[Opinion] Extreme Heavy Rain and Flooding, What We Must Do

Kim In-cheol, Head of Rural Development Division, Haenam-Wando Branch, Korea Rural Community Corporation

Due to abnormal weather caused by global warming, heavy rainfalls frequently occur nationwide. This results in damage to both urban areas and farmlands.

The Korea Meteorological Administration has started sending disaster alert messages for 'extreme heavy rain' to reduce damage caused by heavy rainfalls and prepare for subsequent damage. Usually, when the rainfall exceeds 30mm per hour, it is called a 'heavy rain.' The concept of 'extreme heavy rain' goes beyond this, referring to rainfall exceeding 50mm per hour and a cumulative rainfall of 90mm over three hours. It causes various disasters such as landslides, flooding, and river or valley overflows. The introduction of the 'extreme heavy rain' concept is a clear example of how drastically rainfall patterns have changed due to climate anomalies.

From the 19th to the 21st of last month, under the influence of Typhoon No. 14 'Pulasan,' extreme heavy rain exceeding 100mm per hour fell in the Jeonnam region. Haenam experienced an average rainfall of 280mm, with a maximum of 389mm (Haenam valley) of water bombs pouring down. This shows that rainfall patterns with heavy rain in a short time have frequently occurred.

This extreme heavy rain caused widespread flooding damage nationwide. The downtown area of Changwon, Gyeongnam, was flooded in many places, and a large sinkhole 8 meters deep appeared in Busan. In Iksan and Gimje, Jeonbuk, 1,500 hectares of rice paddies were flooded. In about 200 hectares of farmland in Jeonnam, rice ready for harvest was flattened, and field crops were washed away by soil, causing continuous farmland damage.

The Korea Rural Community Corporation is making efforts to prevent flood damage by lowering reservoir storage rates to below 70% during the flood season and pre-releasing water from embankment reservoirs to secure surplus water in preparation for typhoons and heavy rainfalls. However, despite these measures, the frequency of 'extreme heavy rain' is increasing every year, and the damage is gradually becoming more severe.

Therefore, in low-lying or poorly drained habitual flood-prone areas, active promotion of 'drainage improvement projects,' such as maintenance and installation of drainage facilities (drainage pumps, drainage gates, drainage channels), is necessary to permanently resolve flooding. Drainage improvement projects are flood damage prevention projects that build or refurbish disaster prevention facilities such as drainage channels and drainage pumps in farmlands where flooding frequently occurs.

The Haenam-Wando branch of the Korea Rural Community Corporation prevented flooding damage to 289.5 hectares of farmland in Wonho-ri, Hwangsan-myeon, Haenam-gun, through the Gocheonam district drainage improvement project (19.7 billion KRW). Once the Gocheonam 2 district (scheduled to start construction next year) and Gocheonam 3 district, currently in detailed design, begin construction this year, it is expected to prevent flooding and disasters in the Gocheonam area of Haenam, which suffered significant damage from heavy rain in 2021, greatly contributing to safe farming.

Recently, heavy rainfalls due to abnormal weather have occurred regardless of the season, and the risk of flooding damage remains high, highlighting the need for proactive flood prevention projects. Efforts to expand disaster preparedness projects such as drainage improvement projects should continue in the future.

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