phd thesis on hydrobiology

 
     – From early warning to early action
     Gabriela Guimarães Nobre (2019), PhD thesis, VU University, Amsterdam, 286 pp.
The main objective of this thesis is to improve the understanding on links between climate variability and weather-related impacts of both floods and droughts. This relationship is investigated from global to regional scales, and at different lead times, with the purpose of achieving an impact-based forecast that can guide the implementation of early actions effectively before a potential drought or flood materializes.
   This thesis highlights some key challenges and topics that require further investigation in future research. For instance, it suggests that in order to improve the understanding of the impacts of climate variability, research is required regarding the dynamics of climate variability. It also proposes that for improving the understanding on the impacts of climate variability, better data and an investigation on the relationships between human and natural systems is needed. Moreover, this thesis indicates that future studies can enhance impact-based forecasting by improving the forecasting skill and lead-time of indices of climate variability, and by combining the forecast of indices of climate variability with socioeconomic impacts of floods and droughts. Lastly, further research can be performed to identify the underlying interests and incentives that are relevant to stakeholders for mainstreaming DRR into flood and drought risk management and policies, in combination with exploring the benefits of acting early. This thesis advances the understanding on links between climate variability and weather-related impacts of both floods and droughts, which can be used for generating impact-based forecasting and triggering early action.

     – Understanding climate change impacts and challenges across different spatial scales
     René R. Wijngaard (2019), PhD thesis, Utrecht University, Utrecht, 192 pp.
Ongoing global warming has resulted in a widespread retreat of glaciers since the end of the Little Ice Age. To attribute the response of glaciers to natural and anthropogenic historical climate change over time a spatially-distributed coupled glacier mass balance and ice-flow model is developed and applied that does not require a priori information about the flowline geometry of glaciers. The model is applied for the debris-covered Langtang Glacier in the Central Himalayas and the clean-ice Hintereisferner in the European Alps from the end of the Little Ice Age (1850) to the present-day (2016). The model is forced with four bias-corrected climate models that represent region-specific cold-dry, cold-wet, warm-dry, and warm-wet climate conditions. To isolate the effects of human-induced climate change on glacier mass balance and dynamics, runs are selected from the climate models with and without further anthropogenic forcing after 1970 until 2016. The model outcomes reveal that both glaciers experience the largest reduction in area and volume under warm climate conditions and that simultaneously with changes in glacier area and volume, surface velocities generally decrease over time. Without further anthropogenic forcing the analysis reveals that the decline in glacier area and volume is smaller, indicating that the response of the two glaciers can mainly be attributed to anthropogenic climate change. Here, a debris-covered glacier shows a limited retreat and tends to lose less mass due to insulation of the glacier surface by a layer of supraglacial debris, where a clean-ice glacier responds faster to climate change and shows a larger retreat. 

     – Development, testing, and application of a framework for model coupling across scales
     Jannis Michael Hoch (2019), PhD thesis, Utrecht University, Utrecht, 161 pp.
Flooding due to rivers exceeding their bankfull capacity was, is, and will be a major contributor to global flood risk, imperilling economic and societal development of often vulnerable communities. To fathom the current situation but especially to plan mitigation and adaption measures in the light of climate change and changes in flood risk, computer models simulating flood-triggering processes can provide the basis for decision-making and policy-making. Since riverine flooding is a global issue, yet with locally varying dynamics, trends, and developments, employing models covering the entire terrestrial surface can facilitate detecting hotspots of flood risk, analysing climate change scenarios, and decision-making in data-sparse areas.

Even though global and large-scale inundation modelling as well as the development of relevant modelling tools such as Global Flood Models (GFMs) has been advancing rapidly in the last decade, there still lie challenges ahead. For instance, most GFMs employ either hydrologic or hydrodynamic models as computational core, expediting some applications while impeding others. Hydrologic models are designed to simulate the components of the (terrestrial) water cycle but employ simple approximations of the complex Saint–Venant shallow flow equations. Hydrodynamic models, on the other hand, solve higher-order approximations, but typically depend on observed data as model forcing. Besides, hydrologic and hydrodynamic models applied within GFMs differ in their spatial resolutions with the latter employing finer scales, allowing for a better representation of topographical features. In a nutshell, each GFM has its own distinct strengths depending on the development choices made, making them suitable for some applications and less so for others. In this thesis, the author investigates how those strengths of different GFMs can be integrated in a flexible and efficient way to compensate for model-specific shortcomings of other GFMs, yielding synergetic effects. To that end, spatially explicit and online coupling – that is, on a grid to grid basis and at the (sub)time step level – between models was established.

       
     − The Case of Lower Paraná Delta, Argentina
     Verónica Zagare (2018), PhD thesis, Delft University of Technology, Delft, 236 pp.
The Parana River is the third largest river in the American continent, after the Mississippi and the Amazon. Instead of flowing directly to the sea, it flows to the Rio de la Plata (located between Argentina and Uruguay) through a complex delta system. This delta is a large and heterogeneous territory that spreads over three provinces of Argentina and that is characterized by different dichotomies along its extension. On the one hand, the islands of the delta are young alluvial lands in constant transformation due to the processes of sedimentation, and are subjected to pulses of floods influenced by the Paraná River streamflow, droughts, precipitations and strong southeastern winds coming from the Atlantic Ocean. Although these alluvial territories seem to be pristine, they have been moderately altered as a result of the development of economic activities. On the other hand, along the edges of the delta, we find the older territories of the mainland, created in the Pleistocene and less dynamic. Here is a network of cities of dissimilar sizes, that establishes the wealthiest corridor of the country. This delta shows a contrast between the wild and dynamic condition of the islands and the more stable but strongly urbanized edges. There are oppositions regarding economic, policy and social realms, expressed through a polarized, unsustainable and unplanned land use, which turns the area into a vulnerable place, given the uncertain context of climate change.

Urbanizing deltas are subjected to pressures related to urban growth and climate change, within a context of uncertainty and unpredictability. Those pressures interact at multiple scales and temporalities, affecting the components of the systems, as well as the relations between them and with the environment. This complexity reveals the need for the society (including governments, institutions, civil organizations, academia, etc.) to enhance the adaptability of the system of the delta, in order to cope with changes without losing their substantial characteristics. This research is focused on the study of the complexity of self-organizing processes that emerge in metropolitan areas located in (or near) delta territories, in order to link climate adaptation with urban development from an actor-oriented perspective.

 
     Wisam Khadra (2017), PhD thesis, Delft University of Technology, Delft, 211 pp.
Coastal aquifer management has recently emerged as a main scope in groundwater hydrology, especially in arid and semi-arid zones. About two thirds of the human population are currently gathered close to shorelines relying on coastal groundwater resources. Worldwide, these systems are subject to quality deterioration due to a multitude of anthropogenic impacts and subsequent saltwater intrusion (SWI). Many hydrological and hydrochemical features of SWI have been disclosed during the past century through numerous case studies, column studies, scale models, flow and reactive transport modeling. Yet, many scientific and engineering challenges remain, some of which need to be addressed for a better prospecting of future coastal freshwater reserves.
The scope of this thesis is to contribute to the analysis and remediation of SWI by studying the following aspects: (1) response of carbonate aquifers with varying Ca/Mg content to SWI, (2) behavior of trace elements (TEs) where fresh and intruded seawater mix, (3) derivation of groundwater baseline levels in polluted settings, notably salinized aquifers, (4) identification and quantification of major hydrogeochemical processes stimulated by SWI, (5) reliability of complex models (especially in karst) with variable-density and solute transport formulations, and (6) feasibility of SWI mitigation strategies. A structured multifaceted approach to analyze and manage SWI in coastal aquifers from detection to remediation is then provided. It was expanded based on the overall outcome of this research. The proposed tools and methods were successfully applied to a stressed dolomitic limestone aquifer system in Lebanon (Eastern Mediterranean), suffering from salinization and other minor anthropogenic impacts, such as inputs from sewage effluents and agricultural processes. The potential of managed aquifer recharge (MAR) and in particular river bank filtration (RBF) is explored as well, for Lebanon in broad lines, and for the study area, as a karst example.

     − The role of social learning for resilience building in urban water services
     Åse Johannessen (2017), PhD thesis, Lund University, Lund, 115 pp.
The development of cities is increasingly threatened by a worldwide water crisis. Urban water services (including drinking water, sanitation and drainage) are facing complex and multiple pressures, which are becoming increasingly frequent and severe. These pressures include floods, and the depletion, pollution and degradation of water resources and their associated ecosystems. These diverse pressures fall mainly within the domains of flood risk and water resources management: two working fields that are divided by different institutional structures, approaches and practices. Social learning is becoming increasingly popular as an approach that has the potential to “bridge” these silos, and ultimately, contribute to building resilience in urban water services. However, empirical analyses on this issue are rare and fragmented. Against this background, this thesis investigates the role of social learning for resilience building in urban water services. It is based on single and multiple case studies from the urban areas of Cali (Colombia), Cebu (The Philippines), Durban (South Africa), Gorakhpur (India) and Kristianstad (Sweden). The results identify challenges to the integration of the identified silos, what resilience means for urban water services, and the key elements of social learning that can support or inhibit urban water resilience. The results provide important input for new theory, policy and practice related to the United Nations’ Sustainable Development Goals (SDGs), the Sendai Framework for Disaster Risk Reduction and national policies on sustainable water management, risk reduction and climate change adaptation.

 
     − A field and modelling study of dedicated aquifer storage and recovery configurations in brackish-saline aquifers
     Koen Zuurbier (2016), PhD thesis, Delft University of Technology, Delft, 219 pp.
The general objective of this study is to quantify and increase the performance (recovery efficiency) of relatively small-scale Aquifer Storage & Recovery (ASR) systems in areas with brackish-saline groundwater, taking into account recently developed well configurations for performance optimization. A meaningful a priori indication of the ASR performance can be obtained by existing performance estimation methods, which have therefore been included in a mapping tool to identify potential and unviable ASR sites. Application of this mapping tool in the coastal Westland-Oostland area in the Netherlands highlighted that the predicted ASR performance in coastal areas can be spatially highly ariable. There is a potential increase in recovery efficiency that can be attained by implementing dedicated well configurations at ASR systems in brackish-saline aquifers.
The findings in this thesis provide important means to achieve a local, self-reliant freshwater supply in especially coastal areas using temporally available freshwater sources via ASR. In these areas, which suffer most from decreasing freshwater availabilities and growing demands, ASR can now become a viable cost-effective freshwater management option, whereas it was previously neglected due to the limited success of conventional ASR systems.

     – an exploration of peat origin and land use effects
     Karlijn Brouns (2016), PhD thesis, Utrecht University, Utrecht, 190 pp.
Peat is formed in wet and acidic conditions, where net primary production exceeds the decomposition of organic matter. Peatlands cover a small part of the earth surface but hold vast amounts of carbon. Land use change and climate change can turn this large carbon sink into a carbon source, thereby generating a positive feedback for climate change. The peatlands in the Netherlands have a long history of drainage to facilitate agriculture. The downside of these practices is the oxidation of the organic soil, which leads to subsidence and associated desiccation of nature reserves, emission of greenhouse gasses, deterioration of surface water quality, increasing costs for water management and infrastructural maintenance, damage to building foundations, and, in the end, loss of the characteristic landscape. In this thesis, the effects of climate change on the decomposition of peat soils in the Netherlands are explored, focussing on the effects of summer drought and salinisation on peat decomposition. Throughout this research, the distinction is made between peat that was formed in minerotrophic versus oligotrophic conditions (fen and bog peat) and between two types of land use (agriculture and nature management). Because of climate change, it is expected that dry summers will occur more often. We showed that oxygenation of deep peat layers that had not previously been exposed to air led to acceleration of decomposition; moreover, this effect is still measurable in the period after such a dry summer. During dry summers, surface water originating from rivers or lakes is supplied to peat areas to prevent drying out of the soils and limit decomposition. However, during prolonged summer droughts, the river water has a poor quality and may become slightly brackish because of saltwater intrusion and evaporation. We showed that salinisation reduced aerobic decomposition rates and water quality deteriorated. Unexpectedly, no uniform effect of land use or peat origin on respiration rates was found. Subsidence rates were modelled for various case study areas and adaptations measured were explored with local stakeholders, resulting in several options for adaptive peatland management. For instance, freshwater storage and subsurface drainage could reduce the effects of summer droughts. Ploughing and the cultivation of deeply rooting crops should be minimised. Furthermore, it was recommended to stop adapting groundwater levels to the subsiding soil surface level in order to make a gradual transition to peatland regions with virtually no subsidence, which could result in profitable agricultural businesses with lower societal costs, less greenhouse gas emissions and better water quality.

     Joost Delsman (2015), VU University Amsterdam, Amsterdam, 194 pp.
Saline groundwater exfiltration is a common problem in the coastal zone of the Netherlands, but the hydrological processes and physiographic factors that affect this are not fully understood. The research presented in this thesis aims to identify the processes and physiographic factors controlling the spatial variability and temporal dynamics of the exfiltration of saline groundwater to surface water, and hence the contribution of saline groundwater to surface water salinity.
Topics covered include a paleo-hydrogeological model simulation of the Holocene evolution of groundwater salinity as a result of paleo-geographic changes; surface water salinity dynamics in a densely-drained lowland catchment; hydrograph separation in an agricultural catchment; observations of heads, flow, solute concentration and temperature to constrain a detailed, variable-density groundwater flow and transport model; and a model to simulate the salinity dynamics of exfiltrating groundwater to support operational water management of freshwater resources in coastal lowlands. The thesis further outlines the implications of these findings for freshwater management in the Netherlands. It demonstrates that the salinity of groundwater exfiltrating in polders in the Netherlands, and hence surface water salinity, varies on a wide range of spatial and temporal scales.

 
     Pieter S. Pauw (2015), PhD thesis, Wageningen University, Wageningen, 168 pp.
Freshwater lenses are convex bodies of fresh groundwater that are underlain by groundwater with a significant higher salinity. In coastal areas, freshwater lenses are of vital importance for ecosystems and freshwater supply. A major problem of sustaining freshwater supply from freshwater lens is saltwater intrusion, i.e., the invasion of saline groundwater into a fresh groundwater body. In many coastal areas saltwater intrusion has led to well closure and reduced freshwater supply. Furthermore, in the future saltwater intrusion is expected to increase due to sea level rise, climate change, land subsidence, and increasing population density in coastal areas. In the Netherlands, these stresses will also have a severe impact on the fresh coastal groundwater reserves. In view of this, a research project aimed at (1) Improving the insight into the modeling of freshwater lenses and (2) defining measures to increase freshwater supply from freshwater lenses.

     – Impacts of heterogeneity, thermal interference and bioremediation
     Wijbrand Sommer (2015), PhD thesis, Wageningen University, Wageningen, 206 pp.
Aquifer thermal energy storage (ATES) is applied world-wide to provide heating and cooling to buildings. Application of ATES, instead of traditional heating and cooling installations, reduces primary energy consumption and related CO2 emissions. Intensified use of the subsurface for thermal applications requires more accurate methods to measure and predict the development of thermal plumes in the subsurface related to thermal interference between systems and address issues concerning subsurface urban planning and wide spread presence of contaminants in urban groundwater systems.

In this thesis, subsurface heat transport in ATES and the influence on storage performance for thermal energy was assessed. Detailed monitoring of subsurface temperature development around the wells of an existing system was achieved by a unique application of Distributed Temperature Sensing (DTS) using glass fibre optical cables. The measurements reveal unequal distribution of flow rate over different parts of the well screen and preferential flow due to aquifer heterogeneity. Heat transport modelling shows that heterogeneity causes preferential flow paths that can affect thermal interference between systems, mainly depending on well-to-well distance and hydrogeological conditions.

At present, design rules are applied in such way that all negative interference is avoided. This method shows that it is cost-effective to allow a limited amount of thermal interference, such that 30–40% more energy can be provided than compared to the case in which all negative thermal interference is avoided.

Because many urbanized areas deal with contaminated soil and groundwater, groundwater movement induced by the ATES system can result in increased mobility and spreading of these contaminants. However, the combination between ATES and soil and groundwater remediation could be a promising integrated technique, both for improving groundwater quality and development of ATES. Opportunities to use ATES as a continuous biostimulation tool for enhanced reductive dechlorination (ERD) have been explored with a reactive transport model.

     – Improving simulations of flood and drought in large river basins
     Niko Wanders (2015), PhD thesis, Utrecht University, Utrecht, 320 pp.
The aim of this thesis is to assess the different sources of uncertainty in model simulations of hydrological extremes. Uncertainty in observations, model parameterization, model states and other components are dealt with at scales ranging from large-scale river basins to global scale hydrology.

     Jan Verkade (2015), PhD thesis, Delft University of Technology, Delft, 193 pp.
Flood early warning systems provide a potentially highly effective flood risk reduction measure. The effectiveness of early warning, however, is affected by forecasting uncertainty: the impossibility of knowing, in advance, the exact future state of hydrological systems. Early warning systems benefit from estimation of predictive uncertainties, i.e. by providing probabilistic forecasts. The present dissertation describes research in estimating the value of probabilistic forecasts as well as in skill improvement of estimates of predictive uncertainty.

     Marjolein J.P. Mens (2015), PhD thesis, Universiteit Twente, Enschede, 181 pp.
Despite structural measures to prevent flooding and water shortage, 100% protection can never be provided. Therefore, over the past decades, water management has shifted to a risk-based approach. This means that policies do not only aim at reducing the probability of occurrence of floods and droughts, but also include actions to limit the consequences of potential flooding or water shortage. Both types of measures may aid to reduce flood and drought risk to an acceptable level.

This thesis contributes to decision making in flood and drought risk management by developing and testing an additional decision criterion. A robustness analysis method supports the assessment of impacts from extreme events, and is applicable on flood and drought risk systems. A robustness perspective supports decision makers in exploring low-probability/high-impact events and considering whether these impacts are societally acceptable. Quantifying robustness inspires the development of strategies that reduce flood and drought risk in a way that disasters are avoided.

     – Public Perceptions, Politcal Narratives and Traditional Beliefs Surrounding Water and Scarcity in an Arid Region
     Francesca de Châtel (2014), PhD thesis, Radboud University Nijmegen, 193 pp.
The Jordan River has been reduced to 2% of its historic size and is heavily polluted. Across Syria, rivers are shrinking, springs have dried up, and the desert is spreading. The water crisis in the Middle East, the most water-scarce region in the world, is rapidly worsening, yet decision-makers appear unwilling to acknowledge its severity and water remains low on the political agenda. How can this gap between the reality of growing scarcity on the ground and the continued illusion of plenty be explained?

This is one of the key questions Francesca de Châtel explores in «Vanishing Water Landscapes in the Middle East», a study that combines extensive study on the ground in pre-conflict Syria and across the region with historic data to show how high population growth, overambitious agricultural development projects and uncontrolled water use over the last 60 years have irreversibly disrupted the Middle East's fragile ecological balance.

  – Preferential groundwater discharge through boils and interactions between thin rainwater lenses and upward saline
        seepage
     Perry de Louw (2013), PhD thesis, VU University Amsterdam, 202 pp.
More than 50% of world’s population lives in coastal areas and is largely dependent on fresh groundwater resources for domestic, agricultural and industrial purposes. However, in many coastal areas, groundwater is brackish to saline which may pose problems for the sustainable exploitation of fresh groundwater. In low-lying coastal areas that lie below mean sea level, saline groundwater may reach the surface by upward groundwater flow. This process is referred to as «saline seepage» and is the main subject of this PhD thesis. Saline seepage leads to the salinization of surface waters, shallow groundwater and soil water in the root zone. Climate change and future rise in sea level are expected to increase saline seepage and reduce the availability of both fresh surface water and groundwater. Predicting effects of future changes, defining effective water management strategies for a climate proof sustainable freshwater supply and successful implementation of any measure are only meaningful when all relevant processes involving saline seepage are fully understood. This thesis describes the spatial variability and temporal dynamics of salinization processes involving saline seepage in deltaic areas. The research focused on the preferential saline seepage through boils leading to surface water salinization (Part I) and the interaction between thin rainwater lenses and saline seepage leading to the salinization of shallow groundwater and the root zone (Part II). These two processes were identified as important contributors to the salinization of the Dutch delta which was the study area of this PhD research.

 
     Yoshihide Wada (2013), PhD thesis ( ), Utrecht University, Utrecht, 470 pp.
Over past decades, terrestrial water fluxes have been affected by humans at an unprecedented scale and the fingerprints that humans have left on Earth’s water resources are turning up in a diverse range of records. In this thesis, a state-of-the-art global hydrological model (GHM) and global water demand model were developed and eventually coupled to quantify and distinguish human and climate impacts on surface freshwater and groundwater resources. The thesis is composed of three major parts: Part 1. Human and climate impacts on surface freshwater resources; Part 2. Global assessment of groundwater resources; Part 3. Integrated modeling and indicators of global water resources.

The thesis first explores the human and climate impacts on seasonal surface freshwater resources by forcing the global hydrological model PCR‐GLOBWB with daily meteorological fields and by calculating global monthly water demands with the effects of socio-economic and land use change. Increased water demand was found to be a decisive factor for heightened water stress in various regions, while climate variability is often a main determinant of extreme events. Over Europe, North America and Asia, severe hydrological drought conditions are driven by increasing consumptive water use rather than to be merely induced by climate variability; the magnitude of droughts intensified by 10–500%.

Next, the thesis assesses global groundwater resources by estimating groundwater recharge and abstraction. Global groundwater depletion was found to triple in size over the last 50 years, and contributes ~20% to irrigation water supply. Groundwater stress was then assessed using newly developed indicators considering groundwater contribution to environment. The global groundwater footprint was found to be 3.5 times the actual area of aquifers driven by a few heavily overexploited aquifers. The aquifer stress indicator revealed that ~8% of transboundary aquifers are currently stressed due to human overexploitation. Importantly, groundwater depletion was found to be an important contributor to sea-level rise and is likely to dominate over those of other terrestrial water sources. The contribution of groundwater depletion to sea-level increased by more than ten-fold over 1900–2000, and is projected to increase further by 2050.

In the final part of this thesis, an improved modeling framework that dynamically simulates daily water use per source per sector was developed. Human impacts on terrestrial water storage signals were evident in the validation with GRACE satellite observation, altering the seasonal and inter-annual variability over heavily regulated and intense irrigated basins. The newly developed model together with other six state-of-the-art GHMs was applied to simulate future irrigation water demand using the latest CMIP5 climate projections. The increase in irrigation demand varies substantially depending on the degree of global warming and associated regional precipitation changes. GHM dominates the uncertainty throughout the century, but GCM uncertainty substantially increases from the mid-century. To comprehensively assess global water resources, an improved approach was introduced. The Green Water Stress Index is capable of reproducing varying degrees of green water stress conditions, reflecting a multi-decadal climate variability. The Blue Water Sustainability Index revealed an increasing trend of water consumed from nonsustainable surface water and groundwater resources (~30%) worldwide.

       Hylke E. Beck (2013), PhD thesis, VU University Amsterdam, 122 pp.
, the , and the , rather than restricting oneself to case studies in comparatively small homogeneous regions. The aim is to move away from the reporting of the idiosyncrasies of single sites or catchments which has dominated so much of the older hydrological literature, and instead attempt to identify robust, generalizable relationships applicable to different environments worldwide.

     Eddy J. Moors (2012); PhD thesis, VU University Amsterdam, Amsterdam, 291 pp.
Forests are complex ecosystems with a large variability in the horizontal as well as in the vertical space. To study the dissimilarities in water use for different forest types, the water and energy balance of five forest stands in the Netherlands were observed during periods varying from two years to more than 15 years. The main tree species of the stands were: Scots pine, poplar, oak, larch and at one site a mixture of pine, birch, beech and oak.
Under dry conditions the evaporation rate was mainly controlled by the opening and closing of the stomata. Overall the most important driver was the vapour pressure deficit.
For wet conditions it is shown that the evaporation at the end of the shower and just after the shower is much larger than often assumed. In most models this underestimation of the evaporation rate of intercepted water is compensated by an underestimation of the water storage capacity of the leaves.

     Daan Herckenrath (2012); PhD thesis, Technical University of Denmark, Kongens Lyngby, 168 pp.
Over the past decade geophysical methods have gained an increased popularity due to their ability to map hydrologic properties. Such data sets can provide valuable information to improve hydrologic models. Instead of using the measured geophysical and hydrologic data simultaneously in one inversion approach, many of the previous studies apply a Sequential Hydrogeophysical Inversion (SHI) in which inverted geophysical models provide information for hydrologic models. In order to fully exploit the information contained in geophysical datasets for hydrological purposes, a coupled hydrogeophysical inversion was introduced (CHI), in which a hydrologic model is part of the geophysical inversion. Current CHI-research has been focussing on the translation of simulated state variables of hydrologic models to geophysical model parameters. We refer to this methodology as CHI-S (State). In this thesis a new CHI-approach was developed, called CHI-P (Parameter), which applies coupling constraints between the geophysical and hydrologic model parameters.

     J.R. von Asmuth (2012); PhD thesis, Delft University of Technology, Delft, 228 pp.
Careful analysis of groundwater level fluctuations may reveal much of the functioning of systems, and of the effects of individual factors. This is shown by many, but practiced by too few, as traditional time series analysis theory and software are complex. In this thesis, a new method of time series analysis is presented. Its continuous time formulation fits existing physical-hydrologic theory and methods well. It is shown that groundwater level responses generally take the shape of simple distribution functions. This notion, combined with the program Menyanthes that was developed, enable the quick and easy analysis of large numbers of time series. The spatial patterns that emerge in the results of multiple models literally add another dimension to the technique. As time series models are usually accurate also, they may be valuable to every (eco)hydrologist.

     George Lutterodt (2012); PhD thesis, Delft University of Technology, Delft, 148 pp.
The deviation of bacteria transport and deposition patterns on grains in porous media from theory has resulted in the inability to accurately predict transport distances in aquifers, with consequences of polluting drinking water sources (springs, boreholes and wells). Due to the importance of Escherichia coli (E. coli) as an indicator of faecal contamination of drinking water supplies, this thesis research focused on their transport in saturated porous media. The objectives were to (i) study inter-strain and intra-strain attachment variability among multiple E. coli strains, (ii) characterize the distribution of sticking efficiencies within cell populations (iii) develop a methodology to measure minimum values of sticking efficiencies, and (iv) to assess the contribution of various cell properties on bacterial attachment to quartz grains. Most of this research was carried out under laboratory conditions (e.g. column and batch experiments), but a part of this work focused on the transport characteristics of E. coli strains isolated at the termination point of groundwater flow lines (springs) in Kampala, Uganda. The underlying hypothesis was that transport by a group of E. coli strains could possibly be characterized by a similar set of transport parameters.

     – Description, modeling and remote sensing application
     Fouad Alkhaier (2011); PhD thesis, ITC, University of Twente, Enschede, 162 pp.

     – Environmental and economic accounting, modelling and policy analysis
     Changbo Qin (2011); PhD thesis, ITC, University of Twente, Enschede, 186 pp.

– Spatial mapping of environmental and hydrological determinants
     in the Pangani and Upper Ewaso Ng’iro North River basins, Africa
     Jeniffer Kinoti Mutiga (2011); PhD thesis, ITC, University of Twente, Enschede, 202 pp.

     Ype van der Velde (2011); PhD thesis, Wageningen University, Wageningen, 176 pp.

     Martine Poolman (2011); PhD thesis, Delft University of Technology, Delft, 256 pp.
In redevelopment and redesign of small water structures local water governing institutions are increasingly required to and requesting that the planning processes are set up in a participatory manner. Decision making processes that are set-up to be participatory require stakeholders with different backgrounds, ideas, experiences and expertise to come together. Ideally they work collectively towards finding a solution to a problem situation. Because of their differences stakeholders often have different ideas about the problem situation and about the ways to solve it. Discussions take place and ideas are expressed in words or text as each stakeholder tries to explain his view of the situation and possible solution. Horace, however, wrote that »the mind is more slowly stirred by the ear than by the eye«. Visuals could provide a better understanding of a subject than words alone could. This PhD research looks at enabling stakeholders to make and use two-dimensional, still (non-moving) visuals to help identify which differences and similarities there are in stakeholders’ ideas of the problem situation and possible solutions. The main objective of this research was to design a methodology which enables stakeholders to make and use visuals to communicate their ideas about redevelopment and maintenance of small water structures.

     – Information theory, value of information, and public participation
    José Leonardo Afonso Segura (2010); PhD thesis UNESCO-IHE Institute for Water Education, Delft, 200 pp.
Monitoring networks provide data that is analysed to help managers make informed decisions about their water systems. Their design and evaluation have a number of challenges that must be resolved, among others, the restriction on having a limited number of monitoring devices. This book presents innovative methods to design and evaluate monitoring networks. The main idea is to maximise the performance of water systems by optimising the information content that can be obtained from monitoring networks. This is done through the combination of models and two theoretical concepts: Information Theory, initially developed in the field of communications, and Value of Information, initially developed in the field of economics. Additionally, the possibility of using public participation to gather information with mobile phones to improve models is also explored in the research. The results of this research demonstrate that monitoring networks can be evaluated and designed by considering new variables, such as the information content, the user of the information and the potential of current mobile phones for data collection.

     Rogier van der Velde (2010); PhD thesis, ITC, University of Twente, Enschede, 313 pp.

     Miriam Gerrits (2010); PhD thesis, Delft University of Technology, Delft, 146 pp.

     – Study of the Berau estuary, East Kalimantan, Indonesia
     Wiwin Ambarwulan (2010); PhD thesis, ITC, University of Twente, Enschede, 179 pp.

     Reinder Brolsma (2010); PhD thesis, Utrecht University, Utrecht, 160 pp
In temperate climates groundwater can have a strong effect on vegetation, because it can influence the spatio-temporal distribution of soil moisture and therefore water and oxygen stress of vegetation. Current IPCC climate projections based on CO emission scenarios show a global temperature rise and change in precipitation regime, which will affect hydrological and vegetation systems. This thesis provides a quantitative framework for studying eco-hydrology in groundwater influenced temperate ecosystems. This study shows that quantifying and understanding the response of temperate forest ecosystems to climate change requires combined physically-based hydrological and bio-physically-based vegetation models.

     – A remote sensing based study at the source basin of the Upper Blue Nile River
     Alemseged Tamiru Haile (2010); PhD thesis, ITC, University of Twente, Enschede, 229 pp.

     Ruud Bartholomeus (2010); PhD thesis, VU University Amsterdam, Amsterdam, 128 pp.
In order to improve vegetation predictions for the future climate, process-based and climate-proof relationships between site factors and vegetation are needed. This thesis addresses the development of climate-proof relationships between soil moisture conditions and vegetation, and shows that the use of correlative, indirect relationships between site factors and vegetation should be discouraged. The effect of climate change on moisture-related plant stresses is complex; both wet and dry extremes may be affected, and conditions that are not present under the current climatic conditions could occur in the future. In order to capture such effects, climate-dependent processes that directly affect vegetation should be analysed. By providing such analysis, this research contributes to one of the required improvements of habitat distribution models.

– A study in a semi-arid area
     Loes van Schaik (2010); PhD thesis, Utrecht University, Utrecht, 174 pp.
Desertification and landscape degradation is a worldwide problem, which is expected to grow in time due to unsustainable land use and climate change. In view of these problems, knowledge of the interaction between vegetation, soil moisture and surface runoff, with subsequent erosion risk is essential. This requires mapping of the spatial and temporal variability of infiltration and runoff production. The influence of preferential flow thereupon is nowadays widely recognized. Therefore in this thesis the role of preferential flow from plot scale to catchment scale on the hydrology is investigated, using field measurements and model applications.

     Aart Overeem (2009); PhD thesis, Wageningen University, Wageningen, 144 pp.
Extreme rainfall events can have a large impact on society and can lead to loss of life and property. Therefore, a reliable climatology of extreme rainfall is of importance, for instance, for the design of hydraulic structures. Such a climatology can be obtained by abstracting maxima from long rainfall records. Subsequently, a probability distribution is fitted to the selected maxima, so that rainfall depths can be estimated for a chosen return period, which can be longer than the rainfall record. In this thesis, the Generalized Extreme Value (GEV) distribution is used to model annual rainfall maxima.

     Nico de Vos (2009); PhD thesis, Delft University of Technology, Delft, 149 pp.

     Schalk Jan van Andel (2009); PhD thesis, UNESCO-IHE Institute for Water Education, Delft, 182 pp.
Day-to-day water management is challenged by meteorological extremes, causing floods and droughts. Often operational water managers are informed too late about these upcoming events to be able to respond and mitigate their effects, such as by taking flood control measures or even requiring evacuation of local inhabitants. Therefore, the use of weather forecast information with hydrological models can be invaluable for the operational water manager to expand the forecast horizon and to have time to take appropriate action. This is called Anticipatory Water Management.
Anticipatory actions may have adverse effects, such as when flood control actions turn out to have been unnecessary, because the actual rainfall was less than predicted. Therefore the uncertainty of the forecasts and the associated risks of applying Anticipatory Water Management have to be assessed. To facilitate this assessment, meteorological institutes are providing ensemble predictions to estimate the dynamic uncertainty of weather forecasts. This dissertation presents ways of improving the end-use of ensemble predictions in Anticipatory Water Management.

     Hessel Winsemius (2009); PhD thesis, Delft University of Technology, Delft, 186 pp.
Important variables such as rainfall, evaporation, radiation, soil moisture and water storage can nowadays be estimated on the basis of raw satellite observations. This thesis describes the development and application of methods that allow to combine the scarce data, available in poorly gauged catchments, with expert knowledge and modern satellite data, with the purpose to conceptualise, calibrate and validate hydrological models.

     Ruud Hurkmans (2009); PhD thesis, Wageningen University, Wageningen, 196 pp.

     – Evaluation of field methods, process-based modelling, remote sensing and an integrated approach
     Johannes van der Kwast (2009); PhD thesis, ITC, University of Twente, Enschede, 159 pp.

     Ate Visser (2009); PhD thesis, Utrecht University, Utrecht, 188 pp.

     S. Hasan (2009); PhD thesis, Wageningen University, Wageningen, 97 pp.

     Diana Chavarro Rincon (2009); PhD thesis, ITC, University of Twente, Enschede, 159 pp.

     J. M. Schuurmans (2008); PhD Thesis, Utrecht University, Utrecht, 154 pp.
Integration of operationally available remotely sensed and forecasted hydrometeorological variables into distributed hydrological models

     Marloes Mul (2009); PhD thesis, UNESCO-IHE Institute for Water Education, Delft, 144 pp.
Ungauged catchments can be found in many parts of the world, but particularly in sub-Saharan Africa. Information collected in a gauged catchment and its regionalisation to ungauged areas is crucial for water resources assessment. Especially farmers in semi-arid zones are in need of such information. Inter and Intra-seasonal rainfall variability is large in these areas, and farmers depend more and more on additional surface and groundwater resources for their crop production. As a result, understanding the key-hydrological processes, and determination of the frequencies and magnitudes of stream flows, is very important for local food production. This is particularly true for the ungauged Makanya catchment in Tanzania, which is the subject of this study.

     – A case study in the São Francisco River basin, Brazil
     Antônio Heriberto de Castro Teixeira (2008); PhD thesis, ITC, University of Twente, Enschede, 257 pp.

     – The role of bedrock geometry and hillslope-stream interaction
     K. Shahedi (2008); PhD thesis, Wageningen University, Wageningen, 146 pp.

     – An integrated analysis of the hydrological cycle, climate change and agriculture
     Walter Immerzeel (2008); PhD Thesis, Utrecht University, Utrecht, 145 pp.

    
     A. Talebi (2008); PhD thesis, Wageningen University, Wageningen, 137 pp.

     – Analysis of retrospective simulations and future projections of soil moisture
     J. Sheffield (2008); PhD thesis, Wageningen University, Wageningen, 218 pp.

     – Measurement of evaporation and precipitation
     H. Leijnse (2007); PhD thesis, Wageningen University, Wageningen, 164 pp.

     A.J. Teuling (2007); PhD thesis, Wageningen University, Wageningen, 88 pp.

     A.J.W. de Wit (2007); PhD thesis, Wageningen University, Wageningen, 182 pp.

     Obolokile Thothi Obakeng (2007); PhD thesis, ITC, University of Twente, Enschede, 245 pp.

     K.M.P.S. Bandara (2006); PhD thesis, ITC, University of Twente, Enschede, 172 pp.

     – A case study in Cochabamba, Bolivia
     Carlos Saavedra (2005); PhD thesis, ITC, University of Twente, Enschede, 265 pp.

– Putting the promise into practice
     Leon Hermans (2005); PhD thesis, Delft University of Technology, Delft, 235 pp.
»The promise of actor analysis can only truly be fulfilled if water experts commit themselves to the exploration of new ways of supporting policy development, venturing along roads they have not travelled before.«

     Yasir Abbas Mohamed Ali (2005); PhD thesis, Delft University of Technology, Delft, 152 pp.

– in sandy aquifers under environmental pressure
     M.J.M. Vissers (2005); PhD Thesis Utrecht University, Utrecht, 142 pp.

     Mirmasoud Kheirkhah Zarkesh (2005); PhD thesis, ITC, University of Twente, Enschede, 273 pp.

     V.E.A. Post (2004); PhD thesis, Vrije Universiteit, Amsterdam, 138 pp.
The primary objective of Vincent Post’s thesis is to develop quantitative understanding of the processes that caused salinization of groundwater in the coastal area of the Netherlands during the Holocene under natural conditions.

     Hans Peter Broers (2002); PhD thesis Utrecht University, Utrecht, 229 pp.

     B.T. Gouweleeuw (2000); PhD thesis, Vrije Universiteit, Amsterdam, 184 pp.
Ben Gouweleeuw’s thesis investigates the interaction between land use change, climate variability and the regional hydrology in a semi-arid are ain Central Spain. The study has used passive microwave monitoring to investigate spatial variation in soil moisture and produced a model.

     C.J. Hemker (2000); PhD thesis, Vrije Universiteit, Amsterdam, 143 pp.
The focus of this work is deterministic models of saturated groundwater flow in layered aquifer systems. The term ‘layered aquifer system’ is used to denote two types of system: a) a system of multiple aquifers or multi-aquifer system which comprises a series of aquifers separated by confining layers, and b) a vertically heterogeneous, stratified or multi-layered aquifer which is a single aquifer composed of a number of sublayers. Analytical solutions for many different types of well flow in single aquifers are known and used for pumping test analysis, while only few solutions for two-aquifer systems are available. Pumping tests in the Netherlands have shown that sometimes four or more aquifers are involved. The lack of a proper solution for multi-aquifer systems was felt as an omission in well flow theory. The main objective of this study, therefore, was to develop analytical solutions that can be used for determining geohydrological properties from pumping tests in layered aquifer systems. The study was carried out in two separate periods. Flow in multi-aquifer systems was investigated during the years 1979 to 1986 and, more recently, the same solution method was further developed to investigate flow near wells in multi-layered aquifers.

     Joost Herweijer (1997); PhD thesis, VU University Amsterdam, Amsterdam, 277 pp.
This dissertation addresses the problem of adequately describing the hydraulic behavior of a heterogeneous aquifer, specifically the flow towards a well. Typically for a subsurface problem, the quantity of available data versus the number of unknowns, is very limited. Therefore, an adequate hydrogeological description still encompasses a range of possible aquifer responses. Thus, a broad approach has been followed to obtain a more or less, reliable estimation of the range of possible aquifer responses within a limited spectrum of sedimentological options. This broad approach includes the following methods: sedimentological analysis; multi-well and single-well pumping tests; tracer experiments; geostatistics; and numerical modeling of groundwater flow. Any application of only one of these methods can lead to a strongly biased and erroneous estimate of the range of aquifer responses. Thus, this dissertation aims at integrating and combining several direct and indirect methods to identify the aquifer’s structure and to analyze the associated groundwater flow and solute transport behavior. The final objective of this research is to characterize a heterogeneous aquifer in order to better describe contaminant flow; many of the findings are also applicable to the recovery of oil from heterogeneous reservoirs.

     G.H.P. Oude Essink (1996); PhD thesis, Delft University of Technology, Delft.
In this thesis the possible impact of sea-level rise and human activities on vulnerable coastal groundwater flow regimes in the Netherlands for the next millennium is investigated. The focus is on the distribution of fresh and saline groundwater, the volumes of freshwater lenses in the dunes and the seepage and salt load to polders. Since groundwater flow is a slow process, the consequences for the next thousand years are considered. A 2-D model simulating density-dependent groundwater flow and coupled solute transport model is used. The main result is that a severe (irreversible) salinisation process, which is generated by human activities such as the reclamation of the (low-lying) polders during the past centuries, already occurs in the groundwater flow regimes along the Dutch coast, independent of sea-level rise. It is to be expected that sea-level rise intensifies this salinisation process. Feasible countermeasures may, to some extent, retard (but not stop) this salinisation process. The impact of sea-level rise is also discussed in indicative terms for three water management sectors: (1) domestic and industrial water supply from coastal sand-dunes, (2) flushing of water courses of low-lying polders and (3) agriculture in terms of salt damage.

     M.J. Waterloo (1994); PhD thesis, Vrije Universiteit, Amsterdam, 478 pp.

     C. Maas (1994); PhD thesis, Delft University of Technology, Delft, 162 pp.
     (in Dutch) by Harry Boukes (1995) in , vol 1, nr 1, pp 64–65.

     W.J. Zaadnoordijk (1988); PhD thesis, University of Minnesota, Minneapolis, USA, 140 pp.

    
     L.A. Bruijnzeel (1983); PhD thesis, Vrije Universiteit Amsterdam, Amsterdam, 249 pp.

     A Systematic Study of Wave Propagation under Confined, Semiconfined and Unconfined Flow
     Conditions
     Garth S.J.P. van der Kamp (1973); PhD thesis, Vrije Universiteit, Amsterdam, 128
     pp.

BIO6002