Conversion of a Flood Control System to a Sustainable System:  The Energy Requirements for Pipeline Transport of Silt

The reservoirs of flood control systems will eventually fill with sediment, and all flood control will be lost. Well before complete filling, the loss of flood control and competition with other system purposes, such as power generation, will force remediation efforts. The energy required to transport the sediments from the reservoirs back to the river channel has been determined using the Pick−Sloan system of the Missouri River as a representative system. Pipeline transport of the silt and clay requires about 3% of the hydroelectric energy generated by the system. This is small enough to justify a thorough study of the full cost and environmental impact of conversion to a sustainable system. Sand and gravel are more economically moved by rail, but they are probably best used as underlayment for silt and clay to mimic the natural process of fertile flood plain creation. The time frame for remediation is much shorter than often presumed. Using the volume of the permanent pool (25%) as the loss of reservoir capacity allowable before sustainability is achieved, the two lowest of the six Pick−Sloan reservoirs will have filled their permanent pools in less than 25 yr.