2012 Annual Report 1a.Objectives (from AD-416): The objectives of this cooperative research project are to calibrate the Mini-JET and use the Mini-JET to investigate the impact of seepage forces on soil erodibility. 1b.Approach (from AD-416): Work together in. 1)calibrating the Mini-JET by comparing test results to larger scale JET apparatus test results and to flume test results and. 2)conducting tests using the Mini-JET to measure changes in material erodibility under various levels of seepage forces in bench scale sample tests as well as large-scale flume tests conducted at the OSU and HERU facilities. 3.Progress Report: Laboratory bench scale and flume scale tests were completed, comparing soil material erodibility measurements of "original" and "mini" jet erosion test (JET) with measurements from open channel flow flume tests. These tests were conducted to investigate the impact of seepage on erodibility and to determine the validity of using the JET to predict erodibility relative to the impact of seepage. A physically based mechanistic erodibility model that includes the impact of seepage was also developed and validated.