Hinuma is the largest brackish lake in
the capital region and located 5km inland
from Oarai Beach on the Pacifi c coast in
Ibaraki Prefecture. It used to be an inlet
of the sea approximately 6000 years ago.
Over time, with the sea’s recession, it
was separated from the sea by sediments
accumulated on its estuary and formed a
lagoon stretching from east to west with
an area of 935ha and an average depth
of 2.1m. It is fed by several rivers such as
Hinuma River and Kasama River and drains