Aquatic habitats in a 1-km reach of a deeply incised channel draining 91 km2 in northwest Mississippi were modified by adding stone and planting dormant willow posts. Rehabilitation structures (groin extensions and longitudinal toe protection) required addition of only 10% more stone to existing channel stabilization works.
During the year before rehabilitation, baseflow aquatic habitats were characterized by uniform conditions, little woody debris or riparian vegetation, shallow depths, and sandy bed material.
The stage-discharge relationship, channel geometry, and bed material size were unaffected by rehabilitation, but the average depth of scour holes adjacent to extended groins increased from 32 cm to 72 cm, and pool habitat in the lower half of the study reach increased from 2.9% to 14% of water surface area. Median water depth at base flow increased from 9 cm to 15 cm. Woody vegetation cover on one side of the channel increased from 38% to 78%. Groin extensions experienced partial failure due to erosion of sand from underneath stones.
Fish numbers tripled, median fish size increased by 50%, and the number of species increased from 14 to 19.