I live within walking distance to the Emsworth Lock and Dam. I was even there today. There you can see Tree swallows, Barn swallows and Northern Rough-winged swallows all at the same time.
Right now the river is high and all the dam gates are wide open. The power of the river coming through the gates is an amazing site. It is enjoyable too when the river is low and most of the gates are closed. Great Blue herons then wade in the shallows patiently waiting for an easy meal.
Through the seasons, I have found it to be a pretty good birding spot.