Throughout the latter part of the 2nd world war Catalina Flying Boats operated from Perth Water fully loaded with fuel for the "Double Sunrise" flights across the Indian ocean, the Catalina was not known foe sparkling performance full of gas.
So a Caravan on floats will have no trouble !!!!!
When we operated the C206 for a small time on the river it was no issue until the "noise police" got involved in Bullcreek.