Water over the dam - restricted information about Michigan dam operations

Two articles from my old FOIA Friday column are relevant to this week's low water conditions on the Huron River in Ann Arbor. Regulating water over the dam covers the FERC eLibrary, a very easy way to get documents regarding dam operations - easy, that is, unless the documents are labeled "Critical Energy Infrastructure Information". CEII documents are protected under a national security "need to know" blanket restriction and are exempt from FOIA. The second, Rejected for security reasons, notes that these same documents are also exempt from FOIA on the state level. This graphic depicting the inside design of the Barton Dam, which was printed in 1917 and is in the public domain, would be exempt from disclosure under Michigan state law.