Gabions are used frequently to improve aquatic habitat and rehabilitate damaged fish habitat in low-gradient streams. However, gabions should not be installed perpendicular to the stream flow if water velocities are expected to exceed 5 ft/s. This recommendation would preclude the use of gabions to improve fish passage at waterfalls. Also, gabions installed below culverts should be placed well downstream of the culvert. Weirs constructed of reinforced concrete and/or large boulders could be used as alternatives to gabions to provide for fish passage.