The morning news. [volume] (Savannah, Ga.) 1887-1900, 1892-10-07
TIE SPRINGFIELD DRAINAGE

something More About the Matter.
Editor Morning Nelos: Again am con
strained to ask space to answer the letter of
the honorable chairman of the drainage
committee of the city, appearing in your
issue Of this morning.
Mr.. Carson cannot deprecate more than [
newspaper controversy. Heretofore |
nave avoided them, however strong the
| proYocatlon. With great reluctance have
been drawn into CHS, but It seems the
gauntlet has been thrown directly at rue,
| lenge.
1 esteem Mr.. Carson as a gentleman and
as one OF the most active and efficient of the
city's council. For Col Winn. the CITY
engineer, l have high regard and believe
him TO be conscient iously striving 20 do his
whole duty. There shall be nothing per-
sonal in what have to say.
OF the article in last Thursdays paper, to
which Mr.. Carson alludes, knew nothing
until read it.
The many duties Of my Office allowed me
but brief time to answer Mr.. Carson's first
letter, and, as stated in my reply, only
endeavored to point out some Of his errone-
Gus extracts and quotations l will now call
his attention to others.
Extract ,. In my report give the fall
OF the main swamp from the Backwater
dam to the Savannah river to be about 81
foot IN 6,OOO," not so feet per mile - Call
ing attention to the words used by Mr.. Car
son III this extract" | quote from my re-.
port: "Of the area above the Bac kwater
dam some 545 acres drain directly into the
main swamp and the remainder is divided
into four minor watersheds, { y that Of Tel
fair swamp or North Fork, which
drains JAG acres and has fall of about 2
feet to the mile, C2) that of South Fork,
which has fall OF feet to the mile and
drains l, l76 acres, (3) Lamar's swamp and
its tributaries with a drainage area of 1851
acres, and a. Minis swamp which receives
the waters from TAP acres. Properly con-
structed canals through the two last will
have, respectively, an average fall of 5 feet
per mile for the latter and 9 feet
for the former" The first EXTRACT"
given near the top Of the second coll
umn is not correct. Discussing the
meteorological influences the report reads
Causing the average annual rainfall
az the Savannah station to exceed
by more than inches the annual
average given by Gen. Greedy in his
American Weather for the Savannah dis
trict." The 9TH extract in the same coll
umn is erroneous. Ny report says: "Ths
greatest rainfall recorded for any month
was in the yellow fever year. 1876, when
June had nearly 10 inches, etc"
g The 9th "extract" is both erroneous and
misleading. This is what l say: "A rain
falling at the rate of one inch in twenty
four hours delivers upon each acre Of drain
age area about 2. 5 cubic feet OF water each
minute.
"If upon one square mile area with i'm
pervious surface there falls ten inches of
rain in twenty-four hours, and two-thirds
Of this amount flows off in an equal length
of time, then the average rate Of flow will
be l79 cubic feet per second,
If upon the drainage area above the
Backwater dam such rainfall were pre-
cipitated in "a hours,.it would amount to
1SS, 4OS, 765 cubic feet, and the outlet would
be required to discharge in the same length
Of time 1875, sos, S43, or l ,454 cubic feet per
second.
Amy artificial channel cut for a stream
or any trunks or foodgates built to void it
must have ample waterway to pass the flood
at its maximum rate"
The greatest rainfall in twenty-four
hours recorded for Savannah was, accord
ing to Gen. Greedy, go inches in August,
1872, but a number Of greater rainfalls IN
the same length of time is given by the
same authority for the United States In
June, 1886, 21.4 inches in twenty-four
hours were precipitated at Alexandria,
La, and this was not entirely local, since
1873 inches fell during the same time few
miles to the southwark.
At Tridelphia, w. Va, July 10, 1888, 6. Q
inches we're said to have fallen Ia ffty-fUe
minutes. Our $40 inches In twenty-four
hours dwindles to insiguificance in this
comparison. Is it not so. Mr.. Carson7
Now, as to the canal-"97 miles long, IS
feet wide and Z feet lin water Deep
which the 10 inches OF rainfall in "a hours
would fill up, | answer you. Col Winn's
calculations in this particular are entirely
correct 1t would I'LL up a canal Of these
Dimensions, provided none of Il ran out
But what would be the use Of a canal that
would not let its water run off? 1t would
be a great deal worse than the present
Springfield canal, which is only about 2
miles long.
However, Col. Winn's suppositious canal
is an admirable illustration of the magni-
tude of the volume Of water which may
have to be provided for. / used somewhat
similar one in my report Of March II last.
You ask how this immense volume of
water is to be disposed Of. I answer either
enlarge and regrade Springfield, or dig a
new one of the proper dimensions to the
Savannah river, OF dig one sufficiently
large five to six miles longer TO the
Little Ogeechee by either the Shaw's swamp
or Buckhalter route. Unless it were
carried off Somewhere il would continue to
perpetuats the swamps, to render thou
sands of acres of valuable lands unculti-
ease and death rate by its stagnation. Garry
it where you please, but remember this,
however: Sea level is the same everywhere
along the coast Of Chatham county. You
cannot get below it by going to the Little
Ogeecbee. The rise and fall of the tides is
about the same, and the same distractions
from them viii be met wherever the outlet
of the canal may be made.
Regarding the three or four pages OF
tidal Influences upon the discharge" al
luded to in the sixth paragraph Of your letter
Of to-day, answer the same as l did IN my
last, and further add by quoting from my
report: Applying as above referring TO
the tidal diagrams), the tidal influences
upon the discharging capacity OF the sug-
gested canal in the table below, give the
average depths of the water flowing at the
outlet IN channels of different Innings,
for depths of rainfall of from
l to 10 inches in ttoenty-four
hours from oUer the entire area drained
by IL. - Then follows the table. The under
scoring is not in the report, but l use it
here to emphasize my answer.
Now to answer the last paragraph about
the 100000 brick. cannot say, nor do
believe that Mr.. Carson lCiLlfWLty mislsads
in abiding to this part OF my report in the
sense he does but do think he Is very for
getful Of what my report says. l will re-
mind him.
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