Impacts of land use on stream bank erosion in the Northeast Missouri Claypan Region

Sediment can cause great harm to aquatic habitats and is arguably the most pervasive and costly form of water pollution in North America. There is a growing consensus in the literature that stream bank erosion is almost always a significant source of stream sediment, and in many instances, it is the dominant source. The first study in this thesis examines how land use, stream order, and season impact stream bank erosion in the Central Claypan Region of NE Missouri. This study used a three-year data set based on the erosion pin method. Season effects were statistically significant with much larger amounts of erosion occurring during the winter than during spring/summer or summer/fall. The second study investigates the impacts of different types of vegetation and various watershed characteristics on stream bank erosion. Erosion data was used in conjunction with riparian area vegetation survey data and watershed data calculated with a Geographic Information System, in order to examine trends and relationships. The variables used in this study were not good predictors of the observed variation in bank erosion. Finally, the third study investigates the applicability of two procedures used by the Michigan Department of Environmental Quality for estimating bank instability for use in the Central Claypan Region of NE Missouri. We found that the results of these methodologies did not reflect the wide range of actual erosion rates that have been recorded in the study area

Streambank Erosion in Two Watersheds of the Central Claypan Region of Missouri, United States

This study was undertaken to assess the importance of streambank erosion to the total in-stream sediment of two agricultural watersheds within the Central Claypan Areas. The objective of this research was to determine the effect of stream order, adjacent land use, and season on streambank erosion rates. Thirty-four study sites were established in 2007 and 2008 within Crooked and Otter Creek watersheds, two claypan watersheds located in northeastern Missouri. At each site, field assessments of severely to very severely eroding bank length were determined along 300 to 400 m (984 to 1,312 ft) stream reaches. A factorial experimental design was implemented with four land uses (crop, forest, pasture, and riparian forest), three seasons, and three stream orders (1st, 2nd, and 3rd). Each treatment was replicated three times for each stream order, except for the cropped 3rd order treatment as only one suitable treatment site could be found. Streambank erosion was measured using erosion pins, which were installed in randomly assigned plots that included at least 20% of the eroded bank length within each site. The effect of different seasons was assessed by measuring the length of the exposed pins three times per year (March, July, and November). The bulk density and carbon and nitrogen content of bank material were also determined. Sediment loss rates showed that season and the three-way interaction between season, land use, and stream order were highly significant. Erosion rates were consistently higher in the winter months than spring/ summer and fall seasons; however, the significant three-way interaction precluded a simple interpretation of the seasonal effect. Soil nutrient concentration data showed that forest sites had significantly lower C and N concentrations than other land uses. At the watershed scale, bank sediment accounted for 79% to 96% of the total in-stream sediment and 21% to 24% of the total N exported from the study area. These results indicate that streambanks are the dominant source of sediment and a significant source of N in these streams. Therefore, improved management of riparian areas to decrease streambank erosion would result in significant water quality improvement in streams of the Central Claypan Areas in northeastern Missouri

Impacts of land use on stream bank erosion in the Northeast Missouri Claypan Region

Sediment can cause great harm to aquatic habitats and is arguably the most pervasive and costly form of water pollution in North America. There is a growing consensus in the literature that stream bank erosion is almost always a significant source of stream sediment, and in many instances, it is the dominant source. The first study in this thesis examines how land use, stream order, and season impact stream bank erosion in the Central Claypan Region of NE Missouri. This study used a three-year data set based on the erosion pin method. Season effects were statistically significant with much larger amounts of erosion occurring during the winter than during spring/summer or summer/fall. The second study investigates the impacts of different types of vegetation and various watershed characteristics on stream bank erosion. Erosion data was used in conjunction with riparian area vegetation survey data and watershed data calculated with a Geographic Information System, in order to examine trends and relationships. The variables used in this study were not good predictors of the observed variation in bank erosion. Finally, the third study investigates the applicability of two procedures used by the Michigan Department of Environmental Quality for estimating bank instability for use in the Central Claypan Region of NE Missouri. We found that the results of these methodologies did not reflect the wide range of actual erosion rates that have been recorded in the study area.</p

Streambank Erosion in Two Watersheds of the Central Claypan Region of Missouri, United States

This study was undertaken to assess the importance of streambank erosion to the total in-stream sediment of two agricultural watersheds within the Central Claypan Areas. The objective of this research was to determine the effect of stream order, adjacent land use, and season on streambank erosion rates. Thirty-four study sites were established in 2007 and 2008 within Crooked and Otter Creek watersheds, two claypan watersheds located in northeastern Missouri. At each site, field assessments of severely to very severely eroding bank length were determined along 300 to 400 m (984 to 1,312 ft) stream reaches. A factorial experimental design was implemented with four land uses (crop, forest, pasture, and riparian forest), three seasons, and three stream orders (1st, 2nd, and 3rd). Each treatment was replicated three times for each stream order, except for the cropped 3rd order treatment as only one suitable treatment site could be found. Streambank erosion was measured using erosion pins, which were installed in randomly assigned plots that included at least 20% of the eroded bank length within each site. The effect of different seasons was assessed by measuring the length of the exposed pins three times per year (March, July, and November). The bulk density and carbon and nitrogen content of bank material were also determined. Sediment loss rates showed that season and the three-way interaction between season, land use, and stream order were highly significant. Erosion rates were consistently higher in the winter months than spring/ summer and fall seasons; however, the significant three-way interaction precluded a simple interpretation of the seasonal effect. Soil nutrient concentration data showed that forest sites had significantly lower C and N concentrations than other land uses. At the watershed scale, bank sediment accounted for 79% to 96% of the total in-stream sediment and 21% to 24% of the total N exported from the study area. These results indicate that streambanks are the dominant source of sediment and a significant source of N in these streams. Therefore, improved management of riparian areas to decrease streambank erosion would result in significant water quality improvement in streams of the Central Claypan Areas in northeastern Missouri.This article is from Journal of Soil and Water Conservation 67 (2012): 249, doi:10.2489/jswc.67.4.249.</p