Directly located in Guttenberg is Lock and Dam No. 10 with a nice viewing area. Due to security reasons the public viewing area might be closed. Call in advance. Approaching boats can also be watched from the public riverfront park.
Directions:
Lock and Dam No. 10
5 Lock and Dam Lane
Guttenberg, IA 52052-0849
Phone (319) 252-1261
http://www.mvp-wc.usace.army.mil/
http://www.guttenberg-iowa.org/
Satellite picture and map at Google Maps:
Guttenberg, IA