Are there any nice beaches around the Monticello-Dyersville-Anamosa-… Iowa area?

I moved here from MN (this is what I'm used to: http://www.visitusa.com/minnesota/photos/minnesota-zippel-bay-state-park.htm) I've kinda been spoiled a little with the beach situation, but I came here and as of now I see pools or river swimming (river swimming without a sandy beach by the way!) Are there any good beaches around the area?