Page 85 - (DK) Ocean - The Definitive Visual Guide

TIDES AND WAVES 83

PACIFIC OCEAN NORTHWEST
Naruto Whirlpool

FEATURES
Tidal race and
whirlpools
TIMING
Four times daily

LOCATION Naruto Strait, between the islands of
Shikoku and Awaji, Japan
The Naruto is a spectacular system of
whirlpools that develops four times a
day in a narrow channel separating the
island of Shikoku (one of Japan’s main
islands) from Awaji Island, a much
smaller island lying off Shikoku’s
northeastern coast. The channel, called
the Naruto Strait, is one of several that
join the Pacific Ocean to the Inland
Sea, which is a large body of water
lying between Shikoku and Japan’s
largest island, Honshu. Four times
a day, billions of gallons of water move
into and out of the Inland Sea
through this channel, generated by
tidal variations in sea level between
the Inland Sea and the Pacific Ocean
of up to 5 ft (1.5 m).
The tidal flows can reach speeds
of up to 9 mph (15 km/h) during
spring tides (that is, twice a month,
around the time of a full or new moon).
They create vortices up to 65 ft (20 m)
in diameter where they encounter a
submarine ridge. These vortices are
not stationary but tend to move with
the current, persisting for 30 seconds
or more before disappearing. The
whirlpools can be viewed from Awaji
Island, from sightseeing boats that
regularly negotiate the rapids, or from
a /5-mile- (1.3-km-) long bridge that
4
spans the Naruto Strait.
HUMAN IMPACT
ARTISTIC
INSPIRATION

The Naruto Whirlpool has
existed since ancient times. It is
mentioned many times in Japanese
poetry and is possibly the only
tidal phenomenon to feature in a
well-known piece of art, namely
Whirlpool and Waves at Naruto, Awa
Province, by the 19th-century
Japanese artist Utagawa Hiroshige
(a fragment is shown below).

TROUBLED WATERS INTRODUCTION
A walkway hanging beneath the
Onaruto Bridge, which spans the
Naruto Straits, provides an excellent
view of the whirlpools below.