Evening star. [volume] (Washington, D.C.) 1854-1972, 1890-06-07

tOHl VI WHICH ~ Isl 1eet DeIOW mean nlHu
water in the river and extending westward a
distance of 500 feet 10 the point of discharge
into the canal. This sewage is not conveyed
promptly into the river. but ~decomposes in the
sewer and canal, making this locality very
offensive.
The James Creek canal receives the sew
age from 1880 acres of territory not very
densely built upon, but which is growing rap
Idly. This sewage IN collected by the llber
ever, the bottom of which at Pennsylvania
avenue il 3.6i feet below mean high water in
the Potomac river, and the sewage Is dis
charged into the James Creek canal at G street
south. The condition of the sewage in this
canal resembles that in the 18th street canal.
and. like that. it is in warm weather a
nuisance. which must affect the health OF those
who live or labor near I.
The distance in sewer and canal through
which the sewage. retarded by tidal effect.
must travel 10 reach the river is for the b
street ar s, 400 feet. and for the Tiber area
II. $50 feet.
The condition of affairs existing Is above
stated ard which should be radically improved
upon leads naturally 10 4 consideration of the
subject of the Lest method of sewage disposal
for Washington.
The water-carriage system having been
adopted the fouc methods of dispose! to be
considered are. Broad irrigation, intermittent
downward hltratlon, precipitation and crude
discharge into deep water.
DISCHARGE INTO DEEP WATER.
After considering the various methods Mr..
McComb concludes in favor of the last, the
discharge of crude sewage into deep water. He
says this method of sewage disposal is OBJ
viOusiy the simplest and least expensive one,
If the outlets can be SO located that long lines
OF main sewers are unnecessary and if p~urifica-
ton of the sewage can be effected thereby
without causing local nuisances. The Potomac
river below the Great Falls is not used as a
source of water supply, therefore it is unneces-
sary to require, in that portion Of the river.
the same exalted degree of purity which would
be necessary il water was supplied to communi-
ties thereform. Under such circumstances 1t
Is assumed that the minimum quantity OF wa
ter which should be allowed for the ~purifca-
ton of sewage is 1,5O0 gallons per head of pop
uiation per day.
The water shed Of the Potomac river above
Washington contains an area Of aEOu: Il. 200
square miles. The absolute minimum discharge
IS about 695, 600, 900 gallons per day. the mini
mum low season discharge being about l,273,-
600, GOO gallons per day. Upon the basis of a
minimum discharge would afford a d..utlon of
! $3.50 gallons and the minimum low season dis
charge a dliutlon OF 2,5i6 gallons per
head per day. When it is considered
that the periods during which the
absolute minimum discharge occur are of
short duration and are of rare occurrence it
would seem safe to assume that the river may
he depended upon TO purify the crude sewage
OF Washington and Georgetown until the
500. 900 limit of population is reached. which
Will probably be between the years of 1880 and
1910. and II would seem unnecessary Mt the
present time to make provision for 4 larger
population.
In order that local nuisances may be obvi-
ated the position of the outfalls becomes an
important subject for consideration and an eX-
tensive series of float observations was pro-
ltctcd, but the unfavorable weather of the
last season caused and interruption of this
work ana the lapse of the appropriation for
this general object prevented the completion
OF the contemplated observations. The obser-
vations taken are of value for the purpose of
showing the important effect of the wind upon
the surface of the river and they suggest the
necessity of screening the sewage before dis
charge. and also that the sewage should be
discharged at a considerable depth below the
surface of the water.
POINTS OF DISCHARGE.
The location of the points Of discharge will
be discussed with reference to the Potomac
river and Eastern branch, considering the
effect of each Of these streams upon the other.
The Potomac river above the city Is confined
within a narrow channel and near the Chain
Bridge. three miles above the city, 1t becomes
affected by the tides. Further down the stream
a point is reached where. by a balance between
the fuyial discharge and the water backed up
by the flood tide, the water neither flows up
blLtdHAn " uONAb OlI lux II LlilC VI the
maximum effect of the flood tide. This point
varies with the discharge and the tidal effect,
but usually 1t Is located not far from Easby's
point, below which the tidal basin increases in
width and area.
Upon the southeast flank of the city is To-
Gated the Eastern branch OF the Potomac
river, which. draining a limited water shed,
has a small fluvlal discharge, and opposite the
city it has Il large area for the storage OF tidal
water, so that during the flood tide there is a
strong upward current. which tends to carry
the sewage discharge from the James Greek
canal eastward along the shores of the city be-
tween Greenleaf point and the navy yard. At
certain stages of the tide the current flowing
downward III the Virginia channel and upward
below the junction of the rivers and III the
Eastern branch causes the waters from the Vlr-
ginia channel to turn into and go up the East
ern Branch. This effect is augmented in the
summer by the prevailing southeriy winds.
This condition would seem to indicate that
sewage should not be discharged into the East
ern branch and that the points of discharge
should be removed rs far i practicable from
the junction OF the rivers. If the sewage could
be discharged into the river ut a point about Il
mile above the Chain Bridge the effect OF the
steep slope of the river with its rocky bed in
this portion of Its course would seem TO insure
a speedy dllution and oxygenation OF the sew
age. Again. the point OF discharge might be
situated SO far below the city that the sewage
would not return upon the Hood tides. Either
OF these points OF discharge would require all
Of the sewage TO be pumped through long lines
of cOnduIts at a large original cost and entail
ing 4 large annual expenditure. Instead of
either OF these expensive outlets, / propose
that "A greater portion OF the sewage be dis
charged near Easby's point. the practically con-
slant downward current existing there insur-
Ing an ~cffectual dIiution OF the sewage. The
sewage at present dlscharging into Rock creek
Is to be intercepted by a sewer practically par
allel with Rock creek, with overfows, ill order
that during storms the very dilute sewage will
still be carried by the creek.
OTHER INTERPRETING SEWERS.
Another intcrcepting sewer is proposed from
F and North Capitol streets along f street to
18th street. to L street, thence across the
White Lot TO & street. thence to New York ave-
Iue and to Easby's point, with branches inter-
cepting the sewage from the north slope OF
northeast and from the North Capitol street
sewer.
This sewer will be of such capacity that the
surface drainage between L street and New
York avenue and It'll and 18th street, as well as
the surface drainage from the area drained by
the new York avenue sewer and the area drain
ilg to the sewer line between 18th street and
Egsby's point, will be carried, thereby reliey-
ing the Is street sewer, which Is not of capacity
sufficient for the duty imposed upon 1t.
a third maln-lntcrceptlnB sewer will skirt
the shores OF the Eastern branch, commencing
not far from 18th and L xreets northeast and
ending IN the upper portion of the Arsenal
grounds, where viii be located a pumping sta
ton containing machinery necessary to lift the
sewage to be brought by IA fourth ~main-inter-