Intermittent river

[4] The combination of dry crusted soils and the highly erosive energy of the rain cause sediment resuspension and transport to the coastal areas.

[6] During the summer even under no flow conditions the point sources are still active such as the wastewater effluents,[7] resulting in nutrients and organic pollutants accumulating in the sediment.

Prior to 2001, virtually all bodies of water in the United States were considered jurisdictional because of their potential to function as a habitat for migratory birds.

[16] For example, intermittent streams fed by snowmelt and glacial meltwater cease to flow when they either freeze or there is not enough inputs to sustain surface water.

[16] Streams in more arid regions stop flowing due to the depletion of water storage in the surrounding aquifer and channel banks.

This was the case for several large rivers such as the Nile, Indus, Yellow, Amu and Syr Darya, Rio Grande, and Colorado, which became intermittent during the past 50 years due to human interference.

This is a direct consequence of the extensive networks of dams and aqueducts that were built for human withdrawal of water that used to flow into wetlands, deltas, and inland sinks.

In recent years, several U.S. states and Mexico have used significant amounts of water for agricultural and urban uses, which caused flows reaching the Colorado River delta to drop to near zero.

For example, arroyos are intermittent streams that erode deep vertical channels through fine sediment in arid and semiarid regions in the American Southwest during precipitation events.

[22] Many incised arroyos that are destructive to stream beds and adjacent man-made structures were formed as a result of drainage channelization and overgrazing during the late nineteenth century along with the influx of American settlers in the Southwestern United States.

[21] Thus, when lotic (flowing water), lentic (lake), and terrestrial communities are considered together, intermittent rivers can account for a high proportion of regional biodiversity.

[34] During dry periods of intermittent rivers, terrestrial animals can gain access to resources and areas that were otherwise inaccessible, either due to natural or man-made obstructions.

[39] The West Fork Smith River provides vital habitat to different species, including coho salmon, returning to spawn in Oregon.