Midoriko Lake is a tranquil man-made lake in Shiojiri City, Nagano Prefecture, surrounded by lush forests and peaceful natural scenery. The lake was formed by a dam built on the Tagawa River, part of the Shinano River system, originally to secure water for agriculture.
Today, Midoriko is a popular place for local residents and visitors to relax and enjoy the changing scenery of the four seasons. With its calm waters, green forests, walking paths, fishing areas, and seasonal flowers, the lake offers a refreshing escape from the bustle of the city.
As its name suggests, Midoriko, meaning “Green Lake,” is surrounded by abundant greenery throughout much of the year. Each season gives the lakeside a different character.
In spring, flowers begin to bloom around the water. Summer brings cool breezes and sparkling reflections across the lake, while autumn turns the surrounding trees into brilliant shades of red, orange, and gold. In winter, the landscape takes on a quiet, crisp beauty as snow and cold weather create an atmosphere of deep tranquility.
One of the most impressive sights comes in early spring, when approximately 3,800 Asian skunk cabbage plants bloom together around the lake. Their delicate white flowers create an almost dreamlike landscape along the waterside.
This seasonal display attracts photographers, families, and nature lovers who come to enjoy the flowers and the peaceful surroundings. The combination of white blossoms, clear water, and fresh spring greenery makes this one of Midoriko’s most memorable seasonal attractions.
Midoriko is also widely known as a destination for herabuna fishing, a traditional form of freshwater fishing in Japan. Anglers can often be seen around the lake, quietly waiting beside the water or fishing from boats.
In particular, a Herabuna Fishing Tournament is held in early summer, attracting fishing enthusiasts from a wide area. Boats floating on the calm water and anglers concentrating on their fishing rods have become part of the characteristic scenery of Midoriko.
The history of the lake dates back to 1932, when the area was still part of Shiojiri Town. At that time, a reservoir called Tagawaura Tameike was constructed to provide a stable water supply for approximately 125 hectares of farmland.
However, its storage capacity of around 26,000 cubic meters was not sufficient to meet the area’s agricultural needs. Nagano Prefecture therefore planned another reservoir, and construction of Mukozaka Tameike began in 1948. It was completed around 1952 and became an important source of water supporting local agriculture.
As the lake became part of the local community, its role gradually expanded beyond agriculture. In summer, visitors enjoyed boating on the water, while winter once brought opportunities for skating on the frozen lake.
As recreational use increased, a public competition was held in 1958 to choose a new name for the lake. Inspired by the lush greenery surrounding the water, the name Midoriko was selected.
Since then, Midoriko has become one of Shiojiri’s well-known places for enjoying nature and spending time outdoors.
In 1983, Nagano Prefecture carried out a project to improve aging reservoir facilities. The work included the construction of a new spillway and other improvements designed to make the area safer and more comfortable.
In more recent years, efforts have also focused on improving water quality. A system using an aeration device known as the Lake Lifter method circulates the lake water, helping maintain a healthy and attractive aquatic environment.
Volunteer groups also work to protect Genji fireflies in the waters below the dam embankment. On summer evenings, the fireflies can create a magical display of lights around the lake.
These conservation efforts have been recognized as part of Shiojiri City’s “20 Hometown Waters of Shiojiri” selection. The activities reflect the community’s commitment to preserving the lake’s natural environment for future generations.
The area around Midoriko has been developed as a park, with walking paths where visitors can enjoy the scenery throughout the year. Lakeside attractions include an Asian skunk cabbage garden, flower beds, fishing areas, and a boating area.
The peaceful setting makes Midoriko especially appealing to families and couples looking for a relaxing outdoor experience. Nearby, Midoriko Onsen provides an opportunity to unwind after exploring the area.
Visitors can also enjoy activities such as mallet golf and camping, making the lake a destination where both quiet nature experiences and outdoor recreation can be combined.
Midoriko is relatively easy to reach by both public transportation and car. From Shiojiri Station on the JR Chuo Main Line and Shinonoi Line, visitors can take the Shiojiri City Regional Development Bus on the Kitaono Line and get off at the Midoriko-guchi bus stop.
The lake is also approximately 20 minutes on foot from JR Midoriko Station. Until 2023, a local bus service also operated to Midoriko Hana Park.
By car, Midoriko is approximately 10 minutes from the Shiojiri Interchange on the Nagano Expressway, making it a convenient stop for visitors exploring the Shiojiri area by car.
Midoriko has been selected as one of the “30 Selected Places of Shiojiri”, a collection of destinations representing the city’s distinctive attractions.
The lake is more than a scenic reservoir. Its history is closely connected with local agriculture, while its parks, fishing traditions, seasonal flowers, and environmental conservation activities demonstrate the continuing relationship between the community and its natural surroundings.
A leisurely walk along the lakeside is an excellent way to experience the changing seasons while appreciating the harmony between nature and the people who have cared for this landscape over the years.
Midoriko Lake is a place where nature, history, recreation, and community life come together. The white flowers of Asian skunk cabbage in spring, the lively fishing season in summer, colorful autumn foliage, and the stillness of winter each reveal a different side of the lake.
Although it began as an agricultural reservoir, Midoriko has developed into a beloved recreational and natural area where visitors can slow down and enjoy the landscape at their own pace.
When visiting Shiojiri, take time to walk beside the lake, watch the reflections on the water, observe the seasonal plants and wildlife, and simply enjoy the peaceful atmosphere. Midoriko offers a gentle reminder of how a place created for practical purposes can become an enduring part of a community’s natural and cultural landscape.