Environmental Challenges in Chiba Prefecture: The Struggle of Teganuma and Inba Marsh and the Search for Rehabilitation 2001

Environmental Challenges in Chiba Prefecture: The Struggle of Teganuma and Inba Marsh and the Search for Rehabilitation 2001

Around 2001, Chiba Prefecture was at a major turning point in its environmental preservation efforts, as symbolized by the withdrawal of reclamation of the Sanbanse, a tidal flat in Tokyo Bay. At the same time, the inland lake and marsh environment was also facing serious problems. Both Teganuma and Inba-numa were ranked first and second worst in Japan for water pollution, and for a long time were dishonorably called "the dirtiest lakes in Japan. In the background, urbanization and housing development since the period of rapid economic growth, as well as the inflow of domestic and agricultural wastewater, have caused the problems of blue-green algae, bad odor, and poor fishing industry due to eutrophication to become more pronounced.

In the Teganuma Swamp, improvements were attempted since the 1970s through the construction of a sewage system and water conduit projects, but they could not keep up with the increase in the surrounding population, and the COD (chemical oxygen demand) remained high even in the 1990s. While the Inba Marsh also plays a role as a regulating reservoir for the Tone River system, its water quality continued to deteriorate due to the influence of agricultural land development and urban drainage, and this was damaging the living environment of the surrounding residents and its value as a tourist resource.

In response to this situation, in October 2001, Chiba Prefecture under the leadership of Governor Akiko Domoto announced a policy to establish a new fund whose use would be limited to environmental conservation and restoration. Although the prefecture was financially strapped with 1.9 trillion yen in municipal bonds outstanding as of the end of FY2000, plans were nevertheless made to solicit donations from a wide range of municipalities, the private sector, and prefectural residents, and to use the fund to finance projects starting the following fiscal year.

This effort was a symbolic shift from the conventional development policy centered on public works projects toward the restoration of the natural environment with the cooperation of local residents and the private sector. Although the restoration of Teganuma and Inba Marsh was not an easy task, it became a touchstone, along with Sanbanze, for the shift in Chiba Prefecture's environmental policy at the beginning of the 21st century, from an era of destroying nature to one of restoring it.