National | Regional Voices: Tohoku

Sendai launches new waterway project to prevent city flooding

Kahoku Shimpo

Deadly Typhoon Hagibis caused riverbanks to burst across Japan in October, and also led to sewer flooding around Sendai Station, known as the gateway to the Tohoku region, leaving roads and underground passages in the heart of the city underwater.

But for local business operators, the scene of flooded streets is nothing new, given that the flood-prone area west of the station becomes submerged whenever torrential rains hit the region.

In the current fiscal year, the Sendai Municipal Government has set about upgrading the zone’s drainage system to raise rainwater pumping capacity.

“Much of the city’s major functions, including shopping centers, are concentrated around Sendai Station,” a municipal government official said, stressing the need to prioritize flood prevention efforts in the area.

According to the municipal government, Typhoon Hagibis caused flooding as deep as some 40 centimeters along Aoba-dori avenue — Sendai’s main street, stretching west from the station — near Eden, a commercial complex in front of the station.

Rainwater also flooded the underground passage connecting Sendai Station’s east and west sides, as well as the linked subway station. The water also entered underground floors of the main building of S-Pal Sendai, a shopping mall directly connected to the station, seeping into some of its underground stores.

Store operators say the shops located along the main street sustained the most severe damage.

“Even though we had placed sandbags at the entrance, our store was submerged about 15 cm deep, and this happens almost every year,” said Hirokatsu Sasaki, 56, who works at a voucher shop across the street from Eden. “I want the government to do something about this fast.”

According to the city officials overseeing the sewerage system, the area stretching west of the station has a shallow slope. While Hirose-dori avenue to the north of the station is 36.8 meters above sea level, the area just north of Aoba-dori is 35.5 meters above sea level and 35.6 meters to its south. The officials explain that the main street is located in a basin, so floodwaters tend to remain.

The drainage system on the west side of the station was mainly built in the 1950s after World War II.

“Along with the development of the area, the land surface was increasingly covered with asphalt and concrete, and the area of uncovered soil declined,” an official in charge of drainage systems said. “As a result, the area lost its capability of retaining water.”

The municipal government has set about constructing a new major waterway on the west side of the station.

It has allocated ¥11 billion in the current fiscal year to create the waterway, which will cover a roughly 3.8-kilometer stretch from Aer, a 31-story complex at the north of the station, to the Hirose River.

The waterway, expected to be put into use in fiscal 2026, will be up to 2.6 meters wide, compared with 1.65 meters for the existing drainage system, offering a much higher drainage capacity.

The municipal government believes the new system will greatly reduce the possibility of flooding in areas near the main street, even in the event of heavy rainfalls reaching 52 millimeters per hour, which is predicted to occur once every decade.

This section features topics and issues from the Tohoku region covered by Kahoku Shimpo, the largest newspaper in Tohoku. The original article was published on Nov. 14.