Guide
Yanba Dam is a multi-purpose gravity concrete dam located in Nagaoka Village, Agatsuma District, Gunma Prefecture. It was constructed on the middle reaches of the Agatsuma River, a major tributary of the Tone River, and began operations on April 1, 2020. With a height of 116m, the dam creates the beautiful Lake Yanba Agatsuma, which plays a crucial role in supplying water to the Kanto region (including Tokyo), flood control, and hydroelectric power generation. The sheer scale of the structure and the surrounding natural landscape make it a captivating destination for visitors.
The construction plan for Yanba Dam originated from the 1952 Tone River Improvement Project. It was developed through a long-term process involving significant investment to address water shortages in the Tokyo metropolitan area and to prevent devastating floods. The project involved complex historical negotiations and community discussions to reach its current form. In recognition of its architectural and engineering significance, the dam received the Excellent Award at the Japan Society of Civil Engineers (JSCE) Design Award in the 2024 fiscal year.
The dam structure itself is a marvel of engineering. The main gates utilize radial gates, allowing visitors to feel the immense scale of the facility up close. The vast surface of Lake Yanba Agatsuma, framed by surrounding mountains, provides a highly photogenic landscape. The dam crest spans approximately 290.8m, standing as a testament to modern civil engineering. Additionally, the Yanba Power Station is located downstream, utilizing the water flow to generate renewable hydroelectric energy.
The area offers different charms depending on the season. The scenery is particularly stunning when the lake surface is calm or when the surrounding mountains change color. In the summer, seasonal activities such as amphibious bus tours may be available. Please note that certain areas, such as the 'Yanba Mihodai' lookout, may have restrictions or closures during the winter season; it is highly recommended to check the latest local information before your visit. Daytime visits are ideal for capturing clear photos of the massive structure and the shimmering reflections on the lake.
Visitors can enjoy various activities to immerse themselves in nature. Depending on the season, you can experience the area via sightseeing boats or amphibious buses that traverse both land and water. There are also facilities where you can learn about the history and the vital role the dam plays in the region, making your visit both an educational and scenic experience.
The area around the dam features several facilities designed to promote local revitalization. At the 'Michi-no-Eki Yanba Furusato-kan' (Roadside Station), you can enjoy local specialties and gourmet food. Other observation points are also well-maintained to allow visitors to enjoy the lake views. These facilities were established as part of regional development following the dam's construction, offering a deeper look into the local history and modern community life.
As the area is surrounded by nature, we recommend wearing comfortable walking shoes and clothing suitable for outdoor activities. Please prepare for potential weather changes, especially if you plan to participate in seasonal activities. Always follow local rules and safety instructions regarding the dam facilities and surrounding areas to ensure a safe and pleasant visit.