Richmond daily times. [volume] (Richmond [Va.]) 1850-1853, 1851-11-29

The Supply of Water for the Summit Level
There is scarcely any principle in science better es
abiished, than that relating to the uniformity of the
quanly of water falling annually from the atrnosphere
upon given space OF the earth's surface This oman
ty, taking series OF years. constant in the same
place, varies with the altitude proximity to the ocean
prevailing winds and elevation of The country In
the temperate region of the United States this quantity
s equal to 81 inches in depth and at the sites of your
proposed reservoirs among the mountains is doubt
less greater "a considerable portion of this ia AGAIN
returned the atmosphere by Corporations The rest Ell
ther passes directly the ocean along our rivers or
alter percoatng through the soil and rocks below the
surface, affords supply for springs which unite and
form streams. The difference between these two
quantities, that is, between the total amount of rain
and the quantity evaporated, gives the supply of water
available Tor economical purposes
Although this subject has been but little considered
amongst US, and by many it is even viewed as mere
theoretical speculation having no practical value me-
verheess it has been fully investigated eseyy here and
the application OF the results to practical purposes has
ceased to be any longer considered problematical
The annual evaporation from the surface Of wafer
is equal The depth OF rain that falls upon it. and un-
der favorable circumstances it may exceed that quan
rity; for instance, Mr.. Dobsons experiments at Liver
D Dol gave the mean annual quantity OF rain 81 4S
inches and that evaporation 3673 inches. But the
evaporation from soil IS not near great as this and
from the surface of rocks it is almost nothing For
the first experiments this subject we are indebted to
the nsuous Dalton, assisted by Mr.. Hoyle. A
square box was filled with SOIL aud exposed side
by side with ordinary rain guage; the wafer that
perforated through the soil was collected and com
pared with the quantity indicated by the rain gauge
The mean quantity OF ram for that year was 80 Sc
incke and the amount evaporated from the surface of
the soil IS 6 inches, leaving 40 inches, or one fourth
of the whole the available supply.
1t must be observed here that the soil in the exner
ment was placed under the favorable conditions
for evaporaon-the surface being horizontal the wa
ter was readily absorbed and retained for evaporation
conditions that rarely exist where reservoirs are form
ed. Take, tor instance, the valley of Anthony's
creek where the sides of the bounding mountains are
inclined, from top to bouom, at an angle varying be-
tween 90 and As deg, and moreover covered with
but scanty soil, and 10 great extent with even ma.
ked rocks 1t is evident that during rains the water
must flow down with great rapidly into the valley
leaving but little time for absorption evaporation
Mr. Fairbarn distinguished European engineer
In his proposed improvement of the river Bann by re-
servoirs situated under conditions similar 10 those pre-
sented at Anthonys creek, estimates the available wa
ter at five skins Of the whole amount and his esmates
in this respect have generally been exceeded by the
practical results
Knowing the area and contents OF a reservoir. and
the area OF its catchment BASIN draining INTO
it, the application of the simple principles just present.
ed is sufficiently PLAIN
From personal examination of the valley of the
creek have the slightest doubt of the fact that the
auanty of water available will far exceed the cacu.
atious of your engineers. Neverihele g, as I know
that the fed work is completed for minute and ac-
curae survey Of the reservoir and its catchmen basin,
deem it not advisable, If even it proper to enter
into any calculation, in advance OF the report of that
survey In grave question like this the best possible
evidence should be presented, and ia this respect the
Besides the method of arriving at the available
supply of water by calculation, there is another for
which respectfully and earnestly ask attention
it is the gauging for year much longer posi-
be- the water OF the creek. This was first suggested
BY Mr. Lorraae, and is now in operation. The results
obtained in this way present fewer objections and ad
dress themselves the apprehension Of every mind
The water th flows down the creek is obviously the
available water after having been subjected eyapo.a.
ton absorption percolaon and every other conceivable
If n he nada g
the difference between the evaporation from the
of the reservoir and that from the land Submerged
because the creek is guaged before the reservoir is
filed it appears TO give TOO much-but on the other
hand the area submerged is greater than that of the
water and the bottom being horizontal is most favorable
for evaporation so that the two would nearly balance
and even his correction may be omitted and the guam
tity flowing down the creek taken as the available
supply Ill -.-..
down a stream may be collected 10 reservoir. The
Quantity OF available water obtained your Eng-
neers can show that it Is among The simplest appli-
cations oflheir science, to construct embankment
dam across the gorge OF the valley that shall retain
the whole or much OF this waller as shall be re-
quired for the supply OF the summit level with all its
contingencies
tits well known ihatmany of the most important
mails 10 the world have their summit levels supplied from
reservoirs and would be easy to point out numerous
instances where rain wafer thus collected has been APP
piled to economical uses very lsrge'scale. shall
content myself with one-the Shaws Water Works.
The inhabitants of Greenock were anxious to pro
cure a supply OF water for domestic use. Engineers
were employed who examined the scanty streams in
the vicinity, and reported uaavorably At length Mr..
Thorn examined The surrounding country calculated
the supply OF rain water that could be econonsed,
and astonshed the good people OF GreenOck by show
ing that "not Only water spiticient Tor domestic anc
municipal purposes might he brought in, but that
water power might be made available tar me
chanical purposes very great amount. Ills scheme
has been carried into eff ct. HIS calculations have
been more than borae out, and the rap rise o Gree
neck AZ an emporium OF commerce and Industry ia, 10
no small degree due TO the bold foresight Of the engi
OF the Shaw's Water Works"
DR.. Kane, the eminent chemist, who was himself
Investigating this question lor Ireland, writes still fur
ther
'Anxious to obtain information as to the actual con-
ditiOn and performance Of these remarkable Water
Works aud unable personally to visit Scotland have
to thank OF tie most emueAt men that country has
presented 10 the practical sceuces for note dascrp-
i've of the power that Is now produced by the water so
economsed Mr. Scott Russell replied TO my enquiries
IN the following words;
NY Dear Sir | had hoped to have been abe to get |
full and very satisfactory account Of the Saaws Wa
iar Works drawn up for you by a Competent enp- |
Near resident 90 The spot; by find that many delays
ara occurring 10 prevent thls that now write to beg
you Will not calculate upon u; had NY own time per
miiied should have done so myself bat now Just when
/ might have hoped for leisure am taken from home
i have, however procured Z copy oil no~ scarce
pamphlet; printed some thirteen or fourteen years ago
before the works were finished, giving some account OF
them g. proposed | may Id Tor your Information
thai everything predicted has been satisfactorily aod
fully accomplished; that the comp any no" uE'a9
fair per centage their pta though at present
only one halt Ofthe capabe Of the reservoir are EN-
pioyed. There has in all years been an abundant sup
ply,