There is a national clickable map for COE districts at
http://www.usace.army.mil/Locations.aspx Some, such as the Sacramento District, have clickable links to each lake, including camping info if any. Some don't. I did not try them all.
The link for reservations sends you to the main page of Recreation.gov, where it seems like you have to know the name of the lake or facility in order to get any info.
This is definitely NOT the high quality of service we are used to for the COE website! Here's hoping they fix it soon. I have recently had trouble with the BLM sites, too. Perhaps this is some government security issue?