OSM Page: http://wiki.openstreetmap.org/wiki/Tag:waterway%3Ddam QUESTION: should old, disused or ruined dams be included? No OSM tag so perhaps should not.
HB: I'd set those as historic=yes or disused=yes
they are still useful for identifying where you are when you come
RP: yes, include the old dams, with disused=yes. historic is for items of historic significance, so may not be appropriate here
HB: after loading be sure to check neighboring water masses and add landuse=reservoir tags to them as needed.
Chathams uploaded 3 May 2010 (HB)
HB: Besides many "old", fields.well_status has one "disused" and one "ruins" in the mainland. Not sure what the difference between old and disused is supposed to be, but calling them all disused=yes and keeping the LINZ:well_status data in case a revisit is needed.
uploaded for the mainland 5 March 2011 in changeset 7459874 (HB).
Mainland data merged by HB and RobinC in the weeks that followed.