Columbia subject headings:
Romans--Rhine River Valley.
Waterworks--Rhine River Valley.
Harvard subject headings:
Rhineland (Germany)--History.
Romans--Germany--Rhineland.
Stream measurements--Germany--Rhineland--History.
Water levels--Germany--Rhineland--History.
Water-supply--Germany--Rhineland--History.
Princeton subject headings:
Rhineland (Germany)--History.
Romans--Germany--Rhineland.
Stream measurements--Germany--Rhineland--History.
Water levels--Germany--Rhineland--History.
Water-supply--Germany--Rhineland--History.