Long before the new Exchequer Dam was built in the 1960's to form Lake McClure, there was a smaller dam called Exchequer that was completed in 1926. The 1926 dam inundated the original Yosemite Valley RR and a new "high line" was built. At that time, a bridge was built at Barret's and another further up river just below Bagby. In the early 1960's there was a beautiful swimming hole on the river at Bagby. When the New Exchequer Dam was completed in the late 1960's, the Lake filled the first year and went over the spillway taking out much of the road to the dam itself. The "high line" railroad bed can still be seen at low water, as is the tunnel between Barret Cove and McSwain Marina. I lived in Mariposa at the time the New Dam was built and have been swimming at the beautiful pool in the Merced River at Bagby. The town of Bagby is now underwater.
Some good pictures of Lake McClure can be seen at lakedonpedro.org. Though it says Lake Don Pedro, it is Lake McClure and the subdivision between Lake McClure and Lake Don Pedro is called Lake Don Pedro. We built a house in the Lake Don Pedro subdivision in the early 1990's.
Below New Exchequer Dam is McSwain Dam which formed a much smaller lake below McClure. It is used mainly for swimming. We had a houseboat on Lake McClure from 1971 until we sold it in the early 1990's. It is a beautiful lake and brings back many good memories. We raised our kids on this lake, being there nearly every weekend from Memorial Day until well into October.