While the overall water quality of rivers nationwide has improved, 11 of the 50 main rivers saw their conditions deteriorate last year, the Environmental Protection Administration (EPA) said as it announced the results of its Rivers and Oceans Water Quality Improvement Plan.
The second phase of the plan, which began in 2008 and ended last year, focused on the execution of cleanup strategies, including urban river restoration, on-site treatment, integrated watershed treatment and civic participation in river patrols.
EPA Department of Water Quality Protection section chief Chiou Ren-jie (邱仁杰) said several urban river restoration projects have been completed along five rivers in western Taiwan, while two more are planned for later this year.
Chiou said urban river restoration projects are aimed at dealing with domestic wastewater and rivers that are unable to self-purify because of relatively flat riverbeds. Solutions to these problems, Chiou said, included building interceptor sewers and bringing in clean water.
The completed interceptor sewers can now handle about 344,800 tonnes of wastewater a day, Chiou said, adding that after restoration projects along the Tianliao River (田寮河) and Laojie River (老街溪) are completed this year, it is estimated that 434,800 tonnes of wastewater can be treated on a daily basis, which is about the volume created by 700,000 people every day.
Moreover, the water quality of the Tamsui River (淡水河) in New Taipei City (新北市) and the Erjen River (二仁溪), which flows from Greater Tainan to Greater Kaohsiung — both once notorious for their poor water quality — also improved greatly after the projects, Chiou said.
“The percentage of highly polluted sections of the Tamsui River dropped from 21.8 percent in 2003 to 6.3 percent last year, while those in the Erjen River dropped from 100 percent in 2003 to 28.2 percent last year,” Chiou said.
However, the water quality of 11 rivers has deteriorated, department director-general Sheu Yiong-shing (許永興) said.
Greater Kaohsiung’s Agongdian River (阿公店溪) saw its highly polluted section length extend to 28.7km last year, Sheu said, an increase of 8.5km, from 20.2km in 2010.
Other rivers which saw their water quality decline included the Beigang River (北港溪), which flows through Yunlin and Chiayi counties, Tainan’s Jishuei River (急水溪), Taoyuan County’s Nankan River (南崁溪) and Miaoli’s Chungkan River (中港溪), Sheu said.
This may be a result of lower rainfall throughout western Taiwan last year, illegal industrial wastewater emissions along the Agongdian River, as well as illegal emissions from stock farms along rivers such as the Beigang and Jishuei.