Water Quality and Ecological Restoration

1. WaterQuality and Ecological Restoration Bomchul Kim Department of Environmental Science Kangwon National University

2. Contents • Water quality issues in Korea • Turbidity in streams and reservoirs • Water quality survey project in Haean • Control measures to improve water quality

3. Change of water quality issues in Korea • Before 1970s • No pollution problems • No concern about environmental conservation • In 1980s • High BOD from sewage • Fish farms installed in many reservoirs • In 1990s • Sewage treatment systems established • Active operations of fish farms within reservoirs • Eutrophication problems emerged • Algal toxins were reported

4. Current issues in 2000s • Turbidity and siltation – major ecological hazard • TMDL of BOD and TP for water quality management • Phosphorus removal from sewage • Biological assessment – new paradigm • Automatic monitoring – high frequency monitoring

5. Turbid water of the Soyang River on flood days that flows into Lake Soyang (July 15, 2006) Increased rainstorm intensity - Due to global warming ?

6. Two hot spots of turbid water discharge Haean Lake Soyang Jawoon

7. Soil disturbance in Haean (2007. Mar.8)

8. Making flatter fields for better cultivation– a cause of erosion in Haean Original slope Made steeper Made flatter

9. Tilling in Haean basin and the turbidity in Lake Soyang Turbidity

10. Movement of turbid interflow in Lake Soyang(result of simulation by CE-QUAL-W2, 1996)

11. Turbidity increase in Lake Soyang

12. Turbid water lasts 3 months after summer monsoon in the Han River. Reservoirs are filled with turbid water after monsoon. Large dams prolongs the duration of turbid water in downstream. Destroys aquatic ecosystems. SAV is reduced. Fisheries is reduced. Turbidity problem in reservoirs

13. Water blooms in Lake Soyang after turbid storm runoff <Wet years> <Dry years> cyanobacteria

14. Phosphorus loading into Lake Soyang ▲ increasing trend

15. Land use vs. water qualityComparison of clean streams and turbid streams- case study of two couple sites (in 2006) Daeki Bongsan

16. A turbid stream (Jawoon) and a clean stream (Kyebang) In 2007

17. A turbid stream (Daeki) and a clean stream (Bongsan) Result : change and reduction of fish and benthos community

18. Water quality survey project in the Haean basin • Purpose : to evaluate effectiveness of soil erosion control and diffuse pollution control • To assess water quality improvement in subbasins w/wo erosion control measures • To assess efficiencies of each erosion control method • To quantify specific export of nonpoint source pollution • Period : six years from 2009

19. Site of investigation Chungryounggolan Seonghwang Wolsan Kunjigol Doonjunggol Naedong

20. Land use in subbasins (km2)

21. Water level measurement • Water level scales were installed. • Two automatic water level meter (sonic distance meter type) and two automatic water samplers will be installed in next year. Str. Naedong Str. Doonjunggol Str. Kunjigol Str. Seonhwang Str. Chungryunggol Str. Wolsan Str. Mande

22. Rainfall in 2009

23. Pollutograph in rain events Kunjigol Wolsan

24. Specific export coefficient (kg/ha/event) EMCs (mg/L)

25. Effect of suspended sediment on fish No fish is living in the Haean basin

26. Table 3. The export loadings(kg․yr-1․km-2) in each watershed. • The amounts of TP exported from these two basins were considerably high, compared to other many studies

27. Control measures of turbid water • Sociological strategy • Environmental management • Agricultural practice

28. Struggling to control erosion in Haean

29. sometimes…… in vain

30. To protect steep slope

31. Food vs. Water • Disturbed land → poor water quality • Conserved ecosystem → good water quality • Can we choose only one? • The goal of Korea. ;even with intensive agriculture → good water quality Is it possible?

32. Thank you