@"River problems":
How long are these creeks? Are they filled the whole year or only after strong rains? When a river splits one of this arms will dig his bed deeper and gain more of the water until the other eventually dries out (up?). There is practically no chance that a river system with two exits (both reaching the ocean) is stable over a longer timespan. Even river deltas are not stationary, they change rather quickly (over decades).