OBSERVATIONS UPON THE EROSION IN THE HY- 

 DROGRAPHIC BASIN OF THE ARKANSAS RIVER 

 ABOVE IvlTTlvE ROCK. 



By JOHN CASPER BRANNER. 



In October, 1887, I began and carried on for one year a 

 series of observations upon the Arkansas River at Little Rock, 

 for the purpose of determining the efficiency of that stream as 

 an agent of erosion and transportation. These observations 

 consisted of a series of thirty-two measurements of discharge, 

 three hundred and sixty-five gage readings, one hundred and 

 sev^enty-nine determinations of matter carried in suspension, 

 and a similar number of determinations of matter carried in 

 solution by the river water. These observations were so dis- 

 tributed as to be as comprehensive as possible, embracing all 

 the varying conditions of weather, temperature and rainfall ; 

 when the river was rising, when it was falling, when at a 

 standstill ; when low, when high, and whenever there was 

 any considerable change in the volume or character of the 

 water.* 



Method of Observation. \ — A cross section was carefully meas- 

 ured 1,200 feet above the upper bridge, a place in the river 

 where there was least chance of any marked change occurring 

 within the time occupied by the observations. At the place 

 selected one bank is of rock and the other of tough clay. 

 Floats were sent through this section at transverse intervals of 

 twenty-five to fifty feet, and their positions as they crossed the 

 section were located by a transit, and the time occupied in 



* This paper deals only with such conditions and changes as are pos- 

 sible in a given section ; it does not consider the effects of curves 

 or varying depths of the channel. 



t The field observations were entrusted to Assistant Chas. E. Taft, an 

 able civil engineer of wide experience. 



