The Effect of Rainfall on the Water Quality of a Small Reservoir (Lake Wangkung, Korea)

  • Hwang, Gil-Son (Rural Research Institute, Korea Agriculture & Rural Infrastructure Corporation) ;
  • Kim, Jae-Ok (Rural Research Institute, Korea Agriculture & Rural Infrastructure Corporation) ;
  • Kim, Jai-Ku (Dept. of Environmental Science, Kangwon National Univ.) ;
  • Kim, Young-Chul (Dept. of Environmental Engineering, Hanseo Univ.) ;
  • Kim, Bom-Chul (Dept. of Environmental Science, Kangwon National Univ.)
  • Published : 2005.04.30

Abstract

The dynamics of water quality with the storm events were analyzed in a small reservoir for irrigation, Lake Wangkung. Water quality of the inflowing stream fluctuated seasonally with the variation of flow rate. Thermal stratification was consistent from April to October below 2 m depths and anoxic layer was developed below 2 m depth in summer. The unique feature of temperature showed that thermal stratification was disrupted by a heavy rain event during monsoon, but hypolimnetic hypoxia were reestablished after a few days. Phosphorus and nitrogen increased immediately following storm events. The marked increase may be due to the input of P-rich storm runoff from the watershed. Internal phosphorus loading can be one of the explanations for TP increases in summer. When there was a storm, total populations of phytoplankton and zooplankton was reduced immediately following the storm, indicating possible flushing of algae and zooplankton. After a lag period of low-density the plankton population bloomed to a peak again within five days after the storm. Turbid water in lake became clear again which coincided with the time of the phytoplankton buildup. The results demonstrate that water quality is regulated greatly by rainfall intensity in Lake Wangkung.

Keywords

References

  1. American Public Health Association. 1992. StandardMethods for the Examination of Water and Wastewater,18th ed. APHA, Washington D.C.
  2. An, K.G. and J.R. Jones. 2000. Factors regulatingbluegreen dominance in a reservoir directly influencedby the Asian monsoon, Hydrologia Vol. 432:37-48.
  3. Chapman, D. 1996. Water quality assessment (2ndEd.). E & FN Spon. New York.
  4. An, K.G. and J.R. Jones. 2000. Factors regulating bluegreen dominance in a reservoir directly influenced by the Asian monsoon, Hydrologia Vol. 432: 37-48.
  5. Kim, D.-S., B. Kim, G. Hwang and J.-H. Park. 1995.Trend of Eutrophication in Lake Paldang. J. Kor.Soc. Wat. Pol. Res. Con. 11: 295-302.
  6. Kim, B., J.-H. Park, G. Hwang and K. Choi. 1997.Eutrophication of large freshwater ecosystems inKorea. Kor. J. Limnol. 30: 512-517.
  7. Kim, B., J.-H. Park, B.-J. Lim, W.-M. Heo, G.Hwang, K. Choi and K.-S. Chae. 1998. Thelimnological survey of major reservoirs in Korea(2): Lake Hapchon. Kor. J. Limnol. 30: 312-327.
  8. Lee, J.-S., Y.-C. Kim and G. Hwang. 2003. Changesof the sediment properties in small agriculturalreservoirs before and after rainy season. KoreanSociety of Civil Engineers. 23(4B): 359-368
  9. Wetzel, R.G. 2001. Limnology; Lake and River Ecosystems(3rd Ed.), ACADEMIC PRESS. California