Submitted to: Mississippi Water Resources Research Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: April 1, 1998
Publication Date: N/A
Interpretive Summary: Channel incision (increase in channel depth due to erosion) degrades the adjacent streambanks and often leads to the initiation of gully erosion within both the streambanks and upland 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 create two types of aquatic habitats, which are field level wetlands and stream level pools. We collected fish and habitat data from these aquatic habitats in northwestern Mississippi. Our results found that drop pipe habitats contained fishes that typically live in stream pools and ponds. Additionally, we found that aquatic habitats with larger pools contain more different types of fish and greater numbers of fish than smaller pools. These environmental improvements occurred as a result of installation practices which focus on erosion control, not habitat creation. Our results suggests that installation designs which will create larger and deeper field level wetlands and stream level pools will provide the greatest benefits for fish and other wildlife. The improved designs will assist both state and federal resource managers attempting to restore streams damaged by both channel incision and gully erosion.
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 occurring adjacent to incised streams undergoing restoration as part of the Demonstration Erosion Control (DEC) project in the Yazoo River basin. Two types of aquatic habitats which may result from drop pipe installation are field level wetlands and stream level pools. We collected fish and habitat data 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 3803 captures, while 22 species from 668 captures occurred within stream level pools. Regression analysis indicated that within field level wetlands pool area and depth was only positively associated with species richness, while pool area and depth was positively associated with both species richness and numbers per unit effort within stream level pools. The creation of aquatic habitats within impacted riparian zones is an important step towards mitigating the detrimental effects of channel incision and gully erosion. These environmental improvements occurred as a result of standard installation practices that focus on erosion control, not habitat creation. Altering the installation design to facilitate habitat creation should result in aquatic habitats which will provide greater benefits to fish and other wildlife.