Climate change is presently a widely discussed subject in relation to alterations in water storage capacity and the components of the hydrological balance within catchment areas. This research study ...was directed at two main objectives: 1. The indirect estimation of long-term mean annual runoff using an empirical model; 2. The determination of changes in the annual runoff regime of fifty Danube sub-basins. Monthly areal precipitation, discharges, and air temperature data from 1961 to 1990 were collected for selected headwater sub-basins of the Danube River. In the first part, Turc-type empirical equations for the estimation of the long-term average annual runoff
in the Danube basin were employed. The parameters of the empirical equations were determined through nonlinear regression. Given the underestimation of the actual (territorial, balance) evapotranspiration
values determined from the balance equation, the precipitation totals were corrected by +10%. With a 10% increase in precipitation, the values of balance
reached the values
determined by the Budyko–Zubenok–Konstantinov method. In the second part, fifty equations for the estimation of changes in the average annual runoff, depending on increases in the air temperature and changes in the annual precipitation separately for each of the 50 sub-basins, were established. In conclusion, the results suggest that, on average, a 100 mm increase in the average annual rainfall in the Danube River headwater sub-basins, will cause a 50 mm increase in outflow, and a 1 °C increase in the average annual air temperature will lead to a 12 mm decrease in runoff.
Floodplain restoration measures are among the most well-known nature-based solutions for flood risk reduction but practitioners see their limitations in comparison to technical measures when ...considering both their effectiveness and profitability. The aim of this study is to show the co-benefits (besides flood risk reduction) of floodplain restoration and handle them in terms of monetized ecosystem services (ES). Our work focused on six ES groups for three study areas in the Danube catchment along the Krka, Morava, and Danube rivers. ES mapping through stakeholder engagement is also considered. We applied the methodologies suggested in the Toolkit for Ecosystem Service Site-Based Assessment (TESSA) complemented with alternative methodologies (e.g., questionnaires on social media). Results show annual combined benefits of floodplain restoration in a range from 237,000 USD2019 at Krka to 3.1 million USD2019 at Morava, suggesting the utility of ES assessment. The combination of stakeholder workshops and the TESSA guidelines, as well as the newly developed methods, were all central tools to provide decision-makers with arguments to use nature-based solutions for an integrated and holistic riparian land use management.
A source to sink system describes the natural link between mountains, plains and deltas, by analysing the (re)distribution of material at shallow crustal depth and at the Earth's surface, exploring ...the links between coupled tectonic and surface processes. Sediment fluxes are the product of erosion and movement of material in and from sources (mountains), the transport and movement of sediments and solutes by river systems to the plains, and deposition and storage in sink zones. The ESF-EUROCORES TOPO-EUROPE SourceSink programme is a fully integrated research effort to significantly advance our predictive capabilities on the quantitative analyses of coupled active and past drainage systems by means of step-wise 4D reconstructions of sediments mass transfer, integrating geophysics, geology, geomorphology, state of the art high-resolution dating, and numerical and analogue modelling. The area selected for this programme is the Danube River Basin–Black Sea source to sink system, a world-class natural laboratory that is uniquely suited in the heart of Europe's topography, covering almost half of its surface, providing opportunities for excellent field sites to study in integration surface and subsurface data that cover the complete chain of source, carrier and sink. Quantifying and modelling the complete system in relation to the controlling parameters has resulted in significant understanding of forcing factors and linking temporal and spatial scales across multiple orogen and basin systems. This research has provided the opportunity to widen the geographical scope to other natural scenarios, where a number of mountain chains with similar geodynamic genesis separate sedimentary basins with comparable evolution.
► Defining the source–sink concept and an overview of current research in this field of study ► Linking spatial and temporal scales in the study of coupled orogen and basin dynamics ► The application of the Source to Sink concept to the Danube River–Black Sea Basin system ► Defining the links between basins and their integrated evolution across multiple systems.
The consequences of river regulation work and other human interventions from the past can still be followed and cause various effects on the Danube river, especially on the formation and state of the ...islands. We aimed to compile an inventory of the islands along the Hungarian Danube stretch between Vének (1797 rkm) and Budapest (1647 rkm) during the past 250 years, focusing on their landscape history. Real islands were defined as gravel bars that are permanently covered with pioneer woody vegetation, constantly surrounded by water (side-branch is not closed), and their surface remains unflooded at an average water level. We identified 123 real islands that existed on this 150 km long river stretch in the last centuries. These were real islands for a shorter or longer period between the 18th and the 21st century. A total of 66 of them existed at the same time about 200 years ago, i.e., before the large-scale water regulation works, while today this number is only 18, meaning that 73% of current potential Danube islands are at a stage of side-branch succession. Before the river regulation works, the natural successional changes of a real island occurred over hundreds of years, but today they happen rapidly. The formation of new islands became very limited compared to the past due to the lack of sediments and the altered river dynamics. In order to conserve this unique ecological corridor and green infrastructure element in the long run, and restore its damaged floodplain habitats, no more hard-tech interventions should be allowed in the fluvial system. These aspects need to be taken into consideration in decision-making processes with an integrated approach.
During 2009–2011, 50 points of the Daube River Basin were surveyed. In 23 of them, seven species of Unionidae were recorded: U. pictorum, U. tumidus, U. crassus sensu lato, A. anatina, A. cygnea, ...P. сomplanatа and S. woodiana, which is an invasive species. Th e index of occurrence of freshwater mussels in general was 100 % in the Lower Danube River (5 study areas), 42 % in Tisa River (31 study areas), 33.3 % in Seret River (3 study areas), 36 % in Prut River (11 study areas). Th e index of occurrence of species was rather low: 24 % of A. anatina, 22 % of U. tumidus, 22 % of U. crassus, 16 % of U. pictorum, 14 % of P. complanata, 14 % of S. woodiana, and 2 % of A. cygnea. U. crassus was not found in the Lower Danube river, while A. cygnea was found only there outside the main watercourse. Th e invasive species S. woodiana occurred in the Lower Danube River and in the sub-basin of Tisa River (with 83 % and 20 % frequency, respectively. Th e mean values of population densities ranged from 1.00 (A. cygnea) to 6.14 ind./m2 (S. woodiana), and the mean biomass varied from 1.14 (P. сomplanatа) to 797.54 g/m2 (S. woodiana).
The aim of this study was to assess the status of aquatic invasive alien species (IAS) in the shoreline zone of the Bulgarian sector of the Danube River, Danube tributaries, and adjacent standing ...water bodies in the frame of the Joint Danube Survey 4 (JDS4). Seven benthic macroinvertebrates and seven fish IAS were identified. The crayfish Faxonius limosus was frequently found and abundant in the tributaries. The mussels Corbicula fluminea, Dreissena rostriformis bugensis, and Sinanodonta woodiana dominated in the Danube River and the middle and lower reaches of the tributaries, while the fish Carassius gibelio, Perccottus glenii, and Lepomis gibbosus were most abundant in the standing water bodies. The integrated biocontamination estimated by taxonomic groups (crayfish, molluscs, and fish), sampling methods, and type of water bodies ranged from moderate in the shoreline zone of the Danube River, through moderate to high in the canals and lakes, to severe in the Danube tributaries and the reservoirs. The results demonstrate the importance of IAS in the assessment of the ecological status/potential of the water bodies in the DRB. The comprehensive evaluation of the aquatic IAS pressure will provide valuable information and support for the implementation of the national and EU IAS and water policies in the DRB.
Monitoring and forecasting of chemical and physicochemical parameters of groundwater is an important factor in quality control and water management. In order to optimize these processes, the initial ...purpose of this paper was to identify sources of pollution and predict spatial changes in groundwater quality. Patterns of spatial changes in groundwater quality in the Danube river basin (Serbia) have been identified using multivariate statistical techniques. The results of the applied cluster analysis are the indicators of the existance of two spatial clusters. The principal component/factor analysis (PCA/FA) has shown that beside natural, anthropogenic factor has an influence in spatial grouping. Discriminant analysis (DA) was applied in order to identify discriminant groundwater quality parameters. DA reduced the number of data by extracting two parameters (iron and arsenic). The spatial distribution of identified dominant factors and discriminant parameters were graphically represented using GIS. Finally, the artificial neural network technique was used to test the ability to predict spatial changes in the values of discriminant parameters, and the reliability of this technique to predict the spatial variations of the two extracted variables has been proven.
The nutrient loads transported by the Danube River to the Black Sea peaked around the late 1980s, causing massive hypoxia that was accompanied with a severe algae growth. Since then, emissions and ...loads have declined in response to the measures implemented in the Danube River Basin, together with the declining intensity of agriculture. The International Commission for the Protection of the Danube River (ICPDR) initiated Basin-wide activities to support national water policy-making to ensure both the sustainable development of wastewater infrastructure and agricultural production, and the effective protection of freshwater and marine ecosystems.
Major river and flash flood events have accumulated in Central and Eastern Europe over the last decade reminding the public as well as the insurance sector that climate related risks are likely to ...become even more damaging and prevalent as climate patterns change. However, information about current and future hydro-climatic extremes is often not available. The Future Danube Model (FDM) is an end-user driven multi-hazard and risk model suite for the Danube region that has been developed to provide climate services related to perils such as heavy precipitation, heat waves, floods, and droughts under recent and scenario conditions. As a result, it provides spatially consistent information on extreme events and natural resources throughout the entire Danube catchment. It can be used to quantify climate risks, to support the implementation of the EU framework directives, for climate informed urban and land use planning, water resources management, and for climate proofing of large scale infrastructural planning including cost benefit analysis. The model suite consists of five individual and exchangeable modules: a weather and climate module, a hydrological module, a risk module, an adaptation module, and a web-based visualization module. They are linked in such a way that output from one module can either be used standalone or fed into subsequent modules. The utility of the tool has been tested by experts and stakeholders. The results show that more and more intense hydrological extremes are likely to occur under climate scenario conditions, e.g. higher order floods may occur more frequently. Keywords: Danube River basin, Flood risk, Climate services, Climate change
PDF
