Submitted to: Journal of Freshwater Ecology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 1, 1998
Publication Date: N/A
Interpretive Summary: Both channel incision and agriculture have contributed to the degradation of streamside habitat in northwestern Mississippi. Storm runoff flowing over the high unstable streambanks resulting from channel incision often leads to development of gully erosion within the streambanks and adjacent agricultural fields. The Demonstration Erosion Control (DEC) project in the Yazoo River basin utilizes field-scale grade control structures (drop pipes) to control gully erosion occurring adjacent to incised streams undergoing restoration. This structure may replace eroding gullies with two types of streamside aquatic habitats, which are field level wetlands and stream level pools. We collected fish and habitat data from these aquatic habitats and our results found that drop pipe habitats contained fishes that typically live in ponds and stream pools. Additionally, we found that aquatic habitats with larger pools contain more different types of fish and greater numbers of fish than smaller pools. Our results suggests that altering installation designs to facilitate creation of larger and deeper field level wetlands and stream level pools will provide the greatest benefits for fish and other wildlife. Both state and federal resource managers can utilize the improved designs to assist with the restoration of streams impacted by both channel incision and gully.
Technical Abstract: Bed lowering due to channel incision severs the natural floodplain/stream interaction and results in alteration of physical and biological features of the riparian zone. Lateral inflow over high unstable banks, often a result of channel incision, may initiate gully erosion within adjacent riparian zones and agricultural fields. Field-scale grade control structures (drop pipes) are utilized to control gully erosion and may result in the creation of field level wetlands and stream level pools. Fish and habitat data were collected from selected field level wetlands and stream level pools located in northwestern Mississippi from May to September 1996. Field level wetlands contained a total of eight species from 3809 captures, while 22 species from 668 captures occurred within stream level pools. Regression analysis indicated that pool area and depth was positively associated with both species richness and numbers per unit effort within field level wetlands and stream level pools. Our results suggest that altering the drop pipe installation design to facilitate the creation of larger and deeper field level wetlands and stream level pools will provide the greater benefits for fish and other wildlife.