THE OHIO RIVER FLOOD OF 1884. 74 
143,679,798,960 cubic feet. 1 The streams of the valley must expect to carry 
one-third of this bulk, i. e. a daily average should give the streams a supply 
of 131,214,428 cubic feet. A rainfall of six inches over the entire valley is a 
dreadful calamity, and that is not far from the estimate given of this flood. 
Experience with this valley shows with great certainty that the break-up of 
winter will be the annual occasion of great overflows. This year it reached a 
greater magnitude than ever before known. Let the estimate be one-tenth of 
its catch, 14,367,979,896 cubic feet, getang out of the valley in thirty days, or 
at the rate of 4,789,326,632 cubic feet a day. Now we have no power of hand- 
ling this immense bulk of water after it gets in motion. But this is not all. 
This is the estimate upon clean water. It is very far from being that by the 
time it reaches the principal streams and the main river. Things that will come 
to the top are visibly floating in the shape of drift ; things that will not water- 
log, i. e. gravel and silt, are clogging the flow and filHng the space it should 
occupy. 
The bed of this river affords sufficient room for any supply of water to pass 
that ought to find access to it. Its lowest depth and narrowest width between 
Pittsburg and Louisville are to its highest and widest safe gauge as i to 1320. 
If this margin of expansion be not enough no digging or leveeing of human 
devising will long hold its floods in restraint. If we can reduce this variation in 
flow from I to 10, a great deal would be gained. A vast improvement to the 
useful purposes of the river if the variation between extremes were not greater 
than from i to 3. For illustration, say its lowest stage be 400, its highest should 
not exceed 1200 in cross section. If by well-placed catches averaging eighty 
acres to every 25,000 drained, having a vertical margin of from 7 to 10 feet be- 
tween their low and high water discharges, that the one should not exceed the 
other more than ten times, we would I think find a solution of the troubles now 
besetting the drainage of the Ohio Valley. 
The streams of the Ohio Valley have no storing capacity, but being narrow, 
deep, and for the most part of steep slope, they hustle their catch of water into 
the main stream with undue haste. Room should be found in the smaller 
streams and near the top of each watershed for storing its extreme catch, say a 
six-inch rainfall, so that all of it would not leave the watershed for thirty days. 
A 1,000 acre watershed in this valley would give a daily flow of 990 cubic feet. 
A 25,000 acre watershed twenty-five times that, 24,750 cubic feet, daily flow. 
Under the circumstances of the flood of 1884 the catch of the watershed would 
be 2,709,750 cubic feet, over 100 times its daily output. It should be made to 
stand upon the order of its going over sixty days, i. e. for sixty days the reser- 
voirs should have an outflow of nearly twice the average for the year. Make 
the stream capable of delivering two and a half times the 24,750 cubic feet, with 
1. Though this seems a great array of figures is it the smallest I can make. And I am sure 
that the larger figures would only make the demand more evident for handling the bulk in de- 
tail. One estimate of this total annual catch gives the vast bulk of 20,689,887,828,600 cubic feet. 
This would greatly increase the daily average ; but either set of figures is vast enough to demand 
thoughtful consideration, and that too in the line indicated by the article. 
