Saku Power Station is a hydroelectric power station located in Bungo Hachizaki, Hokkitacho, Shibukawa City, Gunma Prefecture. It generates electricity using the abundant water resources of the Tone River basin and is currently operated by TEPCO Renewable Power.
While the power station has supported local industry and everyday life for many years, the surrounding area is also known as a popular cherry blossom viewing spot in spring.
The striking combination of the enormous surge tank rising up the mountainside and cherry trees in full bloom creates a distinctive landscape that can be seen at Saku Power Station.
The most recognizable feature of Saku Power Station is its approximately 80-meter-tall surge tank, which can be seen from a considerable distance.
A surge tank is an important component of a hydroelectric power system. It regulates changes in water pressure that occur when water is transported to the power station and helps protect the water-conveyance facilities. The huge cylindrical tank standing on the mountainside has become a landmark of the Hokkitacho area, together with Mount Tachibana.
The current surge tank is the second-generation structure, rebuilt in 1987. The original tank had a distinctive cocoon-like shape and remained a local landmark for approximately 60 years.
The enormous tank still creates an impressive sight on the mountainside and serves as a symbol of the power station’s history and the surrounding landscape.
The area around Saku Power Station is one of Shibukawa City’s notable cherry blossom viewing spots. Approximately 100 Somei Yoshino cherry trees, around 70 years old, are planted near the water-conveyance pipes. They typically reach full bloom from early to mid-April.
The sight of rows of cherry trees in full bloom alongside the huge surge tank offers a distinctive experience unlike that of a conventional cherry blossom destination. The combination of industrial infrastructure and springtime nature creates a unique landscape characteristic of Saku Power Station.
During the cherry blossom season, many visitors come to enjoy the flowers and the arrival of spring. Depending on the year, a local event known as the Kansui Sakura Festival may also be held.
Saku Power Station generates electricity using water from both the Tone River and the Agatsuma River. By utilizing water from multiple rivers, the facility makes effective use of local water resources to generate electricity.
Water from the Tone River is diverted at Ayato Dam in Iwamoto, Numata City, and transported to the Makabe regulating reservoir in Hokkitacho, Shibukawa City. From there, the water is carried through a penstock to the surge tank and then flows down the mountainside through three additional pressure pipelines before reaching the power station.
Water from the Agatsuma River passes through facilities including Kanai Power Station and Shibukawa Power Station. Near the confluence of the Tone and Agatsuma rivers, the water crosses the river using a siphon system before being conveyed to Saku Power Station.
By combining water from these different sources, the facility operates an efficient hydroelectric power system.
The power station contains multiple generating units. Water conveyed from the Tone River is used to turn Francis turbines in Units 1 through 3, generating electricity.
Water conveyed from the Agatsuma River is used to operate a propeller turbine in Unit 4. After passing through the generating facilities, the water is discharged into the Hirose-Momoki Irrigation Canal. It continues to be used by other hydroelectric facilities in Gunma before eventually flowing through the Hirose River and returning to the Tone River.
The history of Saku Power Station dates back to the Taisho period. Construction began in 1925 under Kanto Hydroelectric Power, a company founded by businessman Soichiro Asano, and the facility was completed in 1928.
At the time, it was an exceptionally large-scale hydroelectric facility and attracted considerable attention. When completed, it was described as “the largest power station in the Orient”.
In 1938, the station also began generating electricity using water from the Agatsuma River. In addition to supplying electricity to the Tokyo metropolitan area, it provided power to industrial facilities constructed across the Tone River.
The name “Saku” is said to have originated from the literary name used by Soichiro Asano’s wife.
The operations of Kanto Hydroelectric Power were later transferred to Japan Electric Generation and Transmission Company and then to Tokyo Electric Power Company. Today, the facility is operated by TEPCO Renewable Power.
Locally, the nickname “Kansui” remains in use. It derives from the abbreviated name of the former operator, Kanto Hydroelectric Power, and serves as a reminder of the area’s industrial history.
In Fureai Park near the power station stands a bronze statue of Soichiro Asano, who was involved in the construction of Saku Power Station.
In 2012, the statue was donated by Himi City in Toyama Prefecture, Asano’s hometown. Known as the “Nine Falls, Ten Rises Statue,” it stands facing in the direction of Himi, symbolizing Asano’s perseverance and his connection to his birthplace.
The statue can also be viewed as a monument symbolizing the exchange between Shibukawa City and Himi City. It is an interesting place to visit when learning about the history of Saku Power Station and the people connected with its development.
Saku Power Station can be reached in approximately 15 minutes by car from JR Shibukawa Station on the Joetsu Line.
The surrounding area features natural scenery and rural landscapes along the Tone River. The area is particularly beautiful during the cherry blossom season, when visitors can enjoy the flowers while learning about the region’s history and the development of hydroelectric power.
Saku Power Station is a unique destination where visitors can experience both the history of a hydroelectric power facility that has supported local communities and the beauty of cherry blossoms in spring.
The striking landscape created by the approximately 80-meter-tall surge tank and around 100 Somei Yoshino cherry trees is a distinctive feature of the site. The surrounding historical facilities and the connection with Soichiro Asano also give the area an appeal beyond that of an ordinary cherry blossom viewing spot.
When visiting Shibukawa City in spring, consider stopping by Saku Power Station to enjoy the cherry blossoms while discovering the history of hydroelectric power and the industrial heritage that has helped shape the region.