The Impact of Retention Polders, Dyke-Shifts and Reservoirs on Discharge in the Elbe River - Hydrological Modelling Study in the Framework of the Action Plan for the Flood Protection in the Elbe River Basin of the International Commission for the Protection of the Elbe River (ICPER/IKSE/MKOL)

A hydrological model simulation study has been carried out in the Elbe basin using detailed data obtained from the relevant Czech and German institutes. The LISFLOOD model has been calibrated for the Elbe river basin using these data. Using this calibrated model setup, two studies have been carried out in the framework of the Action Plan for Flood Protection of the International Commission for the Protection of the Elbe River (ICPER/IKSE/MKOL). The 2002 flood without dyke-breaks: The first part of the simulation study was a simulation of the 2002 summer flood without dyke-breaks. It has been estimated here that without dyke-breaks, the discharge in the lower part of the Elbe river would have been 2.6 ¿ 9.1 % higher (117-384 m3/s). Waterlevels would have between 18 and 54 cm higher. Reservoir Study: The planned scenario for Saale reservoir steering investigated here does not have any significant influence on the discharge of the Elbe. The influence of changing the flood storage in the Bleiloch and Hohenwarte reservoirs in winter from 40 to 55 Mm3 and in summer from 25 to 35 Mm3 on river discharge has been assessed. The scenario results have shown that this planned scenario for reservoir steering in the Saale cascade does not have a significant influence on the discharge of the river Elbe, for the investigated flood events in 1994, 2002 und 2003 at gauging station Calbe-Griezehne (lower Saale). Also the influence on the discharge in the river Elbe is marginal: changes in peak discharge downstream the Saale-confluence are in the order of 0.2% (difference in discharge 4-8 m3/s). Furthermore, the influence of the Vltava reservoir cascade was investigated using two datasets provided by the Czech Hydro-Meteorological Institute (CHMI): one dataset with the actual situation and steering of the Vltava cascade, and a scenario without the Vltava cascade. For floods with a magnitude such as in August 2002, the difference between the scenario with and without the Vltava cascade is between 1.6 and 3.7% (84-171 m3/s) in the German part of the Elbe river. Polder and Dyke-shift Study: The potential effects of 5 polders and 20 dyke-shifts on discharge in the river Elbe have been estimated. The main outcomes are the following: The 20 planned dyke-shifts reduce the peak discharge of the 2002 summer flood with 1.3-4.6% (58-202 m3/s). Waterlevels would have been 10-31cm lower. For the 2006 flood the results are similar in character, but lower in magnitude. The measures reduce the peak discharge of the 2006 spring flood with 0.4-1.3% (10-48 m3/s). Waterlevels would have been 3-10cm lower. The 5 planned polders and 20 planned dyke-shifts simulated here, reduce the peak discharge of the 2002 summer flood with 3.9-10.8% (178-469 m3/s). Waterlevels would have been 23-74cm lower. For the 2006 flood, the results are again lower: the measures reduce the peak discharge of the 2006 spring flood with 1.2-3.3% (31-121 m3/s). Waterlevels would have been 8-21cm lower.JRC.H.7-Land management and natural hazard

The water-energy nexus and the implications for the flexibility of the Greek power system

The operation of the power systems is constrained by the availability of water resources, which are necessary for cooling thermal power plants and determine the generation of hydro reservoirs and run-of-river power plants. The interactions between the water and power systems have impacts on the quantity and quality of the water resources, thus affecting human uses and the environment. The European power system has witnessed in the past several examples of the consequences of reduced availability of water, which range from monetary losses, to demand restrictions, or increased wear and tear of the power plants. The importance of these impacts, and the expectation that climate change will produce similar episodes in the future more often, raises several research questions relevant for policy making. Some of these questions may be addressed by WATERFLEX, an exploratory research project carried out by units C7 (Knowledge for the Energy Union) and D2 (Water and Marine Resources) of the European Commission's Joint Research Centre (JRC). The main goal of WATERFLEX is to assess the potential of hydropower as a source of flexibility to the European power system, as well as analysing the Water-Energy nexus against the background of the EU initiatives towards a low-carbon energy system. The method proposed in the WATERFLEX project for better representing and analysing the complex interdependencies between the power and water sectors consists of combining two of the modelling tools available at the JRC, the LISFLOOD hydrological model [1] and the Dispa-SET unit commitment and dispatch model [2], with a medium-term hydrothermal coordination model. In order to test and validate the proposed approach described above, this document describes a case study carried out to analyse the implications of different hydrologic scenarios for the flexibility of the Greek power system.JRC.C.7-Knowledge for the Energy Unio

The water-power nexus of the Iberian Peninsula power system: WATERFLEX project

Water availability influences power generation and its costs. Policies aimed at keeping the water stress index of thermal power plants within acceptable limits are needed. This report provides a model-based analysis of the water-power nexus in the Iberian Peninsula.JRC.C.7-Knowledge for the Energy Unio

Impact of a changing climate, land use, and water usage on water resources in the Danube river basin

Impact of a changing climate, land use, and water usage on water resources in the Danube river basinJRC.D.2-Water and Marine Resource

Assessing the effects of water saving measures on Europe's water resources: BLUE2 project - Freshwater quantity

Using JRC's LISFLOOD water resources model, the effect of four policy measures on Europe's water resources were investigated under current and future climate. The measures evaluated were increasing irrigation efficiency, urban water use efficiency, cooling water usage for energy production, and urban waste-water re-use for irrigation. The measures were evaluated following their current planned implementation (BAU) under the Water Framework Directive. Furthermore, an Maximum Feasible Technology scenario was investigated for all 4 measures. Increasing irrigation efficiency shows to have the largest effect on improving water resources, under current climate. Under future climate change however, the projected decreases in water availability in especially the Mediterranean are larger than the increases obtained with improving irrigation efficiency. This may indicate that an increased level of ambition in water efficiency measures is required to reduce the impact of climate change on water resources.JRC.D.2-Water and Marine Resource

Summary Report of the 1st Workshop on the use of Ensemble Prediction System in Flood Forecasting (Ispra, 21-22 November 2005)

The first workshop on the use of EPS in flood forecasting was organised by the Joint Research Centre together with researchers from King's College in London (UK) and the Lancaster University (UK). The workshop was organized to address two main concerns of EFAS regarding flood forecasting based on EPS: 1. How to extract meaningful information from the meteorological EPS for medium-range flood forecasting? 2. How to communicate the uncertainty in flood forecasting to end-users? The specific objectives of the workshop were to explore together with flood forecasting experts from the Member States: 3. The usefulness of EPS information implemented in EFAS for operational flood forecasting and decision making, and the perception of uncertainty in flood forecasting. The workshop's concept was to have a small group of flood forecasters from different river basins working through a number of case-studies, each one representing a potential flood situation as forecasted by EFAS. On the first day, the participants worked in groups on each case-study. The second day was targeted mostly to plenary discussions on the use of EPS in flood forecasting.JRC.H.7-Land management and natural hazard

Global warming and drought impacts in the EU

Droughts induce a complex web of impacts that span many sectors of the economy, as exemplified by extensive crop failure, reduced power supply, and shipping interruptions in the EU during 2018 and 2019. With global warming droughts will happen more frequent, last longer and become more intense in southern and western parts of Europe, while drought conditions will become less extreme in northern and north-eastern Europe. With 3°C global warming in 2100 drought losses could be 5 times higher compared to today, with the strongest increase in drought losses projected in the Mediterranean and Atlantic regions of Europe. When expressed with respect to the total size of the economy the effects are dampened relatively, because drought-sensitive sectors like agriculture are projected to become relatively less economically prevalent in future EU economies than they are nowadays. The consequences on ecosystems are typically not monetized and hence are not reflected in the loss estimates.JRC.E.1-Disaster Risk Managemen

Impact of a changing climate, land use, and water usage on Europe’s water resources: A model simulation study

In this work, an assessment of the impacts of climate change on Europe’s water resources has been performed, focusing on the effects of 2°C warming. Climate projections from 1981-2100 were run through a distributed hydrological model assuming constant land use and water demand (year 2006). In this study, the 2°C warming period of five climate change projections was analysed. As a consequence of a 2 degree climate change, it is expected that - except for the Mediterranean region - precipitation will increase in most parts of Europe with the highest values over the Alps and Eastern Europe. These increases in precipitation are most likely linked to the increase in temperature which triggers more convective storms in the summer months. The observed consequences of a 2 degree climate change for the river flow and extreme events – floods and droughts - are: • The annual median river discharge shows an increase in most parts of Europe, except for the Mediterranean area where a decrease in flow is projected in all four seasons. • As a consequence of climate change, extreme peak discharges are projected to increase in almost every part of Europe, even the Mediterranean. The highest increases in flood hazards are found in the summer months for the inland countries whereas coastal zones and parts of Scandinavia show a decrease in floods. These increases are probably linked again to the increase in temperature which triggers more convective storms with a higher probability of floods. Especially urban areas near larger rivers might need more attention to flood risk management and planning, due to projections of growth of urban areas and increased flood hazard. • Streamflow droughts will become more severe in the summer season mainly for the Mediterranean region (Spain, Portugal, Greece). This might have an impact for cooling water intake for industrial and energy production activities, irrigation water availability, critical environmental flow conditions, as well as hydropower potential. • According the climate change projections the most extreme events are projected to occur in summer with an increase in flood risk in the eastern part of Europe (e.g. Poland) and the Baltic countries and extreme droughts in the Mediterranean region. These projected future changes in the hydrological cycle are directly reflected in the water resources indicators. Especially the southern European countries are projected to face increased water shortages: • Climate change projections lead to an increase in the number of days per year that river flows are lower than a critical minimum in the Mediterranean regions and a decrease in the northern latitudes. Especially Spain and Portugal face increased low flow conditions. • The climate change projections lead to a decrease of groundwater resources in the southern European countries and an increase for the northern countries. Further over-abstraction of groundwater in southern European countries – beyond renewable capacity – might lead to critical deep groundwater levels and increased pumping costs to extract the water for use at the surface. • Soil moisture stress conditions - which could reduce agricultural crop yields, are especially increasing under the 2oC warming scenario in the already stressed areas in the Mediterranean. Specific crop yield effects are described in the report on agriculture. - • The southern European regions with already a high current water consumption relative to water availability are projected to be most affected by a 2-degree warming due to a decrease in freshwater resources, and at the same time an increased need for irrigation water due to higher evaporative demands. • In the Mediterranean countries and especially in Spain the water resources situation will become more unsustainable. Inflowing upstream freshwater is also not sufficient to meet local water needs under a 2 degree warming. • For eastern Europe, the projections indicate that some regions will rely to a reduced extent on upstream inflow to meet their local water demands. Policy implications: • Especially in the Mediterranean part of Europe, water savings will be essential to adapt to the decreasing overall water availability; savings could take place to increasing irrigation efficiency, sub-optimal or deficit irrigation strategies, efficiency increases in cooling processes in industry and energy production, public water savings, a better intra-annual management of water resources in a basin (e.g. storing winter water in hydropower reservoirs for irrigation water use in summer. Increased synergies between the water and agricultural policies are needed. • To raise awareness for the importance of water, setting a reasonable price on water will be an essential incentive for users for water savings. As long as water is either free of charge or to cheap, users will likely not be urged for savings. • A better control on and prevention of illegal abstractions is needed to prevent over-abstraction of groundwater in a number of European regions. A better reporting of water abstractions does help the monitoring of water resources as well. • Given the expected increase in flood hazard, especially in the urbanised areas – which in many cases are expected for further grow until 2050 according to JRC’s LUISA projections – flood risk management, prevention and adaptation to floods will become an even bigger issue.JRC.D.2-Water and Marine Resource