This picture shows a hydraulic-fill dam under construction. Mud sludge flows down from the side to fill the body of the dam. When the water content in the sludge is drained, its soil grains are pull together by surface tension forming a well-compact earth structure. No mechanical equipment is seen on the scene. The only piece of mechanical equipment needed is the diesel pump, which is used to pump water up from the gully to create the mud sludge, and to operate the water jet for soil extraction. The loess soil is particular amendable to the hydraulic-fill construction method because (1) the soil is easily eroded by water, which simplifies soil excavation, (2) the soil grain is fine in size, which makes transportation by low-speed water flow adequate, and (3) the soil is uniform in size, which allow compaction without stratification.


Another example of a hydraulic-fill dam in construction.