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Books > Earth & environment > Earth sciences > The hydrosphere > General
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.
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.
Mountains are water towers of our world, but their role in global water resources may be altered due to changing climate. This book provides an integrated assessment of the spatial and temporal variability of both recent and future climate change impacts in the Yellow River source region (YRSR) with specific focus on extremes. The book is structured across four different topics from detecting contemporary hydro-climatic changes, comparing three different statistical downscaling methods, assessing elevation dependency of expected changes in temperature, and projecting future climate-induced hydrologic changes in the YRSR. The detection of historical hydro-climatic changes in recent decades indicates that climate change may already be happening and may pose a serious threat to water availability in this region. However, an ensemble of climate change projections for the periods 2046-2065 and 2081-2100 based on two GCMs and three emission scenarios demonstrates that the future water availability of this region would increase due to climate change. This discrepancy suggests that contemporary hydro-climatic experience based on past records alone may not always provide a reliable guide to the future. This study makes an important contribution toward an improved understanding of climate change impacts in the YRSR. The knowledge generated has major implications for water resources management in the Yellow River and will be instructive for climate change impacts studies in other mountain areas.
The field of ecohydraulics integrates hydrodynamic and eco-dynamic processes. While hydrodynamic processes are usually well described by partial differential equations (PDE's) based on physical conservation principles, ecosystem dynamics often involve specific interactions at the local scale. Because of this, Cellular Automata (CA) are a viable paradigm in ecosystem modelling. All cells in a CA system update their states synchronously at discrete steps according to simple local rules. The classical CA configuration consists of uniformly distributed cells on a structured grid. But in the field of hydrodynamics, the use of unstructured grids has become more and more popular due to its flexibility to handle arbitrary geometries. The main objective of this research is to identify whether the CA paradigm can be extended to unstructured grids. To that end the concept of Unstructured Cellular Automata (UCA) is developed and various UCA configurations are explored and their performance investigated. The influence of cell size was analyzed in analogy with the Finite Volume Method. A characteristic parameter -min distance of UCA- was put forward and tested by numerical experiments. Special attention was paid to exploring the analogies and differences between the discrete CA paradigm and discrete numerical approximations for solving PDE's. The practical applicability of UCA in ecohydraulics modelling is explored through a number of case studies and compared with field measurements.
This study was built to investigate the impact of subsurface drainage on iron toxicity in Tropical Savannah irrigated rice valley bottoms. The research leaned upon two complementary approaches: field investigations and designed experiments. Important results, covering several fields, where achieved. For example, It appeared that single-season irrigation schemes present higher iron toxicity and acidity risks than double-season ones - 750 up to 1800 mg/l of Fe2+ higher in the single-season scheme of Moussodougou than in the double-season scheme of Tiefora. Furthermore, a statistical analysis of flow time series (ARIMA model) data was performed. It showed that with a simple water level measurement probe installed at the main gate of the scheme, it becomes possible not only to quantify irrigation water consumption, but also to diagnose farmers' irrigation schedule, providing them a means to defuse potential conflicts due to inequity in water distribution. Finally, it was shown that subsurface drainage increases ferrous iron concentration in hematite dominant soils soil - from 935 mg/l to more than 1106 mg/l in the case of the soil of Moussodougou - but also fortunately alleviate soil acidity - from pH 5.6 to 7.3 in Moussodougou. This effect will eventually reduce ferrous iron intake by rice roots, alleviating toxicity.
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 research investigated new approaches to control anaerobic methane oxidation coupled to sulfate reduction (AOM-SR) and enrich anaerobic methanotrophs (ANME) and sulfate reducing bacteria (SRB) with the purpose of designing a suitable bioreactor for AOM-SR at ambient pressure and temperature. The current knowledge about AOM and the microorganisms involved in AOM are discussed. The effect of different substrates and pressures was investigated on the ANME and SRB community adapted to the shallow marine Lake Grevelingen, the Netherlands. Further, microorganisms from the Alpha Mound (Spain) deep sediment were enriched with methane gas as substrate in biotrickling filters (BTF) at ambient conditions for 147-230 days of operation. The effect of alternative sulfur compounds (sulfate, thiosulfate and elemental sulfur) were studied and the microbial community was characterized. The highest AOM and sulfate reduction rates were obtained in the BTF fed with thiosulfate as the electron acceptor (~0.4 mmol l-1 day-1), but the highest number of ANME was visualized in the sulfate fed BTF (ANME-2 43% of the total visualized archaea). A BTF was proposed as a suitable bioreactor for the enrichment of ANME and SRB at ambient pressure and temperature which could be potentially used for future biotechnological applications.
Anaerobic oxidation of methane (AOM) coupled to sulfate reduction (AOM-SR) is a biological process mediated by anaerobic methanotrophs (ANME) and sulfate reducing bacteria. It has scientifi c and societal relevance in regulating the global carbon cycle and biotechnological application for treating sulfate-rich wastewater. This research aimed to enhance the recent knowledge on ANME distribution and its enrichment in different bioreactor confi gurations, i.e. membrane bioreactor (MBR), biotrickling fi lter (BTF) and high pressure bioreactor (HPB). Marine sediment from Ginsburg mud volcano, Gulf of Cadiz was used as inoculum in the BTF and MBR. The BTF operation showed the enrichment of ANME in the biofi lm, especially ANME-1 (40%) and ANME-2 (10%). Whereas, the dominancy of ANME-2 and Desulfosarcina aggregates was observed in the MBR. Moreover, HPB study was performed by using highly enriched ANME-2 community from Captain Arutyunov mud volcano. During the study of HPB at different temperature and pressure conditions, the incubation at 10 MPa pressure and 15 C was observed to be the most suitable condition for the studied AOM-SR community. Furthermore, AOM-SR activity in the coastal sediments from marine Lake Grevelingen (the Netherlands) was explored and the microbial community was characterised which was dominated by ANME-3 among known ANME types.
This workbook is a companion to Applied Math for Water Plant Operators (ISBN: 9780877628743) and part of the Applied Math for Water Plant Operators Set (ISBN: 9781566769884). It contains self-teaching guides for all water treatment calculations, skill checks, hundreds of worked examples, and practice problems.
The main objective of this research was to optimize the electron donor supply in sulphate reducing bioreactors treating sulphate rich wastewater. Two types of electron donor were tested: lactate and slow release electron donors such as carbohydrate based polymers and lignocellulosic biowastes. Biological sulphate reduction was evaluated in different bioreactor configurations: the inverse fluidized bed, sequencing batch and batch reactors. The reactors were tested under steady-state, high-rate and transient-state feeding conditions of electron donor and acceptor, respectively. The results showed that the inverse fluidized bed reactor configuration is robust and resilient to transient and high-rate feeding conditions at a hydraulic retention time as low as 0.125 d. The biological sulphate reduction was limited by the COD:sulphate ratio (< 1.7). The results from artificial neural network modelling showed that the influent sulphate concentrations synergistically affected the COD removal efficiency and the sulphide production. Concerning the role of electron donors, the slow release electron donors allowed a biological sulphate reduction > 82% either using carbohydrate based polymers or lignocellulosic bio-wastes, in batch bioreactors. The biological sulphate reduction was limited by the hydrolysis-fermentation rate and by the complexity of the slow release electron donors.
Sanitary landfills are the most widely utilized method of solid waste disposal around the world. With increased use and public awareness of this method of disposal, there is much concern with respect to the pollution potential of the landfill leachate. Depending on the composition and extent of decomposition of the refuse and hydrological factors, the leachate may become highly contaminated. As leachate migrates away from a landfill, it may cause serious pollution to the groundwater aquifer as well as adjacent surface waters. There is growing concern about surface and groundwater pollution from leachate. Better understanding and prediction of leachate generation, containment, and treatment are needed. This book contains a literature review of various methodologies that have been developed for prediction, generation, characterization, containment, control, and treatment of leachate from sanitary landfills. The contents of this book are divided into nine chapters. Each chapter contains theory and definition of the important design parameters, literature review, example calculations, and references. Chapter 1 is devoted to basic facts of solid waste problems current status and future trends towards waste reduction and recycling. Chapter 2 provides a general overview of municipal solid waste generation, collection, transport, resource recovery and reuse, and disposal options. The current status of sanitary landfill design and operation, problems associated with the landfilling, and future trends are presented in Chapter 3. Methods of enhanced stabilization, recycling landfill space, methane recovery, and above grade landfilling, and closure and post closure care of completed landfills are also discussed in detail. Chapter 4 provides a general overview of Subtitle D regulations and its impact upon sanitary landfilling practices. Chapter 5 is devoted entirely to moisture routing and leachate generation mechanisms.
Sediment pollution and accumulation in harbours are major environmental issues and studies that advance their solutions are essential for harbour sustainability. This book provides the first comprehensive assessment of chemical pollution in sediments and sediment accumulation rates in the tropical Tema Harbour (Ghana). This book contributes to improving our ability to use an integrated approach involving sediment chemistry and bioassays in one comprehensive assessment of the contamination state of a tropical coastal environment. Whole-sediment toxicity bioassays using the amphipod Corophium volutator and the polychaete Hediste diversicolor as bioindicators were combined with data on concentrations of total metal and metal binding forms, radionuclides, organochlorine pesticides and polycyclic aromatic hydrocarbons in bottom sediments as well as total metal concentrations in settling silt-clay particles collected by sediment traps to characterise the hazard, risk and impact of sediments from the tropical coastal Tema Harbour.
This volume provides readers with an opportunity to learn from front line water managers of watershed-based agencies across Canada about integrated water management (or integrated water resource management). In common with practice in much of the world, the responsibility for implementing integrated watershed management in Canada is fragmented. Each province and territory in Canada has developed unique approaches or governance models to guide decision making in that regard. Thus, this edited volume enables readers from around the world to gain insight on the best practices in Canada for achieving success and addressing barriers to implement IWM. Although there remains non consensus about how to "best" approach river basin management, some of the main observations include: There is a need to balance a focus on "the big picture", with scoping the scale and scope of planning activities in order that feasible and effective solutions can be implemented Three types of integration are popular among the agencies included in the book: (i) among environment, economy and society, (ii) interactions between people and the environment and (iii) integration (or coordination) of administrative activities. Much more attention is required to achieving effective engagement from Indigenous communities The chapters were originally published in a special issue of the International Journal of Water Resources Development.
Sediment transport in irrigation canals influences to a great extent the sustainability of an irrigation system. Unwanted erosion or deposition will not only increase maintenance costs, but may also lead to unfair, unreliable and unequitable distribution of irrigation water to the end users. Proper knowledge of the characteristics, including behaviour and transport of sediment will help to design irrigation systems, plan efficient and reliable water delivery schedules, to have a controlled deposition of sediments, to estimate and arrange maintenance activities, etc. The main aim of these lecture notes is to present a detailed analysis and physical and mathematical descriptions of sediment transport in irrigation canals and to describe the mathematical model SETRIC that predicts the sediment transport, deposition and entrainment rate as function of time and place for various flow conditions and sediment inputs. The model is typically suited for the simulation of sediment transport under the particular conditions of non-wide irrigation canals where the flow and sediment transport are strongly determined by the operation of the flow control structures. The lecture notes will contribute to an improved understanding of the behaviour of sediments in irrigation canals. They will also help to decide on the appropriate design of the system, the water delivery plans, to evaluate design alternatives and to achieve an adequate and reliable water supply to the farmers.
Over a third of the current 7.3 billion people worldwide are burdened with poor sanitation services. The resulting social, relational and ecological exclusion make the realisation of the human right to sanitation (HRS) a critical concern development concern. However, the literature has evolved in a largely compartmentalised manner, focusing on the formal recognition of the HRS in domestic legal systems, without sufficiently addressing the drivers of poor sanitation services. This research expounds on the impact of the HRS on human wellbeing and the environment within the context of a developing country like Nigeria as a case study. The findings show that contrary to the focus in the literature, the drivers of poor sanitation services are not confined to legal factors, such as the formal recognition of the HRS within domestic legal systems. Rather, the drivers include social, economic and environmental limitations to improved sanitation services. Based on the findings, the book argues that the focus in the literature on the formal recognition of the HRS in national legal systems is insufficient for tackling the main drivers of poor sanitation services. It is therefore necessary to reformulate the HRS discourse using complementary governance instruments that advance social, relational and ecological inclusion.
Primarily written as course material on flood control and drainage engineering for advanced students of civil engineering, this new fourth edition is again thoroughly revised. It accommodates recent developments in remote sensing, information technology and GIS technology. New added material deals with flood management due to Tsunami waves, flooding due to dam failure and breaking of embankments, application of dredging technologies, problems of flood forecasting, flood plain prioritization and flood hazard zoning, and engineering measures for flood control. Drainage improvement is tackled, with particular regard to salinity and coastal aquifer management from the ingress of sea water. The book includes design problem-solving and case studies, making it practical and applications-oriented. The subject matter will be of considerable interest to civil engineers, agricultural engineers, architects and town planners, as well as other government and non-government organizations.
The evolution and utilization of estuarine and coastal regions are greatly restricted by sediment problems. This thesis aims to better understand fine sediment transport under combined action of waves and currents, especially in the wave-current bottom boundary layer (BBL). Field observations, experimental data analysis, theoretical analysis and numerical models are employed. Silt-dominated sediments are sensitive to flow dynamics and the suspended sediment concentration (SSC) increase rapidly under strong flow dynamics. This research unveils several fundamental aspects of silty sediment, i.e., the criterion of the incipient motion, the SSC profiles and their phase-averaged parameterization in wave-dominated conditions. An expression for sediment incipient motion is proposed for silt-sand sediment under combined wave and current conditions. A process based intra-wave 1DV model for flow-sediment dynamics near the bed is developed in combined wave-current conditions. The high concentration layer (HCL) was simulated and sensitivity analysis was carried out by the 1DV model on factors that impact the SSC in the HCL. Finally, based on the 1DV model, the formulations of the mean SSC profile of silt-sand sediments in wave conditions were proposed. The developed approaches are expected to be applied in engineering practice and further simulation.
Pipe failures in water distribution systems can have a serious impact and hence it's important to maintain the condition and integrity of the distribution system. This book presents a whole-life cost optimisation model for the rehabilitation of water distribution systems. It combines a pipe breakage number prediction model with a pipe criticality assessment model, which enables the creation of a well-constructed and more tightly constrained optimisation model. The pipe breakage number prediction model combines information on the physical characteristics of the pipes with historical information on breakage and failure rates. A weighted multiple nonlinear regression analysis is applied to describe the condition of different pipe groups. The criticality assessment model combines a pipe's condition with its hydraulic significance through a modified TOPSIS. This model enables the optimisation to focus its efforts on those important pipes. The whole life cost optimal rehabilitation model is a multiple-objective and multiple-stage model, which provides a suite of rehabilitation decisions that minimise the whole life cost while maximising its long-term performance. The optimisation model is solved using a modified NSGA-II. The utility of the developed models is that it allows decision makers to prioritize their rehabilitation strategy in a proactive and cost-effective manner.
This book provides an overview of recent advances in technologies for water treatment processes, such as green technology, nano-adsorbents, photocatalysts, advanced oxidation, membranes separation and sustainable technologies. Advances in membrane technology and fabrication process is presented in detail. Latest approaches like microbial treatment, electro chemical and solar energy-based treatment techniques were presented. Also, the use of sustainable and energy efficient approaches were discussed.* The book presents the negative impact of inorganic and organic pollutants on the natural environment and human health. It describes and discussing the advanced membrane technologies, novel green adsorbents, microbial treatment techniques, electro chemical and solar based removal techniques It also compares the most effective methods of removing toxic contaminants from water solutions with the use of sustainable and energy efficient approaches It also presents the life cycle assessment of emerging technologies in industrial wastewater treatment and desalination as well as presents the benchmarking of energy efficiency during treatment process
International experts have contributed key chapters to this major
work on groundwater contamination. Section 1: Methodology and
Modeling deals with both organic and inorganic contaminants,
including those from agricultural operations. Section 2: Case
Studies presents contamination scenarios with both inorganic and
organic chemicals including agriculturally-related constituents,
such as the nitrates.
We have identified a need to draw together knowledge of physiochemical and biological aspects of pollution in tropical aquatic systems. This book results from this and we hope will assist in providing management strategies to protect these systems from pollution effects. In organising the book we have, as far as possible, attempted to cover the range of topics important in understanding pollution in tropical areas. Authors who are expert in their particular fields have been invited to contribute. We recognise that many topics remain uncovered but we hope will serve to assist in identifying these and stimulate interest in this area.
Flooding can have devastating impacts on people's livelihood, economy and the environment. An important instrument in flood management is floodplain maps, which assist land planners and local authorities in identifying flood-prone areas, and provide useful information for rescue and relief agencies for their operations. Developing floodplain maps often involves flood inundation modeling. This typically requires precipitation and stream flow data, topographic information, building a hydraulic model and calibration of its parameters. Often however, floodplain maps are built on a single model outcome without an explicit consideration of all the sources of uncertainty in the modeling process. The research presented in this thesis addresses the uncertainty in flood inundation modeling, which may arise from input data and hydraulic modeling approach. The study area is the Sungai Johor basin in Johor, Malaysia, an agriculture-dominated area. The present study analyses the modelling uncertainties arising from estimations of design flow, terrain data sets, geometric description in hydraulic models and different modeling approaches, and develops recommendations for practitioners. Explicit account for uncertainties and studying their impact in flood inundation mapping allow for more informed and effective decision making.
Demand for land and water for agriculture, urbanization, irrigation, hydropower, and industrialization is increasing to meet the demands of growing populations and of growing economies. However, changes in land and water resources are often studied separately. A better representation of the interaction between land-use change and its drivers on the one hand and water resources on the other is imperative for sustainable environmental management. This research investigates and develops spatial analysis methods and tools for the quantification of dynamic feedbacks between land-use change and water resources, by focusing on case study catchments in Ethiopia and South Africa. Furthermore, the research investigates methods for analysing land-use suitability and modelling land-use change. Results show that major changes in land-use have been observed in the past two to three decades in the study catchments. Model representation of the interaction between land-use change and water resources shows that changes in land-use influence hydrologic responses. These influences are especially pronounced during high- and low-flow seasons. Likewise, hydrologic processes and water resources availability influence land-use suitability and hence land-use change responses. Accounting for the dynamic feedback between land-use and hydrology thus produces improved knowledge that can better inform integrated natural resources management.
The Niger delta with its gentle slope and low elevation is extremely sensitive to effects of climate change. Its adaptive capacity is the second lowest in terms of socio-economic development in Nigeria. Quantitative studies on developing measures for coastal planning and management in the lower Niger delta have been limited by data availability and inaccessibility of parts of the delta. The use of satellite data can help bridge the data gap by providing ancillary data (imagery, elevation, altimetry etc.) that can be used to quantify the effects of SLR in the Niger delta. This thesis uses satellite data as the main source for hydrodynamic modelling and GIS analysis. Until recently such data might not have the accuracy and precision of directly measured data. However recent innovative approaches have enabled better exploitation of satellite data to overcome these limitations and produce adequate results to assess the impact of SLR on the Niger delta in an integrated way that will lead to practical recommendations for adaptation. Using projected global eustatic SLR values in combination with land subsidence, this thesis estimated SLR levels for the Niger delta and its effect on inundation areas and flood extent. The results indicate that the Niger delta is very vulnerable to inundation and that even minimal SLR will affect flooding in the lower Niger delta since the area continues to subside. A new coastal vulnerability index was developed in this thesis by evaluating physical, social and human influence indicators of exposure, susceptibility and resilience. The results show that parts of the Niger delta are highly vulnerable to SLR and need adequate mitigation/adaptation measures to protect them. It is recommended that sustainable local resilience practices already being used in parts of the Niger delta should be included in adaptation planning. |
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