Showing papers by "Zbigniew W. Kundzewicz published in 2015"

On Critiques of “Stationarity is Dead: Whither Water Management?”

Abstract: We review and comment upon some themes in the recent stream of critical commentary on the assertion that “stationarity is dead,” attempting to clear up some misunderstandings; to note points of agreement; to elaborate on matters in dispute; and to share further relevant thoughts.

Variability of high rainfalls and related synoptic situations causing heavy floods at the northern foothills of the Tatra Mountains

Abstract: This contribution provides the basics of the clima- tology of the Polish Tatra Mountains in a nutshell, with particular reference to intense precipitation and its relation to atmospheric circulation. Variability of various precipitation characteristics, including selected indices of intense precipita- tioninZakopaneand atKasprowyWierch,isillustratedinthis paper. None of the trends in these characteristics and indices calculated for the entire time interval exhibit a statistical significance, but short-time fluctuations are evident. The oc- currence of intense precipitation in the Tatra Mountains is strongly related to three circulation types. These situations (Nc, NEc, Bc) are associated with cyclones following track Vb after van Bebber. In addition to changing frequencies of circulation,this study also reveals anincrease inthe frequency of the circulation types associated with extreme precipitation.

Modelling climate and land-use change impacts with SWIM: lessons learnt from multiple applications

Abstract: The Soil and Water Integrated Model (SWIM) is a continuous-time semi-distributed ecohydrological model, integrating hydrological processes, vegetation, nutrients and erosion. It was developed for impact assessment at the river basin scale. SWIM is coupled to GIS and has modest data requirements. During the last decade SWIM was extensively tested in mesoscale and large catchments for hydrological processes (discharge, groundwater), nutrients, extreme events (floods and low flows), crop yield and erosion. Several modules were developed further (wetlands and snow dynamics) or introduced (glaciers, reservoirs). After validation, SWIM can be applied for impact assessment. Four exemplary studies are presented here, and several questions important to the impact modelling community are discussed. For which processes and areas can the model be used? Where are the limits in model application? How to apply the model in data-poor situations or in ungauged basins? How to use the model in basins subject to stro...

Analysis of changes in climate and river discharge with focus on seasonal runoff predictability in the Aksu River Basin.

Abstract: The River Aksu is the principal tributary to the River Tarim, providing about three quarters of its discharge. It originates in Kyrgyzstan and flows into the arid areas of the Xinjiang Uyghur Autonomous Region in China, where an extensive irrigated agriculture has been developed in the river oases. The aim of the present contribution is to review the current trends in temperature, precipitation, and river discharge and links between these variables. The temperature in the region and the river discharge have been rising. Changes were studied using multiple trend analyses with different start and end years. Correlations between daily temperature and discharge are high and statistically significant for two headwater subcatchments of the Aksu for most of the time. However, there are episodes in late summer or beginning of autumn when correlations between temperature and discharge for the Xiehela station are absent. This can only be explained by Glacial Lake Outburst Floods from the Lake Merzbacher that are not routinely monitored. On an annual time scale, changes in summer discharge in the highly glacierized Xiehela subcatchment are dominated by changes in temperature. In contrast, in the subcatchment Shaliguilanke, variations in summer streamflow are more strongly influenced by variations in precipitation. A comparison of links between climatic variables and streamflow at different temporal scales is offered. Perspectives for seasonal forecasting are examined.

Analysis of current trends in climate parameters, river discharge and glaciers in the Aksu River basin (Central Asia)

Abstract: Climate variability and change play a crucial role in the vulnerable system of the Aksu River basin located in Kyrgyzstan and northwest China, providing precious water resources for the intense oasis agriculture of the Xinjiang Province (China). Ubiquitous warming and increase in precipitation (in the lower part of the basin) have been detected. Glaciers in the region are retreating. Seasonal trends in river discharge show an increase. A clear link could be demonstrated between daily temperature and lagged river discharge at two headwater stations in summer. However, the correlation breaks over short periods in the end of summer or beginning of autumn at the Xiehela station, when the high (over 95th percentile) flow peaks caused by the glacier lake outburst floods of the Merzbacher Lake occur. This feature is a challenge for the climate impact assessment in the region, as these regular outbursts have to be represented in the projections for the future as well.Editor D. Koutsoyiannis

Grand Challenges Related to the Assessment of Climate Change Impacts on Freshwater Resources

Abstract: The present contribution reviews a suite of grand challenges related to assessment of climate change impacts on freshwater resources Among them are challenges related to the detection and attribution of changes in observed records, projections for the future, changes in hydrologic extremes (floods and droughts), assessing and reducing uncertainty, and adaptation to change under uncertainty The global water system is very complex, so that it is difficult to disentangle individual contributions of various factors to changes in freshwater variables at any scale As for detection and attribution of changes in global river discharge in twentieth century, variations in precipitation were the main force Other major factors were temperature effects on evapotranspiration, direct effects of rising atmospheric CO2 concentration on the physiology and abundance of vegetation, and anthropogenic changes in land cover and land use A general finding regarding possible future trends in the water cycle is that w

Flood risk governance arrangements in Europe

Abstract: . The STAR-FLOOD (Strengthening and Redesigning European Flood Risk Practices Towards Appropriate and Resilient Flood Risk Governance Arrangements) project, funded by the European Commission, investigates strategies for dealing with flood risk in six European countries: Belgium, the UK, France, the Netherlands, Poland and Sweden and in 18 vulnerable urban regions in these countries. The project aims to describe, analyse, explain, and evaluate the main similarities and differences between the selected EU Member States in terms of development and performance of flood risk governance arrangements. It also discusses the scientific and societal importance of these similarities and differences. Attention is paid to identification and characterization of shifts in flood risk governance arrangements and in flood risk management strategies and to determination of triggering factors and restraining factors. An assessment of a change of resilience and appropriateness (legitimacy, effectiveness, efficiency) of flood risk governance arrangements in Poland is presented and comparison with other European countries is offered.

Extreme hydrological events and security

Abstract: . Economic losses caused by hydrological extremes – floods and droughts – have been on the rise, worldwide. Hydrological extremes jeopardize human security and cause serious threats to human life and welfare and societal livelihood. Floods and droughts can undermine societies' security, understood as freedom from threat and the ability of societies to maintain their independent identity and their functional integrity against forces of change. Several dimensions of security are reviewed in the context of hydrological extremes. Floods and droughts pose a burden and serious challenges to the state, responsible to sustain economic development, societal and environmental security – the maintenance of ecosystem services, on which a society depends. It is shown that reduction of risk of hydrological disasters improves human security.

Preface: climate change proof flood risk management

Abstract: It is widely being recognized that climate change is happening. Anthropogenic emissions of greenhouse gases cause warming of the atmosphere and oceans. The resulting changes in the climate system and water cycle are unequivocal and manifest themselves in sea level rise and an increasing likelihood of extreme weather worldwide, evidenced by the increasing frequency of occurrence of hurricanes, tornados, extreme rainfall and heat waves. Moreover, these extreme events affect more and more people and have increasingly larger economic consequences due to demographic and economic developments, because there is a massive migration towards river floodplains, deltas and coastal plains as these provide the largest opportunities for economic development. The records of flood- and drought-related disasters in the past decades leave no doubt about the combined consequences of these geo-ecological and socio-economic developments; disaster risk increases. Mitigation of and adaptation to climate change are complementary strategies for reducing and managing the risks related to climate change. Effective global climate change mitigation is urgently needed and may also be the most efficient strategy as demonstrated by Stern (2006), but it is not in sight yet. Despite all the international policy efforts (including 20 annual conferences of parties of the United Nations Framework Convention on Climate Change, UNFCCC, gathering more than 10,000 participants each), emissions and atmospheric concentrations of greenhouse gases have been growing to unprecedented levels. Mitigation would depend on concerted global action of large players such as China and the USA, the countries with the largest carbon dioxide

Hydrological extremes and security

Abstract: . Economic losses caused by hydrological extremes – floods and droughts – have been on the rise. Hydrological extremes jeopardize human security and impact on societal livelihood and welfare. Security can be generally understood as freedom from threat and the ability of societies to maintain their independent identity and their functional integrity against forces of change. Several dimensions of security are reviewed in the context of hydrological extremes. The traditional interpretation of security, focused on the state military capabilities, has been replaced by a wider understanding, including economic, societal and environmental aspects that get increasing attention. Floods and droughts pose a burden and serious challenges to the state that is responsible for sustaining economic development, and societal and environmental security. The latter can be regarded as the maintenance of ecosystem services, on which a society depends. An important part of it is water security, which can be defined as the availability of an adequate quantity and quality of water for health, livelihoods, ecosystems and production, coupled with an acceptable level of water-related risks to people, environments and economies. Security concerns arise because, over large areas, hydrological extremes − floods and droughts − are becoming more frequent and more severe. In terms of dealing with water-related risks, climate change can increase uncertainties, which makes the state’s task to deliver security more difficult and more expensive. However, changes in population size and development, and level of protection, drive exposure to hydrological hazards.