But in arid country, dry river beds are oases for animals and people alike. They are sources of water and greenery. Worldwide, human societies use the rich and episodically dry land for vegetable patches, orchards, and pastureland, walking and vehicle paths, hunting and hiking, and herding animals to market. We mine the beds for sand and gravel to build homes and businesses. We park our cars in the beds, and hold races and festivals on the flat river bottoms.
Land use changes, climate changes, and diversions to water projects are transforming historically perennial rivers into capricious or seasonal flows. Impoundment behind weirs and dams can completely dry a river course, or, conversely, turn an erratic flow continuous or cyclical through controlled releases. Steward thinks these are good reasons to learn more about the ecology of intermittent river systems.
"Aquatic scientists seem to ignore dry river beds because they don't contain water, and terrestrial scientists seem to ignore them because they are considered to be part of a river!" said Steward. But they are not typically recognized as "rivers" by government programs, she said, complicating monitoring programs.
|Contact: Liza Lester|
Ecological Society of America