Forest roads potentially alter stream hydrology through the rerouting of water, the triggering of shallow rapid landslides, and the delivery of fine sediments to the stream. Fine sediments can wash down from forest road impacted streams into fish spawning streams and clog up the coarser spawning ground substrates, severely impacting the survival of incubating fish. Additionally, fine sediments can fill in fish habitat rearing pools, resulting in shallower depths, higher water temperatures and less habitat area for juvenile rearing in the summer. The impacts make forest roads a potential factor limiting fish production throughout the Pacific Northwest.