BG3.17

Forests are important ecosystems for mitigating CO₂. However, droughts affect the vitality of forests and alter CO₂ uptake. In worst cases, forest ecosystems can even turn from a carbon sink to a source in consequence of water shortage. Forest stands in urban areas are more prone to droughts because of elevated temperatures in comparison to rural land and unfavorable growth conditions such as limited rooting depth and low soil carbon content.

The drought years 2018 and 2019 in the Ruhr Metropolitan Region (Germany) were characterized by a 0.6 K higher mean annual temperature as normal and only 75 % of the normal annual precipitation. During this period, we investigated the CO₂ balance of urban forest ecosystems, considering annual changes in carbon stocks of tree biomass and litterfall and annual CO₂ effluxes from soil respiration, at eleven monitoring sites across the Ruhr Metropolitan Region by combining measuring and modelling approaches. The chosen sites represent the different urban forest types found here: old-grown semi-natural forests (beech, oak, maple), autochthon non-managed succession forests of birch, poplar or willow on brownfields and allochthone mixed forest stands planted in urban parcs and on heaps (urban greening forests).

Tree growth, leaf expansion, and CO₂ efflux decreased at nearly all sites in 2019 in comparison to 2018 in consequence of the ongoing drought. While the semi-natural forests were able to increase CO₂ uptake by 11 % in 2019, the urban greening forests decreased their CO₂ uptake by 62.9 %. The succession forests were CO₂ sources in both years but increased the CO₂ release in the second year by 85 % in comparison to the first year. Two sites turned from carbon sinks in 2018 to carbon sources in 2019. Correlation analyses showed that the soil hydraulic properties such as depth of the rooting zone, soil carbon content, and plant available water were the main influencing factors describing the decrease in tree growth and leaf development. Overall, the results indicate that, semi-natural forests on mesophilic sites are more resilient against droughts due to unlimited rooting zone, high soil carbon content, which favor the amount and accessibility of plant available water, while urban greening and succession forests are more vulnerable to droughts due to limiting rooting zone, low soil carbon content, and low plant available water. More vulnerable to droughts are also semi-natural forests on more extreme sites, like an examined Stellario-Carpinetum, which turned from a carbon sink in 2018 to a source in 2019. Furthermore, two patterns of seasonal changes in soil respiration were found in reaction to the drought. i) those of elevated soil respiration associated to elevated temperature in 2018 and decrease of soil respiration in 2019 in consequence of thermal denaturation of the microbial community, and one ii) those where, the mineralization activity was shifted to winter when the upper soil layer was rewetted, leading to larger soil respiration during the cold season.

Urban planners should ensure a deep rooting zone and carbon rich soils by establishing new urban forest stands to tackle drought periods.

How to cite: Scholz, T., Weihermüller, L., and Schmitt, T.: Drought years of 2018 and 2019 affect CO2 balance of urban forest ecosystems in the Ruhr Metropolitan Region (Germany) differently, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-11030, https://doi.org/10.5194/egusphere-egu21-11030, 2021.

The future development of the runoff conditions, as a consequence of climate change, is of great interest for water managers. Information about the potential impacts of climate change on the hydrological regime is needed for long-term planning of water resources and flood protection.

The aim of this study is to evaluate the possible impacts of climate change on the runoff regime in five selected catchments located in the territory of Slovakia. Changes in climatic characteristics (i.e., precipitation and air temperature) for future time horizons were prepared by a regional climate model KNMI using the A1B emission scenario. The selected climatic scenario predicts a general increase in air temperature and precipitation (higher in winter than in summer). For simulations of runoff under changed conditions, a lumped rainfall-runoff model (the TUW model) was used. This model belongs to a group of conceptual models and follows a structure of a widely used Swedish HBV model. The TUW model was calibrated for the period of 2011 – 2019. We assumed that this period would be similar (to recent/warmer climate) in terms of the average daily air temperatures and daily precipitation totals. The future changes in runoff due to climate change were evaluated by comparing the simulated long-term mean monthly runoff for the current state (1981-2010) and modelled scenarios in three time periods (2011-2040, 2041-2070, and 2071-2100). The results indicate that changes in the long-term runoff seasonality and extremality of hydrological cycle could be expected in the future. The runoff should increase in winter months compared to the reference period. This increase is probably related to a rise in temperature and anticipated snowmelt. Conversely, during the summer periods, a decrease in the long-term runoff could be assumed. According to modelling, these changes will be more pronounced in the later time horizons.

It should be noted that the results of the simulation are dependent on the availability of the inputs, the hydrological/climate model used, the schematization of the simulated processes, etc. Therefore, they need to be interpreted with a sufficient degree of caution

How to cite: Výleta, R., Aleksić, M., Sleziak, P., and Hlavcova, K.: Simulating the impact of future climate change on runoff processes in selected catchments of Slovakia, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-5074, https://doi.org/10.5194/egusphere-egu21-5074, 2021.

The landscape is an open system driven by interactions between natural and anthropogenic elements. Their long-term impact is responsible for the current form and status of the landscape. Integrated landscape management enables to implement particular solutions to mitigate the effects of threats to the ecological stability of the environment, to preserve and support diversity of ecosystems, to improve ecologically less stable parts of landscape and their spatial spread, as well as the possibility to maintain important cultural heritage of the landscape. The aim of the study was to aid local and regional spatial planning in a headwater catchment by a complex quantitative assessment of risks of flash flooding, muddy floods and soil erosion caused by extreme rainfall.  The research on and the design of protection measures were realized in the cadaster of the village situated on the border to Moravia in Slovakia. Generally accepted robust quantitative methods for risk mitigation, which are simple enough, but are yielding reliable predictions, were integrated into complex mitigation measures in order to improve the ecological stability and recreational potential of the area. Present land management practices are increasing the risk of flash flooding and soil erosion, including rill erosion on the arable land in the region with prevailingly flysch geological structures. A set of flood detention storages, infiltration trenches and agrotechnical measures on the arable land were proposed for the reduction of the extreme runoff and erosion. The effectiveness of the proposed measures showed that we were able to reduce the amount of soil erosion to permissible values. The results were integrated into a spatial erosion and flood protection scheme which will be the bases of spatial planning on a local scale for sustainable agriculture and will enable recreational use of the riverine areas and of the hilly landscape.

How to cite: Danacova, M., Vyleta, R., Hlavcova, K., Kohnova, S., and Szolgay, J.: Case study of integrating ecosystem managememnt into spatial planning in rural environment, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-5260, https://doi.org/10.5194/egusphere-egu21-5260, 2021.

The study focuses on future changes in short-term rainfall characteristics. The analysis was performed for the mountainous regions in the northern part of Slovakia at 10 selected climatological stations. The rainfall data are simulated by Community Land Model Scenario which represents the future climate change.  The Community Land Model Scenario is a multidisciplinary project between scientists and several working groups mainly in the USA. The model includes impacts of changes in vegetation on the climate. The scenario has semi- pessimistic characteristics with a predicted global temperature increase by 2.9°C by the 2100. The analysis was performed for five rainfall durations (60, 120, 180, 240 and 1440 minutes) for the historical (1961-2020) and for the future (2071-2100) periods.  The detection of the future changes in short-term rainfall characteristics was made by several methods; for the seasonal changes the Burn´s vector was used, for the trend testing the data the Mann-Kendall test was applied. Results provide information how climate change impacts the short-term rainfall intensities in the mountainous regions of Slovakia.

How to cite: Földes, G., Labat, M. M., Kohnová, S., and Kandera, M.: Detecting future changes of short-term rainfall characteristics in the mountainous regions of Slovakia, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-5268, https://doi.org/10.5194/egusphere-egu21-5268, 2021.

According to the climate change and Water Framework Directive 2000/60/EC (WFD) the analysis od the status of waterbodies and their continuous monitoring has to be carried out based on unified methodologies and standards. Individual prescriptions have to be in harmony with national and international standards, in order to ensure equal scientific value and comparability of the data. The international standard EN ISO 748 entitled „Hydrometry - Measurement of liquid flow in open channels using current-meters or floats” was issued in 2008. This standard is based on the discharge measurement methods in the European Union (EU) and it differs in some aspects from the Hungarian standard (ME-10-231-16:2009). The goal of our study was to identify and answer the questions related to the introduction of this standard into Hungarian practice. The issue is crucial for the hydrometry units of Hungarian Water Directorates, as if the introduction of a new standard is not correctly substantiated the consequences can include avoidable economical burdens and/or changes in the quality of data. The research was initiated and financed by the Hungarian General Directorate of Water management and targeted at the comparative analysis of the measurement and calculation methodologies of the two standards, carried out on watercourses in Hungary. Thus we have executed a series of measurements in 31 cross-sections on 18 different watercourses in Hungary. Based on our results we can state that the difference between the results of the different methodologies generally does not exceed the uncertainties originating from the measurements themselves. Under specific circumstances (e.g. very low flow velocities) the effect of the chosen methodology can be significant.

How to cite: Keve, G., Sziebert, J., Koch, D., Tamás, E. A., Varga, G., Majer, F., Krikovszky, S., Ficsor, J., and Fekete, Á.: The comparative analysis of the Hungarian and European methodology of discharge measurement, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-16109, https://doi.org/10.5194/egusphere-egu21-16109, 2021.

Crop production is applied on about half of Hungary’s land area, which amounts to approximately 4.5 million hectares. The agricultural activity has significant environmental impacts.

Our work aims the time series investigation of the impacts of large-scale agricultural cultivation on environment and primarily on climate change in the test area by applying environmental life cycle assessment (LCA) method.

The investigated area of Lajta Project can be found in the triangle formed by the settlements Mosonszolnok, Jánossomorja and Várbalog, in the north-western corner of Hungary, in Győr-Moson-Sopron county. The area has intense agri-environment characteristics, almost entirely lacking of grasslands and meadows.

We were looking for the answer to the question “To what extent does agricultural activity on this area impact the environment and how can it contribute to climate change during a given period?” The selection of the plants included in the analysis was justified by their significant growing area. We analysed the cultivation data of 5 crops: canola, winter barley, winter wheat, green maize and maize. Material flows of arable crop production technologies were defined in time series by the agricultural parcel register data. These covered the size of the area actually cultivated, the operational processes, records on seeds, fertilizer and pesticide use and harvest data by parcels. The examined environmental inventory database contained also the fuel consumption and lubricating oil usage of machine operations, and the water usage of chemical utilization.

In the life cycle modelling of cultivation, we examined 13 years of maize, 20 years of green maize, 20 years of winter barley, 18 years of winter wheat and 15 years of canola data calculated on 1 ha unit using GaBi life cycle analysis software.

In addition, we also calculated by an average cultivation model for all cultivated plants with reference data to 1 ha and 1 year period.

We applied methods and models in our life cycle impact assessment. According to the values of the impact categories, we set up the following increasing environmental ranking of plant cultivation: (1) canola has minimum environmental impacts followed by (2) green maize and (3) maize with slightly higher values, (4) winter barley has 6 times higher values preceded by (5) winter wheat with a slight difference. The previous environmental ranking of the specific cultivated plants’ contribution was also confirmed as regards the overall environmental impact: canola (1.0%) – green maize (4.9%) – maize (7.1%) – winter barley (43.1%) – winter wheat (44.0%).

Environmental impact category indicator results cumulated to total cultivation periods and total crop growing areas (quantitative approach) display the specific environmental footprints by crops. Increasing environmental ranking of environmental impacts resulted from cultivating the sample area is the following: (1) canola – (2) maize – (3) green maize – (4) winter barley – (5) winter wheat. The slight difference resulted in the rankings in quantitative approach according to the rankings of territorial approach on the investigated area is due to the diversity of cultivation time factor and the crop-growing parameter of the specific crops.

Acknowledgement: Our research was supported by the „Lajta-Project”.

How to cite: Polgár, A., Horváth, K., Mészáros, I., Horváth, A., Bidló, A., Faragó, S., and Elekné Fodor, V.: Investigation of the two-decade environmental impact of large-scale agricultural cultivation and its impact on climate change in the Lajta-Project, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-4863, https://doi.org/10.5194/egusphere-egu21-4863, 2021.

The current climatic conditions of the Hungarian Great Plain is not adequate for the forest cover. Surplus water is essential to maintain good ecological status and growth rate of forests. Moreover, in the drying climate of the Great Plain without excess water the survival of forest vegetation is  questionable.

In this study, we try to indicate the positive effect of the excess water on the growth of the trees next to the Danube in Gemenc wetland (close the southern border of Hungary). The logging data were collected from 2000 to 2009. Sampled forest compartments were clustered into two groups based on the stand position to the levee (exposed to inundation of Danube or not). The effects of the Danube are evaluated using local hydrological measurements (e.g. gauge at Mohács).

The forest growth itself is not the best indicator because it is also influenced by several other ecological variables. To control better these variables two forest stands were selected aged about 110 years. One of them is located behind a summer levee (low crown height levee), which is inundated only by the high floods. Another forest compartment is outside the main levee and never inundated. These stands are sampled to prepare dendrochronological analysis, which gives us higher time-resolution data. We hope these analyses will help us to interpret the relationship between forest growth and water
conditions.

This research has been supported by the Ministry of Agriculture in Hungary.

How to cite: Kaizer, B., Gribovszki, Z., and Kalicz, P.: Riparian forests production related to water supply along southern Hungarian Danube, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-12182, https://doi.org/10.5194/egusphere-egu21-12182, 2021.

In the Hidegvíz Valley experimental catchment in Hungary the meteorological data have been collected since the 1990s and used for various purposes including hydrological studies. Current research began in 2018–19, that aimed to reveal the connections between the hydrological and botanical characteristics in riparian forests and a wet meadow. Changes that occurred in both ecosystems in the groundwater levels, soil moisture and vegetation, showed that the local meteorological events influence these factors. Therefore we decided to analyse longer periods in which meteorological extremes
strongly influenced hydrological conditions and so status of ecosystems. Further measurements and their analysis were also required because more accuracy and detail were needed for future water balance modelling.

The measured data between 2017–2020 were chosen as a starting database. For the first analysis we selected three meteorological parameters, i. e. the precipitation, the air temperature, and the air humidity. These parameters were measured by automated instruments, except for the precipitation. We found that the automated tipping-bucket rain gauge needs validation by a manual measurement (Hellmann-type rain gauge), because the data that collected by the automated device will be invalid if the rain intensity is too high.

In 2017 and 2018, the annual precipitation was distributed evenly, but in the following two years we observed some extremes. In 2019 and
2020, the spring was especially dry, the lowest monthly sum was 1.2 mm in 2020 April. 2019 April was similar (19.5 mm), but after the drought
period intense rainfall events arrived in May, resulted a monthly total of 214.1 mm. Air temperature and air humidity has not been showed such extremes as the precipitation.

This study showed that detailed analysis of meteorological parameters is crucial for hydrological modelling data preparation because errors and extreme event can cause serious problems during modelling process and, also in case of evaluation of model results.

The research has been supported by the Ministry of Agriculture in Hungary.

How to cite: Nevezi, C., Bazsó, T., Gribovszki, Z., Szőke, E., and Kalicz, P.: Hydro-meteorological data preparation for ecosystem hydrological modelling in the riparian forest of Hidegvíz Valley experimental catchment, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-12285, https://doi.org/10.5194/egusphere-egu21-12285, 2021.

Climate change induced drought periods are likely to cause decline in groundwater level,
which can degrade riparian ecosystems (such as riparian forest). With a reasonable water
supply, water scarcity can be stopped and these valuable ecosystems can be preserved.

The aim of the research was to evaluate the impact of water supply interventions regarding
habitat reconstruction of Doroszló meadows near Kőszeg (west Hungary). Groundwater
monitoring wells have been installed at 4 representative sites of the area. Groundwater wells
were 3–5 m deep and screened at their bottoms (2–4 m). The water level of the wells was
recorded manually, on a weekly basis, with an accuracy of 1 mm. In the neighborhood of the
wells surface close soil moisture values were also measured. Data from April 2019 to
October 2020 were collected. Local meteorological data measured in Kőszeg were also
used for analysis.

Evaluating the data from each well in the pre-intervention period (the analysis of the
relationship of the wells with the control well), we came to the conclusion that the Well-1 and
Well-2 behave similarly. The impacts of the water supply on the groundwater level were
analysed using a “double mass curve” and a “treatment-control space-time deviations”
approach. Result showed that the intervention had a positive effect only on the Well-3 from
the examined wells. The data evaluation denoted that unfortunately the control well was also
affected by water supply interventions.

This research has been supported by the Ministry of Agriculture in Hungary.

How to cite: Szőke, E., Csáki, P., Kutschi, P., Kalicz, P., and Gribovszki, Z.: Riparian zone hydrological rehabilitation along the Gyöngyös stream (Hungary), EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-12023, https://doi.org/10.5194/egusphere-egu21-12023, 2021.