Jürgen Jensen

• Prof. Dr.
• Professor (Full) at University of Siegen

Coastal zones are the most densely populated areas in the world and are vulnerable to extreme meteorological events like hurricanes, storm surges, tsunamis and climate change–induced sea level rise. Coasts are subject to constant change because of anthropogenic and natural variations in sea level, currents and wind waves, sediment supply, and so fo...

Life along the coasts of the Baltic Sea has been, is, and will continue to be characterized by storm surge events. In November1872, there was an extraordinary storm surge in the area of the German and Danish Baltic Sea coast of dimensions never reached since (e.g. Jensen and Töppe 1986, 1990). The peak water levels were above all previously known v...

Developed coastlines require considerable investments into coastal protection measures to mitigate the effects of flooding caused by extreme sea levels (ESLs). To maximize the effectiveness of these measures, accurate estimates of the underlying hazard are needed. These estimates are typically determined by performing extreme value analysis on a sa...

Tide gauges provide important water level data for navigation, port management, coastal protection strategies, ecological adaptation measures, or climate change assessments. For these tasks, a reliable availability and high quality of the data is crucial. However, water level data from tide gauges contain technical errors as well as anthropogenic a...

Developed coastlines require considerable investments into coastal protection measures to mitigate the effects of flooding caused by extreme sea levels (ESLs). To maximise the effectiveness of these measures, accurate estimates of the underlying hazard are needed. These estimates are typically determined by performing extreme value analysis on a sa...

The specific ranges of application of suitable hydropower machines are shown for small and medium-sized hydropower plants. By means of the head and the discharge, the hydroelectric power machine that can be used at the site can be determined. In addition to the use of hydropower at unused reaches of a river, there are opportunities for expansion at...

As the oldest known energy source, hydropower is still viable for the future - also in comparison with other renewable energy sources - when efficiency, energy return on investment (EROI), utilization time, ecological requirements and aspects of monument protection are considered. The use of hydropower continues to be indispensable for a successful...

In this article the hydroelectric power machines are presented, which are important for the area of small and medium-sized hydropower. The types of power machines discussed her are the hydrodynamic screws, water column machines, water turbines and the kinetic energy converters.

For the planning, construction and operation of hydropower plants, knowledge of the theoretical and physical principles is important to enable a determination of the hydropower potential available at the site and a design of the hydropower machine and the hydropower plant. The basic physical principles required are presented in the following paper.

Renewable energy sources represent domestic, import-independent, secure and CO2-free electricity generation. This article aims to present the essential instruments for the comparability and evaluation of renewable energy sources as compactly and neutrally as possible. In order to classify hydropower use, comparisons with other renewable energy sour...

Hydroelectric power plant sizing and design requires a selection of the type of hydroelectric power plant and of hydroelectric power machine suitable for the local situation. Due to the variety of possible designs, the various hydroelectric power machines and hydroelectric power plants are discussed with regard to the technical concepts and the hyd...

In addition to the knowledge of basic physical principles, the knowledge and observance of legal and ecological boundary conditions are the prerequisites for the economic realization of theoretical potentials. The local conditions of the foundation soil and the flood conditions must be considered as technical boundary conditions. Regarding water ec...

Der Fachausschuss WW-5 „Wasserkraft“ in der DWA fokussiert sich mit engagierten Expertinnen und Experten aus Behörden, Universitäten und Hochschulen, Unternehmen und Vertretungen anderer Verbände stets auf aktuelle Themen zur Wasserkraft und koordiniert entsprechende temporäre Arbeitsgruppen. Die tiefgreifenden Veränderungen in der Energiewirtschaf...

In Deutschland stammen ca. 3 bis 4 % der Gesamtstromerzeugung aus Wasserkraftanlagen. Davon erzeugen Laufwasserkraftwerke ca. 93 %. Damit haben die Laufwasserkraftwerke in Deutschland im europäischen Vergleich eine große Bedeutung, anders als in Ländern wie Norwegen, Spanien oder Island, wo die Stromerzeugung in Speicherwasserkraftwerken dominiert....

This paper presents the results of the subproject AMSeL_Ostsee A (03KIS0114). The primary goal was the determination of high-quality monthly mean sea level time series (MSL) along the southwestern Baltic Sea coast and the subsequent investigation of long-term changes and variability. As a result, 49 MSL time series with a respective length of more...

The collaborative project AMSeL_Baltic Sea (03KIS0114 & 03KIS0115) was carried out between 2015 and 2018 by the Research Institute for Water and Environment (fwu) at the University of Siegen and the Institute of Hydraulic Engineering at the Technical University Hamburg-Harburg. In particular, the investigation concentrated on the research, acquisit...

Sea dikes are not only an important coastal protection element, but also represent an ecosystem that can supply valuable ecosystem services. The objective of the project EcoDike was to develop and investigate methods and approaches for ecological enhancements of sea dikes and finally compile recommendations for ecologically enhanced and ecosystem-s...

Extreme value analysis seeks to assign probabilities to events which deviate significantly from the mean and is thus widely employed in disciplines dealing with natural hazards. In terms of extreme sea levels (ESLs), these probabilities help to define coastal flood risk which guides the design of coastal protection measures. While tide gauge and ot...

We present the results of the sub-project MSL_Absolut-Rek (03KIS116). The primary goal of the project was the spatial and temporal reconstruction of mean sea level (MSL) along the German coastlines since the early 20th century under the consideration of vertical land motion (VLM). A novel hybrid reconstruction approach has been developed, which fir...

Coasts are those regions of the world where the land has an impact on the state of the sea, and that part of the land is in turn affected by the sea. This land–sea interaction may take various forms—geophysical, biological, chemical, sociocultural, and economic. Coasts are conditioned by specific regional conditions. These unique characteristics re...

Die Tidedynamik und die -wasserstände an der Deutschen Nordseeküste haben sich seit der Mitte des 20. Jahrhunderts verändert. Sowohl großräumige Einwirkungen (z. B. Klimaänderungen und Meeresspiegelanstieg) als auch kleinräumige Effekte (z. B. natürliche morphologische Prozesse und anthropogene Einflüsse) haben zu diesen Entwicklungen beigetragen....

From November 12th to 13th in 1872, an extreme coastal flood event occurred in the south Baltic Sea. An unusual combination of winds created a storm surge reaching up to 3.5 m above mean sea level, which is more than a meter higher than all other observations over the past 200 years. On the Danish, German, and Swedish coasts, about 300 people lost...

The correct representation of the 18.61‐year nodal tide is essential for an interpretation of the evolution of mean sea level, as errors cause misleading bias. The nodal tide is currently estimated by applying correction factors in harmonic analysis, which are derived from the equilibrium tide. From the equilibrium tide, correction values f for amp...

Zusammenfassung Das Projekt EXTREMENESS verfolgte das Ziel, extreme Nordseesturmfluten zu identi-fizieren und zu beschreiben, die zum einen extrem unwahrscheinlich, zum anderen aber noch physikalisch plausibel sind. Darauf aufbauend wurden in einem transdisziplinären Ansatz mögliche Auswirkungen untersucht und diskutiert, welche Maßnahmen und Hand-...

We document an exceptional large‐spatial scale case of changes in tidal range in the North Sea, featuring pronounced trends between −2.3 mm/yr at tide gauges in the United Kingdom and up to 7 mm/yr in the German Bight between 1958 and 2014. These changes are spatially heterogeneous and driven by a superposition of local and large‐scale processes wi...

The ecosystem-based management (EBM) philosophy draws upon the principle that holistic understanding of the system to be governed needs to guide the decision-making process. However, empirical evidence is growing that knowledge integration is still a main bottleneck for EBM decision-makers. This paper argues that transdisciplinary knowledge managem...

In diesem Beitrag werden die beobachteten Meeresspiegeländerungen auf Grundlage von pegelbasierten Wasserstandsmessungen an der deutschen Ostseeküste seit dem 18. Jahrhundert dargestellt. Es werden sowohl die Anfänge der Meeresspiegeluntersu-chungen aufgrund von vertikalen Landbewegungen als auch aktuellste Forschungs-ergebnisse zur Auswertung lang...

Over the 20th century a global mean sea level (GMSL) rise of about 1.3 to 2 mm/yr could be observed and it is projected to further accelerate throughout the 21st century (Church and White 2006, Hay et al., 2015; Dangendorf et al., 2017). However, GMSL rise is neither temporally nor spatially uniform. Because of a number of different factors (e.g. m...

Abstract In many places around the world, tide gauges have been measuring substantial non-astronomical changes. Here we document an exceptional large spatial scale case of changes in tidal range in the North Sea, featuring pronounced trends between -2.3 mm/yr in the UK and up to 7 mm/yr in the German Bight between 1958 and 2014. These changes are...

Ship waves and ship-induced flows are the main hydrodynamic loads on waterway beds and embankments. But the underlying physical processes are not fully understood yet. Recent field measurements, conducted in the Kiel Canal, Germany, allow a better understanding of these loads and the resulting (ship-induced) sediment transport. The measurements inc...

We introduce a novel approach to statistically assess the non-linear interaction of tide and non-tidal residual in order to quantify its contribution to extreme sea levels and hence its role in modulating coastal protection levels, globally. We demonstrate that extreme sea levels are up to 30% (or 70 cm) higher if non-linear interactions are not ac...

Vegetation auf dem Deichvorland kann zum Küstenschutz beitragen, indem sie die Wellenenergie und somit mögliche Erosionen auf der Deichoberfläche reduziert bzw. dämpft. Für die Berücksichtigung der Vegetation als natürliches Küstenschutzelement muss die wellendämpfende Wirkung praxistauglich quantifiziert werden. Dazu wurde auf Basis empirischer Da...

Die Hauptfunktion von Seedeichen liegt im Sturmflutschutz. Seedeiche sind gleichzeitig jedoch auch Teil eines Ökosystems, das wertvolle Funktionen haben kann. Eine ökologische Aufwertung von Seedeichsystemen kann zum einen durch die Aufwertung von Deichvorland und Küstenökosystemen, zum anderen durch die ökologische Aufwertung des Deichbauwerks sel...

Die beiden Wissenschaftsverbände Deutsches Klima-Konsortium (DKK) und Konsortium Deutsche Meeresforschung (KDM) geben mit dieser Broschüre einen verständlichen Überblick über den wissenschaftlichen Kenntnisstand zum Anstieg der Meeresspiegel. Forscherinnen und Forscher ordnen die manchmal verwirrenden Informationen ein, die in der Öffentlichkeit di...

In March 2019 cyclone Idai led to a compound flooding event in Mozambique combining high river runoff and storm induced water level extremes and causing damages up to 2 billion USD and more than 1200 fatalities. The co-occurrence of storm surges, wind waves, and flooding through heavy precipitation and runoff increases the risk of flooding and exac...

Previous studies reconstructed twentieth-century global mean sea level (GMSL) from sparse tide-gauge records to understand whether the recent high rates obtained from satellite altimetry are part of a longer-term acceleration. However, these analyses used techniques that can only accurately capture either the trend or the variability in GMSL, but n...

A novel high quality monthly mean sea level (MSL) dataset for 63 tide gauge stations at the german Baltic coastline until 2015. The dataset was generated in the AMSeL_Baltic Sea research project from 2015 to 2018. We generated a new monthly mean sea level datasets from high-resolution sea level measurements and combined these with historic datasets...

The supply of energy is sustainable only if it is predominantly based on renewable or regenerative energies. For this reason, the use of micro-hydropower plants on rivers and streams is considered recently. This is a particular challenge for the preservation of ecologically permeable streams, so that no dams or similar structures can be considered....

The Halligen are located off the North Sea coastline of Schleswig-Holstein, the most northern federal state of Germany. They are surrounded by the Wadden Sea which was added to UNESCO’s World Heritage List in 2009. The Halligen are small and low lying marsh islands that are inhabited by around 270 residents and most of them are involved in federal...

Over the last decades, changing tides have been reported for the German North Sea coast, a highly complex and sensitive system, which is subject to ongoing hydro- and morphodynamic changes. While mean sea level trends over the past 150 years have roughly followed the global mean, analyses of the mean tidal high and low water levels indicate signif...

In this contribution we present a comprehensive analysis of sea level data around the Baltic Sea from 1777 to the present with a focus on the southwestern part, concentrating on quantifying and understanding long-term trends and the influence of inter-annual and decadal variability. Our analysis focuses on a new monthly mean sea level (MSL) dataset...

This paper describes a framework in which artificial extreme sea levels (ESLs) can be generated for use in flood risk analyses. Such analyses require large numbers of events to accurately assess the risk associated with certain return water levels and quantify uncertainties surrounding the temporal variability of ESL events. Stochastic models satis...

Die Region Emden-Krummhörn in Ostfriesland wird aufgrund ihrer besonderen Lage zur angrenzenden Nordsee von einer Vielzahl hydrologischer Risiken bedroht. Da z. B. große Teile der Region unter dem Meeresspiegel liegen, werden Deiche zum Schutz vor Sturmfluten benötigt. Zudem muss Niederschlag aus dem tiefliegenden Hinterland mit Hilfe von Sielen un...

Westerly and north-westerly storms regularly hit the German North Sea coast causing surges of several meters at the dikes. But extreme events like cyclone Xaver in 2013 are not the largest physically possible events on record. Dangendorf et al. (2016) show that the individual components of the total water level (i.e. mean sea level, surge, and tide...

Global mean sea level has risen over the 20th century (Hay et al. 2015; Dangendorf et al. 2017) and under sustained greenhouse gas emissions it is projected to further accelerate throughout the 21st century (Church et al. 2013) with large spatial variations, significantly threatening coastal communities. Locally the effects of geocentric (sometimes...

Storm surges are one of the most dangerous natural hazards in coastal areas and have the ability to cause great damages including fatalities. To be prepared when another storm surge hits the coast, reliable storm surge forecasts are indispensable. Storm surge warnings are routinely provided for selected tide gauge locations along a coastline throug...

Storm surges are one of the most dangerous natural hazards in coastal areas. To be prepared when another storm surge hits the coast, reliable storm surge forecasts are indispensable. Currently water level forecasts in the German Bight are, however, limited to a certain number of tide gauges along the coast, and the complex coastal geometry does not...

The presented research project was initiated to examine the meteorological potential of storms in the German Bight and to assess the consequences of extremely large and rare but physically possible storm surge events, so called “black swans”. We use these possible meteorological extreme events and resulting hydraulic boundary conditions to simulate...

Storm surges are one of the most dangerous natural hazards in coastal areas. To be prepared when another storm surge hits the coast, reliable storm surge forecasts are indispensable. The focus of this presentation was on the development of a model chain providing real-time flood risk warnings for any coastal site. Therefore, a new methodology based...

Global mean sea level has risen over the 20th century (Hay et al. 2015; Dangendorf et al. 2017) and under sustained greenhouse gas emissions it is projected to further accelerate throughout the 21st century (Church et al. 2013) with large spatial variations, significantly threatening coastal communities. Locally the effects of geocentric (sometimes...

In this presentation we introduce a novel monthly mean sea level (MSL) dataset from 140 tide gauge records in the Baltic Sea covering a period from 1777 to 2015. The dataset has been produced within the BMBF project “AMSeL Baltic Sea” in which we collected high resolution tide gauge data and digitized historical sea level records of varying tempora...

Quantitative estimates of sea-level rise in the Mediterranean Basin become increasingly accurate thanks to detailed satellite monitoring. However, such measuring campaigns cover several years to decades, while longer-term sea-level records are rare for the Mediterranean. We used a data archeological approach to reanalyze monthly mean sea-level data...

Coastal and estuarine regions are particularly vulnerable against the impacts of man-made climate change. Therefore, a systematic analysis of potential changes in tidal dynamics and riverine discharge is a fundamental prerequisite for developing sustainable coastal protection strategies in these regions. Such analyses are noticeably absent for the...

Das KFKI-begleitete, BMBF-geförderte KüNO-Projekt „Extreme North Sea Storm Surges and Their Consequences” (EXTRENENESS) befasst sich mit extremen, bisher noch nicht aufgetretenen aber dennoch physikalisch plausiblen Sturmfluten an der deutschen Nordseeküste. In dem KFKI-Projekt „Modellgestützte Untersuchungen zu Sturmfluten mit sehr geringen Eintri...

Das Poster stellt die grundlegende Vorgehensweise und die Zusammenarbeit in den Teilprojekten EXTREMENESS-D und EXTREMENESS-E dar.

Der Stiller-Energy-Converter (StECon) ist ein Wasserkraftwandler aus der Gruppe der Zykloidalpropeller. Im Vergleich zu anderen Wasserkrafttechniken ermöglichen die kompakte Bauweise und das im Planetengetriebe mittig gelegene Sonnenzahnrad völlig neue Einsatzmöglichkeiten. Die Funktionsfähigkeit ist sowohl komplett im Wasser eingetaucht mit horizo...

In this contribution we present an integrated analysis of the coastal and open ocean seasonal mean sea level cycle in the Baltic Sea using tide gauge records, satellite altimetry observations, hydrographic profiles, and ocean reanalysis data. Within the project “AMSeL Baltic Sea”, which is funded by the German Federal Ministry of Education and Rese...

Quantitative studies of sea level-rise in the Mediterranean are becoming more and more accurate thanks to detailed satellite monitoring campaigns. However, these studies cover several years to a couple of decades at best, while longer-term sea-level records for the area are rare. Long-term sea-level measurements are essential in order to derive acc...

The maintenance of waterways is a challenging task for federal authorities. An expensive subtask is dredging and disposing of accumulated sediments. Dredging volumes are often estimated based on experience while the underlying physical transport processes causing sedimentations are not fully explored yet. For instance, in confined waterways moving...

Coastal protection design heights typically consider the superimposed effects of tides, surges, waves, and relative sea-level rise (SLR), neglecting non-linear feedbacks between these forcing factors. Here, we use hydrodynamic modelling and multivariate statistics to show that shallow coastal areas are extremely sensitive to changing non-linear int...

The StECon (Stiller Energy Converter) is a promising new small hydropower plant for kinetic energy. It is an invention of Mr. Hans-Ludwig Stiller and has several advantages compared to the technologies for the use of hydropower known for millennia. It runs completely submerged forwards and backwards, with horizontal or vertical axis and has a compa...

Jedes Jahr erfordert es einen großen finanziellen Aufwand die Schiffbarkeit von (künstlichen) Seeschifffahrtsstraßen zu gewährleisten. Allein in der Weststrecke des Nord-Ostsee-Kanals (NOK) in Schleswig-Holstein müssen jährlich bei Unterhaltungsarbeiten mehrere 10.000 m³ Sediment ausgebaggert und umgelagert werden. Eine bisher unzureichend beantwor...

The State Reservoir Administration of Saxony is planning to expand the spillway discharge capacity of the 102 year old Malter Dam. After a catastrophic flood in 2002, updated hydrologic modeling indicated that the design discharges for the dam had increased significantly. As a result, the original spillway discharge capacity was insufficient to pas...

In a joint research project between the German Federal Waterways Engineering and Research Institute and the Research Institute for Water and Environment of the University of Siegen the ship-induced sediment transport as a proportion of the totally transported volume is investigated. Therefore, a field campaign in the Kiel Canal was conducted in 201...

Early warning systems for floods and storm surges currently are based exclusively on water level fore-casts. Other loads such as wind, waves, currents or heavy rainfalls as well as the resistance of the flood protection structure itself (e. g. dikes, flood protection walls) are not considered. If they occur simultaneously, the flood protection stru...

Design water levels for coastal structures are usually estimated based on extreme value statistics. Since their robustness depends heavily on the sample size of observations, regular statistical updates are needed, especially after extreme events. Here, we demonstrate the exceptional influence of such an event based on storm “Xaver”, which caused r...

Infolge des extremen Hochwasserereignisses an der Elbe im August 2002 kam es zu Beschädigungen und zur Überlastung der Hochwasserentlastungsanlage der Talsperre (TS) Malter sowie im Unterlauf zu massiven Überschwemmungen der Roten Weißeritz. Nach diesem katastrophalen Hochwasser wurden die Bemessungsabflüsse für die TS Malter überprüft und mussten...

In Deutschland werden Hochwasserschutzbauwerke i. d. R. so bemessen, dass sie einem Hochwasserereignis mit einer definierten Eintrittswahrscheinlichkeit standhalten können. Bei der Festlegung der anzusetzenden Eintrittswahrscheinlichkeit sollten die im Versagensfall zu erwartenden Schäden in dem zu schützenden Bereich berücksichtigt werden. Die erw...

Der Betrieb Oberes Elbtal der Landestalsperrenverwaltung des Freistaates Sachsen (LTV) plant die Wiederherstellung der Überflutungssicherheit (Hochwassersicherheit nach DIN 19 700-10) der Talsperre Malter durch die Erweiterung der Hochwasserentlastungsanlage und die Erhöhung der hydraulischen Leistungsfähigkeit der Armaturen im Umleitungsstollen. A...

Barrier islands characterize up to an eighth of the global coastlines. They buffer the mainland coastal areas from storm surge and wave energy from the open ocean. Changes in their shape or disappearance due to erosion may lead to an increased impact of sea level extremes on the mainland. A barrier island threatened by erosion is Egmont Key which i...

The North Sea is one of the best instrumented ocean basins in the world. Here we revisit sea level changes in the North Sea region from tide gauges, satellite altimetry, hydrographic profiles and ocean reanalysis data from the beginning of the 19th century to present. This includes an overview of the sea level chapter of the North Sea Climate Chang...

In this contribution an overview over the BMBF project AMSeL_Ostsee (2015-2018) for the assessment of mean and extreme sea level changes over the past 150 years in the southwestern Baltic Sea is presented. We compile several high resolution tide gauge records provided by the Water and Shipping Administration (WSV) along the German Baltic Sea coastl...

Many coastal regions worldwide are potentially endangered by storm surges which can cause disastrous damages and loss of life. Due to climate change induced sea level rise, an accumulation of such events is expected by the end of the 21th century. Therefore, advanced storm surge warnings are needed to be prepared when another storm surge hits the c...