The main goal of this project is to monitor the water quality of seven cities and counties in the southern area of Taiwan, and to analyze the degree of pollution in various bodies of water so that trends in water quality can be observed. The result of this investigation can provide grounds for policy making to environmental protection authorities. 　　For river quality, 97 sampling sites covering 29 rivers (including main streams and tributaries) were monitored monthly. The results monitored from 2018 to 2020 showed that the water quality in the area of Zeng-Wen rive and rivers at Ping-Dong county, Tai-Dong county were the best, the area of Er-Ren river and A-Gong-Dian river were found in relatively high extent of pollution. Since there was a major water shortage this year, specifically, a lack of rainfall from January to May, parts of some rivers were nearly dried up, so test results for most pollutants were high, and thus the percentage of serious pollution would tend to look high. Due to a lot of rainfall from June to September, the suspended solids in the rivers tend to be high thus the percentage of unpolluted rivers is low and over 50% of the results indicated the rivers were intermediately polluted. As a whole, the highest percentage of the water quality in the southern Area of Taiwan is about 45% to 50%, it belongs to intermediately polluted rivers. The next is about 30% to 35%, it belongs to unpolluted rivers, and overall water quality is nondifference between the recent years. 　　For ocean monitoring, 42 sampling sites covering eight coastal areas were monitored quarterly. Since the estuary areas were affected by the river during high tide, the concentrations of the inorganic salts were high. The results monitored in the year of 2018 showed that most monitoring data could meet quality criteria of each category, except the results of dissolved oxygen, ammonia nitrogen and pH monitored at estuary areas of Kao-Pin river, Dong-Gang river, Da-Peng Bay and the ampling site on the right side of The 3rd Nuclear Power Plant. Because of typhoon coming in 3rd and 4th quarters, there are some index including salinity and some metals different with the past results. 　　Eighteen sampling sites covering six beaches were monitored from June to August. The results monitored in the year of 2018 showed that most monitoring data could show excellent level. The monitoring of each beach showed that water qualities were worse might be affected by rainfall. 　　Ammonia nitrogen, iron, and manganese were the major analytes with results that reached the regulatory monitoring criteria in 201 ground water sampling sites for the seven cities and counties being monitored quarterly. The failing rates are about 65% for different cities and counties. To analyze graphically each monitoring item by Stiff-plotting and Piper-plotting showed the same trend from 2018 to 2020. To analyze graphically each monitoring item by Stiff-plotting and Piper-plotting showed a trend as same as last two years, there is no significant difference compared to the past. The highest percentage of Stiff-plotting is about 60% to 70%, it belongs to HCO3－+CO32─- Ca2＋ type.The highest percentage of Piper-plotting is about 50% to 75%, it belongs to area of I and II.

Water Quality Monitoring, Water Quality Standards, Method Detection Limit