the soil water interface is calculated adjusting flow rate and velocity allows calculation of the permissible tractive force critical hydraulic shear stress prior to actual removal of soil surface particles further increasing the flow rate initiates surface erosion and the actual erosion rate amount of soil particles removed over time may be observed and documented finally knowing the effective shear stress critical shear stress and erosion rate allows calculation of the erodibility coefficient of a sloped levee surface select embodiments of the present invention for testing levee sites with grasses and weeds for example have approximate dimensions of up to about 8 ft in length up to about 3 ft in width and about 2 ft in depth height in select embodiments of the present invention test gages 23 comprise commercial off the shelf cots water flow rate measurement devices to monitor the flow rate of the pump 19 or alternatively comprise a cots water pressure measurement device to monitor outlet pressure of the pump 19 in select embodiments of the present invention test gages 27 and 29 comprise cots water velocity measurement devices that allow real time monitoring and recordable data collection of water velocity in select embodiments of the present invention recordable data collected from test gages 27 and 29 enable post test calculations of water discharge area velocity.