The Environmental Protection Administration (EPA) has worked in coordination with the Water Resources Agency, Council of Agriculture, and local governments on fugitive dust control since 2011, with well-defined authority and duty, work contents, and goals of improvement for each bureau and department. The Executive Yuan has approved the Riverbed Fugitive Dust Control and Promotion for Improvement Plan (2012 to 2015) in 2013, Air Pollution Prevention and Control Action Plan in 2017, and Air Pollution Prevention and Control Action Plan (2020-2023) in 2020.
Riverbed fugitive dust originates from river bare land subject to strong wind blow. Under the impact of climate change, streamflow variations intensify between flood and non-flood seasons, leading to rapid changes in the area and location of bare land in rivers and adding to the challenge of riverbed fugitive dust control task. Thus, green, sustainable, and resilient remediation approach has to be introduced through inter-ministerial cooperation to reinforce the mechanism of disaster prevention contingency and mitigate the environmental impact brought by climate change.
As a solution to the Zhuoshui River fugitive dust problem, this plan helps EPA review the air quality change, bare land characteristics, conservation forest along the coast, licensed arable land in the high riverbank, and upstream and downstream landslides based on the threefold framework of water conservation, forestation, and disaster prevention contingency according to the Executive Yuan’s instruction. The disaster prevention capacities of Water Resources Agency, MOEA (The 4th River Management Office, Central Region Water Resources Office), Council of Agriculture (Forestry Bureau, Agriculture and Food Agency, Soil and Water Conservation Bureau), and local governments (Changhua County, Yunlin County) are integrated for the implementation of the Zhuoshui River Fugitive Dust Control and Improvement Action Plan. Thereafter, Zhuoshui River fugitive dust incidents decreased by 85% (from 59 incidents in 2017 to 9 in 2020). In view of the promising initial result of the first phase of the action plan, the Executive Yuan approved the Zhuoshui River Fugitive Dust Control and Improvement Action Plan II (2021-2023) on August 28, 2020 to continue the improvement of Zhuoshui River. This plan also helps EPA draw on the Zhuoshui River control experience and apply it to the promotion of the Gaoping River Fugitive Dust Control and Improvement Action Plan in 2021.
For this plan, research is done on both domestic and overseas dust control methods, and appropriate and feasible approaches are proposed with reference to the characteristics of various rivers in the country. Also, assistance is given to convene 2 project meetings and perform 8 site surveys of major rivers. Site surveys are conducted in conjunction with related departments, and division of labor before and after the flood season is performed according to each department’s responsibilities through the meeting platform, with various preventive methods and various control schedules implemented in fugitive dust-prone locations to review the effectiveness of the riverbed fugitive dust control and improvement initiatives. Inter-ministerial collaboration is pushed forward through the action plans, whereby the Water Resources Agency and Forestry Bureau of the Council of Agriculture have kept working on improvement of riverbed bare land in various rivers, as well as plantation and cultivation of conservation forests every year. In 2021, improvement on a total area of 4,417 hectares was made for various rivers by means of vegetative cover, water cover, and other covers (e.g., crop cover, xanthan gum, etc.).
By analyzing the concentrations of suspended particulates in past riverbed fugitive dust incidents and the historical meteorological data, a fugitive dust forecast mechanism is established on the basis of professional meteorological data and such judgment factors as the season, meteorological condition, etc. Fugitive dust forecasting work (7-day, 3-day, and 1-day) is undertaken for Zhuoshui River, Gaoping River, and Beinan River during the fugitive dust-prone periods based on the rivers’ characteristics and seasonal change.
Number of fugitive dust incident days at all rivers gradually declined since 2017, from 75 incidents in 2017 to 7 in 2021 representing a 92% decrease, and of the 7 incidents in 2021, 6 occurred in Zhuoshui River and 1 in Beinan River, none in other rivers. In 2022, 6 riverbed fugitive dust incidents have occurred by the end of September, 1 in Zhuoshui River and 5 in Gaoping River, meaning that greater effort has to be put into fugitive dust control of Gaoping River.