|Lerch, Robert - Bob|
Submitted to: Annual Water Resources Conference
Publication Type: Abstract Only
Publication Acceptance Date: 6/30/2010
Publication Date: 11/1/2010
Citation: Willett, C.D., Lerch, R.N., Peacher, R., Schultz, R.C. 2010. Stream Bank Erosion Rates in Two Watersheds of the Central Claypan Region [abstract]. Annual Water Resources Conference. Sesson No. 15. Interpretive Summary:
Technical Abstract: Streambank erosion and subsequent sedimentation in surface waters of the United States is a significant environmental concern. The objective of this research was to determine the effect of stream order, adjacent land use, and season on stream bank erosion rates. Study sites were established in 2007 and 2008 within Crooked and Otter Creek watersheds, two claypan watersheds located in northeast Missouri. A factorial experimental design was implemented with four land uses (cropped, forest, pasture, and riparian forest) and three stream orders (1st, 2nd, 3rd). Each treatment was replicated three times for each stream order. Erosion pins were installed based on bank height and length at each site to measure bank erosion/deposition rates. The effect of different seasons was assessed by measuring the length of the exposed pins three times per year. Using data from the National Hydrography Dataset, measured bank erosion rates were combined with the total bank length for each stream order in the study area to estimate the sediment, C, and N contribution from stream banks at the watershed scale. The results showed that the seasonal effect was highly significant, with much greater erosion rates in the winter compared to other seasons. Land use and stream order did not significantly affect bank erosion rates, but bank soils in forested sites did have significantly lower C and N concentrations than other land uses. Based on estimates of the total mass of eroded stream banks and overland erosion, bank erosion accounted for 47 to 71% of the total in-stream sediment annually in these two watersheds. Because riparian zones in these watersheds are currently unmanaged, there is considerable potential for reducing bank erosion by implementation of practices designed to stabilize streambanks. However, in these highly disturbed watersheds (nearly 70% of the study area is in row crops), management that addresses the hydrology of the entire watershed system may be required to achieve significant reductions in streambank erosion in claypan watersheds.