The Work of Running Water 



George J. AIiller. 



[Editor's Note. This article and the one that follows give an out- 

 line of the nature-study method of presenting a geography topic by field 

 work and a student's reaction to the same.] 



No attempt is made in this article to discuss all phases of 

 the work of running water, but rather (1) to outline what may 

 be studied readily along nearly any river to be found in a climate 

 having sufficient rainfall for a permanent stream, and (3) to 

 suggest a method of studying such work in the field with a 

 class. Each of the topics here discussed may be presented to 

 the student as a problem to be answered by studying the subject 

 in the field. Each phase of the subject may be studied on 

 separate field trips, e. g., a trip to study the work of erosion, the 

 work of deposition, etc., or all phases may be studied at once. 

 The method to be followed will depend upon the ability of the 

 class and the object sought by the instructor. Personally, I have 

 my classes study all phases of the subject at once, and require 

 an organization of the field work in a written report. For field 

 study of running water the small stream is better than a large 

 one. 



Running Water. 



What are the sources of running water? How does the 

 water run off? What makes it run? To the first problem the 

 student will answer rainfall (including snow and ice), to the 

 second rivers, and to the third gravity. The study of a small 

 permanent stream during the dry season, however, will convince 

 him of the vital importance of ground-water — springs and seep- 

 age — in the maintenance of stream flow. He will learn also 

 that seepage is far more important than springs in maintaining 

 most streams. A tributary of this stream may be dry. H so, 

 he will solve the problems — When does a valley get a permanent 

 stream? Was a valley there before the permanent river? Why 

 do some valleys have streams only when it rains? Why do some 

 streams become dry during the summer? In general, his answer 

 that the water runs off in rivers is correct, but observation 

 during a heavy rain will convince him (1) that some of it runs 

 off in sheets, (2) that slight irregularities in the land surface 

 cause the water to concentrate in the lower places. (3) that these 

 concentrated parts flow faster, erode faster, develope small gul- 

 lies or "washouts." and (4) that these gullies grow in size with 

 successive rains. May they grow into ravines and large valleys? 



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