PART 8
8.1. Conclusion statements
After considering the evaluation of environmental monitoring results in
hydrological year 2005 the Nominated Monitoring Agents conclude:
1. The gauging station Bratislava-Devín plays the key role
in determining of water amounts discharged into the Danube old riverbed
downstream of the Čunovo dam. The average annual flow rate in this station in
the hydrological year 2005 was 2146 m3.s-1, which was the
sixth highest annual average flow rate observed since 1992. Considering the
course of water levels and flow rates during the hydrological year 2005 it can
be stated that no unusual values occurred.
Taking into consideration obligations envisaged in the intergovernmental
Agreement, the Slovak Party was obliged to release an average annual discharge
of 423.9 m3.s-1 into the Danube riverbed downstream of Čunovo
dam. According to the observations carried out at the Doborgaz and Helena
gauging stations, the yearly average discharge released to the Danube old
riverbed downstream of Čunovo in the hydrological year 2005 was 445.1 m3.s-1.
Taking into account the modified method of average discharge calculation,
accepted in the Joint Annual Report on the environment monitoring in 2004,
discharges exceeding 600 m3s-1, while the flow rate in the
Danube was higher than 5400 m3s-1, were reduced to 600 m3s-1.
When subtracting the amount of water over 600 m3s-1
released during the flood events (8 values), the average annual flow rate of
436.2 m3s-1 is obtained, which represents 102.9 % of the
amount requested by the Agreement.. This means that the obligation was
fulfilled. The discharge into the Mosoni branch of the Danube was 42.36 m3.s-1,
which represents 98.5 % of the agreed amount. Taking into consideration the
technical and hydrological circumstances envisaged in the intergovernmental
Agreement and the accuracy of measurements it can be stated, that the amount of
water released to the Mosoni branch of the Danube was fulfilled as well.
2. The surface water quality in the Danube in the observed
period slightly improved compared to the previous year, which is reflected in a
decrease of nutrient contents, CODMn, lower saprobic index and number
of bacteria. Changes in water quality at observation points in the Danube
throughout the year correspond to the water quality fluctuation at Bratislava,
which is characterising the water quality entering the influenced area.
Increased values of some parameters in the Danube during the hydrological year
2005 were related to higher flow rates in the Danube during flood waves. The
reservoir, situated downstream of Bratislava, depending on the actual flow
velocity, plays a certain role in settling and removing of suspended solids. The
better surface water quality consequently influences the water quality in the
territory influenced by temporary measures, realised according to the Agreement.
The fluctuation of water quality parameters in the right side river branch
system follows their fluctuation in the Danube since introducing the water
supply in 1995.
The tributaries and local pollution of settlements, besides the water supply
influence, form the water quality in Mosoni Danube. Before the confluence with
the Danube the water quality is variable in time, which is proved by
unfavourable values of some parameters (electric conductivity, dissolved solids,
Coliform bacteria, chlorophyll-a, CODMn, BOD5, nutrients
and saprobic index). Compared to the previous years the water quality improved,
thanks to investments realized in the water treatment plant at Győr. The
cleanest water was found in the seepage canals, which results from its
groundwater origin.
Considering the surface water quality evaluation in 2005, according to the
Slovak Party the water quality in the Danube at Medveďov is very similar or
even slightly better than the water quality at Bratislava. According to the
Hungarian Party the water quality in the Danube at Medveďov is very similar to
water quality at Bratislava, in some parameter it is better, in some parameters
it is worse.
3. Based on the evaluation of the ground water regime it
can be stated that the water supply into the right side river branch system
plays an important role in influencing ground water levels over the Szigetköz
region. As a result of the measures realised according to the
intergovernmental Agreement, a significant increase in the ground water levels
occurred for low and average flow rate conditions in the Danube. No changes in
the upper and middle part of the Szigetköz region, and a decrease in the ground
water levels along the Danube riverbed can be registered for the high flow rate
conditions..
The monitoring results highlights the necessity of increasing the ground water
level in the lower part of the inundation area on both sides. The ground water
level increase in the lower part of the Ásványi river branch system and in the
Bagoméri river branch systems is being solved by extension of the water supply.
The ground water level on the Istragov Island on the Slovak side could be solved
by extension of water supply system as well, or by measures applied in the
Danube old riverbed upstream of the confluence with the tailrace channel. Such
measures can improve the general situation in this region
An increase of ground water levels in the strip along the Danube old riverbed on
both sides could be ensured only by increasing water level in the Danube by
measures realised in the riverbed. Such measures will improve the ground water
regime in the inundation area and could also help in artificial flooding. The
most simple, quickly realisable measure seems to be the solution applied at
Dunakiliti at rkm 1843, realised according to the “Agreement”. However,
these measures have to conform to the flood protection activities in this area.
4. Summarizing the results of the long-term water quality
observations of 16 groundwater quality observation wells on Hungarian side it
can be stated that the water base of Szigetköz is typically characterised by
higher iron and manganese content. The iron and manganese content permanently
exceed the groundwater quality limits on most of the observed wells. In 2005 the
content of parameters indicating the presence of organic matter, presumably
indicating contamination of agricultural and wastewater origin, slightly
decreased or it did not changed in comparison to the previous year. The low
concentration of oxygen is typical as well. From place to place pollution by
higher amount of iron or manganese occurs, which may indicate reduction
processes. Changes in the ground water quality at some places reflect an
integrated effect of the transformations that occurred in the region, in which
the ground water flow directions, affected and changed by the Szigetköz water
supply, also play a role.
Based on the results of the long-term groundwater quality observation on the
Slovak territory it can be stated that the observed groundwater quality
parameters mostly satisfies the agreed ground water quality limits. Sporadic
exceeding of limit values occurred during the observation period as well. The
manganese content frequently exceeded the given limits in 3 of 10 evaluated
observation wells, while the iron concentrations frequently exceeded the agreed
limits on 2 wells.
In case of the wells used for drinking water supply, it can be concluded that
the water quality parameters are excellent and the water composition is
characterised by high stability on both sides. However, the ammonium ion and
organic matter content are higher in wells in the Győr region. In these wells
also the iron and manganese content occasionally exceeds the drinking water
quality limit values or oscillate around them.
5. The soil moisture content in 2005 was significantly
influenced by precipitation amount at the beginning of the vegetation period,
however regional differences were significant. The hydrological conditions
throughout the year were favourable too. The soil moisture in the Szigetköz
region was positively influenced by higher discharges in March, July and August
2005. Artificial flooding in the right side inundation in May positively
influenced the soil moisture content as well. The amount of water discharged
into the river branch system induced situations characteristic for natural
floods. Moreover the high amount of precipitation in the second half of July and
in August caused that the soil moisture at most of the monitored areas reached
or almost reached the saturation level. The average ground water level during
the vegetation period 2005 was noticeably higher comparing the average ground
water level in 2004. Decrease of soil moisture content was registered at the end
of the vegetation period, when it did not reached the long term average However,
it was higher in comparison to the previous year thanks to the high
precipitation amounts in previous months. The minimal, average and maximal
values were in general higher in comparison with the previous year.
According to the soil moisture observation at monitoring sites situated in the
agricultural area on the Slovak side it can be stated again that the soil
moisture content during the whole observed period remained unchanged.
6. The monitoring of forest stands on the Slovak side was
focused onto various cultivated poplars clones. The monitoring results show that
the growth of poplar clones in different parts of the inundation area is
similar. The height increase of the aged plots is good, even though it has a
decreasing tendency. No significant decrease of growth was observed on plots
where the ground water level dropped below the boundary between the soils and
gravel layer. This can be explained by penetrating of roots downwards to deeper
lying layers. On the other side the growth of newly planted forest seems to be
problematic. The root system of planted trees is not developed, so the access to
the water is difficult. Problems with reforestation of cleared area emphasize
the necessity of hydro-technical measures. The water regime in inundation area
can be improved by ground water level increase, by artificial flooding of the
area and with setting up the water supply into the river branches in lower part
of the inundation area.
In 2005 the health state of forest in the inundation area was evaluated
according to aerial and terrestrial survey. The evaluation was based on
defoliation of trees and terrestrial survey. Results in 2005 did not show any
unfavourable effect of the hydropower plant on the forest health state. The
health state of the forest is very good; the average defoliation did not reached
the Slovak average. In comparison to the results of previous survey in 2002
significant changes occurred sporadically only and were present equally at all
classes of defoliation
The composition of forest stands on the Hungarian side consist mainly of willows
and cultivated poplars. Besides this several hardwood and lowland forest stands
are monitored. According to dendrometric measurements in 2005, the changed
moisture conditions in the Szigetköz region after diversion of the Danube
affected the forest stands, however the impact is strongly dependent on the
forest type and locations. There exist seriously affected stands, which consist
of willows or young poplars, which are situated on locations unsuitable for
these kinds of trees. Significant number of dried trees in planted stands is
warning, increasing number of dried trees was registered in last few years.
Based on these facts new investigation, focused on the natural regeneration
processes and management procedures should be introduced. The health state was
not evaluated in 2005 on the Hungarian side.
7. The vegetation period 2005 was richer in precipitation
in comparison to the previous year. Moreover a large part of the inundation area
was several times naturally flooded, an artificial flooding was performed in the
right side inundation as well. The favourable climatic and hydrologic conditions
were reflected in increase of biomass of the plant layer, the meadow plants were
higher than ever before in the whole monitoring period. The species number was
slightly lower in the evaluated year, but the decrease was not significant. At
most of the monitored sites along the Danube the average leaf area values were
higher on willow stands and on oak stands. No impact on vegetation along the
Mosoni Danube was registered. Stabilized development of phytocoenoses can by
observed in a greater part of the left side inundation area. However,
unfavourable moisture conditions for the lowland forest were found in the area
upstream of the water supply canal and in the region of Istragov Island. Higher
amount of precipitation in 2005 postponed the defoliation and no mosaic
loosening of coverage in the herb layer occurred.
The terrestrial mollusc’s community of large part of Slovak inundation area
are stabilized. In the most moisturized regions typical marshy wetland forest
communities occur. However, worsening of the hydrological regime in the region
of Istragov Island invoked a medium degradation of the malakocoenose. Decrease
in species number, involving bigger species with longer life cycle, at
monitoring sites in the Hungarian inundation was detected. This could reflect
the absence of regular natural flooding, however the inundation area was
artificially flooded in last two years, and the shortcomings of the random
sifting method.
The macrophyte communities are highly dependent on site-specific hydrological
conditions. After the washout by the strong flood in 2002 regeneration and
intensive development of aquatic macrophytes was registered in last two years.
The discharges supplied into the active floodplain on both sides were similar to
discharges in previous years. Large part of the floodplain river branches are
characteristic by higher water depth, which corresponds to stabilized species
composition of aquatic plant communities. The hydrological conditions of the
Hungarian flood-protected area, thanks to the continuous water supply, remained
unchanged in last few years. The species compositions have not changed
significantly as well.
Concerning the aquatic fauna in the Danube the observation results show a
decrease in species number as well as in number of individuals in 2005, probably
due to higher discharges and muddy sediments on the shoreline. In the river
branch system, particularly on the right side, changes in aquatic fauna reflect
the increased flow velocity. Generally it can be stated that along the water
supply path the number of species rose (the number of rheophilous species
increased). The species composition became stabile. Concerning the fish
community in the Danube it can be stated that it has stabilised under changed
condition caused by diverting the river. Spreading of foreign expansionary
species can be considered for a most significant change. However, spreading of
foreign species is independent on hydropower structures. In the right side river
branch system mostly the eurytopic species occur. The reappearance of some
rheophilous species in the ichtyofauna reflects the partial reconnection with
the main riverbed. The characteristics of fish community became stable on
monitoring areas supplied by water on both sides. In the Hungarian
flood-protected area regeneration of ichtyofauna is observed since introducing
the water supply. The species richness became stable and during the last years
was balanced. The ichtyofauna composition at the isolated dead arms on the
Slovak side depends on the actual hydrological conditions (missing ichtyofauna
at monitoring area No. 2612, after drying out of the dead river arm in 2004).
8.2. Proposals
Proposals given in this point will be obligatory for both Parties and do not
require further approval when the actual Joint Annual Report is approved and
signed by Nominated Monitoring Agents.
1. The Parties suggest a modification of the Statute,
reflecting the changes essential for realisation of monitoring tasks in the
frame of the Water Framework Directive, and results presented on Danube
Monitoring Scientific Conference, held in Mosonmagyaróvár, Hungary. The
Hungarian Party will submit the first proposal for the modification, taking into
account the experiences and presented results from 10 years monitoring as well
as the rationalization of the monitoring system.
2. The Slovak Party in relation with negotiations of Expert
Working Groups, carried out in the frame of negotiations on implementation of
the ICJ Judgement, will submit a proposal for monitoring extension on the Danube
stretch between Sap and Budapest.