Reservoir sedimentation management is of critical importance for the sustainable development of surface water resources. Sanmenxia Dam, located on the middle reach of the Yellow River, in China, is notorious for its severe sedimentation problems. Because of the alarming rate of loss of reservoir storage capacity and the unacceptable negative impact induced by the rapid upstream extension of sediment deposited in the river's backwater region, the dam has been reconstructed to provide high sediment releasing capacity, and the dam operation has been changed in order to achieve a balance between sediment inflow and outflow. As a result, the dam is still providing the basin with flood control, irrigation, and hydropower generation, even though some benefits are lower than the original design. Complex sedimentation processes in response to the dam reconstruction and changes of dam operation are discussed in this paper. The engineering experiences and management practices of Sanmenxia Dam are valuable assets to the sustainable use of reservoirs built on sediment-laden rivers.