The Greenville times. [volume] (Greenville, Miss.) 1868-1917, 1880-04-17

aetic. DIR. Marshall quotes Capt. 8
}. Allen, United States Engineer, Q
o call attention to the seven re-
ervoir sites described by him,
md with great exultation points {
o . long row Of figures, which l
'eally Look very formidable, show |
ng that their united capacity to j
tore up water is lOo. .0o0. .00o. 900
;ubic feet. Let Us see what this
amounts to.
In oroer to dispense with lcvecs
re must not permit the river to
rise beyond 10 feet above low
water at vicksburg. But It has
gone lai feet higher than that,
At this stage, 40 feet, tho sand bars
are all covered aud the surface
width IL from bank 10 bank. avera-
ging at least 1000 feet. Without
considering the water which flows
outside the chalnel, lot us SEQ how
much win pass any given point
during = period Of one hundred
days, above the 10 feet mark, At
extreme high water. A volume
Of water 1000 ieet wide an I - l.s
feet deep. passing at tho rate Of 8
feet per secoud, which 10 loss than |
six miles per hour, will amount In
100 days to $1,000. 900, 900
cubic feet Of water to bc withheld
or sii times ~ much a. the lcves
reservoirs mentioned have capacity
10 hold. II may be objected that
tho river does not continue at 90
high astagc for 80 long time, but
we hayc left ont Of the calculate on
all Of the lateral water flowing
over tho adjacent lowlauds, which
PROBABLY will exceed in quantity
that above 40 feet IN the channel.
The question then is, can eligible
sites be found for the two hun
dred and forty.onc reservoirs, OF
average capacity, equal I" those
soyen, which will bc needed to re-
strain al this water 7 ltis possible
that they can bc found, but the
probabilities orc against II. At
Iall events, thorough examinations
should be malo before we jump
at conclusions Oh this subject.
Tho country about tho head wa'crs
Of tho Upper Mississippi, where, |
believe, all Of ths reservoirs sus'
gcsted arc located, 10 peculiarly
susceptible to this application, be-
Ing charactcrizal BY hatncs', an''
tho existence Of nun srou' lakes
but how about tho other tribata'
rios /? Thcir sources are for tho
{ most part In M ,nMtainpas reyion'
whore the SAM facilities prob sbly
, do not exist, for ths constra ,tion
Of reservoirs. In comparativcl!
fiat lands sito. may DO found whcr
| long anil low dams will coniin'
{ much water, by covering lars
: areas. Il can then b. don
economically AMI with little riss
J. but In elevated regions where tn
II ground l. worry uneven, . high dai
J. win cover but = small area, and th
II dificultics and costs increase eno'
+ mously with increased height .
r dam.
. English engineers, IN India, cor
/, structed costly reservoirs to stoi
!. iup watcr for purposes ofirrigatic
!. and there was much didl;ulty
h iudlne practicable sites. II
!. structure cost large sums, aud u
!. lands irrigated werc heavily take
Il to pay . per ccntays on tho outla
~ But there 10 great difference y
Z tween reservoirs for irrigation Al
l. for navigation.
- I will close this paper with
=. plea for s'Levees." A shipwreck
~ man will not leave even q floaii
.v spar, which has borne him safe
:, until he Il suro Of reaching so
- :. better craft. I believe that noa
ho oil engineers, as we'll as piante
,or who arc practically converse
,vo with thu subject concur In the
,.l lief that lcvees alone can certal'
al be relied upon to protect the sr'
81 bulk Of the alluvial lands ff'
=. overflow. flH
=! Among the earliest settlers alo
no the lower Mississippi river,
olo construction Of levecs became
'na obvious necessity. The plau
mo tlon being more or less isolat
=! l'es each individual protected his O.
Inc belonging o. we'll a. he might.