The old check dam at Camp Nine in 2013 during low water

The old check dam, ‘after bay’, was just above the bridge at Camp Nine and was used to manage/moderate flow releases from the penstock (seen in upper left of this photo) up at the powerhouse half a mile upstream.  Normally, water was back up behind it, then started to flow over in the early morning as the releases started sending water downstream.  Compare to how it looked when the releases were flowing. (Army Corp removed it on completion of New Melones Dam; a motorboat obstacle with a full reservoir.)