"In the late 1940s, upon completion of the Castle Rock dam, the Wisconsin and Yellow Rivers backed up to form the Castle Rock Flowage. The towns of Germantown and Werner became just a memory as the flowage covered most of the land where they once existed."
www.dnr.state.wi.us/org/land/parks/specific/buckhorn/history

 In 1949, one of the twin Petenwell and Castle Rock dams was dedicated. These dams were constructed on the Wisconsin River by the Wisconsin Power and Light Company and the Wisconsin River Power Company and were fitted with large hydroelectric generating plants. This damming of the river produced the Petenwell and Castle Rock Lakes which now make up most of the county’s western border. The two largest county parks are located on these lakes. http://freepages.genealogy.rootsweb.com/~adams6/history

www.juneaucounty.com/juno-tour.html

Castle Rock park has over 300 campsites on 160 acres, and is also located on Castle Rock lake which is 16,000 acres. Amenities include spots for tents and trailers, showers, flush toilets, water, playgrounds, picnic tables, swimming (supervised beach), park officer, boating and boat access, fishing, water skiing, canoeing, grills, shelter, electricity, and concessions.