GPAA claims on Arkansas River in CO do not have dredging available last I heard.

Thanks Walter for the reply,  any input on the my newbie question?

using a pump on a sluice or running in high water conditions needs to have a close eye on water input. If pump is to large you can put in a bypass valve off a tee or some pumps have no problem with valve to cut off some of the flow. The alternative is to get a larger sluice. When in a river in high water you will raise the sluice to stop as much water from going into the sluice, if angle is already correct the whole sluice will need to be raised or some rocks in from of the sluice to slow water but not close enough to cause water disruptions within the sluice. On the dredge I would go to a larger sluice or if it was metal I would suggest that you may be able to increase the size of the riffles or add a set of larger expanded metal on top of the mat / carpet to cause a slow water area to catch finer material / gold. Larger sluice is always an option.  For new sluice options I would search the internet for deals.