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Stream Anatomy — Woody Debris

The presence of logs or woody debris (not twigs and leaves) in a stream can slow or divert water to provide important fish habitat such as pools and hiding places. Stream ecologists call this coarse woody debris (CWD). Be careful not to confuse this CWD with chronic wasting disease or equally undesireable CUD (coarse urban debris) as seen in the image on the right.

coarse woody debris (CWD)  coarse urban debris (CUD)