Lake Izunuma is a beautiful freshwater lake stretching across Tome City and Kurihara City in Miyagi Prefecture. Covering approximately 369 hectares, including about 289 hectares of water surface, the lake has a volume of roughly 2.79 million cubic meters.
Izunuma is remarkably shallow. Its average depth is only about 0.76 meters, while its deepest point is approximately 1.6 meters. Because of its shallow waters and rich lakebed, numerous aquatic plants can grow throughout the wetland, creating an important habitat for migratory birds, fish, insects, and other wildlife.
The lake was formerly known as Onuma, or “Large Lake,” and its wetlands have long been closely connected with the lives and livelihoods of people in the surrounding area. Today, however, its greatest importance lies in its role as a valuable natural environment and one of Japan’s most important wintering grounds for migratory birds.
From autumn through winter, large numbers of migratory birds arrive at Izunuma. The lake is particularly famous for greater white-fronted geese and greater bean geese, both of which are designated as Natural Monuments of Japan.
Other waterfowl commonly seen in the area include mallards, northern pintails, Eastern spot-billed ducks, tufted ducks, whooper swans, and tundra swans. The variety and sheer number of birds make the lake an exceptional destination for birdwatchers and nature lovers.
One of the most memorable sights at Izunuma occurs in the early morning and around sunset. Vast flocks of geese suddenly take flight together, filling the sky as the sound of thousands of beating wings and calls echoes across the wetland.
The dramatic soundscape created by the birds has been selected as one of Japan’s “100 Soundscapes of Japan,” recognizing the distinctive sounds of nature and local life that are considered worth preserving.
For visitors, watching a huge flock rise from the lake at sunrise can be an unforgettable experience. The sight combines the changing colors of the sky with the movement and calls of the birds, offering a remarkable encounter with the natural world.
Izunuma and neighboring Lake Uchinuma were designated in 1967 as a Japanese Natural Monument under the designation “Birds and Their Habitat at Izunuma and Uchinuma.” This designation recognizes the importance of the area as a habitat for birds.
In 1985, the lakes were also designated as a Ramsar Convention Wetland of International Importance. Izunuma and Uchinuma became Japan’s second Ramsar site, highlighting the international significance of this wetland ecosystem.
These designations reflect the importance of protecting the lakes not only for visitors today, but also for the many species that depend on this environment during their life cycles.
While winter is the best-known season for migratory birds, summer reveals another spectacular side of Izunuma. From approximately July through August, lotus flowers bloom across the surface of the lake, creating an extraordinary landscape of delicate pink blossoms and green leaves.
Other aquatic plants, including water snowflake and fringed water-lily, can also be seen around the lake. Together, these plants create a colorful and lively wetland environment.
The abundant vegetation also provides a habitat for numerous insects. Species such as the giant dragonfly and butterfly dragonfly can be observed around the water during the warmer months.
With flowers covering the lake, insects flying among the vegetation, and the surrounding landscape filled with summer greenery, Izunuma takes on the appearance of a natural paradise.
The area around Izunuma was once a vast wetland used by local communities as shared land where reeds and thatch were harvested. During the Jōkyō era (1684–1688), land improvement projects began, and efforts were made to develop parts of the surrounding area for agriculture.
Plans to reclaim the lake on a larger scale, however, were eventually abandoned because residents living downstream opposed the project. The low-lying wetlands also remained vulnerable to flooding, creating difficulties for people living and farming in the surrounding area.
During the early Showa period, a farmland improvement association was established, leading to the construction of drainage channels and other improvements to the surrounding agricultural land.
During the Pacific War, large-scale land reclamation was undertaken as part of national agricultural policy. By 1964, approximately 262 hectares had been reclaimed.
The history of Izunuma therefore reflects a long relationship between people and wetlands, including both the use of natural resources and the challenges of balancing agricultural development with environmental conservation.
Despite its rich biodiversity, Izunuma has faced environmental challenges, including declining water quality and the spread of invasive species.
One particularly serious problem was the increase of largemouth bass, commonly known in Japan as black bass. The invasive fish preyed on native small fish, causing their populations to decline significantly.
In response, conservation efforts began using artificial spawning beds to help control the invasive fish population. This approach became known as the “Izunuma Method” and has subsequently been adopted in other areas.
These conservation activities have contributed to signs of recovery in the local ecosystem. In 2015, the zeni-tanago, a native bitterling species that had disappeared from the lake for a period of time, was confirmed once again at Izunuma.
The return of this native fish illustrates the importance of long-term conservation and the possibility of restoring biodiversity when appropriate measures are taken.
In the 2000s, plans were proposed to construct a hot spring facility beside the lake. The project was ultimately canceled following opposition from local residents and nature conservation groups.
As a result, the lakeside environment remained largely focused on its natural value, allowing Izunuma to continue serving as an important refuge for migratory birds and other wildlife.
The history demonstrates that Izunuma is not simply a scenic destination. It is also a valuable wetland whose future depends on maintaining a balance between human activities and the protection of nature.
Birdwatching is one of the highlights of visiting Izunuma. Winter mornings are particularly impressive, when huge flocks of greater white-fronted geese can be seen taking off from the lake.
Observation facilities and walking paths have been established around the wetland, making it possible to enjoy the scenery and wildlife at a leisurely pace. Bringing binoculars is recommended for visitors who want to observe the birds more closely without disturbing them.
Izunuma offers a different landscape throughout the year.
Spring brings fresh vegetation and new growth. In summer, lotus flowers spread across the water and create one of the lake’s most distinctive landscapes. Autumn brings golden rice fields and the arrival of migratory birds, while winter offers snow-covered scenery accompanied by large flocks of waterfowl.
This seasonal variety makes Izunuma an appealing destination for nature lovers throughout the year, even though the best-known wildlife spectacle occurs during the colder months.
Location: Tome City and Kurihara City, Miyagi Prefecture
By train: Approximately 10 minutes on foot from Nitta Station on the JR Tohoku Main Line.
By car: Approximately 20 minutes from Kurikoma-Kogen Station on the Tohoku Shinkansen, or about 30 minutes from Tsukidate Interchange on the Tohoku Expressway.
Izunuma is an environmentally important wetland recognized both nationally and internationally. Visitors are asked to help protect this valuable ecosystem by taking all trash home, avoiding actions that disturb birds and wildlife, and refraining from damaging plants.
Keeping a respectful distance from birds is especially important during the winter season. Quiet observation allows both visitors and wildlife to enjoy the wetland without unnecessary disturbance.
Lake Izunuma is a remarkable destination where migratory birds, aquatic plants, insects, and seasonal landscapes come together. From enormous flocks of geese filling the winter sky to lotus flowers blooming across the water in summer, every season reveals a different aspect of this special wetland.
Its history of agricultural development, environmental challenges, and ongoing conservation also makes Izunuma an important place for understanding the relationship between people and nature in Miyagi.
Whether you visit for birdwatching, photography, seasonal scenery, or simply a peaceful encounter with nature, Lake Izunuma offers an opportunity to experience the rhythms of Japan’s wetlands and the remarkable wildlife that depends on them.