74 



Plate 27.— Classification: SYSTEM Lacustrine, SUBSYSTEM Limnetic and Littoral, class Unconsolidated Bottom and Un- 

 consolidated Shore, subclass Mud, WATER REGIME Permanently Flooded and Semipermanently Flooded, water chemistry 

 Fresh, special modifier Impounded. The photo shows Foster reservoir at full pool. The semipermanently flooded area is 

 inundated in this photograph but would be drawn down from October through March. (Linn County, Oregon; July 1975; 

 Photo courtesy of U. S. Corps of Engineers) 



