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進入《TAIPEI TIMES》 Nine reservoirs eutrophic
The Liyutan Reservoir in Miaoli County is pictured on Saturday. Photo courtesy of the Liyutan Management Center
By Chen Chia-yi and William Hetherington / Staff reporter, with staff writer
A record nine of Taiwan’s 20 major reservoirs produced eutrophic quality water last year, statistics from the Ministry of Environment showed.
Shihmen Reservoir （石門水庫）, which services New Taipei City and Taoyuan, saw eutrophication reach a high in 2022, with quality improving last year. Elsewhere, Tainan’s Jingmian Reservoir （鏡面水庫） and Pingtung County’s Mudan Reservoir （牡丹水庫）, also saw eutrophication reach new highs.
Water quality is measured by the amount of nutrients in the water, up to an optimal eutrophic amount before eutrophication develops. Eutrophication is an excessive amount of nutrients such as nitrogen and phosphorus in a body of water, that causes a large amount of algae to grow and consume the water’s oxygen during decay and decomposition, resulting in serious deterioration of water quality.
Statistics from the ministry showed that the eutrophic nutrient status was reached last year in nine of Taiwan’s 20 major reservoirs: Sinshan （新山）, Baoshan （寶山）, Mingde （明德）, Liyutan （鯉魚潭）, Baihe （白河）, Jingmian, Fengshan （鳳山）, Mudan and Chengcing Lake （澄清湖）, Jingmian and Mudan.
Department of Water Quality Protection Director Wang Yue-bin （王嶽斌） yesterday said that Jingmian has typically produced good quality water over the past five years due to the impact of local agricultural activity. The reservoir has had an average Carlson trophic state index of 58 in recent years, he said, adding that an index of higher than 50 reflects a good level of nutrition.
Jingmian’s water quality improved slightly in 2022 mainly due to the discharge of sludge and a high water-replacement rate, but quality returned to eutrophication last year, he said, adding that last year’s level was still within a good range.
Meanwhile, Mudan’s quality became eutrophic last year mainly due to the completion of maintenance projects, he said.
Shihmen had also undergone general maintenance in previous years, which was stepped up in 2021 when there was a severe drought, he said.
新聞來源：TAIPEI TIMES
