A popular beach has decided to cancel its summer season. The reason is the “disappearance of the sandy beach.” What is happening on Japan’s coast now? Some studies predict that more than 60% of the sandy beaches will disappear by 2100.
■Why? The disappearance of beach sandy beaches The beach in Yaizu City, Shizuoka Prefecture, opened for the season on the 17th. Energetic children are enjoying the sea. The swimming season has officially begun, but there was a beach in Ibaraki Prefecture that was unable to open. It was “Otake Kaigan Hokota Beach.” Known as the “Gold Coast of Ibaraki” for its beautiful scenery and the straight stretch of sandy beach with nothing to obstruct the view, it is a popular spot that usually attracts more than 20,000 beachgoers every year, but… this summer, part of it is off-limits.
The reason is the “disappearance of the sandy beach.” Previously, many tents were set up on the beach, and a beautiful sandy beach stretched out before them, but… now the area of the sandy beach has drastically decreased, and there is no space to set up tents. Waves were crashing right up to the shore. When the program previously covered this location, only six layers of blocks were visible, but now the sand has drastically decreased, exposing blocks that were previously hidden. The sand that was originally there is gone, and holes have formed in the blocks.
Hokota City has decided to cancel the beach opening, taking safety concerns into consideration. The cancellation of the beach opening has had an impact on nearby restaurants. Takuya Onuma of Restaurant Uminokaze: “Some people come to the beach to swim and also stop by the restaurant. I think there will be an impact.” The restaurant is located right by the sea. At this time of year, ramen made with clams caught nearby is popular. The swimming season is one of the busiest times of the year, with around 400 customers visiting on weekends, but… Takuya Onuma: “I think it will affect about 50 to 100 people. I think there are customers who are looking forward to enjoying the sea, so although it is difficult because it is a natural phenomenon, I would like the beach to be opened.” Why did the sandy beach start to erode? Takahisa Shiota of the Ibaraki Prefectural River Division said,
“One major factor is the decrease in the supply of sand to the coast.” According to Ibaraki Prefecture, which manages the coast, the Kashima Sea, where Hokota Beach is located, has maintained its sandy beaches by sediment carried by the waves from the Naka River and Tone River. However, the amount of sediment has drastically decreased compared to the past. The reason for this is the urbanization of the river basin. Takahisa Shiota said, “Dams are being built upstream, and as urbanization progresses, what used to be farmland is being turned into asphalt, making it difficult for sediment to flow into the river. Concrete seawalls are being built in the rivers, and there are various other effects, so the amount of sediment supplied from the rivers into the sea has decreased compared to the past. Erosion is occurring.”
Two years ago, the opening of the beach was canceled due to sandy beach erosion. The following year, construction work was carried out to transport sand to the coast, and the beach was able to open, but the sand that was put in was washed away, and the sandy beach was eroded again. The construction cost around 40 million yen, and adding sand every year is said to be costly. Shiota Takahisa says, “Continuing this indefinitely will not be cost-effective in the long run.”
■60% to disappear by 2100? This “disappearance of sandy beaches” is not limited to Ibaraki Prefecture. The beach in Katagami City, Akita Prefecture, which was once bustling with many swimmers, has also seen increasing sand erosion year after year, with most of the sand now covered by waves. Sandy beach erosion is progressing throughout Japan, and the number of beaches that cannot be opened for swimming is increasing. According to research estimated by Professor Udo and others at Tohoku University Graduate School, there is a risk that more than 60% of the sandy beaches in Japan will disappear by 2100. Is there a way to restore the lost sandy beaches…? [TV Asahi NEWS]
