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The outcome of this wide-spread interference with the 

 established condition of natural drainage has given ground for 

 the almost universal testimony that streams which in former 

 years held a continuous flow throughout the summer no longer 

 run in the dry season. The reservoirs at their head waters are 

 emptied and the supply of ground water is early exhausted by 

 the artificial drainage in their basin. There is also a consider- 

 able concurrence of opinion that, in the smaller streams at 

 least, the floods come more suddenly and rise to greater heights 

 than they did in former years. The "wash" along the banks 

 and consequently the amount of silt carried in suspension by 

 the flood waters are thus increased. 



The presence of under-drainage undoubtedly facilitates the 

 discharge of such water as reaches the drains, but this impetus 

 is in large part counteracted by the greatly increased power of 

 absorption of the soil when thus drained. Heavy rains upon a 

 soil already surcharged with moisture may lead to even a 

 greater run-off than the same rainfall upon the same territory 

 rendered porous and capable of absorbing and retaining, for a 

 short time at least, a large amount of moisture. 



From many points of view the subject of the effect of drain- 

 age of the catchment-basin upon the flow of streams is one of 

 interest and importance. For its adequate discussion records 

 of a long series of years of the stages of tributary streams and 

 the river both before and after the installation of the drainage 

 system are needed. With a view to throwing some light upon 

 the possible effect of drainage upon the floods in the main river, 

 and consequently upon the plankton, I have tabulated the 

 fluctuations (in excess of .25 foot in 24 hours) in the river level 

 at the lower gage at Copperas Creek for an earlier and a recent 

 period, each of five years. The earliest authentic records which 

 I have been able to secure begin with 1879. This antedates the 

 completion of a considerable portion of the artificial drainage 

 of the river basin. I have accordingly chosen the records of 

 1879-1883 inclusive for comparison with those of 1892-1896 

 inclusive. This choice is unfortunate in one respect, for the 

 earlier series lies in a period of heavy rainfall and the later in- 



