I have a small creek on my property that I would like to install a culvert to cross with my tractor/truck now, but would like to possibly close off in the future to create a small pond (1/4 acre 8' depth). At times there is a large amount of flow that I think could be contained by a 10" pipe.
Should I install a 8" pipe as my "culvert" to be used as a drain pipe in the future, and then install another 10" culvert higher up as an emergency overflow?

Does anyone have any suggestions as to a design, and what I should install now?

Thanks in advance