Evening star. [volume] (Washington, D.C.) 1854-1972, 1882-03-29

one case an intercepting sewer along New York
avenue. crossing the White lot and dischargfng
at the mouth ofthe street sewer, relieves the
grounds below it of a large amount of storm
water Other intercepting sewers along the
slopes Of Capitol Hill and on the Slash Run area
are projected.
On a closer examination Of the alignment of
the sewers when considering the grave impor-
lance OF protecting the extensive low lands Of
the Tiber creek valley, it appears to US not to De
sufficiently thorough. A large quantity of
water Is permitted to reach them to be after
wards removed under the most difficult oircum-
stances. The grades become extremely light
and the sizes are therefore increased besides ex-
posing the section more to tidal Influences.
Inc New York avenue sewer, after reaching
10Th street, loses its intercepting nature and
leads with surplus grade directly to the low
lying b street sewer at point about 5000 feet
from the proposed shore line Of the river. 1t
seems to US, from the nature of the topography,
that it could have been continued on New York
avenue, west of the White House to the foot Of
Observatory hill. with better effect dischrging
at the river front and at high water.
The b street and Tiber Creek sewers are 10
Gated along the lowest line of the valleys to
which the water must descend before 1t can be
removed. They are exposed to the tides, have
very light grade and deposit considerable
sewage matter and silt. An interrogation of the
water on higher plane, discharging freely at
the highest tides, would so much reduce the
quantity reaching the lowest lines that what re-
COuiu Tedully Ue removed III d
sewer, with its bottom at a higher level and to
greater extent above the tides.
The engineers of the District hold that It is
advantageous to have the principal main sewers
discharge beto,c high tide. through "broad and
deep channels" asst diffuses the sewage through
the water. "The sewage is checked for time
in the outlet canals by the influx of the tide
which dIlutes while the ef1ux diffuses it,
However true this may be in principle
1t seems to US that the large mass Of water
in fha pixyor &nl b. A<xo
Of the tide, should perform this office rather
than the sewers or outlet canals, where at best
1t would be done much less perfectly. Again,
the rise and fall of the tide in the sewers is
claimed as an advantage in aiding their ventia-
ton, which is said to be especially necessary as
NEARLY all the sewer gas not due to defective
plumbing In houses is probably generated in the
tidal sections of the sewers" We think it
would be rather better to endeavor to prevent
this generation by avoiding tidal sewers as
much as possible. A sufficient number of sur
face openings would always permit of sufficient
ventilation caused by differences of temperature.
We also do not see the advantage of having the
outlet canal Of the street sewer and the James
canal perform the office of settling tanks for
the protection Of the river" If sufficient silt
from the sewers would accumulate in the latter
to require dredging, which seems improbable
after a rectificatlon of the channel, this silt
would not be as detrimental to public health as
when confined to the canals where there will be
more deposit and consequent exhalation, on ac-
count of the reduced velocity In them.
The subject of sewage publication is disposed
OF by comparison with London, and it is shown
that the pollution of the Potomac will be far
less than that of the Thames, and ''while that
city is still debating the question whether the
crude sewage OF London may be turned with
impunity into the Thames, with respect to pos
sible injury to the river and the jewellers on its
banks. we may properly postpone the question
OF distant outfall here" A misleading argu-
ment, however, is embodied in the remark that
as long as sufficient quantity Of water to
greatly dilute the sewage can be provided for
the city. lat less expense than the cumbrous and
complicated system of distant transferto sewage
farms and filtration areas, it will be better to
provide the water" Although highly diluted
sewage, caused by an abundant supply of water,
is conducive to better condition of the sewers
themselves. it does not decrease the amount Of
decOmpOsabe matter which enters the river
The degree of its pollution and the necessity for
publication will depend simply on the ratio be-
tween the minimum flow Of the river and the
population draining into it.