The intensive use of rivers and streams for industrial and municipal water supply, irrigation, transportation, hydropower, cooling of thermoelectric generating plants, assimilation of human waste, and commercial fisheries is summarized in a variety of compendia (CEQ, 1989; Guldin, 1989). Many U.S. cities developed along rivers because of the abundance of fresh water, the ability of rivers to purify human waste (or at least transport it away from population centers), and access to river-borne commerce. Thousands of years ago these same factors, coupled with renewal of the fertility of agricultural lands by deposition of nutrients and soil during annual floods, allowed humans to concentrate permanently in one place, giving rise to the first civilizations along the Nile, Tigris, and Euphrates rivers.
The fertilizing effect of floodwaters is utilized today in some developing countries (Welcomme, 1979), and was used at least into the nineteenth century in England where bottomland fields were diked for the purpose of directing silt-laden floodwaters into them. This practice, known as "warping," presumably resulted in increased fertility as well as a rise in the level of the fields. "Warp" referred to the load of silt and nutrients in river water, and a "fat river'' was one with an especially rich load (Seebohm, 1952; Whitlock, 1965). Today, dikes in lowland agricultural areas of developed countries typically are used to keep floodwaters out of fields, and chemical fertilizers are applied to maintain the productivity of the soil. Following their analysis of the Mississippi River from an energy systems point of view, Odum et al. (1987) conclude:
The annual flood is a potential resource that was effectively used by the original floodplain and deltaic system. By diking, channelizing, and making economic developments that were not adapted to the flood cycle, a benefit was often turned into a stress, a drain on part of the system, a pathological state.
Some attempts have been made to calculate recreational values of streams and rivers. The 1985 National Survey of Fishing, Hunting, and Wildlife-Associated Recreation (U.S. DOI, Fish and Wildlife Service, 1988) reported that a total of $17.8 billion was spent by 38.4 million fishermen for non-Great Lakes freshwater fishing in 1985. The survey also reports that 45 percent of these anglers fished in rivers and streams. If stream fishermen spend amounts comparable to those spent by pond, lake, and reservoir fishermen, then the economic value of the recreational fishery along flowing waters amounts to more than $8 billion per year. This does not include the premium prices paid for recreational property and residences along rivers and streams,