Technical expertise is required for this step. After this information is obtained, a control system can be selected. An established grassed waterway controlling gully erosion in a corn field. Initial establishment of the vegetation can be a problem. Maintenance practices such as fertilization and mowing of the vegetation as well as land management practices above the gully area to prevent sedimentation of the waterway are necessary for this control system to be successful.
Drop structures can either take the form of a chute spillway or a grade control structure.
A chute spillway absorbs the energy of the flowing water. They blend in well with grassed waterways since their shapes are similar. These structures must be underlain with a filter cloth material. Gabion basket grade control structures move water down slopes. These structures should always be backed with a filter cloth material to prevent soil from washing through and causing failure.