The morning call., 1893-09-08
OUR CITY SEWERS.
Elaborate Reports of the
Engineers.
PLAN OF RECONSTRUCTION.
After Long Study Messrs. Hanson
and Grunsky Outline Scheme to
Improve the System.

Manson and Grunsky-after months of
study. have completed two very valuable
reports regarding both the Channel-street
and the Fourteenth street sewers, which
drain such large portion of the city. The
reports are the result of much laborious
work. patient investigation and careful
thought. A vast amount of field work had
to be performed before the reports could
be made.
The engineers had one view and that Is
that their system of reconstruction, for
which the city appropriated $40, 900, should
be based on the strictest scientific prin-
cipes. The adoption of their views means
death blow to the unscientific. irregular
and piecemeal construction which has
hitherto been followed and the putting
into good condition the bad work already
done.
In the report making recomme ndations
for the reconstruction of the Channel-s street
sewer and its tributaries, the engineers
say:
The data collected by this office show
that the cause of the failure of the Bran
nan-stfeet sewer is its improper grade.
The bottom of this sewer rises above the
intended grade by about Ia feet between
Fourth and Fifth streets, and is belO " the
mel streets by rs much as 1.5 feet. Under
these conditions this expensive and other
wise apparently well-cOnstructed sewer is
ot but little service in draining the 1000
acres OF tributary area.
To correct these defects in the Bran
naD-street sewer 1t will be necessary to
take out and rebuild its bottom between
Fourth and Fifth streets at lower level !;
and 10 clean out and raise its bottom by
building in concrete work from Fifth to
Channel street.
1t will also be necessary to construct
number OF flush gates and bulkheads in
connection with the Channel and Bran
nan street sewers, that they can be kept
clean and efficient by flushing. For the
WORK absolutely necessary at this time we
have prepared plans and specifications.
Our recommendations at this time. not
Included In our separate communication
concerning Fourteenth-street sewer, cover
the following items:
1. Correction OF the grade of Brannan-street
sewer Gay by lowering its bottom betw en-
Fourth ana Fifth streets, (b) by raising Its bot.
tom between Fifth and Channel streets.
2. The construction of timber check gate
selfclosing. in Brannan-streeI sewer, under
First strert wharf.
3. The construction of a movable gate or
weir In BraDnan- street sewer, near New Chan
mel street.
street sewer, about 300 feet northeast OF Fourth
street.
8. The construction OF a bulkbead and flash.
board gaze in the Eighth-street sewer at Bran
nau street.
6. The construction of bulkhead and flash
board gate In tie Seyenth-streeJ sewer at Bran
z. The construction of a buIkhead and fash
board gate in Ihe Slxth.street sewer at Branaan
street.
g. The construction OF bulkhead and fash.
board gate In the Fifth-stTeet sewer at Brannan
street.
8. The construction of a casliron f1ushgate in
Fourth-sireet sewer at Brannan street.
10. The construction OF timber bulkhead
ana movable weir or gate In Channel-sJreet
sewer just below Brannan street
IL. Tie construction Of a movable weir or
gate In ChanneEstreet sewer near Sixteenth
street.
IL. The construction OF a three-foot by five
foot brick sewer from the manhole in Market
street on tile center line of Sixth street to the
upper eud OF the Sixtb-stseet sewer, and the
construction of a three-fOOt by five brick sewer
from the manhoie on The cenIer line of Jones
street, near the north line of Market street
souihe easterly TO tie manhole near the center
line OF Mar et street
13. The construction OF a bulkbead and flash
board gaze In the McAllister-street sewer just
east of Polk street
Il. The construction of three-foot by five
foot brick sewer IN Lombard street from the
west line OF franklin street TO the east line of
Cough street. TO replace elghteen-inch ronstone
pipe.
brick sewer in Lombard street from The west
line of Cough street TO the east line OF OctaVia
street, to replace eighteen-nch lrOnstOue pipe.
The engineers state that the cost of these
improvements Will be about S27.95O They
are fully prepared to give plans and speci-
fcations and state that the carrying out of
their recommendations will give immediate
employ ment to large mum Der Of working
men at a time when it is sorely needed If
properly executed the work will give to the
taxpayers better return than can be ad
by an equal expenditure of public funds
in any other channel. as il will give cor
rect drainage TO more than half the built
up area OF the city and will bring into
more effective use sewers whose recurring
overfows cost thousands of dollars an
nually.
The second report relates to improve
ments in the district drained by the Four
teenth-street sewer, in which it is said:
We have at considerable labor made the
SURVEYS necessary TO construct profile of
the Fourteeuth-street sewer, in order to
determine its gradients, and we fiud that
eastward, from point one hundred and
twenty-four Q24) feet west of Harrison
street, the sewer rises and continues to
rise along Fourteenth street, Harrison
street and Alameda street, until quite near
the Channel-stTeet sewer. The actual rise
in the bottom of the sewer is more than
one and One-half 40 feet, and when al
lOwance is made for the inclination which
the bottom of the sewer should have, it is
found that there are portions of the sewer
fully TWO (2) feet higher than they should
be-.
This means that over two (2) feet of silt
will always accumulate in the sewer near
Fourteenth and Harrison streets, and bv
retarding the flow of sewage at and below
that locality. this silt accumulating be-
comes the principal cause Of The inefficien-
cy of this sewer.
Additional obstruction to the flow of
sewage is presented al the intersection of
Fourteenth and Harrison streets, aud of
Harrison and Alameda streets, where in
each case the sewer makes an abrupt angle
of ninety 900 degrees.
lhe engineers recommend: That Four
teenth-street sewer be reconstructed from
point 124 feet west of Harrison street.
along Fourteenth street to Harrison street.
along Harrison street to Alameda, thence
along Alameda street to the Channel
street sewer on lines and grades prescribed
by us and according to plans and specihca-
tions furnished by us, and that We be per-
mitted to supervise construction of this
work, except in so far as il becomes neces-
sary for the City and County Surveyor to
establish official lines and grades.
we nave prepared the necessary plans
and specifications for this work, estimat.
ing the cost Of which at S492O.
The