At full pool, new pond, your water level will likely go down farther than it will go up from the full pool level. Depth the riprap placement varies a lot. I suggest the riprap go downward several feet depending on how you measure the distance on the slope or just by depth. Riprap is often extended down the slope for 7-9ft to 2.5-3ft of water. I prefer to extend it down into deeper water so some riprap is useful when water level goes down 2-3ft during drought periods.
The embankment above the waterline is called free board. Often the riprap extends upward to the top, where the bank levels off, but this varies pond to pond.
