guishes it from adjacent sections. Within such sec- 

 tions, ecological relationships between plants, soil, 

 and climate are essentially similar, so similar manage- 

 ment treatments give comparable results and have 

 similar effects on the environment. They are consid- 

 ered to be biological and physical areas of a specific 

 potential. 



In addition to being relatively undisturbed (no 

 major land disturbing activities within at least the 

 last 5 years), the selected watersheds were also small 

 (10 to 200 square miles), more than 90 percent forest 

 or range land or both, and had a minimum of 5 years 

 ( 1 years when possible) of water quality records that 

 included total dissolved solids, water temperature, 

 suspended sediment, and dissolved oxygen. These 

 data, primarily from STORET,' are presented in 

 table 7.12 to show water quality for these parameters 

 by ecoregion. 



The quality of the water in all of the undisturbed 

 watersheds exceeds the minimum water quality stan- 

 dards of most States. There is, however, a substantial 

 amount of variability in the various measures of 

 quality among the divisions, provinces, and sections. 



Controlling water pollution and improving the 

 quality of the Nation's waters are important public 

 policy objectives. The Federal Water Pollution Act 

 Amendments of 1972 (Public Law 92-500) established 

 a goal of eliminating by 1985 the discharge of pol- 

 lutants into the Nation's navigable waters; an interim 

 goal was to provide by July 1, 1983, wherever attain- 

 able, water quality sufficient for recreation and the 

 protection and propagation of fish, shellfish, and 

 wildlife. The Administrator of the Environmental 

 Protection Agency is charged with directing efforts to 

 achieve these goals. 



The Federal Water Pollution Control Act Amend- 

 ments of 1972 defined two broad sources of pollution 

 — point source and nonpoint source. Point sources 

 are those that generally originate at a known loca- 

 tion, are transported through pipes, and are dis- 

 charged into receiving waters at a fixed point. Non- 

 point sources, on the other hand, are diffuse in origin, 

 their transportation into receiving water is not well 

 defined or constant, their discharge occurs at many 

 diffuse locations, and depends heavily on weather 

 conditions such as rainstorms or snowmelt. 



The initial thrust of the pollution control efforts to 

 reach the goals set forth in the Federal Water Pol- 

 lution Control Act Amendments was related to point 

 sources. Those programs were so successful in con- 

 trolling point source pollution that both the Environ- 



Water quality is in large part a reflection of the land and vegetation 

 from which the water flows. 



mental Protection Agency'" and the Comptroller Gen- 

 eral" identified nonpoint source pollution as the 

 limiting factor in reaching the stated goals in many of 

 the 246 hydrological drainage basins across the 

 Nation identified by the Environmental Protection 

 Agency. '- 



'STORET, an acronym for the Environmental Protection 

 Agency's quality data storage and retrieval program. 



'"U.S. Environmental Protection Agency. National water 

 quality inventory, 1977. report to Congress. Unpublished draft. 



" The Comptroller General of the United States. Report to the 

 Congress. National water quality goals cannot be attained without 

 more attention to pollution from diffused or "nonpoint" sources, 

 December 20, 1977. 



'2 U.S. En\'ironmental Protection Agency. STORET user hand- 

 book. Office of water and hazardous materials, Washington, D.C., 

 June 1977; and associated map EPA-STORET major/ minor river 

 basins, March 1973. 



302 



