The Seattle post-intelligencer. [volume] (Seattle, Wash. Terr. [Wash.]) 1888-1914, 1890-02-22

be sid - Ne IN unusually mc6ernte CO..
cosr % sRAvrYT Axp rrxrsra sTrEns Coz
rAnxnl
In sne prslinf nasy repurs pofnfed ouf Inst
20 pump s.e0eopo gallons PER day nom Ake
wasAsngsDn. = The ssefaes height required. q
the rite of cents per million SALONS osse 1908
high. wsujd equal In cost the interest," - PEI
cfuf. On sele 900. and that Tie co<s Of pumping
500 GO gallons per day vould exceed the Ia
teres& on ibis suya By 916--0W PEI amman e
was also pointed ont thar though 10 close COM
psrafive estimates could then b made ct he
di6essaee in cost between grasify SYSTEM ana
. puxn ping gystem II Lake Washington OF equal
capacity, that IL would not be - much - MIA
Coo and thai Il would rot he iike'y 10 exceed
S6eo6oa II was aisp s9A.ed that 10 may b sateiy
assumed fhsf from the beginning the s4ying IA
annual expenditure. by gravity works. WIN more
than psy the interest on the difference % coss BE-
tween thesc and pumping vofKa
1 an now enabled 20 make comparison ne-
tween gnvity works and pumping works. -
| follows.
pumping works we're bullf on Lake WASH
fnxton. ~ she foot OF Yesler avenue. with high
| duty pumps Of . capacity 20 pnmp rcKulaTfy
e.eh twenty-sour hours 400 COO gallons OF water
into the hsgh-seyvsce reservoir, and i60n.0m
| gallons into the iow-seFviee reservoir. with
buildings. force mains, nlesx- oBe reservoir -
| proposed. pumps snt boilers complete. eSsi-
mate that they would cost. without iow-ssrv-
Ice reservoir. tsisCo against ~ ~ ssa -. the
estimated ecst OF the proposed gravity works.
Swing difference OF s5la7s5 8 o the excess OF
the cost Of gravity works. IS proposed. ever
pumping works capable OF II ndc- Ing the ssrne
service. The interest this sun. ar per cent.
amounts TO $ss.7ss - per sanuzn-
To pump a0o.0c9 gallons Der day into the
high-servsee reservoir, through 24-inch main
the size used in the ess.mafes-the water would
have 20 be lifted, including friction head, 40
feet. which work 10 the equivalent OF 4zSoup,-
600 eaisors enc foot high-o
TO pump Is 0o,000 gsIlons per day into the
low-sesvice reservoir. through a Soinch main,
the water would have to be lifted including
friction head. so feet. which work Is the
equivalent OF s.60o.o,oooo af gallons one foot
high, making in al $50. 900 of gallons per
day. enc foot high.
Al six cents per million gallons. one foot
high. this amounts TO $3.50 50 per day, or sci5.-
III per annum. as against S25.ss96S per an
mum. The Interest. at S per cent. on the diner
enee in cost between the gravity system. ~ pro-
posed and pumping system at Lake Washing
ton which will do the same work.
To state the same proposition in different
form.
II the estimated cost OF pumping-s2l5.
per aaBnm--be capitalized at per cent, IL vii.
represent an outlay OF 81 $3.50. That is, II
gravity works were TO cost this amount more
than pumping works. they would S i'll be -
economical As the latter. when Is. coo 900 gallons
Of wafer per day 10 being used.
II we should base ike comparison on the
amount of wster-not less than one bird OF o.
o0o0oo railons-which will be likely to be used
by ,hoend Of the first year after the works are
put into operation. il would show that II gravity
WORKS were 10 ecst 81. 435. $50 more than pumping
works. the saving In the expense OF operation
would pay the interest .. per cent on this
amount
A similar comparison msdc ON the works en-
"A n 1lf~x.s
can be readily done-would be still more favor
able to the gravity system.
Tire irresistible conclusion TO be drawn from
these figures In. that IL would be better for the
city TO incur a much larger debt than will be
necessary 70 carry out the gravity system. rather
team TO adopt pumping system, even II the
water 10 be had in the two cases would always
be equally pare
QUANTITIES.
Asit 10 impossible 70 tell the exact amount OF
earth excavation until a line is finally located
in AL its details aud cross sectioned. the guam
thy of earth excavation given can only be Con-
slider Approximate. The same should be said
with reference 70 the clearing. for the reason
that the borders of Swan lake have not been
surveyed so rs to determine the area that will
have to be cleared. With these two exceptions.
the quantities given may be considered asnfd-
cientiy close approximation to the truth.
DURABILITY OF woopEx CONSTRUCTION
It Is well established fact. tina. sound wood
immersed in water. or In permanently water
soaked ground. or in damp. impervious clay.is
free from decay.
II has also been demonstrated in cities where
wooden payemeufa have been laid on plank
foundations, and the plank kept fairly welScx-
clnded from the air. that the plank do not rot
There are many old plank foundations in Chi
cago OF pavements laid previous to ISL. which,
after the FIRE. were covered, BY change Of grade
of the street, 10 a depth Of perhaps OF two feet,
that are as sound today - when first laid.
II 10 not uncommon in the central part OF the
city. where the ground was originally but a few
feet above the lake. and where the street has
been raised from time to time. TO cut through
three o. -four layers OF plank In digging trenches,
ct rs many different depths. sll of them sound.
These pauk are almost universally white pine
or hemlock.
Decay in wood is caused by the fermentation
of ito sap. through the agency Of bacterial life
This fermentation only occurs in the presence
of both air and wafer. By the exclusion OF
either one and the presence OF the other, the
wood Is preserved.
BY the accomplishment Of this in the manner
described, 10 Is expected 20 preserve the wood
used in the pavement for the reservoir in the
wooden pipe. and in the fumes below the
water-ine: and in eli cases, ~ the tunnel the
cribs. and ia Cedar river dam. where submerged
in water or kept watersosked.
In gakeS where WOOD Is not permanently pfe-
served il can be replaced from time To time. or
by some other Glass Of structure in the future.
better than go to The expense of such structure
now.
CONTAMINATION or WATER.
As has heretofore been pointed ont there are
no settlements Cedar river above the point
where 1t Is proposed to take water. and the few
houses In the vicinity of Sw m lake could have
little effect, far as the amount of organic inn
puriies so.
b the city acquiring strip OF land on the
shores Of the iase. they pu, into effect any
sanitary regulations necessary 10 prevent CON
termination from al animal matter and excre-
tons
Contamination by vegetable organic matter IL Is
impossible TO prevent ia a country covered with
dense growth OF vegetation aad q network OF
decay ng logs This. under crtinary conditions.
mar b. assumed 10 be unimportan:--a, any rate
IL 10 unavoidable.
II can only be by the propagation of some
form ol plant lie ia the reservoirs such A, Ger.
,ssn vsritEes OF fresh water als.e and their sub
seaueat death and decay. TIA, detrimental
concentration can originate. This seldom II
ever occurs in running streams. and peyer
where Sunlight is excluded. and hence cannot
eccar IN tie main supply pipe or tunnel TIE
conditions Necessary 10 a grsvta OF the varssses
Of aigsr most Objectionable are sualixht and
temperature of water of about 20 degrees
reservoir fed with moun, ala stream is
muea .ess productive of vegetable growth than
II Il j. fed with water from the earth deem
EVssryogr - mash less iiah!e to It than shsllow
one. The considerable depth OF the city reser-