Field survey of the Kohatsu River flood on May 31, 2022

6/2 2022

On May 31st, 2022, a heavy rainfall occured in the Okinawa main island. According to the Japan Meteorological Agency, the precipitation was recorded at around 110 mm per hour arond Tamagusuku and Sashiki in Nanjo City, which led to flooding mainly in the southern part of the Okinawa main island. Since there was information on flooding around the Kohatsu River, which is near the University of the Ryukyus, we went to the Kohatsu River for a field survey.

Root Map.

We saw many traces of the flood, and there were tree branches and the garbage carried away during the flood Points 1,3 and 5.

Photo taken at point 1.

Over flow section. Photo taken at point 3.

Photo taken at point 4.

Over flow section Photo taken at point 5.

The flood also washed large gravel bags used for strengthening the riverbanks against erosion and recently used for construction purposes.

Gravel bags washed out. Photo taken at point 2.

According to this survey, it was found that the Kohatsu River was flooded in several places due to the heavy rain on May 31, 2022.