Significant Improvement in the Ecosystems of Pyeongtaek Namyangho and Gunpo Banwol Reservoirs

The ecosystems of 'Namyangho' in Pyeongtaek and 'Banwol Reservoir' in Gunpo, Gyeonggi Province, have significantly improved.

The Gyeonggi Provincial Institute of Health and Environment announced on the 17th that a survey on phytoplankton was conducted last year at two locations: Namyangho in Pyeongtaek City and Banwol Reservoir in Gunpo City. The results showed that the diversity of major phytoplankton increased in both areas.

In fact, 145 species across 77 genera were observed in Namyangho, and 118 species across 73 genera were observed in Banwol Reservoir, showing an increase in the number of species compared to the 2022 survey results of 105 species across 61 genera and 98 species across 52 genera, respectively.

Gyeonggi-do Institute of Health and Environment is collecting samples for ecosystem analysis.

By period, Namyangho recorded the highest number of species observed (61 species) and cell count (58,491 cells/mL) in September. In Banwol Reservoir, the highest number of species observed (57 species) was in June, while the cell count peaked in September at 13,377 cells/mL.

The dominance index of Namyangho (a measure indicating how dominant each species is within the phytoplankton community) showed little change, from 0.4 in 2022 to 0.39. The diversity, evenness, and species richness indices slightly increased from 2.43 to 2.85, 0.69 to 0.74, and 3.76 to 4.67, respectively.

On the other hand, the dominance index of Banwol Reservoir decreased from 0.78 in 2022 to 0.50. However, the diversity, evenness, and species richness indices significantly improved from 1.24 to 2.40, 0.36 to 0.65, and 3.64 to 5.16, respectively.

Hwang Chan-won, head of the Water Environment Research Department at the Provincial Institute of Health and Environment, stated, "The survey results showed that both Namyangho and Banwol Reservoir have increased not only in phytoplankton diversity but also in how evenly and abundantly species live compared to last year. It can be said that both locations have healthier ecosystems than last year."

However, the institute added that in the case of Namyangho, algae commonly known as green algae are increasing, and measures to address this are necessary.