush, and between the
longitudinal and ties pieces, place suf1i-
cient rock to hold the brush securely
in place The shore end of each wing
dam to be about two feet higher than
it's cutter end A brush mattress about
one foot in thickness and six feet in
width to be placed against each dam on
it's upstream side, and one of like
thickness and ten feet in width to be
placed on the down stream side. The
outer end of each dam to have a brush
mattress extending ten to fifteen feet
into the river and of twenty-three feet
width up and down stream: all mats
to be covered with sufficient stone to
secure them to the river bottom. At
the outer end Of each alternate dam,
drive a cluster of three piles, whose
tops shall be we'll fastened together and
extend above the highest water level.
The only systematic work heretofore
done on the lower river below Sacra-
mento was that at Heacock shoals in
1894, where wing dams We're built on
both sides of the river, and the re-
quired depth was obtained and has
since been maintained. Three tempo
rary wing dams were built in 1S91-9S
by the crew of the United States snag-
boat near the lower end of the reach
which it is now proposed to treat; the
effect was almost immediate. Snags
have been removed by the snagboat
nearly every year. The great mass OF
work heretofore done on the Sacramento
River has been that Of snagging and
the building of temporary wing dams
in that portion of the river above Sac
ramento This has all been done by
the crew of the snagboat. A large
crevasse known as jacobs Slough was
closed in 1898 by contract Respectfully
submitted, S. NJ. MANSFIELD,
Colonel, Corps Of Engineers, U. S. A.
w. H. HEUER,
Major, Corps of Engineers, U. 8. A.
CHAS. E. L. B. DAVIS,
Major, Corps of Engineers, y. 5. A.