This is the final report prepared by the Task Committee on Erosion of Cohesive Materials, Sedimentation Committee, Hydraulics Division, ASCE. The report describes laboratory research, field observations, design criteria, and agricultural land and channel problems as related to cohesive sediments. Much of the literature currently available is reviewed and recommendations are made for practical application to design and for further research. An extensive bibliography, a compilation of design equations and charts, and some design information not now available in the literature are included.