Water Quality and Ecological Restoration

Bomchul KimDepartment of Environmental Science

Kangwon National University

Contents

1. Water quality issues in Korea2. Turbidity in streams and reservoirs3. Water quality survey project in

Haean4. Control measures to improve water

quality

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

Current issues in 2000s

1. Turbidity and siltation – major ecological hazard

2. TMDL of BOD and TP for water quality management

• Phosphorus removal from sewage

3. Biological assessment – new paradigm

4. Automatic monitoring – high frequency monitoring

Turbid water of the Soyang River on flood days that flows into Lake Soyang (July 15, 2006)

Increased rainstorm intensity- Due to global warming ?

Two hot spots of turbid water discharge

Haean

Jawoon

Lake Soyang

Soil disturbance in Haean (2007. Mar.8)

Making flatter fields for better cultivation– a cause of erosion in Haean

Original slope

Made flatter Mad

e

stee

per

Tilling in Haean basin and the turbidity in Lake Soyang

1980 1985 1990 1995 2000 2005 20100

50

100

150

200

250

300

Year

Th

e n

um

ber

of

trac

tor

Tu

rbid

ity

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

0 20 40 60

Dep

th(m

)

0

20

40

60

80

100

120

16 Aug., 1990

Turbidity(NTU)

0 20 40 60

21 Aug., 1995

0 20 40 60

27 Aug., 1999

0 100 200 300

25 Aug., 2006

Turbidity increase in Lake Soyang

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.

Water blooms in Lake Soyang after turbid storm runoff

8/1/03 9/1/03 10/1/03 11/1/03 12/1/03

Sta

nd

ing

Cro

p o

f ot

her

ph

ycea

e(ce

lls/

ml)

0

200

400

600

800

1000

Sta

nd

ing

Cro

p o

f cy

anop

hyc

eae(

cell

s/m

l)

0

10000

20000

30000

40000

50000Cyanophyceae

8/1/04 9/1/04 10/1/04 11/1/04 12/1/04 0

5000

10000

15000

20000

25000

30000

0

1e+5

2e+5

3e+5

4e+5

5e+5

8/1/06 9/1/06 10/1/06 11/1/06 12/1/06 0

500

1000

1500

2000

2500

3000

0.0

2.0e+4

4.0e+4

6.0e+4

8.0e+4

1.0e+5

1.2e+5

1.4e+5

1.6e+5

Cryptophyceae Dinophyceae

Bacillariophyceae Chlorophyceae

<Wet years> <Dry years>

cyanobacteria

T-P loading (1991-2005)

R = 0.79

0

200

400

600

800

91 93 95 97 99 01 03 05

Year

T-P

load

ed(t

P/y

r)

▲ increasing trend

Phosphorus loading into Lake Soyang

Bongsan

Daeki

Land use vs. water qualityComparison of clean streams and turbid streams

- case study of two couple sites (in 2006)

Flo

w r

ate

(CM

S)

0

50

100

150

Flow rate B

OD

(m

g O

2 L

-1)

0

5

10

15

CO

D (

mg

O2

L-1

)

0

5

10

15BOD COD

Time (hour)

6-26 17:00 6-27 08:00 6-27 23:00 6-28 14:00 6-29 05:00

DO

C (

mg

C L

-1)

0

5

10

15DOC

Ph

osp

hor

us

(g

L-1

)

0

500

1000

TP DTP DIP

NS

SS

(m

g L

-1)

0

2000

4000

6000SS

Flo

w r

ate

(CM

S)

0

50

100

150

Flow rate

BO

D (

mg

O2

L-1

)

0

5

CO

D (

mg

O2

L-1

)

0

5

10

BOD COD

Time (hour)

6-26 05:00 6-26 20:00 6-27 11:00 6-28 02:00 6-28 17:00 6-29 08:00

DO

C (

mg

C L

-1)

0

5

DOC

Ph

osp

hor

us

(g

L-1

)

0

50

100

150TP DTP DIP

NS

SS

(m

g L-1

)

0

250

SS

A turbid stream (Jawoon) and a clean stream (Kyebang)

In 2007

Flo

w r

ate

(CM

S)

0

10

20

30Flow rate

BO

D (

mg

O2

L-1

)

0

5

10

15

CO

D (

mg

O2

L-1

)

0

5

10

15

BOD COD

Time (hour)

06-26 18:00 06-27 08:00 06-27 22:00 06-28 12:00 06-29 02:00 06-29 16:00

DO

C (

mg

C L

-1)

0

5

10

15

20

DOC

Ph

osp

hor

us

(g

L-1

)

0

500

1000

1500TP DTP DIP

NS

SS

(m

g L

-1)

0

1000

2000

3000

4000 SS

Flo

w r

ate

(CM

S)

0

25

50

Flow rate

BO

D (

mg

O2

L-1

)

0

5

CO

D (

mg

O2

L-1

)

0

5

BOD COD

Time (hour)

05-06-26 19:00 05-06-27 13:00 05-06-28 07:00 05-06-29 01:00 05-06-29 19:00

DO

C (

mg

C L

-1)

0

2

4

6

DOC P

hos

ph

oru

s (

g L

-1)

0

50

100

150TP DTP DIP

NS

SS

(m

g L

-1)

0

25

50

SS

A turbid stream (Daeki) and a clean stream (Bongsan)

Result : change and reduction of fish and benthos community

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

Site of investigation

Wolsan

Seonghwang

Kunjigol

NaedongDoonjunggol

Chungryounggolan

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 0.00

Kunjigol 6.97 0.49 1.31 5.14 0.02

Seonghwang 6.51 0.32 1.69 4.50 0.00

Chunryounggolan

3.56 0.59 1.32 1.65 0.00

Wolsan 6.69 0.29 1.19 5.18 0.02

Mandae 59.99 5.94 15.61 38.36 0.09

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

Rainfall in 2009

Time(month)

J F M A M J J A

Rai

nfal

l(m

m)

0

50

100

150

200

250

Mandae 2009 Sampling period

Rai

nfa

ll (

mm

)

0

20

40

60

Flo

wra

te(C

MS

)

0

10

20

30

40Rainfall Flowrate

BO

D (

mg

O2

L-1

)

0

5

CO

D (

mg

O2

L-1

)

0

20

40BOD COD

Nit

roge

n (

mg

L-1

)

0

2

4 TN NO3-N NH3-N

Time (hour)

7-09 05:00 7-09 14:00 7-09 23:00 7-10 08:00

DO

C (

mg

C L

-1)

0

2

DOC

Ph

osp

hor

us

(g

L-1

)

0

1000

2000

3000

4000

5000 TP

SS

(m

g L

-1)

0

5000

10000

15000

Tu

rbid

ity

(NT

U)

0

2000

4000 SS

Turbidity

Kunjigol Wolsan

Rai

nfa

ll (

mm

)

0

5

10

15

20

25

30

X Axis 2

2009-7-9 2009-7-10 2009-7-11

Flo

wra

te(C

MS

)

0

5

10

15

20

Rainfall Flow rate

BO

D (

mg

O2

L-1

)

0

2

4

CO

D (

mg

O2

L-1

)

0

20

BOD COD

Nit

roge

n (

mg

L-1

)

0

2

TN NO3-N NH3-N

Time (hour)

7-09 05:00 7-09 14:00 7-09 23:00 7-10 08:00

DO

C (

mg

C L

-1)

0

2

4

6 DOC

Ph

osp

hor

us

(g

L-1

)

0

2000

TP

SS

(m

g L

-1)

0

5000

10000

Tu

rbid

ity

(NT

U)

0

4000

8000 SS

Turbidity

Pollutograph in rain events

Specific export coefficient (kg/ha/event)

Watershed

BOD SS TN TP

Kunjigol 2.7 7,850 2.20 1.69

Wolsan 1.8 2,180 1.26 0.81

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)

Kunjigol Wolsan

Co

nc.

(mg

/L)

0

1

2

3

2000

4000

6000

8000

BOD SS TN TP

Effect of suspended sediment on fish

ReferencesMinimum(mg·L-1)

Moderate(mg·L-1)

Serious(mg·L-1)

<25 25~80 >80 EIFAC, 1964

<25 26~80 >80

Alabaster, 1972, NAS and NAE, 1973, Alabaster and Lloyd, 1980

<25 26~100 >100Newport and Moyer, 1974

<30 30~85 >83 Wilber, 1969, 1983

<10  - - Hill, 1974

0 1~100 >100 DFO, 1983

<10 10~100 >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

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) forest - 407 17.6

Eastern, USA. forest - 300 5~10

Rast and Lee (1978) agricultural - 500 50

Mandae agricultural - forest2,387 1,651 448 2003

4,989 6,794 859 2004

Jawoon agricultural -forest1,087 3,284 258 2005

863 - 151 2006

The amounts of TP exported from these two basins were considerably high, compared to other many studies

Table 3. The export loadings(kg yr․ -1 km․ -2) in each watershed.

Control measures of turbid water

• Sociological strategy

• Environmental management

• Agricultural practice

Struggling to control erosion in Haean

sometimes…… in vain

To protect steep slope

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?

Thank you