Technical Abstract: Grade-control structures are necessary to prevent channel degradation and to stabilize a degrading channel. An acceptable structure for low-drop conditions (drop height/critical depth, h/dc </= 1.0) is not currently available for some locations, especially in urban areas. Two- and three- dimensional physical model studies were conducted to develop design criteria for a low-drop grade-control structure that has good performance characteristics and general acceptance by the engineering community involved with stabilization of degrading channels. The developed structure has rounded entrance abutments, a 2:1 sloping floor at the entrance, 0.5dc high floor blocks with 2:1 upstream sloping face, and a 0.25dc high end sill with a 3:1 upstream sloping face. Criteria are presented to design the structure and stable downstream riprap given the channel width, critical depth, drop height, and tailwater elevation. A minimum tailwater elevation is required for acceptable performance of the structure.