Sediment production in ravines in the lower le sueur river Watershed, Minnesota
Book Chapter
Azmera, LA, Miralles-Wilhelm, FR, Melesse, AM. (2015). Sediment production in ravines in the lower le sueur river Watershed, Minnesota
. 485-522. 10.1007/978-3-319-18787-7_23
Azmera, LA, Miralles-Wilhelm, FR, Melesse, AM. (2015). Sediment production in ravines in the lower le sueur river Watershed, Minnesota
. 485-522. 10.1007/978-3-319-18787-7_23
Ravine erosion is an important occurrence of soil erosion processes. Although its sediment yield is significant, ravine erosion is not usually accounted in routines for predicting soil loss. This study focuses on quantifying explicitly the sediment budget of deeply incised ravines in the lower Le Sueur River watershed, in southern Minnesota. High-rate-gully-erosion equations along with the universal soil loss equation (USLE) were implemented in a numerical modeling approach that is based on a time integration of the sediment balance equations. The model estimates the rates of ravine width and depth change and the amount of sediment periodically flushing from the ravines. Using ArcGIS and ArcHydro tools, topographic characteristics of the study ravines were derived from the LiDAR-based digital elevation model (DEM) of the area. A 30-year survey and sediment data from similar research was used as a case study in an attempt to justify the theoretical framework of the model and characterize model parameters. The model output for the case study was found to compare favorably with the estimates found in previously reported studies. Components of the sediment budget in the study ravines were simulated with the model and results suggest that the ravine walls are the major sediment source in the ravines. A sensitivity analysis revealed that the erodibility coefficients of the gully bed and wall, the local slope angle, and the Manning's coefficient are the key parameters controlling the rate of sediment production. Recommendations to guide further monitoring efforts in the watershed and increased detail modeling approaches are highlighted as a result of this modeling effort.
