Yanba Dam is a dam project that is under construction in Naganohara, Agatsuma District, Gunma Prefecture, Japan. It is being built on the Agatsuma River, a tributary of the Tone River, which flows down through the metropolis of Tokyo, and the dam project is financed by Tokyo and the five prefectures through which the Tone River courses- Saitama, Chiba, Ibaraki, Tochigi, and Gunma. The project is currently under construction, with completion slated for 2019. Work on the dam was halted in 2009 when the Democratic Party of Japan (DPJ) came to power. It was halted as part of dozens of public works projects to be reconsidered. Planning for the dam began in 1947, and it was planned to be completed by 2015. The dam's construction has seen sustained local opposition and a ballooning budget.  Japan has suffered much flood damage, and after World War II dams were planned with the principal intention of protecting the metropolis from floods. Dams have therefore become particularly symbolic because they were favored as a means of flood control and power generation by Japan’s central planners, who have dammed almost every major river in the country. Amid Japan's rapid economic expansion of the 1960s and 1970s, population growth concentrated in cities, municipal water demand grew, and Tokyo and other major urban areas experienced water shortages. Clusters of dams were built upstream of the Tone River as an important facet of city planning, and Yamba Dam was promoted on the back of an emphasis on the necessity of water for domestic and industrial use.  The Agatsuma River, however, has the special characteristic of being fed from acidic rivers flowing down from the Kusatsu hot spring, which was held to make the construction of a concrete dam unfeasible.  Planning was halted but then restarted in 1965 after the construction of a plant in Kusatsu to neutralize the acidity of the water.

The dam, which would dam the Agatsuma River, would flood an area of 316 hectares, require 422 households to relocate, and affect the lives of 1,100 residents.