Analysis of potential impacts of climate and land use changes on the natural water balance and on the water resources management of Lusatia

In den Lausitzer Flusseinzugsgebieten bestehen aufgrund eines verhältnismäßig geringen natürlichen Wasserdargebots und durch die Auswirkungen des Braunkohlebergbaus bzw. dessen abrupten Rückgangs in den 1990er Jahren Probleme hinsichtlich der Bereitstellung von Wasser in ausreichenden Menge und Qualität für die vielfältigen Nutzungen. Vor diesem Hintergrund sind die Auswirkungen potenzieller Klima- (ansteigende Temperaturen und sinkende Niederschläge) und Landnutzungsänderungen (weiterer Rückgang des Braunkohlebergbaus sowie verstärkter Anbau agrarischer Energiepflanzen) auf die regionalen Wasserressourcen von besonderem Interesse. Es stellt sich die Frage, in welchem Ausmaß wasserwirtschaftliche Engpässe möglicherweise verschärft werden bzw. durch gezielte Anpassungsmaßnahmen ausgeglichen werden können. Voraussetzung zur Ableitung von Anpassungsmaßnahmen sind ortsspezifische Antworten hinsichtlich der möglichen Auswirkungen von Klima- und Landnutzungsänderungen auf den natürlichen Wasserhaushalt und die Wassermengenbewirtschaftung. Diese wurden mit einem Ensemble aus den regionalen Klimamodellen STAR und WettReg, Landnutzungsszenarien in Bezug auf Braunkohlebergbau und Energiepflanzenanbau, den hydrologischen Modellen SWIM und EGMO sowie dem Langfristbewirtschaftungsmodell WBalMo untersucht. Als Grundlage für die Analyse wurden mit dem ökohydrologischen Modellsystem SWIM für die Einzugsgebiete von Schwarzer Elster, Dahme, Spree (bis Pegel Große Tränke) und Lausitzer Neiße (bis Pegel Steinbach) je ein Modell zur Simulation des natürlichen Wasserhaushalts aufgebaut. Der klassische Ansatz zur Modellparametrisierung durch Kalibrierung anhand beobachteter Abflüsse ist aufgrund der starken anthropogenen Überprägung des Abflussgeschehens durch Braunkohlebergbau und Wasserwirtschaft erschwert. Daher erfolgte zunächst eine Kalibrierung für weniger überprägte Teileinzugsgebiete, anschließend wurden die Modellparameter durch Regionalisierung auf die Gesamtgebiete übertragen. Bei Simulationen mit SWIM für Klimaszenarien mit ansteigender Jahresmitteltemperatur zeigen sich Zunahmen der potenziellen Verdunstung um bis zu 30 % im langjährigen Mittel. Aufgrund der in diesen Szenarien projizierten Abnahme der Niederschlagsjahressummen steigt die mittlere reale Verdunstung nur um bis zu 10 %, weiterhin ergibt sich ein Rückgang der Jahresmittel von Abfluss und Grundwasserneubildung um bis zu 60 %. Ein Rückgang des Grundwasserabsenkungstrichters und damit die Vergrößerung der abflusswirksamen Einzugsgebietsfläche mindert die Auswirkungen der klimatischen Änderungen geringfügig. Bei einem verstärkten Anbau von Winterraps ergeben sich bei gleichem Klimaszenario aufgrund verringerter realer Verdunstung höhere Abflüsse und Grundwasserneubildungsraten im Vergleich zu Winterweizen als Referenzvariante. Die Ergebnisse der natürlichen Wasserhaushaltskomponenten spiegeln hohe Bandbreiten der Klimaprojektionen wider. Unsicherheiten bestehen weiterhin in der hydrologischen Reaktion auf geänderte klimatische Bedingungen, wie Vergleiche der Ergebnisse von SWIM mit denen des hydrologischen Modells EGMO aufzeigen. Im Vergleich dazu sind die mit den Landnutzungsänderungen verbundenen Unsicherheiten eher von untergeordneter Bedeutung. Durch den Rückgang der natürlichen Abflüsse und von Sümpfungswassereinleitungen ergeben sich in der Simulation der Wassermengenbewirtschaftung mit WBalMo Abnahmen der bewirtschafteten Abflüsse um bis zu 50 %. Das hätte zur Folge, dass die Nutzeransprüche nicht mehr ausreichend erfüllt werden können. Es zeigte sich, dass die negativen Auswirkungen der Klima- und Landnutzungsänderungen durch wasserwirtschaftliche Maßnahmen innerhalb des Untersuchungsgebiets, wie zum Beispiel eine geänderte Speicherbewirtschaftung, nicht ausreichend gemindert werden, die Überleitung von Wasser aus der Elbe jedoch eine geeignete Anpassungsoption darstellt. Die Unsicherheiten bezüglich der natürlichen Wasserhaushaltskomponenten ziehen in der Simulation der Wassermengenbewirtschaftung hohe Bandbreiten der Ergebnisse nach sich. Der Ansatz der ensemblegestützten Analyse erlaubt es, Auswirkungen potenzieller Klima- und Landnutzungsänderungen auf die natürlichen Wasserhaushaltskomponenten und die Wassermengenbewirtschaftung abzuschätzen und damit verbundene Unsicherheiten zu berücksichtigen sowie mögliche Anpassungsoptionen zu identifizieren.In the Lusatian river catchments, the allocation of water in sufficient quantity and of adequate quality for various purposes is constrained by relatively low natural water availability as well as by the consequences of lignite mining and its rapid decrease in the 1990s. Thus, the impacts of potential climate (increasing temperature and decreasing precipitation) and land use changes (further decrease of the mining activities and an increasing cultivation of arable energy crops) on water resources are of major interest. The fundamental question is to what extent the already existing deficits in water management are exacerbated and whether they can be mitigated by adaptation measures. In order to derive adaptation measures, site-specific results regarding the possible impacts of climate and land use changes on the natural water balance as well as on water resources management are necessary. Therefore, an ensemble consisting of the regional climate models STAR and WettReg, land use scenarios in terms of lignite mining and energy crop production, the hydrological models SWIM and EGMO, as well as the long term water management model WBalMo is used. As a prerequisite for the analysis, the ecohydrological model SWIM was set up for the catchments of the Schwarze Elster River, the Dahme River, the Spree River (up to Große Tränke gauge) and the Lusatian Neisse River (up to Steinbach gauge) each in order to simulate natural water balance components. The traditional approach of calibrating hydrological models based on time series of observed discharges is aggravated due to the strong impacts of mining and water management on discharge. Therefore, in a first step the models were calibrated for subcatchments with only minor anthropogenic influence on discharge. In a second step, the model parameters were transferred to the entire catchments via regionalization. In climate scenarios with increasing temperature, SWIM simulates increases in the potential evapotranspiration of up to 30 % on the long term average. As declining precipitation is projected in these scenarios, the actual evapotranspiration increases by 10 % on average only, whereas discharge and groundwater recharge decline by up to 60 %. The declining ground water depression cone and thus the increase of the catchment area contributing to runoff only slightly alleviates the effects of climate change. An increasing cultivation of winter oil seed rape results in slightly reduced actual evapotranspiration and therefore in increased discharge and ground water recharge compared to simulations with the same climate scenario and winter wheat as reference crop. Overall, the simulation results of the natural water balance components reflect high bandwidths of the climate projections. Further uncertainties are added by the hydrological reaction to changing climate conditions, as shown by comparing the results of SWIM with those of the hydrological model EGMO. In comparison, the uncertainties related to land use changes are minor. Due to decreasing natural discharges as well as decreasing mining discharges, which are released into the rivers, simulations with WBalMo show declining managed discharges by 50 % on the long term average. As a consequence, the demands of the water users cannot be satisfied sufficiently. The impacts of climate and land use changes cannot be adequately mitigated by adaptation measures in terms of an altered management within the study region, e.g. reservoir management. A transfer of water from the Elbe River to the study region, however, might be a feasible option to alleviate negative climate and land use change impacts. The uncertainties associated with the simulation of natural discharges also cause high bandwidths in the simulation of water management regarding climate and land use scenarios as well as hydrological models. The ensemble-based analysis allows the assessment of (1) potential climate and land use change impacts on the natural water balance components as well as on the water resources management in the Lusatian river catchments, (2) uncertainties in these impacts and (3) feasible adaptation options

Surface Measure to Depth (SMeTD): a new low-budget system for 3D water temperature measurements for combining with UAV-based thermal infrared imagery

Acknowledgements This work was funded by the School of Geosciences, University of Aberdeen, and the Macaulay Development Trust. We would like to thank Dr. Katya Dimitrova Petrova, Dr. Irma Arts, Douglas Wardell-Johnson and Lucas Christie for their assistance in the field. Funding This work was funded by the School of Geosciences, University of Aberdeen, and the Macaulay Development Trust.Peer reviewedPublisher PD

Long-term daily stream temperature record for Scotland reveals spatio-temporal patterns in warming of rivers in the past and further warming in the future

Peer reviewedproo

Water for all : towards an integrated approach to wetland conservation and flood risk reduction in a lowland catchment in Scotland

Authors thanks Rural & Environment Science & Analytical Services Division of the Scottish Government (SEFARI) project number S100015-00 for funding this work.Strategies for sustainable water resources management require integration of hydrological, ecological and socio-economic concerns. The “Water for all” project has sought to develop a multi-disciplinary science case for innovative management of water levels and flows in a lowland catchment in Scotland. Water demands of arable agriculture, protection from flood risk and conservation needs of lowland mesotrophic wetlands needed to be considered. Water management strategy focused on the outlet zone of Balgavies lake in Eastern Scotland, where the Lunan Water discharges into a partially confined common channel (lade). Water releases to a mill, to the downstream river, and to floodplain wetlands (Chapel Mires) are partially controlled by an existing weir. Based on observations of management of this weir, we postulated that upgrading hydraulic management in this zone could reduce upstream flood risk, help protect mesotrophic wetlands and facilitate downstream water supply at low flows. We considered potential for: (a) installing a remotely operated tilting weir, for improved management of release and routing of flows from the common lade; (b) dredging of the common lade in combination or instead of the tilting weir. Rapid ecological assessment and mixing analysis of the Lunan Water with waters in Chapel Mires showed a gradient of trophic status across the wetlands linked to impact of river-borne nutrients. Stage-discharge relationships, derived from steady-state approximations of the in-channel hydraulics, showed that the proposed tilting weir had potential to divert seasonal nutrient rich water from the upstream Lake away from Chapel Mires. Significant impact of the proposed weir on upstream flood risk was not demonstrated, but carrying out dredging of the channel reduced the current observed probability of upstream flooding. The proposed weir could help to maintain these dredging benefits. Survey and interviews with catchment stakeholders and residents showed constructive interest in the scheme, with half of the respondents willing to pay to support its implementation. The survey also revealed concerns about the proposed project, especially its long-term governance. The lessons learned have wider relevance to development of an integrated approach to water ecosystem services provision, especially where benefits are uncertain and thinly spread across a range of users.PostprintPeer reviewe

Niedrigwassersituation und wasserwirtschaftliche Maßnahmen 2022 in der Stauhaltung Spandau

NIEDRIGWASSERSITUATION UND WASSERWIRTSCHAFTLICHE MASSNAHMEN 2022 IN DER STAUHALTUNG SPANDAU Niedrigwassersituation und wasserwirtschaftliche Maßnahmen 2022 in der Stauhaltung Spandau / Creutzfeldt, Noah Angelo Benjamin (Rights reserved) ( -

Modeling the ecological impact of phosphorus in catchments with multiple environmental stressors

The broken phosphorus (P) cycle has led to widespread eutrophication of freshwaters. Despite reductions in anthropogenic nutrient inputs that have led to improvement in the chemical status of running waters, corresponding improvements in their ecological status are often not observed. We tested a novel combination of complementary statistical modeling approaches, including random-effect regression trees and compositional and ordinary linear mixed models, to examine the potential reasons for this disparity, using low-frequency regulatory data available to catchment managers. A benthic Trophic Diatom Index (TDI) was linked to potential stressors, including nutrient concentrations, soluble reactive P (SRP) loads from different sources, land cover, and catchment hydrological characteristics. Modeling suggested that SRP, traditionally considered the bioavailable component, may not be the best indicator of ecological impacts of P, as shown by a stronger and spatially more variable negative relationship between total P (TP) concentrations and TDI. Nitrate-N (p < 0.001) and TP (p = 0.002) also showed negative relationship with TDI in models where land cover was not included. Land cover had the strongest influence on the ecological response. The positive effect of seminatural land cover (p < 0.001) and negative effect of urban land cover (p = 0.030) may be related to differentiated bioavailability of P fractions in catchments with different characteristics (e.g., P loads from point vs. diffuse sources) as well as resilience factors such as hydro-morphology and habitat condition, supporting the need for further research into factors affecting this stressor–response relationship in different catchment types. Advanced statistical modeling indicated that to achieve desired ecological status, future catchment-specific mitigation should target P impacts alongside multiple stressors

Creating Community for Early-Career Geoscientists:Student involvement in geoscience unions: A case study from hydrology

The American Geophysical Union (AGU) and the European Geosciences Union (EGU) play central roles in nurturing the next generation of geoscientists. Students and young scientists make up about one-quarter of the unions’ active memberships [American Geophysical Union, 2013; European Geosciences Union, 2014], creating a major opportunity to include a new generation of geoscientists as more active contributors to the organizations’ activities, rather than merely as consumers