Abstract: A variable flow device that can be used to dewater an ash slurry is described. The variable flow device includes a pipe section having a plurality of adjustable openings in the sidewall. The variable flow device can be can be attached to a slurry discharge pipe and positioned above the horizontal section of a submerged scraper conveyor (SSC) located remotely from a boiler or furnace where bottom ash is generated. A bottom ash dewatering system is also described which includes an SSC having an overflow trough system. The trough system includes trough sections adjacent each of the sides of the SSC and one or more trough connecting sections. The SSC equipped with the variable flow device and/or trough system can receive a high volume wet ash slurry discharge while minimizing particulates overflowing into the overflow trough system.