Thanks for the response. As I said, I am wary of water lilies. Subsequent to the original post, I did find some information on more manageable lilies:
https://forums.pondboss.com/ubbthreads.php?ubb=showflat&Number=517405. But would value input from others on these - given circumstances of this pond, I would be very wary of any lily that can handle over 3-4' of water.
The Eleocharis is a known issue. It was hyacinth that finally prompted us to drain the pond, but the Eleocharis had made one bay of the pond pretty much unfishable even before the hyacinth took over. I believe it is E baldwiniii, which when growing submersed can create thick mats that basically fill the entire water column - hard to fish and even harder to land them. When the pond was drained, you could see that it absolutely blankets the bottom in this bay, which comprises about a sixth of the main pond. It's one of the shallower, flatter areas of the main pond at ~3-5 feet, and I think would be good bedding ground if not for the Eleocharis.
The pond was created ~20 years ago and has never had much in the way of vegetation other than the Eleocharis, the hyacinth (brought it by ducks, I believe) and some sedges, bulrushes and smartweed in defined areas with gently sloping shorelines. There has never been any intentional planting.
It was actually another post on here that gave me hope the carp would control the Eleocharis:
https://forums.pondboss.com/ubbthreads.php?ubb=showflat&Number=231460. I would prefer carp to repeated spraying with diquat. But I do understand the concern over difficulty in establishing desirable plants, particularly submergents, when grass carp are present. Any other suggestions for controlling Eleocharis while allowing establishment of beneficial submergents?
