The Seattle post-intelligencer. [volume] (Seattle, Wash. Terr. [Wash.]) 1888-1914, 1889-11-16


% their faeompseseHesx, do nos show
Above sn elevation Of 90 feet Il Is safe 70
assume that the buildings win be mainly dwell
ingz or smEIl stores. rsrely II ever more than two
stories in height II reservoir Il built with its
bottom ~ an elevation Of 80 feet and Is Cow
liue ~ 60 feet. II viii satisfactorily sappy all
the territory ranging from 20 to $50 feet above
high tide, and In certain places. as for instance
rear 70 the reservoir il msy reach even higher
than so feet.
TIE best location for such reservoir is on tho
ridge crossed BY Madison street, IN section = or
- This il centrally located for ihc disrrfct 70
be supplied from It. Two such reservoirs with
high tide. can BE fed alternately BY one conduit
from swan lake. While the upper one Is being
ElIed, the connection between the lower one
and the conduit would have 10 be shut OF. The
rate 81 discharge into the upper one would be
about one half that into the lower one. So that
amount of water used by the low service system
II wculd take equal time to supply the reser-
yoirs Of the respective systems
The plan OF water works proposed for the city
may therefore be said 10 embrace high service
and 9 low service gravity system. each supplied
through one conduit from swan lake, and high
service pumping system supplied iron the upper
reservoir for such portions Of the city can not
be reached By the high service gravity works.
The supply being drawn mainly from Rock
creek through swan lake. though intermediate
lakes wiz contribute the amount they are cap
able of furnishing
The distribution pipes for the tao gravity sys-
TENS should be connected through q vsive at
some suitable point so that in case OF ERE or
other emergency, the pressure OF the high SER
vice reservoir can be turned upon the low service
pipes.
The quantity OF water required Is dependent
upon the growth os the city, and of course is
probiematicaL A study of the rates of growth
OF numerous cities Of the United States con-
ysnces me, however. that 1t is not safe or adviS-
able for You 10 proceed with the construction Of
works upon the plan proposed on a basis of less
than $4,000 population. which viii require fully
100000 gallons OF water in twenty-four hours.
One quarter of this amount viii doubtless be
used by the time the works shall have been
fairly put into operation.
Owing 10 the lakes being low, following the
dry season, and 10 othe causes it is now Smpos-
s1ble 10 measure with exactness the amount Of
water that can be obtained from the proposed
sources By the plan proposed the surplus water
of the wet season viii be impounded in Swan
lake. which has an are of perhaps 600 acres. and
thereby largely augment the dry weather sup
ply.
Mr. seury's measurements show nearly
enough water in Rock creek alone 20 meet the
requirements. and without doubt the adcitional
amount-and probably more-may be obtained
from the lakes, which il Is proposed to take into
the system.
In carrying out work of the magnitude pro-
posed, for q city occupying so commanding
commercial position as does Seattle, ard sur
rounded by sHch wonderful natural resources--
which are as yet undeveloped-ii would not be
wise 20 look for city OF but 250,0o0 people, and
the amount OF water necessary only for such a
population. A reserve supply should be sought
out. which. II possible, should be capable of be-
ing utilized in harmony with the proposed
works. Sach q reserve is said to exist in Lit e
Cedar river which enters Cedar river q few
miles aboge Rock creek.
Before entering finally upon the construction
Of the proposed works, a preliminary
survey OF this source should be
made and the head works so planned that IL
possible water from this river may in the future
be conducted into Swan lake without any radi.
cal remcdelirg Of the works.
AoukDUcTs.
II is too soon TO attempt to give in detail the
kind and size OF conduits 20 be used in i'm
pounding the water in Swan lake and la con-
veying it 70 the city. so much depends upon
the topography OF the r0ute-which has as yet
been only partially ascertained-upon the
pressure 10 be sustained at different points, and
upon the cost OF different kinds
of construction and materials, and
upon the safety and durability
ering the ground would probably have TO be
greatly modified. In a general way it may be
said that ii Swan lake Is used q storage Feser-
voir, that II viii be capable of furnishing sew
enty days ssupply Of 100000 gallons without
receiving accesSions from the outside; and that
hence IL Will be safe TO conduct the water from
Rock creek 70 the lake by means OF All open
channel wherever the hydraulic grade can be
held, which win probably be for the whole dis
tanee OF about six miles, except for about so
feet where pressure pipe may be necessary
From the head OF Swan lake TO point or Rock
creek from which water may be drawn, by any
line which Il win be practicable TO follow. is
fully seven and one-haf miles By the utiliSa-
ton Of natural channels, including the lake
itself where II can be done, and the use OF open
bitches as proposed, the cost of this seven and
one-half miles viii he reduced 20 less than one
half OF the cost Of pressure pipe.
From swan lake to the top OF the hin south
east OF Rentos q grade conduit OF masonry or q
ptessure pipe may Be used. according as the pre-
h.e OF the line is found to be favorable 10 or
to the other. From this point 10 the reservoirs
pressure pipe viii be necessary.
CAPACITY or DISTRIBUTING RESERVOIRS.
To be prepared for possible accident to the
pipe lire between swan lake and the city Eeser
vosss they should hold sufficient water for a
three days supply; or. say 50,eo0o0o gallons ca
pacity for the low service reservoir AID - 10000
galioas for the high service neservo1s. shoaId
the sarsng Hill water works come into the pos
session the city II win not be necessary TO
build new low service reservoir at first. IS the
old reservoir which holds about 100000 gal
Tens, can be made TO answer for some years. II
the high s9rsice one. with a capacity OF 25.000-
90 gallons, is built in the beginning.
Is case Of an emergency the low service rescr-
yoiF conia be allied from the high service one,
AID =, 10000 gallons storage capacity Will
answer for several years after the works are put
txto operation.
Conpar4tlss cost OF pumping and gravity
supply.
five assume that one-third OF the water used
hy the city will pass through the high service
reservoir as gn elevation Of go feet. and that
fxo-thfrts viii PASS throagh the low service one
with an elevation OF 80 feet. then the average
height 20 which all the water viii have 10 be
raised 20 attain these elevations il s feet above
high ise, or $50 feet above the level OF Lake
washington. IL 60 tbts we add s. feet for fTlc-
ton head we aAve go let as the equivalent of
the pressure under which pumps stationed
at Lake Washington woald have to work 20
smpplytthe city,
me cost oa pumping sooo,ooo gallons Per day
tor SIS DAYS, 20 THIS height, with The best
pumping machinery. based upon the lowest
Chiesgo cost 81 pamping. via. SIX cents for
600 90 gallons raised one fpot high, il ssasl5,
whieh Is equal 20 tire Interest for 0ne year 81
Per cent On ssleSl0
gaafisM . gravity system were 70 cess tsle..
ooo more Dian . puEping SYSTEM,
the saving in the operation al tie
works wheas 0oo.ufs gallons Of water were being
used Per day, would psy the Interest on The diff
se-encc q cosf: and when 2a.aoo.6ne Of gallons
wtre besng used, Il woaid pag this interest and
eaees . saving % sie2,ae0 per annam.
A5thoueh The SURVEYS and pi4ns are nstf sun
- IL