TY  - THES
A1  - Hattermann, Fred Fokko
T1  - Integrated modelling of Global Change impacts in the German Elbe River Basin
T1  - Integrierte Modellierung der Auswirkungen des Globalen Wandels auf den deutschen Teil des Elbeinzugsgebietes
N2  - The scope of this study is to investigate the environmental change in the German part of the Elbe river basin, whereby the focus is on two water related problems: having too little water and having water of poor quality.  The Elbe region is representative of humid to semi-humid landscapes in central Europe, where water availability during the summer season is the limiting factor for plant growth and crop yields, especially in the loess areas, where the annual precipitation is lower than 500 mm. It is most likely that water quantity problems will accelerate in future, because both the observed and the projected climate trend show an increase in temperature and a decrease in annual precipitation, especially in the summer. Another problem is nutrient pollution of rivers and lakes. In the early 1990s, the Elbe was one of the most heavily polluted rivers in Europe. Even though nutrient emissions from point sources have notably decreased in the basin due to reduction of industrial sources and introduction of new and improved sewage treatment facilities, the diffuse sources of pollution are still not sufficiently controlled.  The investigations have been done using the eco-hydrological model SWIM (Soil and Water Integrated Model), which has been embedded in a model framework of climate and agro-economic models. A global scenario of climate and agro-economic change has been regionalized to generate transient climate forcing data and land use boundary conditions for the model. The model was used to transform the climate and land use changes into altered evapotranspiration, groundwater recharge, crop yields and river discharge, and to investigate the development of water quality in the river basin. Particular emphasis was given to assessing the significance of the impacts on the hydrology, taking into account in the analysis the inherent uncertainty of the regional climate change as well as the uncertainty in the results of the model.  The average trend of the regional climate change scenario indicates a decrease in mean annual precipitation up to 2055 of about 1.5 %, but with high uncertainty (covering the range from -15.3 % to +14.8 %), and a less uncertain increase in temperature of approximately 1.4 K. The relatively small change in precipitation in conjunction with the change in temperature leads to severe impacts on groundwater recharge and river flow. Increasing temperature induces longer vegetation periods, and the seasonality of the flow regime changes towards longer low flow spells in summer. As a results the water availability will decrease on average of the scenario simulations by approximately 15 %. The increase in temperatures will improve the growth conditions for temperature limited crops like maize. The uncertainty of the climate trend is particularly high in regions where the change is the highest.  The simulation results for the Nuthe subbasin of the Elbe indicate that retention processes in groundwater, wetlands and riparian zones have a high potential to reduce the nitrate concentrations of rivers and lakes in the basin, because they are located at the interface between catchment area and surface water bodies, where they are controlling the diffuse nutrient inputs. The relatively high retention of nitrate in the Nuthe basin is due to the long residence time of water in the subsurface (about 40 years), with good conditions for denitrification, and due to nitrate retention and plant uptake in wetlands and riparian zones.  The concluding result of the study is that the natural environment and communities in parts of Central Europe will have considerably lower water resources under scenario conditions. The water quality will improve, but due to the long residence time of water and nutrients in the subsurface, this improvement will be slower in areas where the conditions for nutrient turn-over in the subsurface are poor.
N2  - Ziel der vorliegenden Arbeit ist die Untersuchung der Auswirkungen des Globalen Wandels auf den Wasserkreislauf im deutschen Teil des Elbeeinzugsgebietes. Der Fokus liegt dabei auf Wassermengen- und Wasserqualitätsproblemen.  Die Elbe liegt im Zentrum Europas im Übergangsbereich zwischen ozeanischen und kontinentalen Klimaten, wo die Wasserverfügbarkeit in den Sommermonaten den limitierenden Faktor für das Pflanzenwachstum und die landwirtschaftlichen Erträge bildet. Dies gilt insbesondere für die Lössgebiete im Lee des Harzes, wo die jährlichen Niederschläge unter 500 mm liegen. Es ist sehr wahrscheinlich, dass sich die Wassermengenprobleme in Zukunft noch verstärken werden, denn sowohl das beobachtete als auch das für die Zukunft projizierte Klima in der Region zeigen höhere Temperaturen und fallende Niederschläge, besonders im Sommer. Ein weiteres Problem ist die hohe Nährstoffbelastung der Flüsse und Seen im Elbeeinzugsgebiet. Anfang der neunziger Jahre war die Elbe eine der am stärksten belasteten Flüsse in Europa. Obwohl die Einträge besonders aus Punktquellen durch den Rückgang der Industrie und den Bau von neuen Kläranlagen seitdem gefallen sind, gelangen trotzdem noch große Nährstoffmengen aus diffusen Quellen in die Gewässer.  Die Untersuchungen wurden unter Anwendung des ökohydrologischen Modells SWIM (Soil and Water Integrated Model) durchgeführt, welches über Schnittstellen mit Klimamodellen und agroökonomischen Modellen verbunden wurde. Ein globales Szenario des Klimawandels und des landwirtschaftlichen Wandels wurde regionalisiert, um so die geänderten Randbedingungen für den Szenarienzeitraum zu erhalten. Simulationen mit SWIM dienten dann dazu, die geänderten Randbedingungen in Änderungen im Wasserhaushalt und in den landwirtschaftlichen Erträgen zu transformieren. Außerdem wurde das Langzeitverhalten von Nährstoffen im Untersuchungsgebiet modelliert. Besonderer Wert wurde dabei darauf gelegt, die Unsicherheit der Szenarienergebnisse zu quantifizieren.  Der mittlere Szenarientrend zeigt eine Reduzierung der mittleren jährlichen Niederschläge bis zum Jahre 2055 um ungefähr 1.5 %, wobei die Ergebnisse mit einer großen Unsicherheit behaftet sind: die Spannweite der Niederschläge in den Szenarienrealisationen liegt zwischen -15.3 % und +14.8 %. Die Erwärmung unter Szenarienbedingungen mit ungefähr 1.4 K ist weniger unsicher. Diese relativ geringen Änderungen habe starke Auswirkungen auf den Wasserhaushalt im Elbegebiet: durch die steigenden Temperaturen wird die Vegetationszeit verlängert, und die Niedrigabflussperiode im Sommer wird sich in den Herbst ausdehnen. Insgesamt wird unter dem mittleren Szenarientrend die Wasserverfügbarkeit um ca. 15 % abnehmen. Außerdem werden sich durch die steigenden Temperaturen die Anbaubedingungen für wärmeliebende Ackerfrüchte in der Landwirtschaft verbessern. Die Unsicherheit des Klimatrends ist dort am größten, wo auch die lokalen Änderungen am größten sind.  Die Simulationsergebnisse für das Nuthe-Teileinzugsgebiet der Elbe zeigen, das Retentionsprozesse im Untergrund und in den Feucht- und Auengebieten einen starken Einfluss auf die Wasserqualität und die Nitratkonzentration der Oberflächengewässer haben, da sie durch ihre Lage im Einzugsgebiet eine Schnittstelle zwischen dem umliegenden Einzugsgebiet und den Flüssen und Seen bilden. Die relativ hohe Umsetzung von Nitrat im Einzugsgebiet der Nuthe kann dadurch erklärt werden, dass Nitrat eine relativ lange Aufenthaltszeit im Grundwasser (im Mittel 40 Jahre) mit einer hohen Nitratumsetzungsrate hat, und durch die guten Denitrifizierungsbedingungen in den Feucht- und Auengebieten. Dazu kommt noch, dass große Nitratmengen durch die Pflanzen in den Feuchtgebieten aus dem Grundwasser aufgenommen werden.  Zusammenfassend kann man sagen, das sich die Ökosysteme und die Gesellschaft im Elbeeinzugsgebiet unter Szenarienbedingungen auf niedrigere Wasserverfügbarkeit einstellen müssen. Die Wasserqualität wird sich grundsätzlich zwar weiter verbessern, aber aufgrund der langen Verweilzeit der Nährstoffe im Grundwasser wird dies insbesondere in den Teileinzugsgebieten, in denen die geochemischen Bedingungen für einen hohen Nährstoffumsatz nicht gegeben sind, noch relativ lange dauern.
KW  - Hydrologie
KW  - Modellierung
KW  - Einzugsgebiet
KW  - Mathematisches Modell
KW  - Potsdam-Institut für Klimafolgenforschung
KW  - integrierte hydrologische Modellierung
KW  - Klimaänderung
KW  - Wasserqualität
KW  - Landnutzungsänderung
KW  - Ertragsänderung
KW  - integrated hydrolocal modelling
KW  - climate change impacts
KW  - water quality
KW  - land use change
KW  - ecohydrology
Y1  - 2005
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-6052
ER  - 
TY  - GEN
A1  - Reinhardt, Julia
A1  - Liersch, Stefan
A1  - Abdeladhim, Mohamed Arbi
A1  - Diallo, Mori
A1  - Dickens, Chris
A1  - Fournet, Samuel
A1  - Hattermann, Fred Fokko
A1  - Kabaseke, Clovis
A1  - Muhumuza, Moses
A1  - Mul, Marloes L.
A1  - Pilz, Tobias
A1  - Otto, Ilona M.
A1  - Walz, Ariane
T1  - Systematic evaluation of scenario assessments supporting sustainable integrated natural resources management
BT  - evidence from four case studies in Africa
T2  - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
N2  - Scenarios have become a key tool for supporting sustainability research on regional and global change. In this study we evaluate four regional scenario assessments: first, to explore a number of research challenges related to sustainability science and, second, to contribute to sustainability research in the specific case studies. The four case studies used commonly applied scenario approaches that are (i) a story and simulation approach with stakeholder participation in the Oum Zessar watershed, Tunisia, (ii) a participatory scenario exploration in the Rwenzori region, Uganda, (iii) a model-based prepolicy study in the Inner Niger Delta, Mali, and (iv) a model coupling-based scenario analysis in upper Thukela basin, South Africa. The scenario assessments are evaluated against a set of known challenges in sustainability science, with each challenge represented by two indicators, complemented by a survey carried out on the perception of the scenario assessments within the case study regions. The results show that all types of scenario assessments address many sustainability challenges, but that the more complex ones based on story and simulation and model coupling are the most comprehensive. The study highlights the need to investigate abrupt system changes as well as governmental and political factors as important sources of uncertainty. For an in-depth analysis of these issues, the use of qualitative approaches and an active engagement of local stakeholders are suggested. Studying ecological thresholds for the regional scale is recommended to support research on regional sustainability. The evaluation of the scenario processes and outcomes by local researchers indicates the most transparent scenario assessments as the most useful. Focused, straightforward, yet iterative scenario assessments can be very relevant by contributing information to selected sustainability problems.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 930 
KW  - Africa
KW  - global and regional change
KW  - integrated assessments
KW  - participatory research
KW  - sustainability science
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-445784
SN  - 1866-8372
IS  - 930
ER  - 
TY  - JOUR
A1  - Reinhardt, Julia
A1  - Liersch, Stefan
A1  - Abdeladhim, Mohamed Arbi
A1  - Diallo, Mori
A1  - Dickens, Chris
A1  - Fournet, Samuel
A1  - Hattermann, Fred Fokko
A1  - Kabaseke, Clovis
A1  - Muhumuza, Moses
A1  - Mul, Marloes L.
A1  - Pilz, Tobias
A1  - Otto, Ilona M.
A1  - Walz, Ariane
T1  - Systematic evaluation of scenario assessments supporting sustainable integrated natural resources management
BT  - evidence from four case studies in Africa
JF  - Ecology and society : a journal of integrative science for resilience and sustainability
N2  - Scenarios have become a key tool for supporting sustainability research on regional and global change. In this study we evaluate four regional scenario assessments: first, to explore a number of research challenges related to sustainability science and, second, to contribute to sustainability research in the specific case studies. The four case studies used commonly applied scenario approaches that are (i) a story and simulation approach with stakeholder participation in the Oum Zessar watershed, Tunisia, (ii) a participatory scenario exploration in the Rwenzori region, Uganda, (iii) a model-based prepolicy study in the Inner Niger Delta, Mali, and (iv) a model coupling-based scenario analysis in upper Thukela basin, South Africa. The scenario assessments are evaluated against a set of known challenges in sustainability science, with each challenge represented by two indicators, complemented by a survey carried out on the perception of the scenario assessments within the case study regions. The results show that all types of scenario assessments address many sustainability challenges, but that the more complex ones based on story and simulation and model coupling are the most comprehensive. The study highlights the need to investigate abrupt system changes as well as governmental and political factors as important sources of uncertainty. For an in-depth analysis of these issues, the use of qualitative approaches and an active engagement of local stakeholders are suggested. Studying ecological thresholds for the regional scale is recommended to support research on regional sustainability. The evaluation of the scenario processes and outcomes by local researchers indicates the most transparent scenario assessments as the most useful. Focused, straightforward, yet iterative scenario assessments can be very relevant by contributing information to selected sustainability problems.
KW  - Africa
KW  - global and regional change
KW  - integrated assessments
KW  - participatory research
KW  - sustainability science
Y1  - 2018
U6  - https://doi.org/10.5751/ES-09728-230105
SN  - 1708-3087
VL  - 23
IS  - 1
PB  - Resilience Alliance
CY  - Wolfville
ER  - 
TY  - JOUR
A1  - Huang, Shaochun
A1  - Hattermann, Fred Fokko
A1  - Krysanova, Valentina
A1  - Bronstert, Axel
T1  - Projections of climate change impacts on river flood conditions in Germany by combining three different RCMs with a regional eco-hydrological model
JF  - Climatic change : an interdisciplinary, intern. journal devoted to the description, causes and implications of climatic change
N2  - A general increase in precipitation has been observed in Germany in the last century, and potential changes in flood generation and intensity are now at the focus of interest. The aim of the paper is twofold: a) to project the future flood conditions in Germany accounting for various river regimes (from pluvial to nival-pluvial regimes) and under different climate scenarios (the high, A2, low, B1, and medium, A1B, emission scenarios) and b) to investigate sources of uncertainty generated by climate input data and regional climate models. Data of two dynamical Regional Climate Models (RCMs), REMO (REgional Model) and CCLM (Cosmo-Climate Local Model), and one statistical-empirical RCM, Wettreg (Wetterlagenbasierte Regionalisierungsmethode: weather-type based regionalization method), were applied to drive the eco-hydrological model SWIM (Soil and Water Integrated Model), which was previously validated for 15 gauges in Germany. At most of the gauges, the 95 and 99 percentiles of the simulated discharge using SWIM with observed climate data had a good agreement with the observed discharge for 1961-2000 (deviation within +/- 10 %). However, the simulated discharge had a bias when using RCM climate as input for the same period. Generalized Extreme Value (GEV) distributions were fitted to the annual maximum series of river runoff for each realization for the control and scenario periods, and the changes in flood generation over the whole simulation time were analyzed. The 50-year flood values estimated for two scenario periods (2021-2060, 2061-2100) were compared to the ones derived from the control period using the same climate models. The results driven by the statistical-empirical model show a declining trend in the flood level for most rivers, and under all climate scenarios. The simulations driven by dynamical models give various change directions depending on region, scenario and time period. The uncertainty in estimating high flows and, in particular, extreme floods remains high, due to differences in regional climate models, emission scenarios and multi-realizations generated by RCMs.
Y1  - 2013
U6  - https://doi.org/10.1007/s10584-012-0586-2
SN  - 0165-0009
SN  - 1573-1480
VL  - 116
IS  - 3-4
SP  - 631
EP  - 663
PB  - Springer
CY  - Dordrecht
ER  - 
TY  - JOUR
A1  - Aich, Valentin
A1  - Liersch, Stefan
A1  - Vetter, T.
A1  - Huang, S.
A1  - Tecklenburg, J.
A1  - Hoffmann, P.
A1  - Koch, H.
A1  - Fournet, S.
A1  - Krysanova, Valentina
A1  - Mueller, N.
A1  - Hattermann, Fred Fokko
T1  - Comparing impacts of climate change on streamflow in four large African river basins
JF  - Hydrology and earth system sciences : HESS
N2  - This study aims to compare impacts of climate change on streamflow in four large representative African river basins: the Niger, the Upper Blue Nile, the Oubangui and the Limpopo. We set up the eco-hydrological model SWIM (Soil and Water Integrated Model) for all four basins individually. The validation of the models for four basins shows results from adequate to very good, depending on the quality and availability of input and calibration data.
 For the climate impact assessment, we drive the model with outputs of five bias corrected Earth system models of Coupled Model Intercomparison Project Phase 5 (CMIP5) for the representative concentration pathways (RCPs) 2.6 and 8.5. This climate input is put into the context of climate trends of the whole African continent and compared to a CMIP5 ensemble of 19 models in order to test their representativeness. Subsequently, we compare the trends in mean discharges, seasonality and hydrological extremes in the 21st century. The uncertainty of results for all basins is high. Still, climate change impact is clearly visible for mean discharges but also for extremes in high and low flows. The uncertainty of the projections is the lowest in the Upper Blue Nile, where an increase in streamflow is most likely. In the Niger and the Limpopo basins, the magnitude of trends in both directions is high and has a wide range of uncertainty. In the Oubangui, impacts are the least significant. Our results confirm partly the findings of previous continental impact analyses for Africa. However, contradictory to these studies we find a tendency for increased streamflows in three of the four basins (not for the Oubangui). Guided by these results, we argue for attention to the possible risks of increasing high flows in the face of the dominant water scarcity in Africa. In conclusion, the study shows that impact intercomparisons have added value to the adaptation discussion and may be used for setting up adaptation plans in the context of a holistic approach.
Y1  - 2014
U6  - https://doi.org/10.5194/hess-18-1305-2014
SN  - 1027-5606
SN  - 1607-7938
VL  - 18
IS  - 4
SP  - 1305
EP  - 1321
PB  - Copernicus
CY  - Göttingen
ER  - 
TY  - JOUR
A1  - Aich, Valentin
A1  - Liersch, Stefan
A1  - Vetter, Tobias
A1  - Andersson, Jafet C. M.
A1  - Müller, Eva Nora
A1  - Hattermann, Fred Fokko
T1  - Climate or Land Use?
BT  - Attribution of Changes in River Flooding in the Sahel Zone
JF  - Water
N2  - This study intends to contribute to the ongoing discussion on whether land use and land cover changes (LULC) or climate trends have the major influence on the observed increase of flood magnitudes in the Sahel. A simulation-based approach is used for attributing the observed trends to the postulated drivers. For this purpose, the ecohydrological model SWIM (Soil and Water Integrated Model) with a new, dynamic LULC module was set up for the Sahelian part of the Niger River until Niamey, including the main tributaries Sirba and Goroul. The model was driven with observed, reanalyzed climate and LULC data for the years 1950-2009. In order to quantify the shares of influence, one simulation was carried out with constant land cover as of 1950, and one including LULC. As quantitative measure, the gradients of the simulated trends were compared to the observed trend. The modeling studies showed that for the Sirba River only the simulation which included LULC was able to reproduce the observed trend. The simulation without LULC showed a positive trend for flood magnitudes, but underestimated the trend significantly. For the Goroul River and the local flood of the Niger River at Niamey, the simulations were only partly able to reproduce the observed trend. In conclusion, the new LULC module enabled some first quantitative insights into the relative influence of LULC and climatic changes. For the Sirba catchment, the results imply that LULC and climatic changes contribute in roughly equal shares to the observed increase in flooding. For the other parts of the subcatchment, the results are less clear but show, that climatic changes and LULC are drivers for the flood increase; however their shares cannot be quantified. Based on these modeling results, we argue for a two-pillar adaptation strategy to reduce current and future flood risk: Flood mitigation for reducing LULC-induced flood increase, and flood adaptation for a general reduction of flood vulnerability.
Y1  - 2015
U6  - https://doi.org/10.3390/w7062796
SN  - 2073-4441
VL  - 7
IS  - 6
SP  - 2796
EP  - 2820
PB  - MDPI
CY  - Basel
ER  - 
TY  - JOUR
A1  - Hattermann, Fred Fokko
A1  - Krysanova, Valentina
A1  - Habeck, Anja
A1  - Bronstert, Axel
T1  - Integrating wetlands and riparian zones in river basin modelling
JF  - Ecological modelling : international journal on ecological modelling and engineering and systems ecolog
N2  - Wetlands, and in particular riparian wetlands, represent an interface between the catchment area and the aquatic environment. They control the exchange of water and related chemical fluxes from the upper catchment area to surface waters like streams and lakes. Their influence on water and nutrient balances has been investigated mainly at the patch scale. In this study an attempt was made (a) to integrate riparian zones and wetlands into eco-hydrological river basin modelling, and (b) to quantify the impacts of riparian wetland processes on water and nutrient fluxes in a meso-scale catchment located in the northeastern German lowland. The investigation was performed by analysing hydro-chemical field data and applying the eco-hydrological model SWIM (Soil and Water Integrated Model), which was extended to reproduce the relevant water and nutrient flows and retention processes at the catchment scale in general, and in riparian zones and wetlands in particular. The main extensions introduced in the model were: (1) implementation of daily groundwater table dynamics at the hydrotope level, (2) implementation of water and nutrient uptake by plants from groundwater in riparian zones and wetlands, and (3) assessment of nutrient retention in groundwater and interflow. The simulation results indicate that wetlands, though they represent relatively small parts of the total catchment area, may have a significant impact on the overall water and nutrient balances of the catchment. The uncertainty of the simulation results is considerably high, with the main sources of uncertainty being the model parameters representing the geo-hydrology and the input data for land use management. (c) 2006 Elsevier B.V. All rights reserved.
KW  - riparian zones
KW  - wetlands
KW  - water quality
KW  - groundwater dynamics
KW  - nutrient retention
KW  - integrated river basin modelling
Y1  - 2006
U6  - https://doi.org/10.1016/j.ecolmodel.2005.06.012
SN  - 0304-3800
VL  - 199
IS  - 4
SP  - 379
EP  - 392
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - GEN
A1  - Aich, Valentin
A1  - Liersch, Stefan
A1  - Vetter, Tobias
A1  - Andersson, Jafet C. M.
A1  - Müller, Eva Nora
A1  - Hattermann, Fred Fokko
T1  - Climate or land use?
BT  - Attribution of changes in river flooding in the Sahel Zone
N2  - This study intends to contribute to the ongoing discussion on whether land use and land cover changes (LULC) or climate trends have the major influence on the observed increase of flood magnitudes in the Sahel. A simulation-based approach is used for attributing the observed trends to the postulated drivers. For this purpose, the ecohydrological model SWIM (Soil and Water Integrated Model) with a new, dynamic LULC module was set up for the Sahelian part of the Niger River until Niamey, including the main tributaries Sirba and Goroul. The model was driven with observed, reanalyzed climate and LULC data for the years 1950–2009. In order to quantify the shares of influence, one simulation was carried out with constant land cover as of 1950, and one including LULC. As quantitative measure, the gradients of the simulated trends were compared to the observed trend. The modeling studies showed that for the Sirba River only the simulation which included LULC was able to reproduce the observed trend. The simulation without LULC showed a positive trend for flood magnitudes, but underestimated the trend significantly. For the Goroul River and the local flood of the Niger River at Niamey, the simulations were only partly able to reproduce the observed trend. In conclusion, the new LULC module enabled some first quantitative insights into the relative influence of LULC and climatic changes. For the Sirba catchment, the results imply that LULC and climatic changes contribute in roughly equal shares to the observed increase in flooding. For the other parts of the subcatchment, the results are less clear but show, that climatic changes and LULC are drivers for the flood increase; however their shares cannot be quantified. Based on these modeling results, we argue for a two-pillar adaptation strategy to reduce current and future flood risk: Flood mitigation for reducing LULC-induced flood increase, and flood adaptation for a general reduction of flood vulnerability.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 345 
KW  - simulation-based attribution
KW  - Sahel
KW  - Niger River
KW  - climate variability
KW  - hydrological modeling
KW  - flood mitigation
KW  - flood adaptation
Y1  - 2017
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-400115
ER  -