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Project EULAKES Ref. No. 2CE243P3
European Lakes under Environmental Stressors (Supporting lake governance to mitigate the impact of climate change)
4.1. Vulnerability AssessmentDeliverable 4.1.1 Joint lake vulnerability and risk assessment methodology
Part B: Lake Balaton
Károly Kutics Gábor Molnár, István Hegedűs Lake Balaton Development Coordination Agency
Contents
1
Executive summary......................................................................................................................3
1. Introduction..........................................................................................................................8
2. Methodology.........................................................................................................................9
2.1. Definition of Stressors.......................................................................................................9
3. Current impacts of Climate Change on Lake Balaton...................................................15
3.1. Situation in Hungary......................................................................................................15
3.2. Situation in the Lake Balaton region............................................................................18
4. Vulnerability to the effects of climate change - future scenarios.......................................30
4.1. Hydrology and water quantity.......................................................................................30
4.2. Lake water temperature.................................................................................................37
4.3. Water quality...................................................................................................................38
4.4. Reed belt and peat bogs..................................................................................................43
4.5. Fish and other macrofauna............................................................................................45
4.6. Invasive species................................................................................................................47
4.7. Land use and agriculture...............................................................................................50
4.8. Hunting............................................................................................................................52
4.9. Tourism............................................................................................................................52
4.10. Infrastructure................................................................................................................55
5. Assessment of potential economic impacts..........................................................................56
6. Summary of findings related to vulnerability.....................................................................58
Literature....................................................................................................................................62Executive summary
Vulnerability is the degree to which a system is likely to experience harm due to exposure to a
hazard. The purpose of vulnerability assessment is to determine the hazards in the form of stresses
or perturbations, sensitivity of the system towards these factors and resilience, i.e. the system's
ability to return to the original/favourable condition on its own accord.
2
The framework and methodology described in Part A: Lake Neusiedl was largely adopted.
Available information on climate change predictions (various scenarios) has been analyzed and
receptors of climate and other stresses were identified. The receptors are mostly based on the
investigations of WP 6.1.3 but receptors deemed important to Lake Balaton were determinded as
well.
According to the meteorological data of the past decades, Lake Balaton watershed is warming,
precipitation is slightly decreasing, and the water balance is showing higher variability. Future
climate predictions invariably show increases in temperature, and reduction of water excess in the
natural water balance (NWB or NWRC). Certain scenarios (Nováky, 2008) predict permanent
negative NWB by as soon as 2050. It should be emphasized that there is a great deal of uncertainty
in predictions on the regional scale. However, one of the most vulnerable receptor is water quantity.
The NWB of Lake Balaton may be improved by water transfer from other watersheds, but this
action would result in other stresses and vulnerabilities, such as water shortage on the other
watershed, introduction of foreign species, conflicts of interests, etc.
Lake water temperature is expected to increase in the order of a few oC. This would benefit
tourism, especially on the beaches and water related sports, resulting in higher income for the
tourism sector and reducing economic vulnerability in the region. However, at the same time,
higher temperatures result in adverse effects, such as less favourable water quality, stress on the
ecological system, less (or disappearance of) ice cover making reed management difficult, and
human health problems.
Water quality is very vulnerable due to the extreme shallowness of Lake Balaton. Climate change
would bring unfavourable changes, such as more nutrient release from the sediment and increased
erosion resulting in higher algae levels, increase of dissolved inorganic content due to increased
evaporation and less (or negligible) water exchange.
The reed belts would benefit from more frequent low water level and wide year-to-year level
fluctuations, as it was experienced during the year 2000-2004 drought period. As long as the area of
reed stands grow simultaneously with acceptable water level (i.e. above about 60 to 70 cm), the
ecological system benefits from the phenomenon (in case of extremely low water level reed stands
dry up resulting in (at least temporarily) significant loss of aqueous habitat). However, advance of
reed-covered area would have adverse impact on various uses of the lake, such as bathing,
swimming, sail boating, etc.
Fish population is declining and there are several non-indigenous species in the lake with high
population. Prediction of changes in the fish population is difficult, but thermophilic species would
3
advance with warming. It is expected that one of the problem species, silver carp still will not be
able to spawn in the warmer water.
Warmer and drier summer periods will not favor agricultural production in general. However,
vineyards may benefit from warming due to the reduced damages from frosts and the, possibility to
grow more Mediterranian species.
Tourism may expect favourable changes on the short to mid-term due to higher water and air
temperatures as long as water quality do not deteriorate. This would result in longer tourist seasons
and more visitors engaging in water leisure activities.
Table E1 shows the summary of the results of qualitative vulnerability assessment. Receptors
(indicators) of very high and high vulnerability should be addressed during the development of
measures based on the adaptive capacity at regional and national level.Table E1. Qualitative Vulnerability Assessment for Lake Balaton (up to ca. 2040)
Receptors Current Stresses
Projected Climate Change Impacts
Vulnerability AssessmentSensit-ivity
Adaptive Capacity Vulner-ability
Lake water level
Precipitation deficits
Higher frequency of drought periods
Very High
Outflow control, Water transfer, Water resources management at river basin level
Very high
Flooding Slightly higher frequency of extreme
events
High Increase Sió canal and sluice discharge capacity,
Very high
Ice damage toshorelinestructures
Slightly higher frequency of extreme
events
High Increase Sió canal and sluice discharge capacity
Very high
Peat fires at marshlands adjacent to the Lake
More frequent peat fires due to low water level and dry conditions
High Control water level of marshlands
High
Water temperature
Temperature increase
Occasional algae blooms
High Reduction of external P load
Medium
Water quality Occasional algae blooms
More frequent algae blooms
High Reduction of external P load, Management of Kis-Balaton
High
Growth of benthic filamentous algae Cl. glomerata
Increase in frequency and mass of Cl. glomerata
Very High
Reduction of external P load, Mechanical removal from beaches
High
Appearance of algae toxins
Increased frequency and conc. of algae toxins
Medium Reduction of external P load
Low
4
Pathogens Increased concentration and survival rate
High Urban runoff controlSwan population control
Medium
Flash floods Increase of erosion and pollutant load
High Land management, Urban runoff control
High
Reed belt Changes in reed area, damage at extreme events
More damage at extreme events
Low Water level management, reed harvesting practices
Low
Grasslands Rare drought damage
More frequent drought damage
Low None Low
Vineyards Drought damage More frequent drought damage, more pests
High Species selection, good practices
Low
5
Receptors Current Stresses
Projected Climate Change Impacts
Vu nerability AssessmentSensitivity Adaptive
CapacityVulner-ability
Agriculture in general
Damage due to extreme events
More frequent drought damage, heat stress, erosion, new pests
High Species selection, good practices, melioration
Medium
Forestry Damage due to extreme events, new pests
More frequent drought damage, heat stress, pests
Medium Species selection,understoreymanagement
Medium
Invasive species
Competition with indigenous species
More favourable conditions for propagation
Medium Removal and control efforts
Medium
Human health risks due to allergens
More favourable conditions for propagation
High Removal campaigns, good agric. practices
Medium
Fishery Occasional drying out of spawning areas
More frequent drying out of spawning areas
Medium Outflow control, water transfer
Medium
Reduced possibility of eel removal at outflow
Even less possibility of eel removal
Medium Outflow control Medium
Tourism Influence of extreme weather
More frequent occurrence of low water levels, heat days, less ice cover
High Outflow control, water transfer, attraction development, ice rinks
High
Occasional water quality problem
More frequent water quality problem
High Nutrient load reduction, algae removal
Medium
Human health
Heat days, allergens, algae toxins
More heat days, spread of new allergens, higher level of algae toxins
Medium Heat shelters, allergen control, reduction of pollutant load, rising public awareness
Medium
Receptors Current Projected Vu
nerability Assessment
Stresses Climate Change Impacts
Sensitivity Adaptive Capacity
Vulner-ability
Infra- Increased More erosion High Erosion control Mediumstructure erosion in built-up
area due to extreme events
and pollution from built-up area
measures, rain water storage, treatment, reuse
6
Table E1. Qualitative Vulnerability Assessment for Lake Balaton (up to ca. 2040)(Continued)
Damage to buildings due to ground water level changes
More frequent and larger ground water level changes
High Rain water storage, recharge, ground water level control
High
Odour problem More odor High Odour control Mediumof sewer problems due to measures,pumping stations higher water
temperature and less flow
switching drinking water resources from Lake to karstic water
Problem of Increase of High Modification of Mediumferry, boat and marina use due
frequency of problems
ferry ports, dredging of
to low water marinas, use oflevel smaller boatsDamages to infrastructure
More frequent physical
Medium Development of disaster plans and
Medium
due to extreme damages to measuresevents (winds, infrastructureheavy rain, snow and ice)
and buildings
7
Table E1. Qualitative Vulnerability Assessment for Lake Balaton (up to ca. 2040)(Continued)
1. Introduction
Lake Balaton and its surronding area are relatively well researched and studied region.
However, global changes represent new challenges to this part of Hungary as well. Since the
late 1960s the lake often struggled with algae blooms, but, thank to various water quality
control measures and the radical drop of fertilizer use due to radical land ownership changes
(privatisation) in the 1990s, significant improvement was achieved in the last 15 years. The
severe drought and accompanying water level drop between year 2000 and 2004 drew the
attention to the fact that Lake Balaton is a vulnerable system. At the same time, it became
obvious that new situations and questions may emerge that neither scientists nor politicians or
citizens are able to give simple and easy answers on the basis of our present level of knowledge.
Similar situations such as low water level occured in the past several times (not because of
negative natural water balance) but the lake and its neighbourhood was much less sensitive to
such changes since the area's population, infrastructure and role in the national economy was a
small fraction of the present time. In addition, natural environment of Lake Balaton was not, or
was to a very small degree, under other stresses.
Vulnerability of the Lake Balaton region is determined by two main factors. On one hand, how
much the region is burdened in terms of environmental and socio-economic stresses. On the
other hand, how the region is able to cope with the consequences of these stresses. The stresses
may be related to changes both in the environment or the society, such as sewage load or
demographic circumstances. Some of the stresses originate from inside the region, such as the
loss of habitat due to construction, while others originate from outside the region, such as
climate change.
The natural, social and economic factors are closely interrelated, that is manifested, e.g. in the
relation between the high quality environment (i.e. not crowded, not polluted, noise free,
attractive and rich in natural values) and high-end tourism (i.e. high spending, long-staying
tourists). At the same time, it should be recognized, that the external factors are also
interrelated, which is clear from the global responses to climate change resulting in radical
changes in the use of fossile energy resources (at least on the long run).2. Methodology
2.1. Definition of Stressors
Climate change parameters are real and legitimate stressor stressor of Lake Balaton region since
impacts of climate change are already well documented in the region. Lake Balaton shows more
severe impacts as compared to the Hungarian average. While the western part of the catchment
area (Zala river subcatchment) used to be the wettest region of the country, decrease in pecipitation
8
was most significant there. The water balance of Lake Balaton is determined by inflow, direct
precipitation on lake surface and evaporation. The considerable deficiency in precipitation and
inflow between years 2000 and 2003 and the high evaporation resulted in significant level drop
(some 70 cm). Therefore climate change can be identified as one of the the main stressors to the
lake and its environment. Climate change has also strong socio-economic impacts, since the major
economic sector is tourism in the region. Tourism revenues exceeding 1 billion Euro are realized in
the Lake Balaton Priority Resort Area (LBRA) including the lake and 179 municipalities around it.
1.1.1. Climate scenarios
Various climate scenarios are considered in drawing conclusions and assessing
vulnerabilities of Lake Balaton and its region.
- Climate scenario 2100 (period 2071-2100). This regional climate change scenario was
developed by the AIT Austrian Institute oftechnology within the WP 4.3.2. The
Intergovernmental Panel on Climate Change (IPCC) provides a range of scenarios based on
assumptions of the future development of technologies and society. Out of this the scenario
A1B was selected because it represents a moderate increase of Green House Gases and is
located in the centre of all assumptions (Refer to Part A: Lake Neusiedl for details).
- Climate scenarios of the EU project PRUDENCE as applied in the Balaton Adaptation Project
(2006 -2009) are used to evaluate water quality (eutrophication) - based on B2 and A2
emission scenarios
- Specific scenarios used by researchers to evaluate water balance of Lake balaton (Novaky,
Somlyody and Honti, Thacker).1.1.1.1. Climate parameters 2100
i. Temperature
9
10
Figure 1. Mean seasonal temperature for 30 year periods
Figure 2. Change of mean seasonal temperature for 30 year periods as compared to 1971-2000
EI -
: -i
-i__.! Hi ■ jI CI 1- n-l
„ Fl
1 -- 1961 1971 iqg
I j ' f QQI inni Mn
1 ->rr
L 20 i 20 3 20 ( 20" L-
E: —
'spring
1 summer
S autumn
-
Figure 4. Change of mean seasonal precipitation for 30 year periods as compared to
11
Figure 3. Mean seasonal precipitation in mm/year
%30 25 20 15 10
-10
-15 -20
-25 -30 -35 -40
Change of Mean Seasonal Total Precipitation Sum - Lake Balaton
1971-2000
12
ii. Precipitation
13
iii. Drought and Heat
1961/90 1971/00 1931/10 1991/20 2001/30 2011/40 2021/SO 2031/60 2041/70 20S1/80 2061/90 2071/00
Figure 5. Mean of maximum length of heatwaves for 30 year periods
Figure 6. Change of mean of maximum length of heatwaves for 30 year periods ascompared to 1971-2000
30y Mean of Heat Days (> 30°C) per Year - Lake Balaton
j h U y J y u i u u 1 11961/90 1971/00 19S1/10 1991/20 2001/30 2011/40 2021/50 2031/60 2041/70 2051/80 2061/90 2071/00
Figure 7. Mean of number of heat days for 30 year periods
days 30y Mean of Frost Days (< 0°C) per Year- Lake Balatori110 1------------------------------------------------------------------------------------------------------------------------------
100 ' 9080 ■■------------------------------------------------------------------------------- —
I I 1 I --------------------------------60 -- I-------^m---------—50 v —_
14
days959085 so75 70 55 SO 55 50 45 40 35 50 25 20 15
iv. Extreme Events
1961/90 1971/00 1931/10 1991/20 2001/30 2011/40 2021/50 2031/60 2041/70 2051/80 2061/90 2071/00Figure 8. Mean of number of frost days for 30 year periods
d3y5 30y Mean of Heavy Precipitation Days [> 20 mm/d) per Year - Lake Balaton
1961/90 1971/00 1981/10 1991/20 2001/30 2011/40 2021/50 2031/50 2041/70 2051/80 2061/90 2071/00
Figure 9. Mean of number of heavy precipitation days for 30 year periods 1.2.
Definition of Receptors
Receptors or indicators of change were selected based on the issuesmost relevant to Lake Balaton.
The set of receptors is similar to that of Lake Neusiedl but there are some differences too,
reflecting the difference in importance and utilization of the two lakes. Not only the lake itself, but
its catchment as well as the resort area surrounding it are considered. The receprors include
environmental-ecological and socio-economic receptors as well.
The following receptors were selected:
- Lake hydrology and water quantity
- Water quality
- Water temperature
- Reed belt and peat bogs
- Fish and other macrofauna
- Invasive Species
- Land use and agriculture
- Hunting
- Tourism
- Infrastructure
This list of receptors is based on the investigations of WP 6.1.3. Within this work package
a comprehensive multicriteria assessment matrix was elaborated to describe the influences on the
ecosystem of the lake. Experts of different fields (nature conservation, agriculture, regional
15
planning, hunting management and science) worked out the criteria for the matrix.
3. Current impacts of Climate Change on Lake Balaton 3.1.
Situation in Hungary
Global climate change is an ongoing process supported by ample monitoring data. The overall
situation in Hungary can be described by Figure 10 to Figure 13. In the last 30 years, annual
average air temperatures changed between +1 and +1.8 oC in various regions of the country. In the
Lake Balaton watershed the change is between +1.2 and +1.5 oC. Precipitation during the last 5
decades decreased by a few percent in the country overall, but the change is much larger in the
Lake Balaton watershed where some 15 to 25 percent reduction has been experienced.
The long term trend of the annual average temperature increase is shown in Fig.11, while the
seasonal variability is shown in Fig.12. It is remarkable that the anomalies as compared to the
1971-2009 period increase, and, in the last 15 years, there was only 1 year (1995) when the
anomaly was negative (though almost negligible). The seasonal picture is similar, with Spring and
Summer showing the largest temperature increase.
Precipitation anomalies are shown in Figure 13. The change is negative for almost the whole area
of the country, while the largest decrease in precipitation is experienced in the Lake Balaton
watershed. The most severe decrease is in the Zala river watershed (largest and dominant tributary
of Lake Balaton) with as much as 15 to 25 % decrease in the last 50 years.
These findings set the stage for the evaluation of climate change and climate impact in the Lake
Balaton Region.
16
17
Figure 10. Changes in the annual average temperatures in Hungary during the 1980 -2009 period
(Hungarian Meteorological Services, 2011)
Figure 11. Annual average temperature anomalies in Hungary between 1901 and 2009 as compared
to the average of the 1971- 2000 period. (Hungarian Meteorological Services, 2011)
18
Figure 12. Seasonal average temperature anomalies in Hungary between 1901 and 2009 as
compared to the average of the 1971- 2000 period. (a) Spring, (b) Summer, (c) Autumn, (d) Winter.
(Hungarian Meteorological Services, 2011)
Figure 13. Changes in the annual precipitation in Hungary during the 1960 -2009 period (Hungarian
Meteorological Services, 2011)
3.2. Situation in the Lake Balaton region
3.2.1. Characteristics of the lake and it s catchment
Lake Balaton is large, extremely shallow lake with 588.5 km2 surface area and 3.36 m average
depth at the mean water level of 75 cm (zero point of the level gauge is 103.41 m above Baltic Sea
level), and 605 km2 surface area and 3.52 m average depth at 100 cm water level (Figure 14 shows
the bathimetry of the lake). Area of the lake changes little with increasing water level due to the
constructed (concrete) shoreline that occupies about 46 % of the total.
Extending to 3 counties in western Hungary, Lake Balaton catchment area is 5774.5 km 2. The
largest subcatchment is that of Zala river in the West with an area of 2622 km2.
19
Figure 14. Bathimetric map of Lake Balaton (at 75 cm mean water level)
Drought is a main concern for Lake Balaton. The unprecedented drought from 2000 to 2003
resulted in extreme low water level, loss of some 22 % of lake volume, and no outflow from the
lake for more than 5 years. Such a situation happened for the first time in the recorded history of
the lake.
Another concern is the drop of groundwater level resulting in the sinking of ground and damage to
the built environment as well as the reduction of agricultural production. Additional impacts are the
increase of extreme weather events resulting in occasional flooding and erosion of the steep terrain
along the northern shore.
3.2.2. Documented effects of climate change in the catchment area
The extrordinary drought from 2000 to 2003 is demonstrated by the cumulative precipitation deficit
as shown in Fig.16.
20
Figure 15. Lake Balaton catchment area with its tributaries
21
Figure 16. Cummulative deficit of precipitation (mm) relative to the long term mean
during the 2000-2003 extreme drought period (Source: Kravinszkaja G, Pappné-Urbán J., Varga
Gy.:Száraz és nedves időszakok hatása a Balaton 2000-2005 közötti vízháztartására, 2006)
In the watershed of the largest tributary of Lake Balaton (Zala river, representing some 55 % of
annual inflow on the long term), the precipitation deficit exceeded 700 mm, i.e. more than the
annual average precipitation of the region.
The multiannual low precipitation resulted in an even more severe reduction in the runoff from
the watershed.
Table 1. Precipitation and runoff during and after the drought period (Varga, 2007)Year Precipitation on the watershed Inflow to the lake
as percenage of the long term multiannual average
2000 69 632001 81 412002 82 342003 74 342004 103 632005 114 782006 88 88
22
15228731
Figure 17. Long term annual runoff trend for Lake watershed (blue bars: annual precipitation in
mm, red line: 5-year moving average, black line: linear trend line)
The long term trend of runoff is negative, but fluctuation is very significant. The last 2 decades
show repeatedly low runoff values.
Precipitation to Lake Balaton shows similar trend with almost lmm/year decrease in the last 9
decades, resulting in some 90 mm decrease overall.
As a result of the drought, the natural change of water balance, i.e. Precipitation + Inflow -
Evaporation became negative in year 2000 for the first time since reliable monitoring have been
introduced in 1921, and remained negative for three more years (Fig.19). Since water withdrawal
from the lake is insignificant (corresponds to some 30 mm annually) regulation of water use is not
a viable measure to prevent the dropping of the water level. Figure 20 shows the change of water
level in the drought years. The minimum level was 23 cm as opposed to the optimum 90 to 100 cm.Consequences of low water level
23
Figure 18. Long term annual precipitation trend for Lake Balaton (blue bars: annual precipitation in
mm, red line: 5-year moving average, black line: linear trend line)
Level drop for extended periods result in dried-up shoreline, formation of sand shelves, loss of
spawning area.
In addition, low levels inconvenience bathing tourists since they have to walk several hundred
meters to find water deep enough for swimming.
Low levels result in extreme shallow water where filamentous benthic algae (such as cladophora)
can grow in large masses. Wind action moves such algae mats to the shore or to the rip-rap, where
they decompose resulting in smell and aesthetic problems.
24
Figure 19. Annual Variation of the Natural Change of Water Resources (NCWR = Precipitation +
Inflow - Evaporation) for Lake Balaton.
130
1 1
1 1 1 I 1 1 1 1 1 1 1 1 1 i i i ■i i j
1 1 i im/U ft IT *
f n J
iAlL.. h i h ! 1 h
[Aiy11,
V J y Ji T 1 : T : : T i i i
i-fV- 1 I I I 1 1 1 1
_ _ _ _ j _ _ r 1....r1 rv Jr . h i ^ r I / J Pi ! r 1 r
i ii 1 j jf^l 1 i | i V1 I 1 1 1 1
ii ■ j r II 1 I
1 1 I 1 1 1
i ii ! / 1 1 1 1 1 1
i i 1 1
i i i i i i i 1 1 I 1 1 1
3= « j= » ,"9 .3 IS .2 ^I 13 I =ID —7 fU ' —
1 Tl .1 •3 = CO
I- o ft —? | in 3
Jis Q 13 3s 3 3 2 3iI -?
i D i/l 3
Figure 20. Seasonal change of water level (gauge) during and after the drought years (Thick blue
line: daily average water level, cm; thin blue line: lower control limit; thin red line: upper control
limit; thick red line: legal maximum level)
Water balance of the Lake is shown in the figure below. It can be observed that the long term
balance is positive, i.e. there is a considerable outflow from the lake, therefore salt content did not
build up, and there is an outflow of nutrients as well (10 to 20 t/year of TP). However, it is clear
that in recent decades the outflow decreased, and it was practically zero for the drought period
25
.a so
70
20
3
■ nap all va. - also sz. sz_ -op(. f. sz.
3
from 2000 to 2003. The indicated 2 mm outflow is negligible and it was necessary to prevent
anoxic and odorous conditions in stagnant water of the outflowing Sio Canal in summer.
26
Inflow Precipitation
A B C A B C900 850 400 618 600 500
YY\V V V
Water use
A B C50 50 50
Evaporation A B C920 950 980
Outflow
A B C610 500 2
Figure 21. Water balance of Lake Balaton in lake mmA: long term average (1921-2003); B: average between1986-2003; C: average between 2000-2003.
27
shallow water (< 40 cm)
Due to the lack of outflow some 10 to 20 tons of phosphorus (i.e. some 10 to 15 % of total
P load) was not discharged from the lake - thereby worsening the nutrient situation.
The lack of outflow had two other serious adverse effects. One is the impossibility to catch
eel with eel-traps placed at the outflow sluice. In an average year the Balaton Fishing
Company could catch some 100 t of eel at very low cost (almost free). Since there was no
outflow for 5 years, the fishing company suffered huge losses. The other is the
impossibility of the traffic of boats and ships through the Sio canal connecting Lake
Balaton and the Danube river.
Due to the low level, a considerable part of spawning surfaces and aqueous habitats dried
up. Figure 23 and 24 show the difference of water covered shore line at 0 cm and 120 cm
water level.
At low water level, yachting and commercial shipping becomes difficult. Some larger
ships and yachts are stranded, load restrictions should be applied and harbours should be
dredged frequently.
At low water level, wind induced resuspension of the sediment is more effective resulting
in higher turbidity and potential problems of the feeding of zooplankton.
28
Figure 22. Excessive growth of filamentous algae Cladophora glomerata in extremely
Surface area of water-covered substrate (m2)
0 cm vízállás esetén
: .10000,010000,1 20000,0
--- 20000,1 30000,0
--- 300001 40000,0
— 40000,1 50000,050000,1 60000,0
_ 60000,1 70000,0
70000,1 80000,0
--- 80000,1 90000,0
A
Figure 23. Distribution of estimated water covered
shore surface area (potential substrate) at 0 cm
water level (Paulovits et al., 2007)
Surface area of water-covered substrate (m2)
29
\
X /
Figure 24. Distribution of estimated water covered shore surface area (potential substrate) at 120 cm
water level (Paulovits et al., 2007)
120 cm vízállás esetén 0.0
0,1 - 10000.0
10000,1 -20000,0— 20000,1 - 30000,0
— 30000,1 - 40000,0
— 40000,1 ■ 50000,0
50000,1 - 60000,0
60000,1 - 70000,0
------- 70000,1 - 80000,0
------- 30000,1 - 90000.0
Dry weather also affects vineries and other
agricultural production. During the experienced
extreme dry year from 2000 to 2003, vineries
considered building water retaining facilities and
irrigation systems and applied soil cover by
mulch-like materials to reduce evaporation.
30
Effects of high water level
Due to the increase of extreme weather, occasional increases of lake level due wind action as
well as seasonal high levels due to excessive precipitation are experienced. As a consequence of
wind action, level displacement of as much as 1 m was experienced causing damage to
transportation infrastructure. Winter high levels caused ice damage to the shoreline concrete
structures (beaches) as well as flooding of low-lying areas in the south-western end. Flooding
threatens houses close to the shoreline.
Effects of increased temperature
Németh et al. (2007) analyzed the thermal bioclimate and applied the physiologically equivalent
temperature (PET), the well-known and one of the most frequently used bioclimate index based
on the human energy balance models (Höppe, 1993, 1999, Matzarakis et al., 1999, VDI, 1998).
For calculating PET they used the RayMan model (Matzarakis et al., 2001, Matzarakis and
Rutz, 2005). For the calculation they need to possess four meteorological parameters (air
temperature, relative humidity, wind speed and cloudiness) as well as some standard
physiological parameters (age, genus, bodyweight, height, average clothing and working). The
daily PET series (at 12 UTC) were calculated for the period 1966-2006 (Some of the results are
shown in Figure 25 and 26).
31
------YEAR -------------------Linear trend (Year)Figure 25. Mean annual PET for the town of Siofok, period 1966-2006
Figure 26. Variation of hot days at Siófok (Németh et al., 2007)
While the annual and seasonal means of PET are increasing, the number of comfortable days is
on the decrease. If these trends will continue in the next years, we should expect both positive
and negative results. The increasing demand for the waterside (beaches) as well as the
increasing length of the tourism season are the possible positive results. Negative impacts may
be the overcrowded beaches, the ecological problems resulting from the crowd, and the
increasing frequency of certain extreme weather events (heat waves, storms, droughts,
vegetation fires, etc.). These possible impacts mean that the tourism industry needs to draw up
adaptation plans on behalf of the sustainable tourism.
4. Vulnerability to the effects of climate change - future scenarios
4.1. Hydrology and water quantity
In case of Lake Balaton alarming reports (in the media) appeared in 2002 and 2003, talking
about the shrinking or even the disappearance of Lake Balaton. Due to the potential impacts of
extended low level periods, Lake Balaton Development Council initiated studies about water
transfer to the lake from other watersheds. It has been proven that such water transfers are
technically possible (from at least 3 rivers) but the ecological impacts of such a step are largely
unknown, just as the extent of adverse economic impacts.
32
Figure 27: Mean daily temperature in the Zala catchment (1960-2002) (From Thacker, S.: Climate
Change, Water, and the Possible Impacts on Riverine Habitats: A Case Study for the Zala Catchment
(Hungary), Master Thesis, Potsdam Institute für Klimafolgenforschung, August, 2011)
Novaky (2008) studied the impact of climate change on the water balance of Lake Balaton by
using IPCC emission scenarios and climate models. He found that increase in annual
temperature by 1.58 oC and decrease in annual precipitation by 5% are likely to lead to
considerable decrease in water recharge of lake. If an increase in annual temperature by 2.88 oC
is coupled with a decrease in precipitation by 10%, Lake Balaton could turn into a closed lake
without outflow. It is concluded that „despite the uncertanties involved, climate change will be a
great challenge for Lake Balaton"
33
Figure 28. The interval of variability of annual NWCR (red line) with 98% probability is
indicated for present and unchanged climate by the straight (blue lines) and for changed climate
by the broken (blue) lines. (Novaky, 2008)
Change of the relative frequency of daily average flows below 2 m3/s as well as 3 m3/s (Zala river at Zalaapati)
1965 1970 1975 1980 1985 1990 1995 2000 2005 2010Years
o Öu &£
15 tó
1965 1970 1975 1980 1985 1990 1995 2000 2005 2010
Years y = -0.0008 x + 1.6811
Figure 30. Zala river extreme high flows
34
Figure 29. Zala river extreme low flows
Change of the relative frequency of daily average flows over 10 m3/s as well as 20 m3/s
Change of runoff
In figure 31, runoff from the catchment area of Lake Balaton is shown in 40 km2 cells for the
reference period of 1961-1990. A similar figure (Fig.32) has been constructed for the B2 climate
scenario, for 2025.
HRunoff: mm | 0-25 25-50 51-75 76-100 101-125 | 126- |
Figure 31. Mean annual runoff in catchment of Lake Balaton for present climate (1961-1990).
(Novaky, 2008)
B2SRES. Had CM3. 2025
Runoff, mm C-25 25-5C 51-75 7i-1 CO 101-125
Figure 32. Mean annual runoff in catchment of Lake Balaton for changed climate
35
S
(2025). (Novaky, 2008)
36
------------1960-1979 ------------------------------1980-2000 -----------------------------2011-2030_Low ............................ 2011-2030_Mid
------------201 l-2030_Higtl 2031-2050_Low 2031-2050_Mid 2031-2030_High
Figure 33: Discharge for the Zala Catchment STAR +2 Degree Rise (Monthly Averages)
(Low, Mid and High correspond to 10th, 50th and 90th rank of precipitations from 100 runs, with 2 oC
temperature forcing)
0 -I ------- T ----- T ----- T ----- T ----- T ----- T ----- T ----- T ----- T ----- T -----
1 2 3 4 5 6 7 S 9 10 11 12
Month
(Source: Kutics and Szalay, 2006)
37
Month
Figure 34. Changes in monthly average inflow to Lake Balaton Reference period 1970-1990. A2.B2 scenarios 2020-2040
120
Initiated by concern of low water level between 2000 and 2003, Honti and Somlyody (2005)
studied the necessity of water transfer as well as the probability of filling up of the lake to
normal level at present and under changed climate.
The changes considered until 2035 are as follows: Average temperature increases by 1.58C and
0.58C in the winter and summer respectively. This induces an increase in evaporation. Rainfall
on the whole watershed increases by 5% in winter and decreases by 15% in summer. This
directly appears in the precipitation falling onto the lake surface (P) and indirectly in the inflow
(I). They assumed a linear relationship between rainfall and runoff.
38
Figure 35. Lake Balaton and Rába River watersheds indicating the potential transfer(Somlyody & Honti, 2005)
2003 2004 2005 2006 2003 2004 2005 2006
Figure 36. The effect of climate change on the restoration of lake level starting from December
2003. Mean and 80% confidence interval from 1500 predictive simulations. Dots indicate
observed water levels in 2004 (Somlyody & Honti, 2005)
They concluded that water transfer is not necessary in the short run, but the events of extreme
drought may become more frequent, i.e. their probalility increases almost an order of magnitude
(from once in 100 year to once in a few decades). Their conclusion that the low level causes no
adverse changes in the ecological status is arguable (e.g. excessive benthic algae growth is
undesirable - refer to the photo) Another conclusion that keeping spring water level higher (and
thus storing water in the lake) is also subject to criticism since low laying areas are already in
danger of flooding at the present 110 cm maximum level. They emphasize the great deal of
uncertanties involved in prediction and decision making.
In yet another paper, Honti and Somlyody conducted a stochastic simulation study of the water
balance of Lake Balaton under climatic pressure. The comprehensive statistical analysis proved
39
Figure 37. Annual minimum water level probabilities during the Monte-Carlo simulations with
the three climatic scenarios ("Present", Nova' ky and CLIME). White circles indicate the
corresponding probabilities derived from the 1921-2006 NCR database. All simulations utilized
the „0verflow1100" water level regulation strategy (i.e. keeping water level at maximum 110
cm when water is abundant) (Honti, M. and L. Somlyody: Stochastic water balance simulation for Lake
Balaton (Hungary) under climatic pressure Water Science & Technology 59, 3, 2009)
that the water budget of Lake Balaton remains positive under all of the expected climatic
scenarios, so the lake will no dry out in the following decades. In this sense, there is no
justification for artificial water transfer. However, extremely low levels may occur during
drought periods and the degree of climate change will significantly alter the frequency of low
levels in the future.
All the climate change studies on Lake Balaton point out the vulnerability of this extremely
shallow lake to climate changes and the great deal of uncertanties involved in climate scenarios
and modelling. In general, it can be concluded that the expected direction of climate change
(i.e.considerable warming and less precipitation) will have adverse effects on the water balance
of the lake, and requires adaptation steps to reduce these effects.
4.2. Lake water temperature
Lake water temperature is going to follow air temperaure changes, except in winter since no
negative water temperatures occur. The correlation between air and water temperatures is shown
in figure 38 for non-negative air temperatures.
The measurements were carried out from 1977 to 2005 in the middle of the Siófok basin. Air
and water temperatures were measured simultaneously in the framework of the regular water
40
Figure 38 Correlation of non-negative air and water temperature at Siofok basin lake centerline (1977-2005
n=1033)30
0 5 10 15 20 25 30 35 40
Air temperature. oC
quality monitoring process, in the morning hours. In beaches, water temperatures approaching
30 oC can be measured in shallow waters but in the middle of the lake at about 4 m depth the
temperature values are lower.
4.3. Water quality
In case of Lake Balaton eutrophication and accompanying algae blooms constitute the
challenge of water quality control. Eutrophication started in the 1960s as a result of reckless
nutrient management in agriculture and the absence of appropriate sewage treatment. After
the large scale blooms of 1982, serious nutrient control measures were introduced and after a
two decades water quality seemed to stabilize. However, during the extreme drought period
between 2000 and 2003 higher temperatures and low water levels resulted in less favourable
water quality in terms of chl-a (Figure 39)
41
Figure 39. Temporal and spatial change of annual maximum chla-concentrations in lakeBalaton.
The key nutrient responsible for eutrophication is phosphorus. The external total phosphorus
(TP) load was considerably reduced through sewer development and sewage treatment with P
precipitation, diversion of treated effluents to other watershed and the radical (though partly
unplanned) reduction of agricultural use of fertilizers. The lake responded to the TP control
measures with some delay, as it can be seen in figure 40.
Change of complex water quality of the most important tributaries is shown in figure XYX. The
complex water quality indicator (5 is worse, 1 is best) is calculated from the concentration of
nutrients (P, N), BOD5, COD, Chl-a and suspended solids (SS) . The general trend is that the
water quality slowly improves since the mid 1980s.
Chl-a concentration has stabilized after the mntioned drought period, and it is generally
acceptable in all four basins of Lake Balaton (Figure 41).
Water level is an important factor in determining algae concentration in the lake. Vörös
42
Figure 40. Change of TP load and Chl-a concentration in the most eutrophic basin of LakeBalaton
studied the relation of themass blooms of benthic filamentous algae Cladophora glomerata and water level. He found that below 50 cm level, large masses of the algae can be expected. The 50 cm level means that at some parts of the lake (especially along the shallow southern shore) the effective water depth is reduced to a few 10s of cm. Cl. glomerata has high light radiation tolerance (including UV) and proliferates in the shallows. Wind action moves the algae mat from the bottom to the rip-rap along the shores resulting in an unpleasant view and occasional smell. Kutics (2008) determined a logistic curve to qunatitatively describe the relation between Cl. glomerata mass and water level.
3.5
32.5
£ 2 ratM.5£ rz5 1
0.5 0
Figure 41. Water quality indicator for the most impoerant tributarioes of Lake Balaton
43
-•— Fenek puszta Z a l a ' Z a l a a p a t i Egerviz —■—Ny jgati Övcsatorna —»—Tapolca patak
T—r—T—i—i—T—T—1—i—r—T—T—r—1—i—1—t—T—i—r—r—i—T—1—i—T—T—T—r—i—r—1—i—T—I—~i—TC
OO <
NCO
□O
o CJ -rf
CO
DO
o <\i
-a-
(O
CO
o OJ
** CD
U5
fc t- CO
<0 e0 OO
oo cn Ol
Ol Oi
Ö o Q o
o>
O) cr>
O)
CF>
cn (?) CJ>
O) m pi (?> o Q o o
<M
C J
r>j
C 1
Year
Water level (H). cm
The relation between water level and phytoplankton chl-a is shown in figure 44. As it can be
seen, higher water level results in less algae, most probably due to more light limitation.
44
Figure 43 Relationship between Cladopliora biomass andwater level in Lake Balaton (after Voros L , 2007) ,45 !----- , -
5 0 20 40 60 SO 100 120
OKIR, KDT KTVF Database)( S o
Kutics et al. (2008) studied the effect of water temperature increase on expected annual peak
chl-a concentration through a P cycle model developed by Wake et al. (JICA, 1997, 2003)
and modified by Kutics and Szalay (2006). Two local climate scenarios corresponding
roughly to the IPCCs B2 and A2 scenarios were tested with external P loads kept
unchanged . The results are shown in figure 45. Simulations show that both scenarios result
in water quality deterioration, with BALALONE (A2) resulting in as high as 35% increase in
chl-a level in the cleanest (Siófok) basin of the lake. These finding indicate the importance of
further reduction of external P load to the lake.
45
Figure 44. Water level vs. phytoplankton Chl-a concentration
4.4. Reed belt and peat bogs
The reed belt behaviour was studied by Herodek et al. recently in light of the extreme drought
period. It was found that water level change assists the advance of reed towards the open water,
which can be attributed to the possibility of proliferation through seeds as well as the reduced
wave action (less mechanical stress). It can be seen in figure 46 that the reed front moves when
water level is low or variable, and receeds when the water level is fixed at high value. One
would state that low water level is favourable, but from other aspects the low level poses threat
to reed itself due to the increased risk of reed fires that are difficult to control due to the slow
and difficult accessibility (mostly from boat).
On the other hand, low water level results in less habitat and spawning area for fish and other
fauna.
46
Figure 45. Effect of climat e change on summer peak chl-a concentration (simulation)
between 1952 and 1982, mostly constantly high (controlled) from 1983 to 1999, andlow between 2000 and 2003). (Source: Herodek S.: A Balaton vízszintváltozásának hatásai a tó
ökológiai állapotára, Balatoni Partnerségi Program, Csopak, 2007. március 13.)
There are extensive peat bog areas around Lake Balaton since in the past the lake extended to as
much as 900 km2 area, with vast marshlands that connected to the lake (Figure 47). These peat
bogs are especially vulnerable to dry weather and low water level. In the dry year of 2003 some
250 ha of peat burned out south of the lake and near the shore line. People had to be evacuated
in the vicinity of the town of Fonyód, traffic on main roads was stopped due to extensive smoke
and extingusing the fire would take several weeks and much human and other resources. Since
peat mining is still going on at some places, the market value of the burned peat can be
estimated at 10 billion HUF. Reed and peat fires are generally interconnected and can be caused
by negligence, focused sun heat or lightning.
47
Figure 46. Movement of reed front at different time intervals (water level was variable
4.5. Fish and other macrofauna
Lake Balaton, as the largest freshwater lake in Central/Eastern Europe, is a critical site for
migratory species. Ducks Anas platyrhynchos, A. clypeata, A. penelope, Aythya ferina, A.
marila, A. fuligula , Bucephala clangula, Melanitta fusca and Mergellus albellus, geese Anser
anser and A. fabalis, swan Cygnus olor, coot Fulica atra, and diver Gavia arctica, use the site
as a staging area, and over 1% of the global Anser fabalis population can be found on the
lake. Among endangered resident species, the black stork (Ciconia nigra) and black
woodpecker (Dryocopus martius) are prominent. Some other ecologically important
protected species include Egretta alba, protected since 1922, E. garzetta, Ardea purpurea,
Ciconia nigra, and Grus grus. The lake itself contains about 2000 species of algae, 1200
species of invertebrates and 51 species of fish. The flora and fauna of the surrounding
landscape are particularly diverse due to the mild, Mediterranean-like climate. A large
number of rare and protected plant species can be found in the area, including several rare,
sub-mediterranean plant species, such as Sternbergia colchiciflora and Scilla autumnalis on
grasslands surrounding the lake. The area is especially rich in insects: over 1,000 species
have been identified. About 800 species of butterflies occur, some of them are extremely
rare, such as the ruby tiger (Phragmatobia fuliginosa) and the red underwing (Spialia
sertorius). The Kis Balaton, as a huge wetland habitat is unique in the whole of Europe,
which is why it has always been recorded by international nature conservation. In recognition
of its importance for
48
Figure 47. Marshlands (pink circles) that are still functioning or became peat bogs
biodiversity, Lake Balaton has been designated a seasonal Ramsar site between October 1 and
April 30 each year, while the adjoining Kis-Balaton, a reconstructed wetland and water
pollution control structure in the westernmost end of the lake received year-round designation
and protection (Ramsar Convention 2003a, Ramsar Convention 2003b). The Uplands Balaton
several basins, (Pecsely basin, Kali basin, Tapolca basin), representing unique ecosystems.
According to the national red data book around 30 important plant species are currently or
potentially endangered and fall under the protection and / or strict protection regimes
Commercial fish catch in Lake Balaton is declining since the end of the 1950s. (The increase
experienced in the first half of the 20th century is due to the improvement of fishing equipment
and enlargement of the operations - Figure 48.) The declining catch may be attributed to the
loss of spawning area due to the developement of shoreline protection concrete and stone
structures (Figure 49). Although, probably it is not the only factor, it has been recognized that
constructed shoreline structures increase the vulnerability of the lake ecosystem, and no more
such construction was done in the last decade.
49
rSb Aqfbq<bc&oSb £> A/ft/ft A rS>
Figure 48. Five year average fish catch from Lake Balaton (Bercsényi, 2005)
1600
1400 &
1200
^1000
800 600
400 200
0
75 85
95 105
L
e
n
g
h
t
o
f
c
o
n
st
r
u
50
Relation between the length of constructed (concrete) shoreline and annual fish catch (1970-2000)
(Source: LB Fishing Co.., Pannon University: Dr. Bercsényi Miklós)
y = -18.86x +2,693.59 R2
=0.78
■ - (Total shoreline length: 235.6 km)
o o
E
65
115
c
t
e
d
s
h
o
r
e
li
n
e
,
k
m
Figure 49. Constructed shoreline vs. annual fish catch
4.6. Invasive species
4.6.1 Plants
51
Perhap
s most
import
ant
invasiv
e
plants
are
ragwee
d
(Ambr
osia
artemis
iifolia)
and
golden
rod (
(Solida
go
canade
nsis
scabra
), as
well as
tropica
l,
nitroge
n
fixing
52
blue-
green
algae
(Cylin
drospe
rmopsi
s
racibor
skii).
During
mass
algae
blooms
in the
past
(e.g. in
1982,
1992,
1994),
C.
racibor
skii
was
the
domin
ant
algae
species
. It
53
constit
utes
risks
due to
potenti
al
toxin
produc
tion.
Ragwe
ed
causes
proble
ms due
to
compet
ition to
agricul
tural
produc
ts (e.g.
sunflo
wer)
and
due to
its
highly
allegen
ic
54
nature.
Unfort
unately
,
histori
cally
the
most
ragwee
d-
infecte
d area
is the
Lake
Balato
n
region
(Figure
50).
55
56
57
1922-1926
1945
Figure 50.
Historical
advance of
ragweed in
Hungary
(Source:
Priszter 1957 1960,
Béres -Hunya
di 1991).
Recent
situatio
n of
ragwee
d
polluti
on is
shown
in
Figure
51. We
can
see,
that in
most of
the
waters
hed,
ragwee
d
constit
utes a
modera
tely
serious
to
serious
proble
m.
58
59
Figure
51.
Inciden
ce of
ragwee
d in
2003 in
the
Lake
Balato
n
Waters
hed
Green:
0-1%,
yellow:
2-10%,
orange:
11-
25%,
red:
over
25%
(Sourc
e:
Hungar
ian
Soil
and
Plant
Protect
ion
Service
s)
It is
exp
ect
ed
that
rag
we
ed
wo
uld
bec
om
e
mo
re
co
mp
etiti
ve
wit
h
cli
mat
e
cha
nge
ther
efo
re
60
seri
ous
con
trol
me
asu
res
sho
uld
be
intr
odu
ced
.
4.6.2. Animals
Zeb
ra
mu
ssel
(Dr
eiss
ena
pol
ym
orp
61
ha)
and
a
Pon
to-
Cas
pia
n
am
phi
pod
(Co
rop
hiu
m
cur
vis
pin
um
)
wer
e
intr
odu
ced
to
Lak
e
Bal
62
ato
n
by
cha
nce
,
thr
oug
h a
bar
ge
fro
m
the
Da
nub
e.
Bot
h
are
inv
asi
ve
spe
cies
;
ver
y
goo
63
d
filt
ers
of
phy
topl
ank
ton.
D.
pol
ym
orp
ha
cau
ses
tro
ubl
e
by
stic
kin
g to
wat
er
wit
hdr
aw
al
equ
64
ipm
ent,
boa
ts,
pier
s,
etc.
So
me
orei
gn
fish
spe
cies
wer
e
intr
odu
ced
to
Lak
e
Bal
ato
n
inte
ntio
nall
y .
65
Pur
pos
e:
Fis
h
pro
duc
tion
(eel
),
eutr
oph
icat
ion
„co
ntr
ol"
(sil
ver
car
p,
gra
ss
car
p).
Res
ults
:
Ma
66
ssiv
e
kill
s of
eel;
Exc
essi
ve
dep
end
enc
e of
the
fish
ing
ind
ustr
y
on
eel
cat
ch/
exp
orts
;
Dis
tur
ban
ces
67
in
the
foo
d
we
b;
agi
ng
pop
ulat
ion
of
silv
er
car
p
("bi
olo
gic
al
bo
mb
");
Los
s or
dec
rea
se
in
68
the
pop
ulat
ion
of
indi
gen
ous
spe
cies
(e.g
.
pik
e,
Eso
x
luci
us)
.
Eee
l
(An
guil
la
ang
uill
a)is
om
niv
69
oro
us
and
tho
ugh
no
see
dlin
gs
are
intr
odu
ced
sin
ce
the
199
1-
199
2
ma
ss
kill
s,
ther
e is
still
a
con
70
sid
era
ble
pop
ulat
ion
in
Lak
e
Bal
ato
n.
Wh
ite
silv
er
car
p
(Hy
pop
hth
alm
icht
hys
mol
trix
)
and
spo
71
tted
silv
er
car
p
(Hy
pop
hth
alm
icht
hys
nob
ilis)
are
pla
nkti
vor
ous
.
The
y
gro
w
up
to
60
kg,
has
no
72
nat
ural
ene
mie
s in
Lak
e
Bal
ato
n,
and
ma
y
die
bec
aus
e of
age
.
Ver
y
diff
icul
t to
cat
ch,
jum
ps
ove
73
r
net
s
like
dol
phi
ns.
Gra
ss
car
p
(Ct
eno
pha
ryn
god
on
idel
la)
is
her
biv
oro
us.
Sel
ecti
ve
fish
ing
74
for
silv
er
car
p is
an
ong
oin
g
pro
ject
.
It is
expect
ed that
climate
change
would
not
reduce
(or
rather,
increas
e) the
popula
tionof these species.
75
4.7. Land use and agriculture
The
distr
ibuti
on
of
mai
n
land
use
cate
gori
es is
sho
wn
in
Tabl
e 3.
Lak
e
Bala
ton
catc
hme
nt
76
has
muc
h
less
arab
le
land
than
the
nati
onal
aver
age,
cons
ider
ably
mor
e
fore
sts,
vine
yard
s
and
orch
ards
and,
of
cour
77
se
mor
e
surf
ace
wate
r.
Table 3.
Land use in
the Lake
Balaton
catchment as
compared to
national
figuresHungary Lake Balaton Lake Balaton direct
Land use category catchment (total) catchment
km2 % km2 % km2 %
5589 6,0 334 5,8 184 5,8
49002 52,7 1779 30,8 807 25,6
Vineyard, orchard 2118 2,3 265 4,6 193 6,1
Misc. Agricultural 3309 3,6 257 4,5 93 2,9
11813 12,7 695 12,0 375 11,9
17960 19,3 1640 28,4 832 26,4
1260 1,4 170 2,9 81 2,6
1962 2,1 635 11,0 588 18,6
93013 100 5775 100 3153 100
78
On
Figu
re
52,
CO
RIN
E
land
cove
r is
sho
wn.
Mos
t of
the
„pla
ntati
on"
cate
gory
mea
n
vine
yard
in
the
Lak
e
Bala
79
ton
regi
on.
Ara
ble
land
is
alm
ost
negl
igibl
e in
the
nort
hern
part
of
the
wate
rshe
d,
whic
h is
a
step
p,
hilly
area
with
80
fore
sts,
mea
dow
s
and
vine
yard
s.
A
stud
y
cond
ucte
d by
Koh
lheb
et al.
(200
9)
on
the
desir
able
chan
ges
in
land
use
81
taki
ng
the
poss
ible
imp
acts
of
clim
ate
chan
ge
into
acco
unt
resul
ted
in
the
chan
ged
land
use
map
sho
wn
in
Figu
re
82
53.
The
chan
ges
incl
ude
the
incr
ease
of
the
area
of
fore
sts
and
past
ures/
mea
dow
s
and
the
exte
nsiv
e
culti
vati
on
83
(i.e.
less
fertil
izers
and
che
mica
ls)
of
arab
le
land
.
Acc
ordi
ng
to
the
prop
osed
chan
ges,
inte
nsiv
e
agri
cult
ural
land
84
use
beco
mes
alm
ost
negl
igib
el in
the
catc
hme
nt
area.
The
prop
osed
chan
ges
are
in
line
with
the
qual
itati
ve
pict
ure,
i.e.
85
incr
ease
of
fore
sted
and
past
ure/
mea
dow
area
wou
ld
be
usef
ul
both
for
miti
gati
on
of
and
adap
tatio
nto
the
imp
acts
86
of
clim
ate
chan
ge.
87
88
Artif. Surface Arable land Pasture, meadowPlantation Forest Wetland Surface water Other
Figure 52. Surface cover according to CORINE database. (Source: Szent
István University, Environment and Landscape Management Institute,2009)
Figure 53. Proposed land use pattern under to alleviate the effects of climate change (Source:
Szent István University, Environment and Landscape Management Institute,2009)
Present forest Proposed forrest Present pasture Proposed pasture Extensive arable land Intensive arable land
Lake Balaton catchment area is highly vulnerable to erosion and surface movement of soil (e.g.
loess walls collaps from time to time). The erosion potential map of the catchment area is shown
in figure 54. The proposed land use changes would reduce vulnerability to erosion as well. This
is very important since the combinded effects of
the
increa
se of
the
freque
ncy of
extre
me
weath
er
events
and
the
chang
e of
the
season
al
distrib
ution
of
precip
itation
(less
precip
itation
in the
vegeta
tion
89
period
)
would
increa
se the
vulner
ability
.
90
91
Figure
54.
Classif
ication
of sub-
catchm
ents of
Lake
Balato
n
Catch
ment
based
on
erosion
potenti
al
Light
pink: 0
to 20,
pink:
20 to
40,
red:
over 40
tons/ha
/year
(Sourc
e:
Máté,
F.:
Szabál
yozási
alternat
ívák a
4.8. Hunting
The
genera
l
tenden
cy is
that
large
game
popula
tion is
2 to
10
times
higher
than
desira
ble
(depen
ding
on
specie
s),
while
small
game
is at
about
92
50%
of the
favour
able
figure.
The
latter
is due
to the
the
high
popula
tion of
carniv
ores
such
as fox.
It is
unclea
r how
climat
e
chang
e
would
influe
nce
huntin
g.
93
Expec
ted
reduct
ion of
yield
in
agricu
ltural
produ
ction
may
result
in
tighter
contro
l of
games
and
theref
or
reduct
ion of
the
popula
tion of
most
damag
ing
specie
94
s such
as
wildb
oar
and
roe.
4.9. Tourism
With
more
than 5
millio
n
guest
nights
annual
ly,
touris
m is
the
most
import
ant
sector
of the
econo
95
my in
the
Lake
Balato
n
region
.
Theref
ore,
the
econo
my is
vulner
able to
96
changes in environmental conditions, including climate change. Figure 55 shows the municipal GDP (estimated by a methodology developed by Lőcsei and Németh,
97
2005) as a function of registered guest nights. Unfortunately, many of the guest nights go unregistered for various reasons, including tax evasion. The
98
real figure, including guest nights spent by „weekend house" owners, can be as high as 12 million/year.
Figure 55 Relation between
guest nights and
local GDP in
the towns of the
99
Lake Balaton Priority Resort
Area (1994-2004)
♦
♦_____A--. ♦
♦ •A--- y = 2.22x +228.49
R- = 0.8264
50100150200
100
Guest night/permanent resident/year
One
would
expect
that
there
is a
clear
correla
tion
betwee
n
summ
er
temper
atures
and
guest
nights.
Howe
ver,
Figure
56 and
57
shows
101
80
0
70
0
600
50
0
40
0
30
0
200
10
0 0
01
OJ .Ph
ffioOo
Ph
Qp
o250
no
appare
nt
correla
tion in
the
period
of
analysi
s
(1990
-
2006).
The
effect
of
temper
ature
is
clear if
numbe
r of
people
enterin
g the
beache
s is
analyz
ed. On
102
a
repres
entativ
e
beach
(Balat
onalm
ádi), a
strong
correla
tion
has
been
found,
and an
icrease
of 1
oC in
summ
er
averag
e
water
temper
ature
result
in
about
8 to 10
103
%
increas
e in
the
numbe
r of
people
buying
entran
ce
tickets
(Figur
e 58)
104
105
Figure 56. Guest nights vs. summer average air temperature in the Lake Balaton Resort Area
Figure 57. Guest nights vs. summer average water temperature in the Lake Balaton Resort Area
4.10. Infrastructure
4.10.1. Buildings
In the extreme dry period from 2000 to 2003 the ground water table decreased by more than 1 m
at some locations (e.g. near Kis-Balaton wetland). This resulted in the displacement of the
foundation of buildings due to the shrinking of the underlying soil (clay, etc.). Subsequent wet
weather and increase of ground water level resulted in some displacement again. The
consequence was the development of cracks in the foundations and walls of buildings. Since the
occurence of extreme periods is going to increase, buildings around lake Balaton become more
vulnerable to such damages.
Another type of vulnerability emerge from the the extreme weather events such as strong wind,
storms, lake level displacement, falling down of trees, etc.
4.10.2 Roads and other linar infrastructure
Highway No 7 runs along the southern shore of the lake, crossing the massive wetland
„Nagyberek". Large scale water level changes in this wetland may damage the highway
infrastructure. Extreme events increase the probability of erosion of unpaved or weakly paved
surfaces in steep urban areas.
106
Main sewer lines extend for about 40 km along the north-east shore of the lake, transferring raw
and treated sewage to the Balatonfuzfo sewage treatment plant. High temperatures would
aggrawate the already existing odour and corrosion problem of this infrastructure.
Low water level causes problems in the operation of marinas and the ferry boat services. In case
of extreme low level anticipated in the future, new docking infrastructure of ferries as well as
regular and costly dredging of marinas becomes necessary. In addition, srew damage of motor
boats of the Balaton Shipping Company would be more frequent.
5. Assessment of potential economic impacts
Lake hydrology and water quantity
Low water level between 2000 and 2003 caused quantifiable and non-quantifiable (or
difficult to quantify) economic damages. Kutics (2004) estimated the economic impacts
of low water level and the lack of outflow from the lake.
Commercial shipping: 1.0 to 2.0 million Euro/year
Commercial fishing: 0.5 to 0.7 million Euro/year
Dredging of harbors and bathing areas: 1.3- 1.6 million Euro/year
Clean-up of cladophora biomass from shallow waters: 0.1 to 0.2 million Euro/year
Reduction of entrance fee revenues of beaches: 0.5 million Euro/year
Halt of shipping in Sio Canal: ?
Ecological damages: ?
The total quantifiable damages can be estimated to be in the 3.4 to 5.0 million Euro/year.
Further potential damages that are difficult to quantify are
- Decrease of the number of tourists (guest nights)
- Yacht owners chose harbours at other lakes or the Adriatic due to the low level
- Overall decrease of tourism related incomes (total such income is estimated at
1,300 million Euro/year)
- Value reduction of homes and second houses due to the loss of popularity of Lake
Balaton region (total value of the houses is estimated at 8.6 billion Euro)
Water quality
In case of mass blooms, regular removal of Cladophora glomerata biomass at ca. 50 beaches -
50 x 10,000 Euro = 0.5 millio euro
P load reduction measures : urban and agricultural runoff control - see at erosion control
Water temperature
107
Increased water temperature may result in unsuitability of Lake Balaton water as drinking water
resources. In such a case, karstic water resources should be developed. Reed belts and peat bogs
Reed belt and peat bog fires can potentially result in tens of million euros in losses due to the loss
of reed and peat as commodities as well as loss of habitat. Fish and other macrofauna
Costs of selective silver carp catch is in the order of 0.1 million euro annually. Eel can be
eliminated only if there is (more or less) constant outflow from the lake. Invasive Species
Amount of ragweed can only be reduced through national level action. Loss of agricultural
production as well as work hours due to allergic reactions can go up to millions of euros. Land
use and agriculture
Change of land use patterns, forestation, irrigation of arable land and change of vinegrape species
involve large sums in the order of 10 millon euros. Erosion control both agricultural and urban
would cost at least 100 million euro for the lake-side municipalities. Tourism
Tourism income in the region is in the order of 1 to 1.5 billion euros. If problems with water
quality, quantity or other environmental problems occur, a 10% decrease would result in 100
million euro in losses for the businesses and subsequently less tax revenues for the municipal
governments. Infrastructure
The total value of houses is about 8.6 billion euro. Any percentage of damage due to grounfd
water level changes or extreme events can be expessed in tens of millions of euros.
108
6. Summary of findings related to vulnerability
Table 4. Qualitative Vulnerability Assessment for Lake Balaton (up to ca. 2040)Receptors Current Stresses Projected Climate
Change ImpactsVulnerability Assessment
Sensit-ivity
Adaptive Capacity Vulnerability Existence of (semi) quantitative assessment
Lake water level
Precipitation deficits Higher frequency of drought periods
Very High
Outflow control, Water transfer, Water resources management at river basin level
Very high Probability of drought, water balance
Flooding Slightly higher frequency of extreme events
High Increase Sió canal and sluice discharge capacity,
Very high
Ice damage to shoreline structures
Slightly higher frequency of extreme events
High Increase Sió canal and sluice discharge capacity
Very high
Peat fires at marshlands adjacent to the Lake
More frequent peat fires due to low water level and dry conditions
High Control water level of marshlands
High
Water temperature
Temperature increase Occasional algae blooms High Reduction of external P load
Medium Correlation eq. with air temperature
109
Receptors Current Stresses Projected Climate Vulnerability AssessmentChange Impacts Sensit-
ivityAdaptive Capacity Vulner-
abilityExistence of (semi)
quantitative assessment
Water quality Occasional algae blooms More frequent algae blooms High Reduction of external P load, Management of Kis-Balaton
High Simulation model for Chl-a and load scenarios
Growth of benthic filamentous algae Cl. glomerata
Increase in frequency and mass of Cl. glomerata
Very High
Reduction of external P load, Mechanical removal from beaches
High Equation to estimate chl-a from lake level
Appearance of algae toxins Increased frequency and conc. of algae toxins
Medium Reduction of external P load
Low
Pathogens Increased concentration and survival rate
High Urban runoff control Swan population control
Medium
Flash floods Increase of erosion and pollutant load
High Land management, Urban runoff control
High
Reed belt Changes in reed area, damage at extreme events
More damage at extreme events Low Water level management, reed harvesting practices
Low
110
Grasslands Rare drought damage More frequent drought damage Low None LowVineyards Drought damage More frequent drought damage,
more pestsHigh Species selection,
good practicesLow
Agriculture in general
Damage due to extreme events More frequent drought damage, heat stress, erosion, new pests
High Species selection, good practices, melioration
Medium
Forestry Damage due to extreme events, new pests
More frequent drought damage, heat stress, pests
Medium Species selection,understoreymanagement
Medium
Table 4. Qualitative Vulnerability Assessment for Lake Balaton (up to ca. 2040) (continued)Receptors Current Stresses Projected Climate Vulnerability Assessment
Change Impacts Sensitivity Adaptive Capacity Vulner-ability
Existence of (semi) quantitative assessment
Invasive Competition with More favourable conditions for Medium Removal and control Mediumspecies indigenous species propagation efforts
Human health risks due to More favourable conditions for High Removal campaigns, Mediumallergens propagation good agric. practices
Fishery Occasional drying out of More frequent drying out of Medium Outflow control, Medium Connection ofspawning areas spawning areas water transfer spawning substrate to
water levelReduced possibility of eel Even less possibility of eel Medium Outflow control Medium Otflow -eel catch
111
removal at outflow removal relationTourism Influence of extreme weather More frequent occurrence of low
water levels, heat days, less ice coverHigh Outflow control, water
transfer, attraction development, ice rinks
High
Occasional water quality problem
More frequent water quality problem High Nutrient load reduction, algae removal
Medium
Human health
Heat days, allergens, algae toxins
More heat days, spread of new allergens, higher level of algae toxins
Medium Heat shelters, allergen control, reduction of pollutant load, rising public awareness
Medium
Table 4. Qualitative Vulnerability Assessment for Lake Balaton (up to ca. 2040) (continued)Receptors Current Stresses Projected Climate Vulnerability Assessment
Change Impacts Sensitivity Adaptive Capacity Vulner-ability
Existence of (semi) quantitative assessment
Infra-structure
Increased erosion in built-up area due to extreme events
More erosion and pollution from built-up area
High Erosion control measures, rain water storage, treatment, reuse
Medium
112
Damage to buildings due to ground water level changes
More frequent and larger ground water level changes
High Rain water storage, recharge, ground water level control
High
Odour problem of sewer pumping stations
More odor problems due to higher water temperature and less flow
High Odour control measures, switching drinking water resources from Lake to karstic water
Medium
Problem of ferry, boat and marina use due to low water level
Increase of frequency of problems High Modification of ferry ports, dredging of marinas, use of smaller boats
Medium
Damages to infrastructure due to extreme events (winds, heavy rain, snow and ice)
More frequent physical damages to infrastructure and buildings
Medium Development of disaster plans and measures
Medium
113
LiteratureAIT Austrian Institute oftechnology, WP 4.3.2.Varga György: A Balaton vízháztartásának aktuális kérdései, a vízszint várható alakulása (in Hungarian)Balatoni Integrációs Kht., Regionális Oktatási Program Csopak, 2007. március 13. Kutics K.: Az alacsony vízállásról: következmények és teendők (in Hungarian) Konzílium a beteg Balatonért Konferencia, Balatonfüred, 2004. március 27. Paulovits, G.et al.: A halállomány szaporodásának és ívási körülményeinek módosulásai a vízszintváltozás hatására (in Hungarian), MTA Balatoni Limnológiai Kutatóintézet, Tihany, 2007.Németh, A. Et al.: Variations of thermal bioclimate in the Lake Balaton tourism Region (Hungary) in Developments in Tourism Climatology - A. Matzarakis, C. R. de Freitas, D. Scott, 2007Nováky, B.: Climate change impact on water balance of Lake Balaton, Water Science & Technology, 58(9), 2008.Somlyódy, L and M. Honti: The case of Lake Balaton: How can we exercise precaution? Water Science & Technology , 52(6), 2005.Honti, M. and L. Somlyódy: Stochastic water balance simulation for Lake Balaton (Hungary) under climatic pressure, Water Science & Technology , 59(3), 2009. Ramsar Convention. (2003) Contracting Parties to the Ramsar Convention on Wetlands. Gland, Ramsar Convention. (2003 a) A Directory of Wetlands of International Importance. Hungary 3HU012. Lake Balaton. Gland, Switzerland: Ramsar Convention.< http://www.wetlands.org/RDB/Ramsar_Dir/Hungary/HU012D02.htm > Ramsar Convention.
(2003b) A Directory of Wetlands of International Importance. Hungary 3HU004. Kis-Balaton.
Gland, Switzerland: Ramsar Convention.
< http://www.wetlands.org/RDB/Ramsar Dir/Hungary/HU004D02.htm >.
Wake, A. et al: Hydrodynamic, thermodynamic and water quality model for Lake Balaton,
JICA, 2003.
Kutics, K., Szalay M.: A Balaton sérülékenység vizsgálata a klímaváltozás függvényében-
Modell vizsgálatok, Siófok, 2006.
Kohlheb N., Podmaniczky L., Skutai J., Magyarország felszínborítottságának lehetőségei az
éghajlatvédelemben, Körtáj Tervező Iroda Kft., 2009.
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