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Introduction How Rivers Run Stories Value Of A River What We Can Do
Flow of a River - Hydrology
Factors of flow: Land use (pg 11 of 11)

Human land use has greatly affected the flow of water into rivers and streams. Clear-cutting of forests, plowing land for agriculture, paving land for roads and parking lots, compacting land through heavy use, and draining wetlands-all have increased the speed with which water runs off the land into nearly streams and lakes. In most cases, erosion and movement of soil have also increased.

By speeding the flow of water into rivers, these land use changes alter the hydrology of a stream, causing streamflows to rise faster and peak at higher levels. The higher flows carry greater amounts of sediment. As surface runoff increases (and the contribution of groundwater proportionately decreases) stream temperatures generally rise. Increased temperature, turbidity, and current velocity affect stream life, usually for the worse.

Click photo to enlarge

Click photo to enlarge
Marsh Creek Watershed in west-central Minnesota in 1938, about 20 years after wetland drainage began. Photo of same location taken in 1991, after considerable ditching and draining of wetlands had occurred.
Which watershed condition do you believe would result in faster runoff and higher peak flows?

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Water cycle
Stream order
Factors of flow
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