Delaware tribune. [volume] (Wilmington, Del.) 1867-1877, 1874-11-19
LOCAL AFFAIRS.


LITTER FROM THE CONSULTING ENGINEER TO THE
WATER COMMITTEE, ADVISING A SMALLER BASIN,
AT SAVING OF $4,000.
7l5 WALNUT ST., PHILApELruIA,
r.. October 2sth, 1874.
W. NJ. Canty, Esq, Chairman Of he Water
gon.midee Of Wilmington,
DEAR SIR l have examined the lot purchased
by your city for reservoir purposes, extending
from 10th to 10Th and from Franklin to Jackson
streets. The proper and judicious size Of the
new reservoir is question that ought to be care
fully examined and intellgently decided. Hav-
ing made report to your predecessors in 1870,
upon an enlarged supply of water for your city,
IL seems proper, On my part, that should pres
ent my views upon this subject before going on
TO construct the new reservoir.
At present, the population within the water
district is estimated at 80, ,000 aud the daily aver
age consumption at 1880, 600 gallons. being GO
| gallons for each inLabitant. II q reservoir be
constructed to cover the whole lot purchased,
with depth in the excavated portion of Is feet,
it's contents would be about 60 million gallons.
At the above mentioned rate of consumption,
this reservoir, when ful would contain 331G
days supply for the present city. And at the
same rate would furnish 100, 900 people supply
for 10 days without considering the water deliv-
cred from the Rodney Street Basin.
II . reservoir were constructed to occupy the
upper half part Of tho lot, with IL feet depth of
water, itwould contain 2sS million gallons, being
nearly l5s1 days supply for the present demand.
By raising its surface . feet. which could safely
be done after the banks have become well set-
tied and proved by time and at small cost, by
only raising the banks one foot, the capacity OF
the reservoir would be increased to 80 million
gallons, furnishing at the same rate of consump
ton ~ days supply for 100, 900 peope, not
13s,0OO
The City of Wilmington has a large surplus
NJ 10. tt,a1
therefore there is no necessity to store up wa
ter in reservoirs to meet failure of the
stream. 1t is only required that the reservoir
capacity should be large enough to give oppor-
tunity for the water to settle, at such times o.
the streams are turbid. With division bank in
the reservoir, over the top Of which the water
flows from the receiving to the distributing
apartment, or other efficient arrangement for
surface distribution, three days supply is usually
sufficient for the water to become well cleared
From these facts it is evident |
that the smaller reservoir is ample
to meet the requirements Of your city until its |
population shall exceed 100000.
The comparative cost Of building tho two res
ervoirs il NJ follows
Large one, occupying the whole lot, and |
holding 60 million gallons, ........ slS3, 900 |
Small one, occupying half the lot, and
holding 2s1G million gallons. ........... $4,000 |
Full details Of the estimate are herewith on
closed.
The elevation of surface Of the large reservoir |
adopted for the foregoing estimate is 10 IT.
above the overflow at 10th and Market SITS. To |
make it higher would add very materially to the
cost. and would require earth to be 'borrowed,"
or the bottom Of the reservoir deepened, which |
is Objectionable, and would also add to the
depth and pressure Of water against the high
bank at Jackson st., which, at the surface, as
proposed, has already depth of &c feet.
The adopted elevation Of the smaller one is 8
feet higher than the larger, being % feet above
the overflow at 10th and Market.
The estimate includes filling the bottom Of the
smaller reservoir to the established grade line,
giving uniform depth Of water at all points of
lS feet.
In comparing the two plans, the advantage of
this increased height should not be forgotten.
In view Of the foregoing facts and figures
recommend that the city should build the small
or reservoir. ...
Respectfully, WM. E. MoRRIs, Engineer.
Accompanying the ubo7e stt6. were the rui-
lowing estimates
COST OF LARGE RESERVOIR, COVERING WHOLE lot |
CONTENTS ABOUT $1,000, 900 GALLONS.
Surface of reservoir, 10 feet above overflow at
10th and Market.