| 1. |
- Åhlén, Imenne, 1991-
(författare)
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Ecosystem services of wetlands and wetlandscapes under hydro-climatic change : Impacts of water flow and inundation patterns
- 2023
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Wetlands provide ecosystem services valuable for human society and are therefore often considered as nature based solution to different environmental problems. However, with centuries of wetland degradation due to anthropogenic pressures, such as agricultural expansion and forest industry, as well as pressures from climate change, there are large challenges for sustainable wetland management. Thus, for wetland protection and restoration practices to be successful, a deepened understanding on the actual mechanisms controlling wetland functions is required. Understanding how wetlands are connected, with and influenced, by their surrounding environment is also needed. Although most pressures experienced by wetlands operate on scales beyond the individual wetland scale, relatively few studies have thus far addressed large-scale functions and ecosystem service provision from hydrologically interconnected wetlands at the scale of wetlandscapes (i.e., the wetlands’ aggregated hydrological catchments in the landscape). The aim of this thesis is to investigate ecosystem service delivery from wetlands and wetlandscapes under hydro-climatic changes, considering 25 different wetlandscapes located in four different climate zones of the world. The thesis also systematically quantifies ecohydrological characteristics important for ecosystem service delivery and biodiversity support of wetlands and wetlandscapes in the Norrström Drainage basin located near Stockholm, Sweden. Conducted hydro-climatic analyses showed that impacts of climate change on wetlandscapes cannot be fully understood from average changes in climatic variables of the climate zones within which the wetlandscapes are located. This may be due to the fact that wetlands are not randomly and evenly distributed within climate zones, but may be located in areas subject to stronger climatic changes than regional means. In addition, anthropogenic pressures were on average shown to have higher impacts on runoff in wetlandscapes in comparison to climate change. The pressures however showed relatively large variability between different wetlandscapes, which needs to be considered in mitigation strategies against wetland degradation and deterioration. Similarly, regarding wetlandscape ecohydrological characteristics, results indicated that there are variability between wetlandscapes of different sizes, where larger wetlandscapes showed features that can support ecosystem services to larger degree than small wetlandscapes. Large spatial variability in wetland ecohydrological characteristics was also seen within a wetlandscape. For instance, water storage dynamics and buffering capacity varied depending on the position of the wetland in the landscape. These differences in hydrological conditions were shown to result in different inundation dynamics between wetlands, which for instance also showed to impact insect community composition.Overall, this thesis shows that assessments of wetland ecosystem services need to be addressed using a wetlandscape approach, combined with actual on site hydrological measurements. The approach used in this thesis could help decrease uncertainties related to the impacts of hydro-climatic changes and anthropogenic pressures on wetlands and wetlandscapes, supporting location-specific wetland management strategies related to creation, restoration and sustainable use of wetlands and their ecosystems.
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| 2. |
- Levi, Lea, 1984-
(författare)
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Data-driven analysis of water and nutrient flows: Case of the Sava River Catchment and comparison with other regions
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- A growing human population and demands for food, freshwater and energy are causing extensive changes in the water and biogeochemical cycles of river catchments around the world. Addressing and investigating such changes is particularly important for transboundary river catchments, where they impose additional risk to a region’s stability. This thesis investigates and develops data-driven methodologies for detecting hydro-climatic and nutrient load changes and their drivers with limited available data and on different catchment scales. As a specific case study, we analyze the Sava River Catchment (SRC) and compare its results with other world regions. A past–present to future evaluation of hydro-climatic data is done on the basis of a water balance approach including analysis of historic developments of land use and hydropower development data and projections of the Coupled Model Intercomparison Project, Phase 5 (CMIP5) output. Using observed water discharge and nutrient concentration data, we propose a novel conceptual model for estimating and spatially resolving total nitrogen (TN) and total phosphorus (TP) input and delivery-retention properties for a river catchment and its nested subcatchments, as well as detection of nutrient hotspots. The thesis identifies hydroclimatic change signals of hydropower-related drivers and finds consistency with other world regions. The proposed nutrient screening methodology provides a good distinction between human-related nutrient inputs and landscape-related transport influences on nutrient loading at subcatchment to catchment scale. A cross-regional comparison of the SRC data with the Baltic region shows similarity between nutrient-relevant indicators and driving socio-economic and hydro-climatic conditions. The study highlights a number of complexities with regard to CMIP5 model representation of water fluxes. The large intermodel range of CMIP5 future projections of fluxes calls for caution when using individual model results for assessing ongoing and future water and nutrient changes.
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| 3. |
- Sjöberg, Ylva, 1982-
(författare)
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Linking water and permafrost dynamics
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The extent and dynamics of permafrost are tightly linked to the distribution and movement of water in arctic landscapes. As the Arctic warms more rapidly than the global average, profound changes are expected in both permafrost and hydrology; however, much is still not known about the interactions between these two systems. The aim of this thesis is to provide new knowledge on the links between permafrost and hydrology under varying environmental conditions and across different scales. The objectives are to (i) determine how permafrost distributions and patterns in morphology are linked to hydrology, (ii) determine how groundwater flow influences ground temperature dynamics in permafrost landscapes, and (iii) explore the mechanisms that link permafrost to groundwater and streamflow dynamics. A range of methods have been applied within the four studies (papers I-IV) comprising the thesis: geophysical (ground penetrating radar and electrical resistivity tomography) and GIS techniques for mapping and analyzing permafrost distributions and related morphology; numerical modeling of coupled heat and water fluxes for mechanistic understanding permafrost-hydrological links; and statistical analyses for detecting trends in streamflow associated with permafrost thaw. Combining these various methods here allows for, and may be considered a prerequisite for, novel insights to processes. The thesis also presents statistical analyses of field observations of ground temperatures, ground- and surface water levels, as well as lake and shore morphological variables. Discontinuous permafrost peatlands are heterogeneous environments regarding permafrost distributions and thickness which is manifested in surface systems such as lake geometries. In these environments, lateral groundwater fluxes, which are not considered in most permafrost models, can significantly influence ground temperature dynamics, especially during high groundwater gradient conditions. River discharge data provide a potential for monitoring catchment-scale changes in permafrost, as the magnitude and seasonality of groundwater fluxes feeding into streams are affected by the distribution of permafrost. This thesis highlights the need to understand water and permafrost as an integrated system with potential internal feedback processes. For example, permafrost thaw can lead to increases in groundwater discharge which in turn can lead to increased heat transfer through the ground, resulting in further acceleration of permafrost thaw rates.
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| 4. |
- Engström, Rebecka Ericsdotter, 1984-
(författare)
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Exploring cross-resource impacts of urban sustainability measures : an urban climate-land-energy-water nexus analysis
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In an increasingly urban world, cities' global resource uses grow. Two fundamental resources for making cities liveable are water and energy. These resources are also closely interlinked – systems that convert and deliver energy to cities require water, and urban water systems use energy. In addition, these two resource systems affect and are affected by land use and climate change. This ‘nexus’ between climate, land use, energy and water (CLEW) systems has been extensively studied in the past decade, mainly with a focus on national and transboundary CLEW systems. This doctoral thesis develops the CLEW nexus research from an urban perspective.Two quantitative analyses examine how different types of sustainability measures in cities affect intended and unintended CLEW systems. First, the CLEW impacts of a set of sustainability measures in New York City are assessed - from water conservation to emission reductions. Results show that every measure affects (to varying degrees) all studied sustainability dimensions - water, energy and climate - and that the impacts can be quantified through a reference-resource-to-service-system (RRSS).The second quantitative study focuses on how CLEW impacts from a city's sustainability efforts spread beyond local and international borders. It investigates how global water and land use are affected in alternative scenarios to achieve climate neutrality in 2030 in the town of Oskarshamn, Sweden, using an energy systems simulation model. The study finds that both the magnitude and the geographical distribution of land and water requirements vary between scenarios. A strategy to achieve climate neutrality that invests in electrification leads to increased national water use, while a strategy that relies on biofuels has a greater impact on water and land use internationally. When results are translated to interactions between the UN's sustainable development goals (SDGs), they reveal that SDG synergies and trade-offs are 'strategy-dependent': different options for achieving SDGs on energy, sustainable cities and climate action have varying consequences for the advancement of SDGs on sustainable water, food production and biodiversity.To shed light on how data challenges affect quantitative urban nexus studies, uncertainty assessments of selected thesis’ results are conducted and complemented with a thematic analysis of a set of recently published urban nexus papers. Together, they indicate that analytical choices, uncertainties in results and - as a consequence - research foci are influenced by data limitations in both this thesis and in other urban nexus studies.Lastly, the finding from the Oskarshamn analysis – that SDG interactions are strategy-dependent – is deliberated with experts within sustainability sciences and SDG interaction research. From this, a research agenda is proposed with measures to make SDG 'spillovers' visible in local level decision-making.Taken together, the thesis contributes to filling several knowledge gaps on how urban sustainability measures within the CLEW systems interact within and beyond city limits, and proposes analytical approaches to quantify these interactions. It further points out how current data challenges constrain quantitative urban nexus analyses and highlights research needs to improve data management as well as other key efforts to enable consideration of nexus interactions, including SDG 'spillovers', in cities' sustainability work.
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| 5. |
- Finné, Martin, 1981-
(författare)
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Climate in the eastern Mediterranean during the Holocene and beyond – A Peloponnesian perspective
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis contributes increased knowledge about climate variability during the late Quaternary in the eastern Mediterranean. Results from a paleoclimate review reveal that regional wetter conditions from 6000 to 5400 years BP were replaced by a less wet period from 5400 to 4600 years BP and to fully arid conditions around 4600 years BP. The data available, however, show that there is not enough evidence to support the notion of a widespread climate event with rapidly drying conditions in the region around 4200 years ago. The review further highlights the lack of paleoclimate data from the archaeologically rich Peloponnese Peninsula. This gap is addressed in this thesis by the provision of new paleoclimate records from the Peloponnese. One stalagmite from Kapsia Cave and two stalagmites from Glyfada Cave were dated and analyzed for stable oxygen (δ18O) and carbon (δ13C) isotopes. The Glyfada record covers a period from ~78 ka to ~37 ka and shows that the climate in this region responded rapidly to changes in temperatures over Greenland. During Greenland stadial (interstadial) conditions colder (warmer) and drier (wetter) conditions are reflected by depleted (enriched) δ13C-values in the speleothems. The Kapsia record covers a period from ~2900 to ~1100 years BP. A comparison between the modern stalagmite top isotopes and meteorological data shows that a main control on stalagmite δ18O is wet season precipitation amount. The δ18O record from Kapsia indicates cyclical humidity changes of close to 500 years, with rapid shifts toward wetter conditions followed by slowly developing aridity. Superimposed on this signal is a centennial signal of precipitation variability. A second speleothem from Kapsia with multiple horizons of fine sediments from past flood events intercalated with the calcite is used to develop a new, quick and non-destructive method for tracing flood events in speleothems by analyzing a thick section with an XRF core scanner.
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| 6. |
- Darracq, Amelie
(författare)
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Long-term development, modeling and management of nutrient loading to inland and coastal waters
- 2007
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Environmental and water system protection and restoration require accurate knowledge and quantification of waterborne pollutant transport, retention-release and transformation processes taking place in the subsurface, river, lake and sea water systems, and at the interfaces between these systems. This thesis investigates the importance of spatial model resolution for such quantification and the possible long-term nutrient load development under different human perturbations and nutrient source management scenarios in the Swedish Norrström drainage basin, based on simulations with the GIS-based dynamic nutrient transport-attenuation model POLFLOW. The results indicate substantial nutrient load contributions from the subsurface water system (soil water and groundwater) to surface waters, which may largely control present and future nutrient mass loads from drainage basins to downstream inland and coastal waters. This role of the subsurface water system needs to be acknowledged, in conjunction with the effects of expected climate change and population and lifestyle developments, for achieving successful and sustained decreases in nutrient loading to inland and coastal waters. The results point also towards a need for downstream nutrient load control and abatement measures, to complement nutrient source reduction programs. The results further indicate the importance of the chosen spatial model resolution and account for subgrid variability for the accuracy of the necessary coupled transport and attenuation modeling of nutrient spreading in, and export from, river networks to coastal systems. Failure to correctly conceptualize and accurately account for the physical transport processes and their subgrid variability in this modeling may also yield systematic misinterpretation of the biogeochemical processes and process rates. Further, this may have important practical implications for the necessary abatement effectiveness and efficiency of nutrient and other waterborne pollutant loading to inland and coastal waters worldwide.
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| 7. |
- Hannerz, Fredrik, 1977-
(författare)
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Making water information relevant on local to global scale – the role of Information Systems for Integrated Water Management
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Relevant information is essential for finding solutions in Integrated Water Management (IWM). Complex water systems and a need for increasing integration of sectors, actors and scales in IWM require new methods for developing and managing such information. This thesis investigates the role of information within the IWM process, as well as the main challenges for development of representative, accessibleand harmonized information. Results show how information needs and the information production process for IWM may be systematized, and indicate a large potential for information system development for IWM. However, in order to reach the full potential, today’s limited and heterogeneous water information needs to become more comprehensive, transparent, interoperable, dynamic, scalable and openly accessible. Large pressures on water systems are found in coastal catchment areas that are unmonitored across the local to the global scale, indicating a large importance of these areas for nutrient and pollutant loading. The globally accessible runoff data from catchment areas that are rich in pressures from population, agriculture and general economic activity further exhibit a rapidly declining trend during recent years. Major water system changes may therefore pass unnoticed if analyzed on the basis of openly accessible runoff global data. Furthermore, large discrepancies are found between land cover databases, which may result in major uncertainties in quantification of water and evapotranspiration flows. Identified information challenges may be relatively easily overcome by making better use of available information, while other challenges such as development of consistent baselines of core data and a possible re-prioritization of water-environmental monitoring programs may be both difficult and costly.
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| 8. |
- Jantze, Elin, 1983-
(författare)
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Waterborne Carbon in Northern Streams : Controls on dissolved carbon transport across sub-arctic Scandinavia
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Waterborne carbon (C) forms an active and significant part of the global C cycle, which is important in theArctic where greater temperature increases and variability are anticipated relative to the rest of the globe withpotential implications for the C cycle. Understanding and quantification of the current processes governing themovement of C by connecting terrestrial and marine systems is necessary to better estimate future changes ofwaterborne C. This thesis investigates how the sub-arctic landscape influences the waterborne carbon exportby combining data-driven and modeling methods across spatial and temporal scales. First, a study of the stateof total organic carbon monitoring in northern Scandinavia was carried out using national-scale monitoringdata and detailed data from scientific literature. This study, which highlights the consistency in land cover andhydroclimatic controls on waterborne C across northern Scandinavia, was combined with three more detailedstudies leveraging field measurements and modeling. These focused on the Abisko region to provide insightto processes and mechanisms across scales. The thesis highlights that the governing transport mechanismsof dissolved organic and inorganic carbon (DOC and DIC respectively) are fundamentally different due todifferences in release rates associated with the nature of their terrestrial sources (geogenic and organic matterrespectively). As such, the DIC mass flux exhibits a high flow-dependence whereas DOC is relatively flowindependent.Furthermore, these investigations identified significant relationships between waterborne C andbiogeophysical as well as hydroclimatic variables across large to small spatial scales. This thesis demonstratesthat both surface and sub-surface hydrological processes (such as flow pathway distributions) in combinationwith distributions of C sources and associated release rates are prerequisite for understanding waterborne Cdynamics in northern streams.
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| 9. |
- Johansson, Emma, 1979-
(författare)
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The influence of climate and permafrost on catchment hydrology
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The cycling of water in the landscape is influenced by climate change on different time scales and in different directions regarding warming or cooling trends. Along with a changing climate, also the landscape and subsurface conditions, such as permafrost extent, may change in a long-term perspective. Permafrost and hydrology are intimately connected but the interactions between them are poorly understood, and the hydrological response to climate change is complex. The first part of this thesis investigates the effects of different drivers of future changes in hydrological flow and water storage components in the present day temperate Forsmark catchment in Sweden. The role of taliks and their influence on the exchange of deep and shallow groundwater in permafrost environments are also studied. This is done by a simulation sequence where the site is exposed to the landscape, climate and permafrost changes expected from site-specific numerical modeling. In the second part of this thesis, present day periglacial hydrological processes are studied in the Two Boat Lake catchment in western Greenland by field and model investigations of the site. The presence of a through talik below the Two Boat Lake, and data from a deep bedrock borehole into the talik, enable studies of the hydrological interactions between the lake and the talik. The spatial and temporal variability of the different water balance components of the catchment are quantified and the interactions between the surface water and the supra- and sub-permafrost groundwater are analyzed.The results show that the investigated changes in climate and permafrost influence hydrology more than the investigated landscape changes. Under permafrost conditions, the general direction of the exchange between deep and shallow groundwater may change relative to unfrozen conditions. The simulation studies of Forsmark show that the relative topography between taliks governs the recharging and discharging conditions, which is consistent with results from Two Boat Lake. The lake is located at high altitude relative to other taliks and hydraulic measurements indicate recharging conditions. The talik recharge is small compared to other water balance components and does not influence the lake level, which instead is found to be controlled by evapotranspiration and water inflow from the active layer. This is concluded from numerical simulations that take into account and combine evapotranspiration with other surface and subsurface hydrological processes. This thesis highlights the need to integrate surface and subsurface process modelling in order to quantitatively understand and represent the dynamics and complexity of hydrological interactions in periglacial catchments.
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| 10. |
- Kåresdotter, Elisie, 1987-
(författare)
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Water in a Changing World : Unraveling the Complexities of Conflict and Cooperation
- 2024
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Water is a crucial resource that can unite or divide nations, but throughout history, people have generally cooperated to solve water-related issues. However, as freshwater scarcity intensifies due to climate shifts and escalating human demands, it is critical to identify water-related conflicts and cooperation dynamics. For instance, changes in water patterns, including floods, droughts, and dam construction to manage varying precipitation, could lead to increased competition and conflict over water resources. Effective water management and collaboration could help resolve these issues and foster peaceful water governance. The main aim of this thesis is to examine the connections between how humans, the climate, and changes in water have affected cooperation and conflicts over water. This research involves investigating the interactions between changes in freshwater availability, water-related events such as conflicts and cooperation, and changes in human activities and climate. The focus is mainly on global and regional large-scale levels, and the work comprises four parts: (i) a scoping review of previous scientific literature to identify important conflict factors and research gaps; (ii) hydrological modeling to determine the direction and magnitude of hydroclimatic change relating to human activities; (iii) creation of an updated water-related conflict and cooperation database and analysis of current trends; and (iv) analyses of how socio-economic and climatic factors affect water events and cooperation mechanisms behind successful conflict mitigation.The combined results from the four parts reveal that governance, policy, and climate change are important conflict factors worldwide. Agriculture emerges as particularly important in Africa and Asia, but there are regional variations in the importance of different conflict factors to these water conflicts. A significant research gap emerges for regions outside Africa and parts of Asia. This is problematic since influencing conflict factors appear to differ between regions. Scrutiny of the updated water event database showed that water events are increasing in frequency in most regions of the world but that cooperation is decreasing in parts of Africa, the Middle East, and South America. Changes in water events appear to be largely driven by climate change in Africa and by human activities in Asia. Changes in population density, urban-rural distribution, and precipitation have only small effects on conflict and cooperation outcomes, while economic factors such as gross domestic product (GDP) and export dependency have significant effects.The thesis reveals the interplay between human activities, climate change, and water governance, shedding light on the global dynamics that shape water conflicts and cooperation. The results underscore the critical need for adaptive water management strategies informed by comprehensive, region-specific insights. Future studies should, therefore, seek to develop innovative governance frameworks, predictive models for conflict prevention, and resilient water-sharing agreements that can withstand the challenges posed by global environmental changes. Such work will require an integrated approach, combining socio-economic, hydrological, and climate perspectives, to foster sustainable water management and peacebuilding efforts in an era of increasing uncertainty.
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| 11. |
- Ma, Yan, 1991-
(författare)
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Quantifying hydroclimatic change impacts on infectious diseases : Signals and geographies from local to global scale
- 2023
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Hydroclimatic change has the potential to directly or indirectly increase the occurrence and expand or shift the geographical range of infectious diseases. This may pose particular threats in the Nordic-Arctic Region, where warming is more rapid than in other parts of the world, but the climate sensitivities of various infectious diseases still remain to be investigated in this and other regions. This thesis aims to further our understanding of and predictive capability for the relationships between hydroclimatic change and infectious diseases. To achieve this aim, statistical correlation relationships were analyzed between seven potentially climate-sensitive infectious diseases and a range of hydroclimatic variables across various geographical scales and parts of the Nordic-Arctic Region. The studied diseases were: borreliosis/Lyme disease, tularemia, leptospirosis, Q fever, TBE, Puumala virus infection, and cryptosporidiosis. Hydroclimatic sensitivity has also been investigated through a statistical disease model, site-specifically parameterized at local scale, for the case of tularemia at different Swedish sites (counties) and for different scenarios of future hydroclimatic change. Moreover, for the relatively widespread Lyme disease and cryptosporidiosis, a scoping review approach has been applied to investigate how the complexity of the hydroclimate-disease relationships is considered and quantified in research so far and what key research gaps remain to be bridged.Results identify distinct hydroclimatic variables that are significantly correlated with six of the seven studied human diseases at large spatial scale over the Nordic-Arctic Region. The indicated hydroclimatic disease-driving variables and associated change relationships are to some degree consistent with previous reasoning-based discussions of climate-sensitivity of infectious diseases as increasing threats for humans. Notable exceptions are TBE and leptospirosis, which tend to decrease with increasing regional temperature and precipitation. Borreliosis (Lyme disease) exhibits consistent climate sensitivity at different geographical scales and region parts, considering the whole or either the southern or the northern part of the studied Nordic-Arctic Region. In contrast, tularemia does not exhibit any particular climate sensitivity signal at the large regional scale, even though such sensitivity is evident in local-based statistical disease models. This shows that, in general, investigations at multiple geographical scales and regions, and with different quantitative approaches are needed to obtain a complete picture of hydroclimate-disease relationships. Furthermore, along a latitudinal gradient across Sweden, the likely most realistic medium climate forcing scenario indicates future disease decreases (intermittent or overall) for the relatively southern Swedish counties, and disease increases of considerable or high degree for the intermediate and more northern counties. The projections also show that scenarios of steeper future climate warming do not necessarily lead to a steeper increase in future disease outbreaks and that uncertainties in the disease projections may be large and stem from both the disease models and the climate models. Important research gaps are further identified in research so far on the hydroclimate-disease relationships for Lyme disease and cryptosporidiosis. The gaps regard in particular water-related and socioeconomic factors for Lyme disease, and land-related factors for cryptosporidiosis. For both diseases, climate and other driver-pressure interactions with host and parasite communities are overall understudied. In addition, Asia and Africa emerge as main geographical research gaps for Lyme disease and cryptosporidiosis, respectively. Overall, the consistencies and controversies emerging from the statistical analysis, the uncertainties appearing in the scenario projections, and the research gaps identified by the scoping review in this thesis indicate possible biases in our understanding of hydroclimate-disease relationships and propose relevant directions for future research.
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| 12. |
- Mazi, Aikaterini, 1969-
(författare)
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Seawater intrusion risks and controls for safe use of coastal groundwater under multiple change pressures
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In the era of intense pressures on water resources, the loss of groundwater by increased seawater intrusion (SWI), driven by climate, sea level and landscape changes, may be critical for many people living in commonly populous coastal regions. Analytical solutions have been derived here for interface flow in coastal aquifers, which allow for simple quantification of SWI under extended conditions from previously available such solutions and are suitable for first-order regional vulnerability assessment and mapping of the implications of climate- and landscape-driven change scenarios and related comparisons across various coastal world regions. Specifically, the derived solutions can account for the hydraulically significant aquifer bed slope in quantifying the toe location of a fresh-seawater sharp interface in the present assessments of vulnerability and safe exploitation of regional coastal groundwater. Results show high nonlinearity of SWI responses to hydro-climatic and groundwater pumping changes on the landside and sea level rise on the marine side, implying thresholds, or tipping points, which, if crossed, may lead abruptly to major SWI of the aquifer. Critical limits of coastal groundwater change and exploitation have been identified and quantified in direct relation to prevailing local-regional conditions and stresses, defining a safe operating space for the human use of coastal groundwater. Generally, to control SWI, coastal aquifer management should focus on adequate fresh groundwater discharge to the sea, rather than on maintaining a certain hydraulic head at some aquifer location. First-order vulnerability assessments for regional Mediterranean aquifers of the Nile Delta Aquifer, the Israel Coastal Aquifer and the Cyprus Akrotiri Aquifer show that in particular the first is seriously threatened by advancing seawater. Safe operating spaces determined for the latter two show that the current pumping schemes are not sustainable under declining recharge.
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| 13. |
- Muliyil Asokan, Shilpa, 1979-
(författare)
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Hydro-climatic changes in irrigated world regions
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Understanding of hydro-climatic changes in the world’s river basins is required to ensure future food security. Different regional basins experience different levels of hydro-climatic change depending on the endorheic or exorheic nature of a hydrological basin, along with the climatic conditions and human land and water-use practices, for instance for irrigation. This thesis has analyzed long-term hydro-climatic changes in two main irrigated regions of the world: the Mahanadi River Basin in India and the Aral region in Central Asia. Thesis applies a basin-wise, data-driven water balance-constrained approach to quantifying the hydro-climatic changes, and to distinguish their main drivers in the past century and for future. Results point at human water-use and re-distribution for irrigation within a basin as a major driver of water balance changes, which also affect surface temperature in the region.Cross-regional comparison focused on the climatically important changes of water, vapor and latent heat fluxes at the land surface, and also on the changes to water resource availability in the landscape. Results show that irrigation- driven changes in evapotranspiration, latent heat fluxes and associated temperature changes at land surface may be greater in regions with small relative irrigation impacts on water availability in the landscape than in regions with severe such impacts. This implies that one cannot from the knowledge about only one aspect of hydro-climatic change simply extrapolate the impact importance of those changes for other types of water changes in a region.Climate model projections results show lack of consistency in individual GCM performance with regard to temperature and to precipitation, implying difficulties to identify well-performing GCMs with regard to both of these variables in a region. In Aral region, the thesis shows that ensemble mean of different GCM outputs may provide robust projection of future hydro-climate changes.
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| 14. |
- Page, Jessica Faye, 1991-
(författare)
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Sustainable Urban and Regional Development and Related Ecosystem Services and Water-Climate Interactions
- 2023
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- To accommodate a growing global population while mitigating climate change, urban areas must grow while minimising environmental impacts. To achieve this, a city must be treated as a complex socio-ecological system in which many actors and subsystems act in unclear and unpredictable ways. This thesis explores the workings and interactions of this complex socio-ecological system by assessing how urban and regional planning and policy decisions affect the contributions of cities to climate change, and whether appropriate planning and policy tools can minimise these contributions. Computer models were developed to investigate and couple planning and policy decisions and their potential impacts on the environment, particularly in terms of greenhouse gas (GHG) emissions to the atmosphere. The models were then employed for generation of scientific knowledge and for converting this knowledge into practical planning tools and recommendations.Methods used in developing models that reflect complex urban systems included cooperation with experienced county planners to improve model accuracy; coupling of sub-system models in a socio-ecological framework for scenario analysis of the outcomes of planning and policy decisions in terms of GHG emissions; systems breakdown analysis of green-blue contributions to the urban carbon cycle; and modelling to identify how these contributions could be harnessed to reduce net urban emissions. The main study area was Stockholm County, Sweden, with later extension of the modelling approach to 54 major European cities. Cooperation with Stockholm County planners during model development resulted in an improved tool for scientific research that was also suited to practical planning, increasing the potential for knowledge developed through scientific research to be applied in reality. Scenario analysis of policies for Stockholm County revealed that zoning reduced the extra GHG emissions associated with necessary urban growth by 72% compared with a baseline scenario. Analysis of the urban carbon cycle in Stockholm County showed that vegetative carbon sequestration helped offset GHG emissions locally, but that re-emissions via surface waters compromised the potential to reach ‘net-zero’ emissions from Stockholm County. However, climate action goals for Stockholm could still be achieved if its ambitious emissions reduction plans are realised and if the current sequestration capacity of Stockholm County’s many green areas can be maintained in coming decades. Extensive modelling of urban emissions in multiple European cities showed potential for green-space sequestration and revealed that nature-based solutions (NbS) applied at city scale could help reduce urban emissions. Incorporation of NbS into climate action plans for these cities would maximise the associated GHG emissions reduction and increase the likelihood of the cities achieving their climate action goals. In conclusion, the climate change impacts of future urban expansion could be mitigated by incorporating planning and policy tools such as zoning, protection of green-blue spaces and NbS into whole-system urban and regional development plans. This could bring cities closer to achieving truly sustainable urban development.
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| 15. |
- Verrot, Lucile, 1988-
(författare)
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Modeling long-term variability and change of soil moisture and groundwater level - from catchment to global scale
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The water stored in and flowing through the subsurface is fundamental for sustaining human activities and needs, feeding water and its constituents to surface water bodies and supporting the functioning of their ecosystems. Quantifying the changes that affect the subsurface water is crucial for our understanding of its dynamics and changes driven by climate change and other changes in the landscape, such as in land-use and water-use. It is inherently difficult to directly measure soil moisture and groundwater levels over large spatial scales and long times. Models are therefore needed to capture the soil moisture and groundwater level dynamics over such large spatiotemporal scales.This thesis develops a modeling framework that allows for long-term catchment-scale screening of soil moisture and groundwater level changes. The novelty in this development resides in an explicit link drawn between catchment-scale hydroclimatic and soil hydraulics conditions, using observed runoff data as an approximation of soil water flux and accounting for the effects of snow storage-melting dynamics on that flux. Both past and future relative changes can be assessed by use of this modeling framework, with future change projections based on common climate model outputs. By direct model-observation comparison, the thesis shows that the developed modeling framework can reproduce the temporal variability of large-scale changes in soil water storage, as obtained from the GRACE satellite product, for most of 25 large study catchments around the world. Also compared with locally measured soil water content and groundwater level in 10 U.S. catchments, the modeling approach can reasonably well reproduce relative seasonal fluctuations around long-term average values.The developed modeling framework is further used to project soil moisture changes due to expected future climate change for 81 catchments around the world. The future soil moisture changes depend on the considered radiative forcing scenario (RCP) but are overall large for the occurrence frequency of dry and wet events and the inter-annual variability of seasonal soil moisture. These changes tend to be higher for the dry events and the dry season, respectively, than for the corresponding wet quantities, indicating increased drought risk for some parts of the world.
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| 16. |
- Vigouroux, Guillaume, 1991-
(författare)
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Managing coastal eutrophication : Land-sea and hydroclimatic linkages with focus on the Baltic coastal system
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Eutrophication endangers coastal ecosystems all over the world and is most often associated with an increase in anthropogenic nutrient loads to coastal waters, which fuel the growth of algae and create a variety of environmental problems. This is also the case for the Baltic Sea where coastal waters may be affected by various land, coast-sea, and hydroclimatic drivers and feedbacks, over different scales, including the eutrophic open sea. This thesis aims at improving our understanding of how these drivers affect coastal eutrophication and its management opportunities across the various coupled scales of the Baltic land-coast-sea system. To achieve this aim, the interactions between land-catchment, coastal, and open sea processes, and their influences on coastal eutrophication have been investigated through water quality modelling with applications to specific Baltic coastal waters. Hydroclimatic influences on the propagation of change-impacts through the land-coast-sea continuum to coastal eutrophication have also been investigated via the water quality modelling and additional analysis of actual water quality trends over the last 30 years along the Swedish coast. Moreover, coastal eutrophication research on the Baltic Sea system has been investigated through scientific literature analysis with focus on how the reported research has accounted for and linked components in the land-coast-sea system, and the aim to identify possible research gaps.Results show that impacts of water quality improvements in the open sea propagate to a large share of the coastal waters, especially for phosphorus and phytoplankton, while impacts of reducing nutrient loads from land are more localised and more pronounced for nitrogen than for phosphorus. Therefore, reducing coastal nitrogen, phosphorus and phytoplankton concentrations requires both regional measures for open sea improvements and local land-catchment measures for reduction of nutrient loads to the specific coast. Moreover, data analysis shows that trends in coastal Summer chlorophyll a (Chl-a) are well correlated with those in open sea Summer Chl-a and in riverine nitrogen loads. Regarding hydroclimatic drivers, warmer and wetter conditions are found to complicate remediation of coastal eutrophication in comparison to drier and colder conditions. In addition, trends in coastal Summer Chl-a are well correlated with those in sea-ice conditions. These results highlight the various land-based, coastal, open sea, and hydroclimatic drivers and conditions that mix, interact in and influence the coastal waters. The various driver, management, and ecosystem components involved are overall included in Baltic coastal eutrophication research. However, specific coastal management measures, and feedbacks between drivers and impacts of coastal eutrophication are under-investigated, and the social and ecological components of the whole land-coast-sea system are not well-connected in the research.Furthermore, long-lived legacy sources on land, as well as at sea, have not been much accounted for in coastal eutrophication research so far. This calls for further research on recovery time scales and specific remediation measures that can be effective against such sources, like mussel farming and wetlands. Finally, coastal eutrophication management needs to account for the influences on local coastal conditions from a melting pot of multi-scale drivers and biogeochemical as well as ecological impacts and feedbacks.
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| 17. |
- Bring, Arvid, 1980-
(författare)
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Arctic Climate and Water Change : Information Relevance for Assessment and Adaptation
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The Arctic is subject to growing economic and political interest. Meanwhile, its water and climate systems are in rapid transformation. Relevant and accessible information about water and climate is therefore vital to detect, understand and adapt to the changes. This thesis investigates hydrological monitoring systems, climate model data, and our understanding of hydro-climatic change, for adaptation to water system changes in the Arctic. Results indicate a lack of harmonized water chemistry data, which may impede efforts to understand transport and origin of key waterborne constituents. Further development of monitoring cannot rely only on a reconciliation of observations and projections on where climate change will be the most severe, as they diverge in this regard. Climate model simulations of drainage basin temperature and precipitation have improved between two recent model generations, but large inaccuracies remain for precipitation projections. Late 20th-century discharge changes in major Arctic rivers generally show excess of water relative to precipitation changes. This indicates a possible contribution of stored water from permafrost or groundwater to sea level rise. The river contribution to the increasing Arctic Ocean freshwater inflow matches that of glaciers, which underlines the importance of considering all sources when assessing change. To provide adequate information for research and policy, Arctic hydrological and hydrochemical monitoring needs to be extended, better integrated and made more accessible. This especially applies to hydrochemistry monitoring, where a more complete set of monitored basins is motivated, including a general extension for the large unmonitored areas close to the Arctic Ocean. Improvements in climate model parameterizations are needed, in particular for precipitation projections. Finally, further water-focused data and modeling efforts are required to resolve the source of excess discharge in Arctic rivers.
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| 18. |
- Lindgren, Georg, 1973-
(författare)
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Physical process effects on catchment-scale pollutant transport-attenuation, coastal loading and abatement efficiency
- 2006
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Pollutants follow various subsurface and surface water pathways from sources within a catchment to its outlet and may cause detrimental effects on downstream water quality and ecosystems. Along their different transport pathways through a catchment, pollutants may be attenuated subject to different physical and biogeochemical processes. In this thesis, physical process effects on such catchment-scale pollutant transport and attenuation, resulting coastal pollutant loading and its efficient abatement are investigated. For this purpose, pollutant transport-attenuation is modeled both generically using a Lagrangian Stochastic Advective-Reactive (LaSAR) approach and site specifically for the Swedish Norrström basin using the GIS-based dynamic nitrogen transport-attenuation model POLFLOW. Furthermore, the role of such modeling for catchment-scale pollutant abatement is also investigated by use of economic optimization modeling. Results indicate that appropriate characterization of catchment-scale solute transport and attenuation processes requires accurate quantification of the specific solute pathways from different sources in a catchment, through the subsurface and surface water systems of the catchment, to the catchment outlet. The various physical processes that act on solute transported along these pathways may be quantified appropriately by use of relevant solute travel time distributions for each water subsystem that the pathways cross through the catchment. Such distributions capture the physical solute travel time variability from source to catchment outlet and its effects on reactive pollutant transport. Results of this thesis show specifically that neglect of such physical solute travel time variability in large-scale models of nitrogen transport and attenuation in catchments may yield misleading model estimates of nitrogen attenuation rates. Results for nitrogen abatement optimization in catchments further indicate that inefficient solutions for coastal nitrogen load reduction may result from simplifying physical transport assumptions made in different catchment-scale nitrogen transport-attenuation models. Modeling of possible future nitrogen management scenarios show also that slow nitrogen transport and reversible mass transfer processes in the subsurface water systems of catchments may greatly delay and temporally redistribute coastal nitrogen load effects of inland nitrogen source abatement over decades or much longer. Achievement of the national Swedish environmental objective to reduce the anthropogenic coastal nitrogen loading by 30% may therefore require up to a 40% reduction of both point sources, for achieving a fast coastal load response, and diffuse sources, for maintaining the coastal load reduction also in the long term.
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| 19. |
- Mård Karlsson, Johanna, 1979-
(författare)
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Arctic Water System Change and its Interactions with Permafrost and Ecosystem Changes
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Climate change and various changes in the landscape itself, such as permafrost thaw, may trigger and mediate substantial changes in the inland water system of the Arctic. Many climate change responses in the Arctic landscape and ecosystems are then related to alterations in the hydrological system. The nature of all these change interactions is not well understood. This thesis aims to improve our understanding of changes in the Arctic inland water system and their interactions with permafrost and ecosystem changes. Investigation of the spatial coverage of systematic hydrological monitoring data and observation data for hydro-climatically related ecosystem shifts, such as large-scale lake-area change, shows that this overlap is small. Yet some monitoring hotspot areas exist, where such data overlap and can be used to improve our understanding of linked hydrological, permafrost and ecosystem changes in the Arctic under climate change. Analysis of lake-change patterns in such hotspot areas indicates permafrost thaw as a main change driver/mediator of some change patterns. However, clear indication of basin-wide influence of permafrost thaw on hydrological discharge dynamics was only found in two relatively small out of total six investigated permafrost basins of different scales. Further, both permafrost and non-permafrost basins exhibit large-scale lake-area changes. A salient change pattern emerging across all investigated basins is an opposite direction of runoff change to that of precipitation change. This contrast is explainable by apparent evapotranspiration changes that may be due to observed changes in surface water (lake) area and associated water-storage changes. Patches of local lake-area change can thus add up to considerable large-scale effects on evapotranspiration and runoff changes. Overall, this thesis shows that linking water system change to permafrost and ecosystem changes is essential for advancing our understanding of Arctic environmental change.
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| 20. |
- Persson, Klas, 1979-
(författare)
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Quantifying pollutant spreading and the risk of water pollution in hydrological catchments : A solute travel time-based scenario approach
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The research presented in the thesis develops an approach for the estimation and mapping of pollutant spreading in catchments and the associated uncertainty and risk of pollution. The first step in the approach is the quantification and mapping of statistical and geographical distributions of advective solute travel times from pollutant input locations to downstream recipients. In the second step the travel time distributions are used to quantify and map the spreading of specific pollutants and the related risk of water pollution. In both steps, random variability of transport properties and processes is accounted for within a probabilistic framework, while different scenarios are used to account for statistically unquantifiable uncertainty about system characteristics, processes and future developments. This scenario approach enables a transparent analysis of uncertainty effects that is relatively easy to interpret. It also helps identify conservative assumptions and pollutant situations for which further investigations are most needed in order to reduce the uncertainty. The results for different investigated scenarios can further be used to assess the total risk to exceed given water quality standards downstream of pollutant sources. Specific thesis results show that underestimation of pollutant transport variability, and in particular of those transport pathways with much shorter than average travel times, may lead to substantial underestimation of pollutant spreading in catchment areas. By contrast, variations in pollutant attenuation rate generally lead to lower estimated spreading than do constant attenuation conditions. A scenario of constant attenuation rate and high travel time variability, with a large fraction of relatively short travel times, therefore appears to be a reasonable conservative scenario to use when information is lacking for more precise determination of actual transport and attenuation conditions.
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| 21. |
- Shibuo, Yoshihiro, 1976-
(författare)
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Modelling water and solute flows at land-sea and land-atmosphere interfaces under data limitations
- 2007
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Water and vapour flows from land to sea and the atmosphere are important for water resources, coastal ecosystems and climate. This thesis investigates possible methods for modelling these flows under often encountered unmonitored hydrological conditions and data limitations. Two contrasting types of drainage basin and associated data limitation/availability cases are considered: the Swedish unmonitored near-coastal catchment areas Forsmark and Simpevarp, for which detailed spatial but not much temporal variability data is available; and the much larger Aral Sea Drainage Basin (ASDB), for which spatial hydrological information is limited, while there is relatively well-known temporal change occurring in the Aral Sea itself and in the land and water use of the region over the last 50 years.The hydrologic modelling for the Forsmark and Simpevarp catchment areas showed that the relatively large focused stream flows, and the mean values and total sums of the diffuse small stream-groundwater flow fields in between the large stream flows from land to sea are largely constrained by the catchment hydrological balances and relatively robust and certain to estimate. The ASDB hydrologic modelling indicated an evapotranspiration return flow to the atmosphere from the irrigation water input on irrigated land that is much higher than previous estimates in atmospheric modelling, implying possible considerably larger than previously estimated non-local water and climate effects of the world’s irrigated areas. The more detailed groundwater-seawater dynamics modelling carried out for the coastal parts of the ASDB showed that regional topography and bathymetry largely influence coastal water fluxes during sea level lowering, with the Aral Sea shrinkage decreasing the seawater intrusion risk into the coastal groundwater considerably more for steeper than for flatter coastal topography parts of the region.
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