The Portland daily press., 1885-03-04


lies above the crown of the proposed sewer and
one half its entire aow, being 1.9l, must be re-
ceived, giving volume of 16 90 cubic feet per sec
ond below Franklin street. From the end Of this
brick section plank sewer 5x5 feet, rectangular
area 25. of the above described construction to
tend 669 feet to point opposite The foot of Smith
street taking the combined dry weather flow of
Boyd and Mayo streets, 0 12 cubic feet per second
and making here volume of 17U5 cubic feet.
From this point to outfail 3466 feet the sewer to
be of piles and plank, 5x6 feet, taking the dry
weather flow of Smith, Anderson and Fox streets,
O.6S cubic feet per second, giving present flow
of 1853 cubic feet per second. OF this the storm
flow is IL. .9S dry weather flow 5.65, leaving the
flow from possible sewers on 22 acres north of Fox
street, o. IL cubic feet per second, amounting TO the
684 cubic feet above assumed as base OF estimate
For length of 1900 feet from the point of out
fall 5x6 suice-way will be required to admit and
discharge the water of the tide to and from the
cove OF 1612 acres area between the sewer in Fox
street and the Shore in which water to the depth Of
four feet would otherwise be impOunded.
The mean rise of the tide is 81 feet length Of
sewer 7542.7 feet, fall in that distance Al feet
giving structural inclination of 0O564 Plus or
21-32 inch per 100 feet, being l foot in lSO4.5
feet This of course is good for head only at GER
tain stages of the tide hereinafter indicated but
in the Mill Pond sewer. of which the proposed
is only extension lie the possibilities of
cumulation of any fiietional head and the result
ant hydraulic slope required for continual dis
charge The Mill Pon0 sewer is entirely covered
by earth and has an area of IL feet, being of six
inch plank. supported by piles for a part of its
length and then by timber framing to a point 736
feet above its connection with the proposed sewer
at which point point its crown is A feet above NJ.
H. w. and its beo bed at n. II. W.
492, or at the rate of / inch in 1896 feet. At the
head of this section comes in brick sewer with
area of 6.3 feet, on an inclination of in So. Add
sewer at 7542.7 and we have for working at high
water a sewer 8279.7 feet long with a crown
same at oufal receiving at head 2.S6 cubic feet Of
street street 1898 cubic G feet anu = head AHA for or
discharge at food tide must always be higher at tide
level at nOiDf of discharge. At the time of biph
water this head must stand higher than ele va tion
81 and the sewer will then have been working
from about the time of half food under hydraulic
slope qnte different from that of structural incn
alton. That inclination Of in substantially 1900,
giving fall of AIS is sufficient for discharge with
tull outlet. Now TO that lS add another 4 1S and
the sum s. SO will not reach the grade OF the Mill
pond sewer at head which is 81, having its crown at
3 1 and sewer with an inclination of l in 35
as direct afluent. A head of foot above NJ. II.
W. would therefore add 30 feet to sewer for pur-
pose OF inquiry, making its lengh S3l4 feet with
bed at 10.l. Tue mean tide rises 8. feet in 6.25
hours and although its velocity is not constant its
average may be properly taken as such for 10 pres
ent purpose its average Iise would be foot in O6S6
hour or 456 feet in one hour and would reach the
height of sewer bed at head Ais feet in 2S6 hours
or hours 81 minutes, SO seconds. The inwards
flow would therefore have velocity in the sewer of
073 per second. AT the end of Alp hours hood the
sewer will be full to the crown at outlet and there
will be then depth of 1.S2 feet at the head
ming out to nothing in distance of 272 feet up the
Mill pond sewer. the crown of which at that point
is four feet above the bed. At the end of hours
there will have gone past this point and down the
sewer 42,419 cubic feet of water. The
feet circle at Franklin street may be
taken as the average of the system. Its elements
are when running full: Area 1896, perime ter
10 z, hydraulic radius 25 structural fall per mile
2.64, giving velocity of 1856 feet per second
when free of tide The volume of sewerage here is
Of 0.S62 feet per second will be required for the
discharge of this quantity. The inward tide flow
being at the rate of 073 feet per second its ratio
to O.S62 is as L to LIS. and the outflow
should be 1.19 times, O.862 giving a requi-
site velocity of 102 feet per second, representing
head Of LIT and hydraulic slope Of .0OO140s5,
being O.741 feet per mile. Working the feet
sewer on an inclination of .0.74l feet per mile the
free velocity would be 1,247 feet per second and
duced to LOS per second, agreeing substantially
with the above I.02. The elevation of he head
would then stand at 1927, and this height Of tide
Will not nll any sewer in Lincoln street, with the
exception of that in Wilmot street, which
Il would MI to point 10 feet beyond
length of the lateral sewers relatively to
the crown of the main sewer has been quite mis-
apprehended. Those of Brattle, Paris, Hanover,
Preble Elm and Chestnut streets could pass en-
tirely over this crown on grade of in 400 from
the elevation of Lincoln street and with the excep-
tion Of those in Green. Wmot and Franklin streets
above accounted for the entire storm flow may
be passed to the outfalls. 1t is as if the
struggle which must occur high water we're to be
the constant condition of the case. 1t will 20 on
increasing in practical difficulty III about three
hours from half food until the moment of high
water. Upon the turn of the tide relief viii be
given, TO continue during about nine hours.
through the whole Of the ebb and back to half
food.
Such are the main features of the proposed low
level sewer. of its value compared with any
ether scheme have now no arguments TO advance.
Estimated cost of entire work SOL AGO 90
Balance on hand, substantially IL 10000
Balance required. ..,.............$ $50, 10000
At the distance of 5643 feet from the Sc wer head
is deep pool at low having direct communi-
cation with the chaunel of the Bay through one of
the thirty feet waterways of the Marginal Way.
Here the work of the first season may properly
close and training wall of sheet piling. included
in the above estimate, would direct the flow OF the
sewer so that iG would not reach the inaer fats
til covered by the tide. If the whole work should be
thus divided the estimate for this section would be
tional appropriation required, $4,000
Under the appropriation Of Sl5 900 made dur
ing the season for beginning the work, the Of
$3,s52 OF was expended in extending the laterals
in putting in ventilating shafts near high water
mark and in driving the req lsite piles The SOM
pended balance of sll ,l47.47 is available for the
next years work. This in the above estimate has
been taken as S11 600.
The old Mill pond had at its head long creek on
the northerly side of Deering's Oaks, into which
fell natural water course with two branches the
northerly of which came in from the valley north
OF Portland street. crossing that street Harris
tannery. The other had its source in and around
the horse pond on the southerly side of Congress
street, the two coming together between Portland
and Congress streets, the united stream flowing
through The Almshouse valley into the above named
northerly creek. In of time these branches
had been obstructed by defect in the cuvert under
the railroad embankment, and swsmpy expansions
had occurred along the streams which above that
embankment had become stagnant.
In the year 1871 a committee OF the City Council
was appointed 'for the reclamation of swamp lands
in Ward Seven," referring to the area now under
consideration. The result. after careful instru
mental observation was the construction of brick
drain TO lead the northerly branch through Port
land street from the above named culyert to the
head of the creek through the Almshouse valley
the laViuQ of nine drain main drain
the southerly branch, the clearing of OBJ
structions from the natural channels, the
moving of hags.and other coarse herbage, and the
subsequent filling by their owners of the areas of
swamp, 10 the extent not only of abatement eff
nuisance, but of making pasturage OF the greater
part of the lowest of the lands. Soon afterwards
the city overseers of the poor took in hand the |
swamp parts of the Aims house valley, enclosing |
the main stream with stone or stone lined walls and
reclaming foul areas of swamp Including the CITY
piggery, and making tillage land of what had been
as foul as stagnant water and tainted stream on
filling is required to convert every part of this low
level area into tillage land safe from overflow.
The following elevations will show the conditions
OF daily drainage OF these lands on the lines of
their present water courses. The head of the brick
sewer through Portland street, from Hart's |
tannery, is eleven feet above mean low water; cul-
of drain through Aims house valley, 81; culvert
Grove street, TO From this point IA sewer to the
Mill Pond sewer at elevation, 495. being 115 feet
above the head of the intercepting sewer. would
have fall of 2.65 feet in distance of 1860 feet,
or In about 766. The grade of the Mill Pond
sewer was laid thus low this point for the pur-
pose of receiving a sewer through the northerly
creek This, though not now part of the proposed
sewer, may at some time into it, and the pro-
vision has been above indicated for the reception of
0 o cubic feet per second of its drainage.
ALI the area west of st. John street above the |
contour of 1S feet above mean low water may be |
drained to Fore river at not inordinate expense.
In conclusion l would respectfully reilerate the
clauses of my reports for the several years past
on the subject or a careful attention TO the
cleanliness of the shore Of Back Cove particularly
there should be any choice to those relating TO the
cleaning of privy vaults, for one quite ready |
to suggest and talk less the subject and do more.
Respectfully submitted, |
VIM. A. GOODWIN,
City Civil Engineer.
superintendent of schoOls' Report.
The increase over last year in the number of pu-
pills has necessitated the employment of few
teachers. This, with the increased pay given to |
young teachers, has caused the salary |
bills to somewhat exceed the appropriation. An ae
count of the particular schools shows them TO be in
a prosperous condition. The buildings have been |
kept by the superintendent of school buildings in /
good repair, and one of them, the Casco
street primary No A, has been enlarged by the ad-
dition of three rooms. and improved throughout. |
As "A primary school house Of eight rooms il is a /
model Of convenience and safety. 1he School Il
mad