Hyporheic Zone

That region of a river which typically starts at the benthic zone and goes downward until groundwater from the river is no longer included in the substrate. This is a relatively new area for ecological study. It is strongly suspected that this poorly oxygenated zone serves as a reservoir for stream life, particularly macro invertebrates, at times of drought, flood, and other environmental stress. Channelization destroys this zone, along with the benthic zone, as well.

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