The Memphis appeal. [volume] (Memphis, Tenn.) 1886-1890, 1888-07-23
one and two-tenths below. In Lake Lee,
about eight-tenths below.

Again, below Mayersville, ut Ben Do
mond, the flood Of 1883 was two-tenths
below extreme high water (lSSD. At
Filters Landing, three-tenths below. At
Arcadia, foot below. At Duvall's, two
feet below. At Brunswick, two feet and
three-tenths below. At Vicksburg, four
feet and eight-tenths below.
''lf we were sure that the same invariablo
conditions were to remain, il would be no
very difficult matter to fix from these data,
grade for our levees which should be safe
against flood like 1882. With the river
out Of it, banks and against the levees
throughout the whole reach under consid-
Grafton, and entirely free from the disturb
ing influences OF either tributaries or out
lets, there should be no great difference in
general dimensions Of cross sections for the
upper four OF five feet thereof and conse-
qucntly rise Of a given amount above the
high water plane OF this year, ut Arkan.
sas City, ought TO be attended by a rise OF
nearly similar amount throughout the
whole inclosed reach.
"Now observations have been taken by
the engineers Of the Mississippi river
commission Of the discharge at various
points, from which itappcar, by conserva-
tive estimate, that II the whole Hood OF 1882
had been confined within levces the gauge
ut Arkansas City would have stood at a
stage Of about iorty-nino feet, or two feet
higher than II actually reached. The
gauge reading ut this same point during
the flood just past was I5.2. In other
words, n grade 3.S feet above tho high
water of 1883 would probably have been
nearly on a level with the flood OF 1882 II
confined, and levees built 10 such grade
would have been Just awash. OF course
we are all we'll aware that IL is not safe TO
build lcvces on any such principle. There
is margin Of safety required for protec.
ton against settling or degradation OF any
kind, mistakes OF calculation or construc-
ton, erroneous fixing Of grades, local ir.
regulariiies OF high water slope, effect Of
winds and waves, an well ~ by way Of
making provision for perhaps even greater
Hoods. Add 10 this that the data from
which we make our calculations are them
selves subject 10 many sources OF error,
and that the principle on which We are
proceeding II by no means vigorously
true, and we shall come to the
conclusion that a grade five feet
above 1883 is low enough, allow
ing only n margin Of IL feet for all the
contingencies alluded 10. This estimate
applies with propricty only 10 that portion
of our line below Arkansas City, but il
affords some kind OF u criterion above that
point, subject tO correction for local pecu-
harities. According 10 this mode OF rea-
soDing, our loyees In upper Bolivar, rs far
down ~ Mound Landing, are high enough
already, and our attention must be turned
to the unchanged levees below that point,
especially 10 the reach between Lake Lee
and Filters Landing. This implies a rails.
ing Of our present grade in those localities
nearly two feet There is, however,
great deal Of old lcvco that is already high
enough, having been constructed under
the system OF grades adopted in 1850, which
was, for DcSoto and Tunica counties four
feet above high water, for Coahoma 4.5
feet, for Bolivar and Washington five feet,
aud for lssaquena 5.i feet.
"ln these calculations no account has
been taken Of the effect Of scour, and yet
II is an element that should not by any |
means be forgotten. The position seems |
10 be correct that the high water slope Of |
streams Of the type Of tho Mississippi IL
nearly invariable, depending on the sta.
lility of the soil, aud subject only TO local
disturbances, particularly from bend effect
and being only slightly effected in
permanent way by diminu,ion of volume
rom crcyasscs or otherwise. Should the
volume thus diminished bc restored 10 iis
original dimensions, the high water slope
will eventually become the same. or
little lea, owing % the general law that
the greater the volume the less the slopc.
II Is evident, however that during this
period Of rcadiuslmcnt there will be con.
siderable elevation OF the high water sur.
face in the reach 10 which the volume |
formerly distracted Is suddenly restored, |
~ has been abundantly excmphiied dur. |
ing the past food. Throughout this reach |
the slope will bc iirst naticncd, then nor.
mai, then stcepcncd, so that tho scour
must bcgin nj the lower end thereof and
work upward. What time may be- con.
sumcd In this process IL a matter on which
there Ia great diversity Of opinion. For
our purposes this scour cannot bc taken
into account-for We have not time 10 let
II operate. To be- safe, We must proceed
~ though the very next food were 10 bc
~ high ~ 1889, and build our lcyces nc.
corIingly.
II Is believed that the grade recon.
mcndcd, though certainly not 10 high as
II desirable. will bc sufficient 10 keep out
~ great Hood ~ 1882 and Il IL believed
that 1852 was no greater. Above Green.
vile Il attained less hight than 1852.
Why IL should have been NO high below, |
do not know probably on account Of the
recent completion Of the lcvcc system nj
that time throughout the reach affected,
joined with the effect OF back.wuicr from
the lazoo u NickshuV. In the language
Of the United States lcycc commission Of
1874 "Thc Hood Of ls62 must probably
always remain source Of anxious per
plcxity Ia engineers having the direction
OF the lcycc system OF the Mississippi"
II Is hoped that with the complete OK.
clnsion Of blck.wnicr from tho laEoo
basin these excessive nights from Provi.
dcncc 90 Nickshurg may never again occur,
and that even the gauge reading Of 1867
and 1854 at the latter pOint-forty-ninc
bet, may not be- reached in future.
"a complete line oi levels was run over
the lcyccs Of the entire district last sum.
mcr, and from the notes Of that survey and
NJ the now constructions and repairs II the
season Just past, new set Of pronles has
been prepared from which careful csti.
mates have been made Of the amounts
necessary 30 raise the whole line to the
grade recommended These estimates arc
herewith presented. but are not incorpor.
atcd In the report, lur the reason that they
somewhat exceed ability, and Il Is recon.
mcndod that the all Of the Mississippi
river commission he asked In carving
them out. Surveys an now In progress
on the Arkansas side, under the direction
OF Capt Rosscll, corps II engineers, United
states army, with view Of asccriaining
the amount necessary 10 raise the Arkan.
sas lcyc,S ~ u raic padc-andi Il isthought
1 that Ii such a work h untiertakon law the