The enhanced biological removal of phosphorus (EBPR) is a popular process due to high removal efficiency, low operational costs, and the possibility of phosphorus recovery. Nevertheless, the stability of the EBPR depends on different factors such as: temperature, pH, and the presence of toxic compounds. While extensive studies have researched the effects of temperature and pH on EBPR systems, little is known about the effects of different toxic compounds on EBPR. For example, sulphide has shown to inhibit different microbial activities in the WWTP, but the knowledge about its effects on EBPR is limited. Whereas the sulphide generated in the sewage can cause a shock effect on EBPR, the continuously exposure to sulphide potentially generated in WWTP can cause the acclimatization and adaptation of the biomass. This research suggests that sulphate reducing bacteria can proliferate in WWTP, as they are reversibly inhibited by the recirculation of sludge through anaerobic-anoxic-oxic conditions. The research enhances the understanding of the effect of sulphide on the anaerobic-oxic metabolism of PAO. It suggests that the filamentous bacteria Thiothrix caldifontis could play an important role in the biological removal of phosphorus. It questions the ability of PAO to generate energy from nitrate respiration and its use for the anoxic phosphorus uptake. Thus, the results obtained in this research can be used to understand the stability of the EBPR process under anaerobic-anoxic-oxic conditions, especially when exposed to the presence of sulphide.

This book provides an overview of facts, theories and methods from hydrology, geology, geophysics, law, ethics, economics, ecology, engineering, sociology, diplomacy and many other disciplines with relevance for concepts and practice of water resources management. It provides comprehensive, but also critical reading material for all communities involved in the ongoing water discourses and debates. The book refers to case studies in the form of boxes, sections, or as entire chapters. They illustrate success stories, but also lessons to be remembered, to avoid repeating the same mistakes. Based on consolidated state-of-the-art knowledge, it has been conceived and written to attract a multidisciplinary audience. The aim of this handbook is to facilitate understanding between the participants of the international water discourse and multi-level decision making processes. Knowing more about water, but also about concepts, methods and aspirations of different professional, disciplinary communities and stakeholders professionalizes the debate and enhances the decision making.

This book outlines the current status of water resources management in Central Asia countries, and provides a review of the history, policies and transboundary cooperation regarding water resources in the region. Particular attention is given to the water-energy-food-environmental nexus, and to the application of the UNECE Environmental Conventions in Central Asia. Readers will also learn about the US and German environmental policies applied in Central Asia, and will discover specific case studies on water resources policies in Kazakhstan, China, Kyrgyzstan, Uzbekistan, Tajikistan, Turkmenistan, and Afghanistan. Together with the companion volumes on Water Bodies and Climate Change in Central Asia and Water Resources Management in Central Asia, it offers a valuable source of information for a broad readership, from students and scientists interested in the environmental sciences, to policymakers and practitioners working in the fields of water resources policy and management, international relations, and environmental issues.

For integrated water resources management both blue and green water resources in a river basin and their spatial and temporal distribution have to be considered. This is because green and blue water uses are interdependent. In sub-Saharan Africa, the upper landscapes are often dominated by rainfed and supplementary irrigated agriculture that rely on green water resources. Downstream, most blue water uses are confined to the river channels, mainly for hydropower and the environment. Over time and due to population growth and increased demands for food and energy, water use of both green and blue water has increased. This book provides a quantitative assessment of green-blue water use and their interactions. The book makes a novel contribution by developing a hydrological model that can quantify not only green but also blue water use by many smallholder farmers scattered throughout the landscape. The book provides an innovative framework for mapping ecological productivity where gross returns from water consumed in agricultural and natural vegetation are quantified. The book provides a multi-objective optimization analysis involving green and blue water users, including the environment. The book also assesses the uncertainty levels of using remote sensing data in water resource management at river basin scale.

In The Netherlands, Belgium and other European countries, manganese is removed by conventional groundwater treatment with aeration and rapid (sand) filtration. Such a treatment process is easy to operate, cost effective and sustainable, because it does not make use of strong oxidants such as O3, Cl2, ClO2 and KMnO4 with the associated risk of by-product formation and over or under dosing. However, application of aeration-filtration is also facing drawbacks, especially the long ripening time of filter media. Due to the long ripening time, water companies have to waste large volumes of treated water, making this process less sustainable. Also, costs associated with filter media ripening (man power, electricity, operational and analysis costs) are high. Therefore decreasing the filter ripening time, regarding manganese removal is a big issue. Although already extended research has been carried out into manganese removal, the controlling mechanisms, especially of the start up face of filter media ripening, are not fully understood yet. The emphasis of this thesis is to provide a better understanding of the mechanisms involved in the ripening of virgin filter media, regarding manganese removal and how to shorten or completely eliminate the long ripening period of filters with virgin material. This thesis therefore highlights the role of the formation of a manganese oxide coating on virgin filter media. Characterization and identification revealed that the responsible manganese oxide for an effective manganese removal was Birnessite. It was found that Birnessite, formed at the beginning of the ripening process was of a biological origin. Based on the knowledge that manganese removal in conventional groundwater treatment is initiated biologically, long ripening times may be reduced by creating conditions favouring the growth of manganese oxidizing bacteria, e.g., by limiting the back wash frequency and / or intensity. Additionally, this thesis also shows that the use of freshly prepared manganese oxide, containing Birnessite, can completely eliminate filter media ripening time.

Throughout the ages, people have experienced the life-giving and healing forces in water. Water is integral to life, and surrounds us in nature and in our own bodies. But not all water is the same. Water can carry good energies, and bad energies. How can we understand water enough to know the difference? Theodor Schwenk, the renowned author of Sensitive Chaos, founded an institute for water research in the Black Forest in Germany. He developed the Drop Picture Method, which displays the characteristics of water clearly for the non-specialist. Today, the Institute continues his work and here presents momentous findings about the quality of our drinking water, groundwater, spring water and river water. Stunningly illustrated in colour, this book offers a unique insight into the world of water.

Water is intertwined in the daily life of humans in countless ways. The importance of water as a driver for health, food security, and quality of life and as a pillar for economic development is unique. As water affects human lives, the mankind also effects the hydrological cycle, in all dimensions from the local to the global scale. Food production accounts for 90% of water use in developing countries. Hydropower production evokes emotions; yet sustainable energy production is among cornerstones of economic development. The damages caused by floods and droughts are escalating all over the world. The human impacts on ecosystems are increasing as well. Water is largely a political good since a bulk of the mankind lives in river basins shared by two or more nations.
These complexities are approached in the book in depth. The analyses include consideration of how developments in seemingly unrelated processes and sectors such as globalisation, free trade, energy, security, information and communication revolutions, health-related issues such as HIV/AIDS, as well as emerging developments in sectors that are linked more conventionally to water, such as population growth, urbanisation, technological development, agriculture, infrastructure, energy, management of water quality and ecosystem health, are likely to affect water management in the future. For the first time, a pragmatic attempt is make to define a realistic framework for water management in 2020 with leading experts from different parts of the world as well as different disciplines.

Now in its second edition, Water Resources: An Integrated Approach provides students with a comprehensive overview of natural processes associated with water and the modifications of these processes by humans through climate change and land management, water-related health issues, engineering approaches to water and socio-economic processes of huge importance to water resources. The book contains chapters written by 24 specialist contributors, providing expert depth of coverage to topics. The text introduces the basic properties of water and its importance to society and the nature of the different regional imbalances between water resource availability and demand. It guides the reader through the changing water cycle impacted by climate and land management, water flows in river basins, surface water quality, groundwater and aquatic ecosystems, and covers the role of water in human health and associated hazards before turning to engineering solutions to water and wastewater treatment and reuse. The book deals with physical and social management strategies required for water resource planning, the economics of water and treatment of issues associated with conflict over water. The concept of virtual water is covered before the text concludes with a chapter considering the challenges of predicting future water issues in a rapidly changing world and where environmental systems can behave in a non-linear way. The need to work across disciplines to address challenges that are connected at both local and global scales is highlighted. Water Resources also includes global examples from both the developing and developed world. There are 58 case study boxes. Each chapter is supplemented with these case studies and with reflective questions, project ideas and further reading, as well as links to a glossary of terms. The book is richly illustrated throughout with over 160 full-colour diagrams and photographs. The text provides a novel interdisciplinary approach to water in a changing world, from an environmental change perspective and interrelated social, political and economic dimensions. It will be an indispensable guide to undergraduates studying water resources and management, geography of water, and water in the environment.

This work investigated two different approaches to optimize biological sulphate reduction in order to develop a process control strategy to optimize the input of an electron donor and to study how to increase the feasibility of using a cheap carbon source. Feast/famine regimes, applied to design the control strategy, were shown to induce the accumulation of storage compounds in the sulphate reducing biomass. This study showed that delays in the response time and a high control gain can be considered as the most critical factors affecting a sulphide control strategy in bioreactors. The delays are caused by the induction of different metabolic pathways in the anaerobic sludge, including the accumulation of storage products. On this basis, a mathematical model was developed and validated. This can be used to develop optimal control strategies. In order to understand the microbial pathways in the anaerobic oxidation of methane coupled to sulphate reduction (AOM-SR), diverse potential electron donors and acceptors were added to in vitro incubations of an AOM-SR enrichment at high pressure. Acetate was formed in the control group, probably resulting from the reduction of CO2. These results support the hypothesis that acetate may serve as an intermediate in the AOM-SR process.

This book presents an overview of copula theory and its application in hydrology, and provides valuable insights, useful methods and practical applications for multivariate hydrological analysis using copulas. In addition, it extends the traditional bivariate model to trivariate or multivariate models. The specific applications covered include the study of flood frequency analysis, drought frequency analysis, dependence analysis, flood coincidence risk analysis and statistical simulation using copulas. The book offers a valuable guide for researchers, scientists and engineers working in hydrology and water resources, and will also benefit graduate or doctoral students with a basic grasp of copula functions who want to learn about the latest research developments in the field.

The aim of this book is to contribute to understanding risk knowledge and to forecasting components of early flood warning, particularly in the environment of tropical high mountains in developing cities. This research covers a challenge, taking into account the persistent lack of data, limited resources and often complex climatic, hydrologic and hydraulic conditions. In this research, a regional method is proposed for assessing flash flood susceptibility and for identifying debris flow predisposition at the watershed scale. An indication of hazard is obtained from the flash flood susceptibility analysis and continually, the vulnerability and an indication of flood risk at watershed scale was obtained. Based on risk analyses, the research follows the modelling steps for flood forecasting development. Input precipitation is addressed in the environment of complex topography commonly found in mountainous tropical areas. A distributed model, a semi-distributed model and a lumped model were all used to simulate the discharges of a tropical high mountain basin with a paramo upper basin. Performance analysis and diagnostics were carried out in order to identify the most appropriate model for the study area for flood early warning. Finally, the Weather Research and Forecasting (WRF) model was used to explore the added value of numerical weather models for flood early warning in a paramo area.

Understanding and being able to predict fluvial processes is one of the biggest challenges for hydraulics and environmental engineers, hydrologists and other scientists interested in preserving and restoring the diverse functions of rivers. The interactions among flow, turbulence, vegetation, macroinvertebrates and other organisms, as well as the transport and retention of particulate matter, have important consequences on the ecological health of rivers. Managing rivers in an ecologically friendly way is a major component of sustainable engineering design, maintenance and restoration of ecological habitats. To address these challenges, a major focus of River Flow 2016 was to highlight the latest advances in experimental, computational and theoretical approaches that can be used to deepen our understanding and capacity to predict flow and the associated fluid-driven ecological processes, anthropogenic influences, sediment transport and morphodynamic processes. River Flow 2016 was organized under the auspices of the Committee for Fluvial Hydraulics of the International Association for Hydro-Environment Engineering and Research (IAHR). Since its first edition in 2002, the River Flow conference series has become the main international event focusing on river hydrodynamics, sediment transport, river engineering and restoration. Some of the highlights of the 8th International Conference on Fluvial Hydraulics were to focus on inter-disciplinary research involving, among others, ecological and biological aspects relevant to river flows and processes and to emphasize broader themes dealing with river sustainability. River Flow 2016 contains the contributions presented during the regular sessions covering the main conference themes and the special sessions focusing on specific hot topics of river flow research, and will be of interest to academics interested in hydraulics, hydrology and environmental engineering.

Many estuaries are located in urbanized, highly engineered environments. Cohesive sediment plays an important role due to its link with estuarine health and ecology. An important ecological parameter is the suspended sediment concentration (SSC) translated into turbidity levels and sediment budget. This study contributes to investigate and forecast turbidity levels and sediment budget variability at San Francisco Bay-Delta system at a variety of spatial and temporal scales applying a flexible mesh process-based model (Delft3D FM). It is possible to have a robust sediment model, which reproduces 90% of the yearly data derived sediment budget, with simple model settings, like applying one mud fraction and a simple bottom sediment distribution. This finding opens the horizon for modeling less monitored estuaries. Comparing two case studies, i.e. the Sacramento-San Joaquin Delta and Alviso Slough, a classification for estuaries regarding the main sediment dynamic forcing is proposed: event-driven estuary (Delta) and tide-driven estuary (Alviso Slough). In the event-driven estuaries, the rivers are the main sediment source and the tides have minor impact in the net sediment transport. In the tide-driven estuaries, the main sediment source is the bottom sediment and the tide asymmetry defines the net sediment transport. This research also makes advances in connecting different scientific fields and developing a managerial tool to support decision making. It provides the basis to a chain of models, which goes from the hydrodynamics, to suspended sediment, to phytoplankton, to fish, clams and marshes.

This book focuses on the river morphodynamics and stream ecology of the Qinghai-Tibet Plateau. The objective of the book is to summarize and synthesize the recent studies based on field surveys undertaken in the period 2007-2014. This book was written to serve as a graduate-level text for a course in river dynamics and stream ecology and as a reference text for engineers and researchers engaged in hydropower engineering, fluvial geomorphology and aquatic ecology. The first two chapters serve as an introduction of geomorphological characteristics as well as uplift and its impact on river morphology of the Qinghai-Tibet Plateau. Chapters 3-5 cover meandering rivers and cutoff, wetlands and wetland shrinkage,desertification and restoration strategies in the Sanjiangyuan region. Chapter 6 discusses the interaction between erosion and vegetation, and Chapter 7 characterizes the aquatic ecology of the Yarlung Tsangpo and the Sanjiangyuan region.

The push-pull test is a powerful site characterization technique that has been applied to a wide range of problems in contaminant hydrogeology. The theoretical and practical apsects of push-pull testing were initially developed to characterize groundwater acquifers but the method has now been extended to saturated and unsaturated soils and sediments as well as to surface water bodies. Dr. Istok and his collaborators have been instrumental in the development of these techniques and he is widely recognized as the world's leading expert push-pull testing. This is the only reference book available on this powerful method.

The Gezira Scheme is Sudan's oldest and largest gravity irrigation system. The scheme has played an important role in the economic development of the country, and is a major source of foreign exchange. The farming system of the Gezira Scheme is dominated by crop production. The main crops grown are sorghum, wheat, groundnut and the oilseed crop sesame. Sunflower (Helianthus annuus L.) is an important oil crop in the world and a new edible oil crop in Sudan. Knowledge of the effects of irrigation scheduling on sunflower production and water productivity under water stress conditions is becoming increasingly important. Irrigation scheduling is particularly important since many field crops are more sensitive to water deficit at specific phonological stages. Sunflower has several growth stages: emergence, vegetative, reproductive, flowering, seed formation and maturity. Water stress in each stage results in reduction in seed yield and oil content. The treatments in the test plots, which were conducted to study the effect of water stress at different growth stages, showed that sunflower was significantly affected by water stress that occurred in the sensitive flowering and seed formation stages. Highest seed yield was obtained when water stress was avoided during these stages. The AquaCrop model was used to simulate the seed yield and water productivity. The model was able to precisely simulate seed yield, but overestimated water productivity under different irrigation treatments.

This work explores coastal zones in the vicinity of tidal inlets, which are commonly utilized for navigation, sand mining, waterfront developments and fishing and recreation, are under particularly high population pressure and will only be exacerbated by foreshadowed climate change (CC). Although few recent studies have investigated CC impacts on very large tidal inlet systems, the nature and magnitude of CC impacts on the more commonly found small tidal inlets (STIs) remains practically un-investigated to date. The combination of pre-dominant occurrence in developing countries, socio-economic relevance and low community resilience, general lack of data, and high sensitivity to seasonal forcing makes STIs potentially very vulnerable to CC impacts. This study was undertaken to develop methods and tools that can provide insights on potential CC impacts on STIs, and to demonstrate their application to assess these CC impacts. Two process based snap-shot modeling approaches for data poor and data rich environments are used to assess CC impacts and an innovative reduced complexity model is developed to obtain rapid predictions of CC impacts on the STI's stability. Results show that STIs are unlikely to change their types, but that their stability level is likely to change under CC impacts. The main driver for the change is the future variations in wave directions, not SLR as is commonly thought.

The Enhanced Biological Phosphorus Removal (EBPR) process is a biological process for efficient phosphate removal from wastewaters through intracellular storage of polyphosphate by Phosphate-Accumulating Organisms (PAO) and subsequent removal through wastage of excess sludge. Although many studies have demonstrated the existence of different PAO clades, the functional differences among these clades and potential implications for the process performance remained unclear. Furthermore, the salinity effects on the EBPR process had not been properly investigated, which is necessary to assess its applicability for the treatment of saline wastewaters. The first part of the thesis focuses on the functional diversity among PAO clades. It demonstrates significant functional differences in the main characteristics of the anaerobic metabolism of two different PAO clades and provides fundamental insight in the metabolic response of PAO to different influent P/C ratios. In addition, it shows how these functional differences provide competitive advantages to specific PAO clades in a selection study and discusses their potential implications on process performance, in particular for combined biological and chemical systems for nutrient removal and recovery. The second part of the thesis describes the salinity effects on the metabolism of PAO and their competitors that do not contribute to phosphorus removal; the so-called Glycogen-Accumulating Organisms (GAO). It shows how salinity affects the different metabolic processes (kinetics and stochiometry) of PAO and GAO and provides a model that describes the salinity effects on their kinetic rates. Finally, it discusses the potential implications of sudden saline shocks in wastewater treatment systems that are not regularly exposed to salinity.

Estuaries are natural highly dynamic and rapidly changing systems, comprising a complex combination of physical processes on many different time- and space- scales. The research conducted a systematic study on the topic of fine sediment physical processes in a meso-tidal convergent alluvial estuary. By means of multi-approaches (field survey, laboratory experiment and numerical modeling) and from multi-angles (data-driven analysis and process-based modeling) we highlight that multiscale (including micro- and macro- scale) physical processes jointly characterize the current and sediment regime in a fine sediment estuarine system. The study presented in this book investigates micro- and macro- scale physical processes of a large-scale fine sediment estuarine system with a moderate tidal range as well as a highly seasonal-varying freshwater inflow. Based on a series of measured, experimented and modelled data, the research highlights that (i) along-channel fresh-salt gradient near an estuarine turbidity maximum zone is a key parameter controlling local density stratification and sedimentation in the channel; (ii) the salinity-induced baroclinic pressure gradient forces are a major factor impacting internal velocity and suspended sediment concentration (SSC) structures; (iii) vertical profiles of current, salinity and SSC within a river plume are dependent on a correct prediction of the development of turbulence; (iv) both suspended particulate matter availability and local residual flow regime are of critical importance for trapping probability of sediment and the occurrence of fluid mud; (v) river discharge impacts the horizontal and vertical distribution of residual current; (vi) seasonally varying wind effect alters the residual currents near the riverine limit; (vii) seasonally varied mean sea level and wind climate jointly shape the saltwater intrusion length near the estuarine front.

Human beings strongly depend on the sustainable availability of resources, such as food, water and energy. The continued supply of these resources can only be assured by sustainable land uses but these are easily threatened by inappropriate human activities. Human behavior is intermingled with hydrological, biogeochemical, atmospheric and ecological processes through land use and land cover change (LULCC). LULCC is a locally pervasive and globally significant environmental trend and has become a process of paramount importance to the study of global environmental change. This thesis investigates LULCC and its links with soil hydrology, soil degradation and climate variability through combining results from fieldwork, laboratory work and Remote Sensing. Seasonal, inter-annual and broad timescale land transitions are analyzed for a robust identification of biophysical change. The determinants of LULCC are determined using spatially explicit statistical modelling of most systematic land transitions. This thesis explores soil hydrological impacts of LULCC for a better soil water management. The thesis further explores the climatic factors leading to the observed trends in vegetated land cover for improved understanding of the link between climate and carbon fixation and water use by vegetation.

This thesis aims to explore the potential and limitations of low-cost, space-borne data in flood inundation modelling under unavoidable, intrinsic uncertainty. In particular, the potential in supporting hydraulic modelling of floods of: NASA's SRTM (Shuttle Radar Topographic Mission) topographic data, SAR (Synthetic Aperture Radar) satellite imagery of flood extents and radar altimetry of water levels are analyzed in view of inflow and parametric uncertainty. To this end, research work has been carried out by either following a model calibration-evaluation approach or by explicitly considering major sources of uncertainty within a Monte Carlo framework. To generalize our findings, three river reaches with various scales (from medium to large) and topographic characteristics (e.g. valley-filling, two-level embankments, large and flat floodplain) are used as test sites. Lastly, an application of SRTM-based flood modelling of a large river is conducted to highlight the challenges of predictions in ungauged basins. This research indicates the potential and limitations of low-cost, space-borne data in supporting flood inundation modelling under uncertainty, including findings related to the usefulness of these data according to modelling purpose (e.g. re-insurance, planning, design), characteristics of the river and considerations of uncertainty. The upcoming satellite missions, which could potentially impact the way we model flood inundation patters, are also discussed.

Focuses On an Emerging Field in Water Engineering A broad treatment of the Tsallis entropy theory presented from a water resources engineering point of view, Introduction to Tsallis Entropy Theory in Water Engineering fills a growing need for material on this theory and its relevant applications in the area of water engineering. This self-contained text includes several solved examples, and requires only a basic knowledge of mathematics and probability theory. Divided into four parts, the book begins with a detailed discussion of Tsallis entropy, moves on to hydraulics, expounds on the subject of hydrology, and ends with broad coverage on a wide variety of areas in water engineering. The author addresses: The Tsallis entropy theory for both discrete and continuous variables The procedure for deriving probability distributions One-dimensional velocity distributions Two-dimensional velocity distributions Methods for determining sediment concentration Sediment discharge Stage-discharge rating curve Precipitation variability Infiltration and the derivation of infiltration equations An introduction to soil moisture, soil moisture profiles, and their estimation Flow duration curves The eco-index and indicators of hydrologic alteration (IHA) Measures of redundancy for water distribution networks, and more Introduction to Tsallis Entropy Theory in Water Engineering examines the basic concepts of the Tsallis entropy theory, and considers its current applications and potential for future use. This book advances further research on water engineering, hydrologic sciences, environmental sciences, and water resources engineering as they relate to the Tsallis entropy theory.

Climate change on earth is having significant impacts on water resources management in Southeast Asia. Knowledge of climate variations and climate change can be valuable for water resources management in agriculture, urban and industrial water supplies, hydroelectric power generation, and ecosystem maintenance. This book presents the findings of case studies on forecasting climate change and its impacts on water availability, irrigation water requirements, floods and droughts, reservoir inflows and hydropower generation, and crop yield in specific basins of Southeast Asian countries such as Thailand, Myanmar, and Vietnam. All case studies start by forecasting the climate change and investigating its impacts by employing several hydrological reservoir simulations and crop water requirement models. The findings provide sound and scientific advice for water managers on the real impacts of climate change and how to adapt to its many challenges.

The relationship between environmental agencies and polluters is especially challenging in the context of micro and small sized enterprises (McSEs) in developing countries. The focus is mainly at end-of-pipe solutions that are usually unaffordable for McSEs. In order to engage them in achieving national environmental policy goals, this thesis reflexively combines the theoretical fields of Action Research and Negotiation/Conflict Resolution to fill the gaps in knowledge. A methodology was developed that is problem-driven and iterative by using longitudinal data collection rather than snap-shots. Along with a comparative study of two regional tannery cases, a new approach based on Action Research named SASI (Systematic Approach for Social Inclusion) was designed and tested for six years on cleaner production (CP) implementation with a third tannery case. The results highlight how institutional barriers in Colombia negatively affect the McSEs. The research shows that CP implementation needs comprehensive, systemic mechanisms based on participatory approaches that take into account the concerns and contexts of McSEs. Doing Action Research through SASI generated both theoretical insight and positively changed the lives of the tanners engaged in the research. It contributed to breaking the cycles of their exclusion and simultaneously facilitated innovation and use of local knowledge.

The Abay / Upper Blue Nile basin contributes the largest share of discharge to the river Nile. However, the basin exhibits large spatio-temporal variability in rainfall and runoff. Moreover, human activities also impact hydrological processes through intensive agriculture, overgrazing and deforestation, which substantially affect the basin hydrology. Thus, understanding hydrological processes and hydro-climatic variables at various spatio-temporal scales is essential for sustainable management of water resources in the region. This research investigates the hydrology of the basin in depth using a range of methods at various spatio-temporal scales. The methods include long-term trend analysis of hydroclimatic variables, hydrologic responses analysis of land cover change, stable isotope techniques and process based rainfallrunoff modelling. A combination of field investigations with new measurements of precipitation, water levels and stable isotopes as well as existing hydro-climatic data offered gaining new insights about runoff generation processes in headwater catchments. The use of rainfall-runoff modelling in two meso-scale catchments of the Abay basin depict that a single model structure in a lumped way for the entire Abay basin cannot represent all the dominant hydrological processes. The results of the different approaches demonstrated the potential of the methods to better understand the basin hydrology in a data scarce region.