BYBEE-MALOTT : THE FLOOD OF 1913 



207 



and the prairie region. Should not, therefore, forests which give 

 off into the atmosphere much larger c^uantities of moisture than a 

 free water surface, have at least a similar influence upon the region 

 into which the prevailing air currents flow.' 



Then follows the interesting studies made by Professors Francis 

 E. Nipher and George A. Lindsay on the rainfall of the State of 

 Missouri, and the discharge of the Mississippi River at St. Louis, 

 and at Carrollton, Louisiana. To quote from his article: 'Nipher 

 found that the average discharge of the Mississippi River at St. 

 Louis during the ten years ending December 31, 1887, was 190,800 

 cubic feet per second. The amount of water falling upon the whole 

 state during the same interval was 195,800 cubic feet per second, or 

 within two per cent of the discharge of the Mississippi River at 

 St. Louis. If, however, a comparision is made between the total 

 rainfall on the basin draining past St. Louis, and the river dis- 

 charge at that point, it appears that the drainage area of the Mis- 

 sissippi and the Missouri Rivers above St. Louis, is 733,120 square 

 miles, or over ten times the area of Missouri. These figures show 

 that a small portion of the total rainfall over the drainage basin 

 of the Mississippi River is led into the rivers and conducted back 

 to the sea. It is evident that by far the larger portion of the pre- 

 cipitation that falls over the drainage basin is evaporated back from 

 the land into the atmosphere, and is not returned to the sea through 

 the medium of drainage. These figures show further that the source 

 of precipitation of the Mississippi drainage area is from evapo- 

 ration over the land and not derived from evaporation over the 

 sea. Mr. Lindsay computed the discharge of the Mississippi 

 River at Carrollton, Louisiana, and found that the average for 

 fourteen years was 117 cubic miles per year, or 545,800 cubic feet 

 per second, which is less than three times the precipitation over 

 the state of Missouri.' 



It seems to the writers that forests have something to do with 

 the amount and distribution of the rainfall of the Ohio Valley. 

 It is impossible to say, how much, until a long series of experiments 

 over the entire drainage basin of the Ohio Valley are perfected. 

 Owing to the rapid decrease -in our forest areas these experiments 

 should be carried out as soon as possible, for it takes many years 

 to replace a forest once it is entirely removed. 



Deforestation in the northern part of this State has had less 

 to do with the increase of flood frequency and height than the great 

 amount of ditching that has been done in the last forty years. The 

 ditching has been of two kinds; first, large open ditches known as 



