Wetland Development
History of Wetland Development
In 1920, a major flood occurred on the Kushiro River, resulting in many casualties. This disaster led to the implementation of a comprehensive flood control project for the river. The residential area of Kushiro was located in a low-lying area of the wetland. As a result, floodwaters spread widely across the wetland and caused damage to the town. Then a shortcut channel was planned to convey floodwater directly from the upstream area of the town to the Pacific Ocean. However, the construction work proved to be extremely challenging.
The most advanced construction machines available at that time were introduced to excavate the 11.2-km-long new waterway, and 20-ton locomotives were used to transport the excavated soil. Excavation work in wet areas, however, was extremely difficult, and accidents such as locomotive derailments occasionally occurred.  
About 10 years after construction began, the new waterway was completed. This significantly reduced flooding in downtown Kushiro. 
After World War II, river improvement projects were widely undertaken across Japan to enhance flood control. In Hokkaido, including the Kushiro region, many rivers were channelized to increase flood discharge capacity and expand land use. The Kushiro River was also straightened as part of these projects. As a result, Hokkaido significantly expanded its arable land area and became Japan's primary food production base. However, these river improvement works and subsequent land use changes led to the degradation of the wetland environment. 
Kushiro Wetland Restoration ProjectKushiro WetlandWetland Restoration Restoration Site 1 : Kayanuma, Old Channel Restoration 1 Restoration Site 2 : Numaoro, Old Channel Restoration 2 Restoration Site 3 : Kuchoro, Sediment Retention Basin Restoration Site 4 : Hororo, Reconversion of Farmland into Wetlands Kushiro Wetland Nature Restoration Council Project Goals Sediment reduction flowing into the wetland Implovement of habitat for fish Restoring Wetland Vegetation History 1 : Wetland Development History 2 : Shift Toward Wetland Conservation and Restoration Peatland |