What is the best method to remove settled ash from industrial coal plant lagoons and ponds?

CCRs including ash can considerably cut down on the safety and produtivity of coal power plants. Coal ash can be removed through dredging with a cutter head and pump that is connected to a flexible pipe. The material is then pumped to another area for proper settling and dewatering. Mechanical dredging with an excavator can be performed as well.  The determination of the best method is often limited by access to the pond or lagoon from the shoreline and where the coal ash or fly ash needs to be disposed of.  If the dredge can pump the ash directly into the disposal area, that method may be most effecieint.  If the excavator can load trucks along the shoreline or a peninsula for offsite disposal then that method may be the best way to remove coal ash.