242 



ARBORICULTURE. 



THE LEVEE AT LAWRENCEBURG, INDIANA, BEING STRENGTHENED WITH BAGS OF SAND 



while again they separate tO' a cHstance 

 of three or foiir miles. 



Originally they occupied the valley as 

 a great plain, the strata on either side be- 

 ing identical ; and through this plain the 

 river bed has been plowed by the force 

 of ice and water until at present the bed 

 is from 400 to 500 feet below the hill 

 tops. 



Usually, where the abrupt hills ap- 

 proach the stream upon one side, there 

 is a broad fertile valley upon the opposite 

 side O'f the river ; but at Cincinnati the 

 hills are but a mile apart, confining the 

 water to quite a narrow valley. 



If the rainfall throughout the entire 

 200,000 miles comprising the watershed 

 of the Ohio' \"alley was an average of 

 ten inches in a month's time, it would be 

 equivalent in volume to a column of wa- 

 ter one mile square and thirty-one miles 

 in height, all of which would, under our 

 present condition of treeless country, be 

 forced with great rapidity through the 

 present bed of the Ohio River in order 

 tO' reach the Mississippi and, finally, the 

 Gulf of Mexico. 



It is ])lain that every obstruction 

 placed in the way of this enormous body 

 of water, as narrowing the channel with 

 piers, or raising it by dams, must neces- 

 sarily raise this surface proi>ortionately ; 

 consequently the important question is, 

 Will the advantages afiforded to the 

 steamboat interests by increasing the 

 low-water stage by additional obstruc- 

 tions, equal or surpass the injury to the 

 man}' thousands who are affected in va- 

 rious ways when the flood waters flow 

 over their farms, enter their houses, 

 drown their stock, cut O'ff supplies, in- 

 terfere with all manner of land and wa- 

 ter transportation and the general demor- 

 alizing of business? 



It may not be an easy matter to regu- 

 late the flow of the Ohio so- as to secure 

 free navigation in low stage for boats 

 drawing nine feet O'f water ; but that is 

 not at all necessary ; a seven-foot: stage 

 ma\' be secured by dredging and blast- 

 ing, and there is no real necessity of an 

 all-the-year stage of more than six or 

 seven feet. 



If the channel can be excavated to con- 



