The EPA has listed the Lao-Jie River and Nankan River in Taoyuan as key rivers for water remediation. Including the Dahan River, downstream of which is a freshwater souce, the EPA has subsidized more than NT$700 million for water remediation of these 3 rivers over the past 5 years. Moreover, the EPA has also subsidized the Chaoyang Water Educational Park NT$64,460,000 to further improve the water quality of the Nankan River. The Chaoyang Water Educational Park not only serves as a new city attraction but also maximizes the efficiency of water purification in the meantime.

The Chaoyang Water Educational Park is equipped with a gravel contact oxidation treatment system and an underground trail designed for observing and learning about the treatment system. The system treats household wastewater diverted from the Dongmen River, which is an upstream branch of the Nankan River, to an on-site water treatment facility located by the riverside in Chaoyang Forest Park. It began construction in December 2016 and is now complete and capable of the purification of 10,000 tons of household wastewater per day. The gravel contact oxidation method that the treatment facility employs is a natural self-purification process through the biofilms in the water and has a pollutant removal rate of at least 70%. After being processed, the purified water will be sent to the rivers, ponds, and fountains in the educational park.

In the future, Taoyuan City will also use the Taoyuan BOT sewerage system to intercept 34,000 tons of household wastewater daily going to wastewater treatment plants. With the completion of subsewer connections to households and construction subsidized by the EPA, the EPA expects to make significant improvements to the water quality of the Nankan River.