Ökohydrologische und hydraulische Fließgewässermodellierung zur Beschreibung aquatischer Habitate

Naturnahe Einzugsgebiete, Fließgewässer und die aquatische Vielfalt wurden primär aufgrund der Auswirkungen der industriellen und urbanen Entwicklung sowie der Intensivierung der Landwirtschaft weltweit degeneriert. Diese Veränderungen haben auf verschiedenen Skalen stattgefunden und daher sind Rehabilitationsmaßnahmen in Fließgerinnen und Einzugsgebieten notwendig, um die Bedingungen für aquatische Lebewesen zu verbessern. Modelle, die für die Planungen von Renaturierungsmaßnahmen angewendet werden, zielen meist auf einzelne Komponenten der komplexen Kette, die Abiotik und Biotik verbindet; so werden Modelle z.B. für die Prognose von hydrologischen und hydraulischen Zielgrößen verwendet. Dadurch wird die Wirkungskette unterbrochen, die die Antriebskräfte, Belastungen, Zustand und Auswirkungen auf das Gewässersystem verbindet. Es gibt kaum Modelle, die das Gesamtsystem EinzugsgebietFließgewässerHabitataquatische Lebewesen betrachten. Daher fehlt es an Werkzeugen, mit denen die Auswirkungen solcher Maßnahmen auf den aquatischen Lebensraum, möglichst schon während der Planungsphase, getestet werden können. Ziel dieser Dissertation ist daher die Erstellung eines integrierten, geographischen Informationssystems (GIS)basierten Modellverbundes, der eine ganzheitliche Betrachtung der Wirkungskette vom Einzugsgebiet über das Fließgerinne zum aquatischen Lebewesen ermöglicht. Der Datenbedarf der Modelle umfasst die klimatischen und physischen Eigenschaften von Einzugsgebieten, sowie die Geometrie und Struktur der Fließgerinne. Dies ermöglicht es, den Einfluss des globalen Wandels sowie regionale und lokale Veränderungen auf den Lebensraum im Fließgewässer zu bewerten. Der Ansatz dieser Arbeit basiert auf dem "DriverPressureStateImpact(Response)" (DPSI(R)) Konzept, und beinhaltet die Verknüpfung von einem ökohydrologischen, zwei hydraulischen, und zwei Habitatmodellen: Das ökohydrologische Modell "Soil and Water Assessment Tool" (SWAT) wurde genutzt, um das Abflussregime und die Erosionsprozesse auf Einzugsgebietsebene in Abhängigkeit von Landnutzung und Klima abzubilden. Im Rahmen dessen wurden zwei flachlandspezifische Werkzeuge entwickelt und in der hydrologischen Modellierung angewendet: Erstens, eine Methode zur Berücksichtigung des hohen Oberflächenretentionspotentials des Einzugsgebietes und zweitens, ein Abschätzungsmodell für die Bestimmung der Proportionen der Sedimenteintragspfade, um den Sedimenteintrag aus der Fläche, den Drainagen und Ufererosion zu quantifizieren. Auf Fließgewässerebene wurden dann die Abfluss und Sedimentzeitreihen aus der hydrologischen Modellierung genutzt, um hydraulische Simulationen durchzuführen. Hierfür wurden mit dem Modell "Hydrologic Engineering Center River Analysis System" (HECRAS) eindimensional und mit dem "Adaptive Hydraulics Modelling system" (AdH) zweidimensional Wassertiefe, Fließgeschwindigkeit, Substratveränderungen und Sedimenttransport in variablen Auflösungen simuliert. Zusammen mit Gewässertrukturkartierungen wurden die zeitlich und räumlich dynamischen hydraulischen Modellergebnisse genutzt, um den Makrozoobenthoslebensraum zu beschreiben. Basierend auf verschiedenen Parametern fanden zwei unabhängige Simulationen statt: Erstens wurde mit dem Habitatmodell BIOMOD die Flussmuschel Sphaerium corneum basierend auf verschiedenen Sedimenttransport und hydraulischen Habitatparametern abgebildet. Dies fand in Zusammenarbeit mit dem Senckenberg Forschungsinstitut Gelnhausen statt. Zweitens wurde im Rahmen dieser Arbeit und in Zusammenarbeit mit der Fakultät für Biologie, Aquatische Ökologie, Universität DuisburgEssen das "Habitat Evaluation Tool" (HET) entwickelt. Mit dem HET Modell wurde die im Fließgewässer vorhandene Makrozoobenthosgemeinschaft basierend auf dem Gewässersubstrat modelliert. Die Modellausgabe sind Karten und Statistiken des räumlichen Vorkommens der Arten an unterschiedlichen Zeitpunkten, die mit den vorherrschenden Umweltbedingungen verbunden sind. Das Modellsystem wurde am Beispiel des ländlich geprägten Kielstau Einzugsgebietes im Norddeutschen Tiefland erstellt und erfolgreich angewendet. Die Ergebnisse der Teilmodelle zeigen eine sehr gute Übereinstimmung mit gemessenen hydrologischen und hydraulischen Parametern und eine gute Übereinstimmung mit beobachteten räumlichen und zeitlichen Erosionsformen. Simulierte räumliche Artenverteilungen sind realistisch im Vergleich zu beobachteten Verteilungen, abgeleitet aus Probenahmekampagnen. Die Methodik ist übertragbar und wurde bereits während der Entwicklung in anderen Einzugsgebieten angewendet. Die Entwicklung des Modellsystems führt zu einem Voranschreiten der integrierten Modellierung, aber zukünftige Verbesserungen sind notwendig. Dies betrifft vor allem die Simulation von abiotischen Parametern, die Erforschung von Präferenzen der Organismen, die kombinierte Simulation mehrerer Organismengruppen sowie die Simulation von Interaktionen und Rückkopplungseffekten. Solch ein umfassenderer Modellierungsansatz könnte am effektivsten durch interdisziplinäre Teams entwickelt werden kann.Natural catchments, streams and aquatic diversity were globally degraded due to the impacts of industrial and urban development, as well as the intensification of agriculture. Degradation occurred at different spatial scales and rehabilitation measures are required in both streams and catchments, to improve conditions for the aquatic biota. Models, applied for planning restoration measures, are mostly targeting individual components of the complex chain linking the abiotic and biotic environment; e.g., models might be used just for predicting hydrological or hydraulic variables. Hereby, the causeeffect chain is compromised, which links drivers, pressures, state and impacts of the riverine system. There are almost no models considering the overall system catchmentstreamshabitataquatic biota. Thus, tools are unavailable, with which the effects of measures on the stream ecosystem can be tested, ideally already during the design phase. It is the scope of this dissertation to build an integrated, Geographic Information System (GIS)based model system considering the causeeffect chain from the catchment to the stream and aquatic biota. The models require data on climatic and physical catchment properties, and on the geometry and structure of the streams. This enables the assessment of the impact of global change as well as of more regional and local changes on the stream ecosystem. The approach of this thesis is based on the DriverPressureStateImpact(Response) (DPSI(R)) concept and includes the linkage of one ecohydrologic, two hydraulic and two habitat models: The ecohydrologic model Soil and Water Assessment Tool (SWAT) was used for depicting the discharge regime and erosion processes controlled by land use and climate on the catchment scale. As part of this, two lowlandspecific tools have been developed and have been used for hydrologic simulations: First, a method for incorporating the high surface retention potential of the catchment and second, an estimation model to evaluate the ratios of sediment entry pathways for quantifying sediment input from the field, tile drains and the river bank. The discharge and sediment time series resulting from the hydrologic modelling were used for hydraulic simulations on the reach scale. Water depth, flow velocity, substrate changes and sediment transport were simulated in variable resolutions with the Hydrologic Engineering Center River Analysis System (HECRAS) onedimensionally and with the Adaptive Hydraulics Modelling system (AdH) twodimensionally. Combined with structural river mapping, the temporally and spatially dynamic results of the hydraulic models were used for describing macroinvertebrate habitats. Based on different parameters, two independent simulations were carried out: First, the distribution of a single species, the freshwater clam Sphaerium corneum was modelled with the species distribution model (SDM) BIOMOD, based on parameters related to hydraulics and sediment transport. This took place in cooperation with the Senckenberg Institute Gelnhausen. Second, within the scope of this thesis and in cooperation with the Faculty of Biology, Aquatic Ecology, University DuisburgEssen the Habitat Evaluation Tool (HET) was developed. The HET model was used to simulate the prevailing macroinvertebrate community in the stream based on the river's substrates. Model results are maps and statistics of the spatial occurrence of species at different points in time which are connected to the prevailing environmental conditions. The model system was developed and successfully applied in the northern German lowland catchment of the Kielstau. Results of the submodels show very good agreement with observed hydrological and hydraulic parameters and good agreement with observed spatiotemporal erosion. Simulated spatial species distributions are realistic when compared to observed distributions derived from sampling campaigns. The methodology is transferrable and has been applied already during the development phase in different catchments. The developed model system advances integrated modelling, but future improvements are necessary. This particularly concerns the simulation of abiotic parameters, investigation of organism preferences, the combined simulation of numerous organism groups and the simulation of interactions and feedback loops. Such a more comprehensive modelling approach would most effectively be developed by interdisciplinary teams

Climate model variability leads to uncertain predictions of the future abundance of stream macroinvertebrates

Climate change has the potential to alter the flow regimes of rivers and consequently affect the taxonomic and functional diversity of freshwater organisms. We modeled future flow regimes for the 2050 and 2090 time horizons and tested how flow regimes impact the abundance of 150 macroinvertebrate species and their functional trait compositions in one lowland river catchment (Treene) and one mountainous river catchment (Kinzig) in Europe. We used all 16 global circulation models (GCMs) and regional climate models (RCMs) of the CORDEX dataset under the RCP 8.5 scenario to calculate future river flows. The high variability in relative change of flow among the 16 climate models cascaded into the ecological models and resulted in substantially different predicted abundance values for single species. This variability also cascades into any subsequent analysis of taxonomic or functional freshwater biodiversity. Our results showed that flow alteration effects are different depending on the catchment and the underlying species pool. Documenting such uncertainties provides a basis for the further assessment of potential climate-change impacts on freshwater taxa distributions

A high-resolution streamflow and hydrological metrics dataset for ecological modeling using a regression model

Hydrological variables are among the most influential when analyzing or modeling stream ecosystems. However, available hydrological data are often limited in their spatiotemporal scale and resolution for use in ecological applications such as predictive modeling of species distributions. To overcome this limitation, a regression model was applied to a 1 km gridded stream network of Germany to obtain estimated daily stream flow data (m3 s−1) spanning 64 years (1950–2013). The data are used as input to calculate hydrological indices characterizing stream flow regimes. Both temporal and spatial validations were performed. In addition, GLMs using both the calculated and observed hydrological indices were compared, suggesting that the predicted flow data are adequate for use in predictive ecological models. Accordingly, we provide estimated stream flow as well as a set of 53 hydrological metrics at 1 km grid for the stream network of Germany. In addition, we provide an R script where the presented methodology is implemented, that uses globally available data and can be directly applied to any other geographical region

Minimal resources for linear optical one-way computing

We address the question of how many maximally entangled photon pairs are needed in order to build up cluster states for quantum computing using the toolbox of linear optics. As the needed gates in dual-rail encoding are necessarily probabilistic with known optimal success probability, this question amounts to finding the optimal strategy for building up cluster states, from the perspective of classical control. We develop a notion of classical strategies, and present rigorous statements on the ultimate maximal and minimal use of resources of the globally optimal strategy. We find that this strategy - being also the most robust with respect to decoherence - gives rise to an advantage of already more than an order of magnitude in the number of maximally entangled pairs when building chains with an expected length of L=40, compared to other legitimate strategies. For two-dimensional cluster states, we present a first scheme achieving the optimal quadratic asymptotic scaling. This analysis shows that the choice of appropriate classical control leads to a very significant reduction in resource consumption.Comment: 5 pages, 2 figures, title changed, presentation improved, bounds improved, minor errors corrected, references update

Hydrography90m: a new high-resolution global hydrographic dataset

The geographic distribution of streams and rivers drives a multitude of patterns and processes in hydrology, geomorphology, geography, and ecology. Therefore, a hydrographic network that accurately delineates both small streams and large rivers, along with their topographic and topological properties, with equal precision would be indispensable in the earth sciences. Currently, available global hydrographies do not feature small headwater streams in great detail. However, these headwaters are vital because they are estimated to contribute to more than 70 % of overall stream length. We aimed to fill this gap by using the MERIT Hydro digital elevation model at 3 arcsec (∼90 m at the Equator) to derive a globally seamless, standardised hydrographic network, the “Hydrography90m”, with corresponding stream topographic and topological information. A central feature of the network is the minimal upstream contributing area, i.e. flow accumulation, of 0.05 km2 (or 5 ha) to initiate a stream channel, which allowed us to extract headwater stream channels in great detail. By employing a suite of GRASS GIS hydrological modules, we calculated the range-wide upstream flow accumulation and flow direction to delineate a total of 1.6 million drainage basins and extracted globally a total of 726 million unique stream segments with their corresponding sub-catchments. In addition, we computed stream topographic variables comprising stream slope, gradient, length, and curvature attributes as well as stream topological variables to allow for network routing and various stream order classifications. We validated the spatial accuracy and flow accumulation of Hydrography90m against NHDPlus HR, an independent, national high-resolution hydrographic network dataset of the United States. Our validation shows that the newly developed Hydrography90m has the highest spatial precision and contains more headwater stream channels compared to three other global hydrographic datasets. This comprehensive approach provides a vital and long-overdue baseline for assessing actual streamflow in headwaters and opens new research avenues for high-resolution studies of surface water worldwide. Hydrography90m thus offers significant potential to facilitate the assessment of freshwater quantity and quality, inundation risk, biodiversity, conservation, and resource management objectives in a globally comprehensive and standardised manner. The Hydrography90m layers are available at https://doi.org/10.18728/igb-fred-762.1 (Amatulli et al., 2022a), and while they can be used directly in standard GIS applications, we recommend the seamless integration with hydrological modules in open-source QGIS and GRASS GIS software to further customise the data and derive optimal utility from it

Если человечество не изменит концепцию своего развития, оно погибнет

Сложная современная политическая, социально-экономическая, межнациональная, религиозная и пр. ситуация в мире требует от интеллектуальной элиты и особенно от политиков, ученых обществоведов, экономистов сформировать и предложить новую концепцию развития мира.Складна сучасна політична, соціально-економічна, міжнаціональна, релігійна та ін. ситуація в суспільстві вимагає від інтелектуальної еліти і особливо від політиків, вчених суспільствознавців, економістів сформувати та запропонувати нову концепцію розвитку суспільства.Complicated modern political, socio-economic, international, religious and other situations in the world call on all the brainpower and especially policy-makers, scholars, social scientists, economists to elaborate and offer a new concept of the world development

When is a hydrological model sufficiently calibrated to depict flow preferences of riverine species?

Riverine species have adapted to their environment, particularly to the hydrological regime. Hydrological models and the knowledge of species preferences are used to predict the impact of hydrological changes on species. Inevitably, hydrological model performance impacts how species are simulated. From the example of macroinvertebrates in a lowland and a mountainous catchment, we investigate the impact of hydrological model performance and the choice of the objective function based on a set of 36 performance metrics for predicting species occurrences. Besides species abundance, we use the simulated community structure for an ecological assessment as applied for the Water Framework Directive. We investigate when a hydrological model is sufficiently calibrated to depict species abundance. For this, we postulate that performance is not sufficient when ecological assessments based on the simulated hydrology are significantly different (analysis of variance, p < .05) from the ecological assessments based on observations. The investigated range of hydrological model performance leads to considerable variability in species abundance in the two catchments. In the mountainous catchment, links between objective functions and the ecological assessment reveal a stronger dependency of the species on the discharge regime. In the lowland catchment, multiple stressors seem to mask the dependence of the species on discharge. The most suitable objective functions to calibrate the model for species assessments are the ones that incorporate hydrological indicators used for the species prediction

Modelling of riverine ecosystems by integrating models: conceptual approach, a case study and research agenda

Aim Highly complex interactions between the hydrosphere and biosphere, as well as multifactorial relationships, characterize the interconnecting role of streams and rivers between different elements of a landscape. Applying species distribution models (SDMs) in these ecosystems requires special attention because rivers are linear systems and their abiotic and biotic conditions are structured in a linear fashion with significant influences from upstream/downstream or lateral influences from adjacent areas. Our aim was to develop a modelling framework for benthic invertebrates in riverine ecosystems and to test our approach in a data-rich study catchment. Location We present a case study of a 9-km section of the lowland Kielstau River located in northern Germany. Methods We linked hydrological, hydraulic and species distribution models to predict the habitat suitability for the bivalve Sphaerium corneum in a riverine system. The results generated by the hydrological model served as inputs into the hydraulic model, which was used to simulate the resulting water levels, velocities and sediment discharge within the stream channel. Results The ensemble model obtained good evaluation scores (area under the receiver operating characteristic curve 0.96; kappa 0.86; true skill statistic 0.95; sensitivity 86.14; specificity 85.75). Mean values for variables at the sampling sites were not significantly different from the values at the predicted distribution (MannWhitney U-test P &gt; 0.05). High occurrence probabilities were predicted in the downstream half of the 9-km section of the Kielstau. The most important variable for the model was sediment discharge (contributing 40%), followed by water depth (30%), flow velocity (19%) and stream power (11%). Main conclusions The hydrological and hydraulic models are able to produce predictors, acting at different spatial scales, which are known to influence riverine organisms; which, in turn, are used by the SDMs as input. Our case study yielded good results, which corresponded well with ecological knowledge about our study organism. Although this method is feasible for making projections of habitat suitability on a local scale (here: a reach in a small catchment), we discuss remaining challenges for future modelling approaches and large-scale applications.Aim Highly complex interactions between the hydrosphere and biosphere, as well as multifactorial relationships, characterize the interconnecting role of streams and rivers between different elements of a landscape. Applying species distribution models (SDMs) in these ecosystems requires special attention because rivers are linear systems and their abiotic and biotic conditions are structured in a linear fashion with significant influences from upstream/downstream or lateral influences from adjacent areas. Our aim was to develop a modelling framework for benthic invertebrates in riverine ecosystems and to test our approach in a data-rich study catchment. Location We present a case study of a 9-km section of the lowland Kielstau River located in northern Germany. Methods We linked hydrological, hydraulic and species distribution models to predict the habitat suitability for the bivalve Sphaerium corneum in a riverine system. The results generated by the hydrological model served as inputs into the hydraulic model, which was used to simulate the resulting water levels, velocities and sediment discharge within the stream channel. Results The ensemble model obtained good evaluation scores (area under the receiver operating characteristic curve 0.96; kappa 0.86; true skill statistic 0.95; sensitivity 86.14; specificity 85.75). Mean values for variables at the sampling sites were not significantly different from the values at the predicted distribution (MannWhitney U-test P > 0.05). High occurrence probabilities were predicted in the downstream half of the 9-km section of the Kielstau. The most important variable for the model was sediment discharge (contributing 40%), followed by water depth (30%), flow velocity (19%) and stream power (11%). Main conclusions The hydrological and hydraulic models are able to produce predictors, acting at different spatial scales, which are known to influence riverine organisms; which, in turn, are used by the SDMs as input. Our case study yielded good results, which corresponded well with ecological knowledge about our study organism. Although this method is feasible for making projections of habitat suitability on a local scale (here: a reach in a small catchment), we discuss remaining challenges for future modelling approaches and large-scale applications

Twenty-three unsolved problems in hydrology (UPH) – a community perspective

This paper is the outcome of a community initiative to identify major unsolved scientific problems in hydrology motivated by a need for stronger harmonisation of research efforts. The procedure involved a public consultation through on-line media, followed by two workshops through which a large number of potential science questions were collated, prioritised, and synthesised. In spite of the diversity of the participants (230 scientists in total), the process revealed much about community priorities and the state of our science: a preference for continuity in research questions rather than radical departures or redirections from past and current work. Questions remain focussed on process-based understanding of hydrological variability and causality at all space and time scales. Increased attention to environmental change drives a new emphasis on understanding how change propagates across interfaces within the hydrological system and across disciplinary boundaries. In particular, the expansion of the human footprint raises a new set of questions related to human interactions with nature and water cycle feedbacks in the context of complex water management problems. We hope that this reflection and synthesis of the 23 unsolved problems in hydrology will help guide research efforts for some years to come