This sounds so cool! From the link,
"Explore the magic of the Mississippi River and learn how science can unlock its secrets! How do bugs tell us about water quality? How many fish can we catch with a net and how are they special to the river? How big is an opsrey nest and can we find old lava on the river's shore? River geology, birds and water quality are all covered in this fun day. Reservations required"

And here is the link