Evening star. [volume] (Washington, D.C.) 1854-1972, 1912-09-25
TAP THE PATUXENT
Plans for Increasing the Dis
trict's Water Supply.
WOULD DAM THE RIVER
Proposed Construction of a Three
Mile Tunnel.
RESULTS OF LONG STUDY
Estimated at 10000, 900 Gallons a
Day Could Be Brought to the City.
Cost, $4,000, 900.

According to Col. Langftt, Corps of
| Engineers. and those associated with him
| in the study of the needs of the District
| water supply system, the PatuXent river
| in Maryland possesses many advantages
| as possible source of increase to that
| supply. That is shown in an official re-
| port just received by Gen. Bixby chief
| of engineers of the army, giving the
results of prolonged study and considera-
| ton of the subject, based on an act of
| Congress directing an investigation of
the availability and adaptability Of the
PatuXent river as source OF water
| supply for the District of Columbia. This
is the second investigation of that sub
| ject made by army engineers, and was
| based primarily on official reports that
the existing water supply might be in
| sufficient to meet demands unless radca!
| measures were adopted better to control
| the consumption and waste under the
existing system.
| Col. Langitt, who forwarded the re-
| ports. shows in an accompanying memo
| randum that the PatuXent river is avail
| able and adaptable for the purpose of in
creasing the District water supply at
| total cost slightly less than would be
| entailed by the construction of an ad-
ditional conduit from the Great Falls of
| the Potomac. He purposely refrains.
| however, from committing himself on the
| general proposition as to the necessity OF
an increased water supply at this time
or in the immediate future.
Dam 800 Feet Long.
Generally, the report submitted adopts
the plans originally outlined by Maj.
Morrow, Corps Of Engineers, in his re-
port on the same subject in 1909. They
dam, 20 or so feet high and about 800
feet long, founded on rock, to be thrown
across PatuXent river at some point Of
the gorge near the Columbia turnpike
about nine miles in length, which, with
| a reservoir over the Patuxent valley
abuot nine miles in length, which, with
its contributary branches, would provide
storage sufficient to provide D,O0O,0OO
gallons of water per day for this city,
even during the most unfavorable sea-
sons. 1t is designed that the elevation
of the reservoir shall be sufficient to de-
liver the water to the filtration plant
near the Soldiers Home in this city by
gravity alone, and at the same time per-
init the use of a smaller conduit than
would be necessary to obtain the same
amount of water from Great Falls.
The plans also contemplate the con-
struction Of a tunnel about three miles
long from the reservoir, through the
ridge between the valley of the Patuxent
and the valley of the Paint branch of
the Anacostia river in the general vicin-
ity of College Park, and bringing the
water from that point to the city filter
beds through steel pipe conduit over
| a route described as direct and easy. The
proposed route covers a distance of about
twenty-five miles and practically par
allels the line Of the Baltimore and Ohio
railroad between this city and Laurel
According to the plan of construction
adopted 1t has been variously estimated
that the Patuxent river project would
cost between s5,O0O,OO and s6OOO,OOO
The exact estimates of the work made
by Col Langfitt will not be made public
until after the Secretary of War has
officially submitted the matter for the
action of Congress.
Data Regarding the Patuxent.
Col. Langfitts report is accompanied
by various tables. prepared by E. D.
Hardy, superintendent of the District
filtration plant, in regard to the avail
able supply from the Patuxent, the dis
charges, by rainfall, the monthly run
off. typographical features, etc, and by
comments on the results of those cal
culations by Allen Hazen, an expert
90.O00,000 gallons daily to be con-
SENTATIVE rating of the capacity of the
stream available for the District water
supply. The minimum elevation of the
water in the proposed reservoir is taken
at 315 feet, and the elevation of the
District filtration beds is given as 165
feet An elevation of 315 feet has been
selected as the lowest at which water
in the reservoir could be drawn into
the conduit. The height of the dam
was determined by calculation of the
storage capacity needed to practically
conserve the food discharges
Quality of the Water.
tuxent water from samples taken at
Laurel show that the water is very
good. but it is admitted that filtration
would be necessary, even allowing for
reduction in bacteria. due to the long
storage that the proposed reservoir would
give, estimated at from 55 to 300 days
1t found that the turbidity of the
Patuxent rises abruptly and falls as
rapidly. That condition indicates to the
engineers that coagulation would be nee
essary in the treatment of the water.
1t was found that coagulaton could be
provided for economically by small
subsidiary reservoir formed by an earthen
dam across a ravine near the right end
of the main dam. The elevation of the
earth dam would be the same as that of
the main dam. the water in the two res
ervors always being at the same eleva-
ton. thus providing for coagulation with
out loss of head on the conduit 1t was
found that owing to the size Of the reser-
voir and the necessarily unused capacity
at the bottom injurious filling from sedi-
ment might not be expected for many
years. Therefore, such contingency has
been neglected in the consideration of
this river source of supply. Soft
ness of water Is especially desirable and
Mr.. HaZen. in his report, lays much stress
on that point. The average found in the
Patuxent is stated at 20, as compared
with 30 in the Potomac. difference of
30 in favor of the former.