A class on creating rain gardens was held at Nanryo High School.

On June 23rd, we held a class on river basin flood control and rain gardens at Kumamoto Prefectural Nanryo High School (Asagiri Town). We invited a lecturer, Researcher Tamura from Kyushu University, to give a lecture on river basin flood control at the beginning of the class.

Next, we measured infiltration capacity (how much water seeps into the soil) at various locations on the high school grounds.

The infiltration capacity was measured using the double-ring method, in which a metal ring is buried in the soil and water is poured into it. This is a picture of an infiltration test being conducted at Minamiryo High School. The water level inside the ring is read out using a ruler and recorded every 30 seconds.

After measuring the infiltration capacity, we returned to the classroom and reviewed the results of the infiltration tests together. We found that infiltration capacity was low on the ground and high in fields and forests. The students were surprised to see that infiltration capacity changes depending on the quality of the ground.

In the future, based on these results, we plan to discuss where to create a rain garden on the high school grounds.