Life and Culture on the Shimanto River
Life in the Shimanto area revolves around the river, which is virtually untouched by modern development. The winding Shimanto River has carved a 196-kilometer valley through densely forested mountains on its way to the sea, creating a landscape of steep cliffs, floodplains, and stony beaches. Rather than trying to tame the waters with dams and embankments, the communities along the river are committed to preserving its natural beauty and delicate ecosystem.
The river’s bounty
The local community depends on the Shimanto River’s abundant aquatic life, which in turn depends on its pristine waters, rich with nutrients. The ayu (sweetfish) in particular, requires unpolluted waters that support the algae on which it feeds. Goby, eel, tenaga-ebi (long-armed river shrimp) and Japanese mitten crab thrive in the area, from the middle reaches to the mouth of the river. Aosa nori (green laver) seaweed grows in the brackish water where the river meets the Pacific Ocean and is harvested and sold around Japan.
Traditional fishing methods and strict fishing seasons help maintain the ecological balance of the river. It is still possible to see fishers using traditional techniques like shibazuke, a method of catching river shrimp and eels in bundles of submerged leafy branches. On summer nights, fishers swing flaming torches (or more recently LED lights) to scare ayu into their nets, a technique called hiburi-ryo. From a young age, local children learn about the fishing traditions of the river, including how to spot the telltale marks on river stones where ayu have fed off the algae, and how to make simple shrimp traps from plastic bottles.
Living with annual floods
Floods are a part of life along the Shimanto River. The area experiences a high annual rainfall from June to October, during the rainy season and subsequent typhoon season. Villages are built on the hillsides, above historical flood levels. Rice is planted on the flat floodplains close to the river, while vegetables are planted further up the hillsides. Roads running above the fields provide access to the houses, built high above the river. Temples and shrines are positioned highest on the hills, offering spiritual protection to the communities as well as shelter during natural disasters. Some years, the floodwaters reach the vegetable fields, and occasionally the roads. About once a decade, floodwaters lap at the front steps of the houses.
Submersible bridges
The area’s bridges are designed to withstand the forces of the river. Built low to the river, chinkabashi (submersible bridges), are built without balustrades to reduce their resistance to floodwaters and driftwood. Originally, small ferryboats were the only way to cross the river. These crossings could be very dangerous because of frequent floods. The submersible bridges were first built in the 1930s to connect the developing network of roads replacing the ferry crossings. Small stone statues of Jizo (a bodhisattva that protects travelers and watches over the spirits of the deceased), were placed on opposite sides of the river at ferry crossings, and the statues now stand guard over the bridges that replaced the crossings. The chinkabashi remain essential lifelines connecting communities and are popular with visitors for their rustic appearance.