Chapter 18 



STREAM-CHANNEL CONTROL 

 Stafford C. Happ 



Geologist, Corps oj Engineers, Department of the Army 

 Kansas City, Missouri 



Stream-channel control is a term commonly applied to engineering 

 projects intended to provide deeper water for navigation, hasten the 

 runoff of flood waters or confine them within restricted limits, improve 

 drainage of adjacent lands, or check stream bank erosion. 



The principal channel-control methods are canalization of natural 

 rivers by dams, with locks to pass boats or barges ; open-channel regu- 

 lation by training dikes, jetties, or wing dams to deflect channels into 

 a more desirable alignment or confine them to lesser widths, with dikes 

 or dams to close secondary or other undesirable channels and thus di- 

 vert or concentrate the stream into a preferred course and, in some 

 cases, ground sills, or weirs, to prevent undesired deepening of the bed 

 by erosion ; or dredging or other forms of excavation to enlarge existing 

 channels, remove local bars or other obstructions, or form new chan- 

 nels which may be either larger, straighter, or different in alignment. 

 Bank revetment by paving, riprap, or protective mattresses to retard 

 erosion is commonly undertaken in connection with either of the 

 methods of regulation, or often independently for protection of border- 

 ing lands. Earth levees and concrete or masonry flood walls are often 

 built to confine flood waters in connection with channel-control proj- 

 ects. Impounding dams or reservoirs contribute to the channel control 

 by restricting the size of flood flows and increasing low-water flows. 

 Propagation of willows or other vegetation is often undertaken to aid 

 in bank stabilization on small streams. 



A large proportion of the major rivers are now extensively affected 

 by channel-control works of one type or another. In the United States 

 most of the larger river projects are carried on by the Corps of Engi- 

 neers of the Department of the Army. Within the past 15 years there 

 has also been very widespread construction of channel-control projects 

 on small streams throughout the country, especially bank protection 



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