A Study on the Biological Estimation of Water Pollution Levels by the Aquatic Insects in Kyungan Stream, Kyunggi-Do

경안천수계에 있어서 수서곤충에 의한 생물학적 수질평가

The present study was accomplished from March to August, 1990 in order to examine the community structure of aquatic insects and the biological estimation of water pollution levels by the aquatic inseets of Kyungan stream in Kyunggi-do. 1. The aquatic inseets of whole area composed of 78 species, 42 genera, 26 families in 8 roders. 2. The occurrence species number show highest at Gungpyung-ri(29 species) and lowest at Yongin town(1 species) 3. Dominance indices show lowest at Gungpyung-ri(0.35) and highest at Yongin town(1.00) and Choboo-ri(1.00) 4. Species diversity indices show highest at Gungpyung-ri(3.53) and lowest at Yongin town(0.00) 5. The biological estimation of each area's water quality levels based on the diversity index are as follows. Oligosaprobic area : Gungpyung-ri, Muchu-ri $\alpha$ mesosaprobic area : Yooeun-ri, Choboo-ri(K4), upper site of Wangsanri, Yeuk-ri, Wangsan-ri. $\beta$ mesosaprobic area Gonjiam-ri, Dopyoung-ri, Kyungan-ri, Wondang-ri. Polysaprobic area : Yongin town, Choboo-ri(K5)