The morning news. [volume] (Savannah, Ga.) 1887-1900, 1893-08-20

sHatNAaHttNAAs NHtAfiNs ~ VI carter WAS
lected and requested by both the com
missioners and by Mai Blaudford 10 do
the work On the LIST of June Messrs.
| Dale ana Chaplin. accompanied by Mr.
I OSlna, went out and measured up the
work done by the steam dredre on that
attenOon-again on the Both Of June they
took Col. VIM, the city engineer. out
with them and again measured up the
work
AT the meeting held on the 25th and
9th of July, Chairman Dale sought to iu-
! troduce the figures of Col Winn and MIR.
| Usina and have them accepted by the
board. This was objected to- Col
! Winn's figures represented the work done
at something like l2,4O0 or $500 cubic
| yards. Mr. Usina's figures conincided
with those of Col Winn differing only
| measurements aggregated % Sol cubic
! yards-about IS per cent. more than
! either of the above. This determined the
majority of the commissioners to ask
/ Capt. Carter to appoint some one to meas
| ure up this particular work. A resolu-
| ton was introduced by Commissioner
! Charlton and adopted asking Capt O. NJ.
| Carter "tO engage competent engineer
! to calculate, under his direction, the
amount of material taken from the
| Casey canal by the dredge, from the be-
! ginning of its operations to July 1, 1898,
and to report as early as August 9th,
| prOx., or sooner if possible"
Capt. Carter appointed Mr.. r. S. Bur
nett
Mr.. BURNETT's REPORT.
Report of Mr.. r. s. Burnett c. E.. on
amount of material removed from New
! Casey canal from beginning Of operations to
| July /, 1898.
| Savannah, Ca. Aug. 10. 1s93.-The Honor
| able Commissioners of Chatham County Ca:
Gentlemen:-"ln compliance with your reSo-
! tuition OF July y, 1893, Capt. o. M. Carter
! corps of engineers United States army. des-
| ignated me to make the necessary measure
| ments and calculations to determine the
amount Of material removed by the county
! dredge in making the excavation for the New
| Casey canal, from the beginning OF its opera
! tion to July /, 1893.
| l would respectively state that all informa-
| ton needed was cheerfully given me by the
| county engineer and his assistants and every
| facility and courtesy was shown me in making
my measurements. All drawings, as well as
| note books containing the original field notes
| from which Maj BlaudfOrd computed the
| quantities of material excaVated by the
! dredge for his reports to your honorable body,
quest.
CONDITION OF CUT.
Had this cut been made through hard, stiff
| earth, rock or clay, simple measurements of
! depths and widths made after the cut had
| stood for six months subject to heavy rains
| would readily have determined within very
! few cubic yards what had been taken out by the
dredge On the contrary, this cut is rough
and irregular, through swamp marsh com
! posed of decayed vegetation, alluvial deposit
and marsh muck, all of which are easily
| eroded and have been washed by heavy rains.
! The eXcavated material has been dumped on
| the side of the cut, its weight causing the
! sides to press in and the bottom to Ooze up
ward Cattle running at large and seeking
water have trampled down in many places
| the soft sides of the newly made cut. StumDs
/ the EDGES Of the Cnf have hnnu blasted
| throwing considerable quantities of mud and
| other material into the cut, and making the
| problem Of determining the amount of mate
| rial the dredge removed anything but simple.
CUBIoAL CONTENTS OF CUT.
What your honorable body required was
! the amount of material handled by the dredge
while it has been at work, and not what the
| cubtcal contents of the cut as it stands to-day
! are.
1t would be absurd in view of the above
! mentioned facts, to state that the amount of
| material handled by the dredge was only
| what the cubical contents of the cut, as il
now stands indicate. l consider that the re-
| port submitted to your honorable body by the
| county engineer, made up from daily record
of work done, must be more nearly correct
| than any figures obtained by measurements
| made at this late day.
MEASUREMENT OF DUMP-PILE.
In measuring the dump-pile, as a check or
the measurements of the cut, have allowed
/ 10 per cent. of material excavated foi
| nature of the material.
| The measurement of the dump-pile was
made with some difficulty, and allowance had
to be made for material washed away and for
| settlement. Material of this nature when
| first eXcavated and loosely dumped into an
| embankmeDt on the side, at first measures al
| least 20 per cent more than when in its origi
| nal place; yet, when placed in embank
| ment and at repoSe, it gradually settles and
| shrinks into less bulk than it occupied be
| fore being excavated.
I
The material trampled in by cattle, as well
| as that thrown in by blasting stumps on the
! sides, consider Offset by the amount of
material left standing in the cut in the shape
| of StumpS and adjacent mud.
The weight of material deposited on the
| right side OF the cut, forcing the side in and
| causing the bottom of the cut to OoZe up; the
| tramplihg by cattle and the blasting in of the
| sides; the wash in from the dump pile, caused
! by heavy rains washing down the rough
| slope, and the general sitting up of the bot
| tom, have filled up the cut to an average OF
| one foot in depth, and reduced the average
width very materially throughout its entire
| length and depth.
sHRINKAGE OF MATERIAL.
Trautwine, on shrinkage of embankments
places puddled clay at % per cent. and loose
| vegetable surface soil at Is per cent The
| material eXcavated at Casey canal resembles
a mean of these two kinds. 1t has been
| covered for years by water, and, when mixed
| by the dredge grapple in excavating and
| dumping it on the side, it shrinks to at least
% per cent of that reported from day to day.
EFFECTS SIMILAR To THOSE MET WITH AT
NEW CASEY CANAL.
| The instances where the above allowances
| have been made under similar circumstances
| to the New Casey canal are numerous, and /
| cite few of them.
In eXcavating through the swamps along
! the Panama canal the official reports show
| that in some instances the bottom of the cut,
| originally dredged to the required depth, had
| been raised more than nine feet by bank
| pressure, forcing the greasy clay or marsh
| mud up underneath. In the ParaisO section
| 30 600 cubic meters were washed into the cut
| by heavy rains. Piles driven on the sides of
| this same cut to anchor the railroad embank-
| ment-though driven verucally-were found
| standing at an angle of 45o, they being pushed
! or forced this much out OF line by bank pres
| sure.
In all calculations on this canal from 20 to
| . per cent. of material eXcavated was eSti-
mated for wash-in and bank pressure, and,
| In many cases, this amount was largely ex-
| ceeded in the practical work, so much so that
! where cut of 30 feet in depth had been made
| a few years ago it was found impracticable to
| float out the dredges engaged in the excava-
| tion work. the cut having filled up in places
| more than twenty feet
| Dredging through the marsh islands in the
| vicinity of Savannah, in the inside passage,
! and at other points, has demonstrated what
! bank pressure viii do in forcing material up
| from the bottom and out from the sides Of
| cuts.
| In 1890 a channel 100 feet wide and 10 feet
| deep was cut through the lower end of Marsh
! Island above the city Seven weeks after the