This report serves to document research conducted under Specific Cooperative Agreement between ARS and the School of Geography, University of Nottingham. Additional details of research can be found in the report for the inhouse project 6408-13000-017-00D, Integrated Assessment and Analysis of Physical Landscape Processes that Impact the Management of Agricultural Watersheds. Monitoring of field instruments that measure pore-water pressure at the Goodwin Creek Experimental Bendway, and results of numerical simulations indicate that lateral seepage forces can be an important control of mass failure along streambanks and at vertical sections of gully headwalls. Preliminary results were presented and published at a national technical meeting. An investigation into the variability of geotechnical properties and their effect on estimates of bank stability was also completed. Results show that variations in bank strength can cause significant differences in stability estimates, particularly for models that use single values of certain strength variables. Models that allow for a range of parameter values in a probabilistic framework offer a means of accounting for this variability. Research results have been prepared as a journal article submission. Research findings are critical in modeling soil erosion from streambanks and bank-side gullies from these features.