Environmental Management Administration

In earlier times, the Erren River's downstream section was known as Erchenghang or Erzhanhang River. By the 1980s, the area became a hub for scrap metal recycling and refining factories. Initially centered in the Wanli area of Tainan City, the industry gradually expanded to neighboring regions such as Rende Township (originally in Tainan County) and Qieding and Hunei Townships (originally in Kaohsiung County). Scrap metal processing predominantly relied on open-air burning and crude acid-washing methods. While these techniques extracted valuable metals from scrap, open-air burning generated air pollution, and untreated wastewater from chemical agents was discharged directly into the Erren River. Large quantities of waste byproducts were also dumped along the riverbanks, leading to severe environmental degradation.

On Aug. 22, 1987, the Environmental Protection Bureau of the Department of Health, Executive Yuan, was upgraded to the Environmental Protection Administration, Executive Yuan. By 1989, the import of scrap metals was banned and in 1993, all scrap metal parallel imports were banned. To combat illegal smelting operations, the EPA (now the Ministry of Environment) established the Erren River Illegal Smelting Pollution Remediation Task Force on Sept. 27, 2000. On Oct. 2, the Erren River was included in the "Taiwan Rivers and Oceans Management Plan," and a patrol team was formed. After decades of efforts, by 2020, the proportion of severely polluted stretches along the Erren River had decreased from 65.2% to 24.1%. Additionally, the Sixth River Management Branch of the Water Resources Agency, Minstry of Economic Affairs, along with the Tainan and Kaohsiung city governments, has removed over 180,000 tons of industrial waste from several disposal sites along the riverbanks.

The Sixth River Management Branch of the Water Resources Agency commissioned the "Waste Assessment and Testing Service Plan for Erren River's Estuary to Erchengxing Bridge Section" in 2020, investigating pollution in the middle and lower reaches of the river. Based on the plan, the "Second Phase Implementation Plan for Erren River Waste Cleanup (Draft)" was proposed. The cleanup targeted four key disposal sites, including Under Erren River Bridge (right bank), 450 meters upstream of Nanding Bridge (right bank), sixth to seventh Water Gates (left Bank, opposite Erxing Temple), and 170 meters downstream of Nanding Bridge (left bank).

Water quality analysis based on River Pollution Index (RPI) and heavy metal testing data was conducted at water quality monitoring stations upstream and downstream of waste disposal sites, Erchenghang Bridge and Nanding Bridge, near the Erren River waste disposal sites. The RPI water quality monitoring is conducted monthly, and heavy metal monitoring is conducted quarterly.

From 2013 to 2020, the water quality RPI at the Erchengxing Bridge and Nanding Bridge monitoring stations showed a downward trend, indicating moderate pollution. However, starting in 2021, there was a slight increase in RPI due to bank protection and bridge reconstruction works on the upstream tributary, Sanyeh River, which led to sediment and riverbed disruptions. Excluding the impact of these works in 2021 and 2022, the overall trend of water quality improvement in the downstream Erren River is stable.

Over the years, manganese has been the only heavy metal exceeding standards. However, manganese is a naturally occurring element often found in mineral forms alongside iron. Therefore, its presence above standard levels in certain basins is a natural phenomenon rather than a result of pollution. All other heavy metals meet environmental benchmarks for human health protection.

The water quality monitoring data from the Erchengxing Bridge and Nanding Bridge stations in downstream Erren River have shown continuous improvement. Furthermore, the concentration levels of heavy metals (excluding manganese) are stable and comply with health-protective environmental benchmarks, indicating a gradual improvement in the river's water quality. For the newest water quality testing data, please visit the ministry's Environmental Water Quality Information website.

In Sept. 2022, the administration commissioned a professional contractor to implement the "Erren River Waste Disposal Site Environmental Investigation and Cleanup Program Evaluation Plan." Relevant results were submitted to the Water Resources Agency, Ministry of Economic Affairs, for incorporation into the "Second Phase Implementation Plan for Erren River Waste Cleanup (Draft)" as reference for amendments. To verify whether cleanup methods could more efficiently handle waste and its environmental impacts, additional funding was granted in July 2023 to the Tainan City Environmental Protection Bureau for the "Erren River Waste Cleanup Pilot Project," which has been completed. Going forward, the ministry will provide funds for cleaning to local governments; once local governments submit cleaning plans, the ministry will submit them to the Executive Yuan for approval before they are executed.

For information on the progress of waste disposal site management in the Erren River basin, please visit the Tainan City Environmental Protection Bureau's "Erren River Basin Waste Disposal Site Management Progress" section. A timeline and updates are available for reference.

Through the joint efforts of the administration and local governments, the pollution of Erren River has significantly improved, and the proportion of severely polluted sections has greatly decreased. Future cleanup plans will continue to be implemented, further enhancing the environmental quality of the Erren River basin. The public can access the latest updates and relevant information through the Tainan City Environmental Protection Bureau.