What are those plants, please, that are in the water, right next to River Road? Water chestnut? The herons look beautiful perched on them! Thank you. :-)

Yes they are, Mr. Rider explained it best.

It's Trapa natrans, commonly known as water chestnut. Actual water chestnut that you'll find in a store or restaurant is a different species that's a sedge. Water Caltrop is a highly invasive species that has taken over large areas of the Hudson (Muheakantuck) river. Watch out for the seed pods. They have spikes that can pierce your feet.

Thank you, Mr. Rider, and Mr. Durkin. After being overseas for 40+ years, we are enjoying our lovely environment and continuing to explore. :-)