Toyama, Japan Sister City since 1989:
Located on a delta plain between the Sea of Japan and the towering Southern Japanese Alps, Toyama was completely rebuilt after WW II bombing raids. It is now a thriving modern metropolis and a "City of Medicine".
The "Mountains -- Waterways" connection is that Toyama lies at the base of the towering Southern Japanese Alps.
Pictured below: Students from the Toyama College of Foreign Languages attend a Tea Ceremony at the Toyama Sister Cities Tea Pavilion at Sarah P. Duke Gardens at Duke University.