10 20 „call for a green china” 0 budapest university 30...
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Budapest University
of Technology and
Economics
Prof. László Somlyódy
SHALLOW LAKE EUTROPHICATION AND
CLEANUP
International Experiences
Department of Sanitary and Environmental Engineering
www.vkkt.bme.hu
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[years]
TP
ret
enti
on [
%]
„Call for a Green China”
Conference, 15 May, Nanjing
Lake Eutrophication
Control P Load Algae
1919
这是湖This is a lake
Comparison of various lakes: OECD assessment
(annual average Chl-a vs normalized P load)
Transfer of experiences
Lake Balaton 1919
1946First Warning
Area: 600 km²
Depth: 3 m
LAKE BALATON: EXTERNAL PHOSPHORUS
LOAD
KESZTHELY BASIN (1945-2002)
Total P (t/year)
Load increase: tourism and agriculture
0
20
40
60
80
100
120
1945
1950
1955
1960
1965
1970
1975
1980
1985
1990
1995
2000
July - August
Yearly average
Clorophyll-a (mg/m3)
LAKE BALATON: ALGAL BIOMASS
KESZTHELY BASIN (1945-2002)
Control strategy & DM
0
20
40
60
80
100
120
19
45
19
50
19
55
19
60
19
65
19
70
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75
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80
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85
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90
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95
20
00
July - August
Yearly average
ALGAL BIOMASS TARGETS
KESZTHELY BASIN (1945-2002)
A
BC
Clorophyll-a (mg/m3) Targets
Lake Balaton: Control and Impacts
Control P Load Algae
No ReactionCylindrosp.
Raciborskii
1983
1994
191919461983
Travelling with C. Raciborskii
Lake Balaton: Control and Impacts
Control P Load Algae
No ReactionCylindrosp.
Raciborskii
Global
Stress1994
Sediment
Renewal
Sudden
Improvement1995
1919194619831994
WASTEWATER
TREATMENT
DEPOSITION FROM
THE ATMOSHERE NON-POINT
SOURCES
OUTFLOW
SEDIMENTATION
SEDIMENT
INTERNAL LOAD
EXTERNAL
LOAD
THE ROLE OF THE SEDIMENT
WASTEWATER
TREATMENT
DEPOSITION FROM
THE ATMOSHERE NON-POINT
SOURCES
OUTFLOW
SEDIMENTATION
SEDIMENT
INTERNAL LOAD
EXTERNAL
LOAD
THE ROLE OF THE SEDIMENT
LAKE BALATON: EXTERNAL LOAD
KESZTHELY BASIN (1945-2002)
0
20
40
60
80
100
120
140
160
1945
1950
1955
1960
1965
1970
1975
1980
1985
1990
1995
2000
Total P (t/yr)
Inflow
Catchment for calibration
Catchment for simulation
Shoreline area
Non-point sources: scales, models and estimations
Spatial scale
Temporal scale
hour
day
year
Soil profile,
paved areasmall to medium
catchment large watershed
minute agricultural field
settlement
Processes,
research
Field
management,
planning of
good agricultural
practice
Watershed
management
planning
(lumped or distributed
Parameter models)
Strategic
analysis
m2 km2 1000 km2 106 km2
PhosFate
SWAT,
GWLF, WETSPA
MONERIS
SWMM
STORMNET
ARES
Advanced tools
Diffuse P loads: Zala River basin areal distributions
(cell level, long-term average)DP emission [kg/ha/a] PP emission [kg/ha/a]
TP loads [kg/a] TP retention [%]
0.00
0.09
0.17
0.34
0.69
1.38
0
10
22
44
87
174
349
700
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1
10
100
1000
10000
0 %
25 %
50 %
75 %
100 %
0
20
40
60
80
100
120
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45
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50
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55
19
60
19
65
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70
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75
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80
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85
19
90
19
95
20
00
July-august
Yearly average
Clorophyll-a (mg/m3)
LAKE BALATON: LOAD RESPONSE
KESZTHELY BASIN (1945-2002)
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DIFFUSE
LOADS
Phosphorus load and algal biomassLake Balaton
Phosphorus load and algal biomass
Hysteresis: structural changes & sediment
Lessons
Lake - watershed problem: scientific knowledge is there
Time lag and unusual load responses: sediment, blue-greensand non-point sources
Approach: - data and monitoring (present state)- nutrient limitation (P and/or N)- external load estimates (background-, non-controllable-, point- and diffuse sources)
- internal load (sediment)- likely load-response and targets- control measures and costs- action plan- implementation & institutions
Total load control is not enough
Many hypertrophic shallow lakes in China
