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Water Quality and Ecological Restoration

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Presentation on theme: "Water Quality and Ecological Restoration"— Presentation transcript:

1 Water Quality 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

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

11 Turbidity increase in Lake Soyang

12 Turbidity problem in reservoirs
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.

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 quality Comparison of clean streams and turbid streams - case study of two couple sites (in 2006) Bongsan Daeki

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)
Watershed Total Paddy Upland Forest etc. Naedong 4.63 0.52 1.74 2.37 0.00 Doonjunggol 1.01 0.15 0.42 0.44 Kunjigol 6.97 0.49 1.31 5.14 0.02 Seonghwang 6.51 0.32 1.69 4.50 Chunryounggolan 3.56 0.59 1.32 1.65 Wolsan 6.69 0.29 1.19 5.18 Mandae 59.99 5.94 15.61 38.36 0.09

21 Water level measurement
Str. Naedong Str. Doonjunggol Str. Kunjigol Str. Seonhwang Str. Chungryunggol Str. Wolsan Str. Mande 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.

22 Rainfall in 2009

23 Pollutograph in rain events
Kunjigol Wolsan

24 Specific export coefficient (kg/ha/event)
Watershed BOD SS TN TP Kunjigol 1.07 3,624 0.94 0.76 Wolsan 0.69 773 0.46 0.29 EMCs (mg/L) Watershed BOD SS TN TP Kunjigol 2.7 7,850 2.20 1.69 Wolsan 1.8 2,180 1.26 0.81

25 Effect of suspended sediment on fish
References Minimum (mg·L-1) Moderate Serious <25 25~80 >80 EIFAC, 1964 26~80 Alabaster, 1972, NAS and NAE, 1973, Alabaster and Lloyd, 1980 26~100 >100 Newport and Moyer, 1974 <30 30~85 >83 Wilber, 1969, 1983 <10  - - Hill, 1974 1~100 DFO, 1983 10~100 Mills et al. 1985 >25 (<10 d/yr), >80 (< 5 d/yr) >25 (11~30 d/yr), >80 (5~10 d/yr) >25 (> 31 d/yr), >80 (> 11 d/yr) No fish is living in the Haean basin

26 Table 3. The export loadings(kg․yr-1․km-2) in each watershed.
Land use BOD TN TP Reference EPA, USA Mixed agricultural - 1,650 113 Reckhow et al.(1980) forested 286 23.6 urban 997 191 USA and Europe forest 100~630 0.7~88 Loehr et al.(1989) Rural cropland 2,100~7,960 6~290 Wisconsin, USA agricultural 669 26.2 Clesceri et al.(1986) 407 17.6 Eastern, USA. 300 5~10 Rast and Lee (1978) 500 50 Mandae agricultural - forest 2,387 1,651 448 2003 4,989 6,794 859 2004 Jawoon agricultural -forest 1,087 3,284 258 2005 863 151 2006 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


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