Huong H.T.L.,Vietnam Institute of Meteorology |
Pathirana A.,UNESCO-IHE Institute for Water Education
Hydrology and Earth System Sciences | Year: 2013
Urban development increases flood risk in cities due to local changes in hydrological and hydrometeorological conditions that increase flood hazard, as well as to urban concentrations that increase the vulnerability. The relationship between the increasing urban runoff and flooding due to increased imperviousness is better perceived than that between the cyclic impact of urban growth and the urban rainfall via microclimatic changes. The large-scale, global impacts due to climate variability and change could compound these risks. We present the case of a typical third world city - Can Tho (the biggest city in Mekong River Delta, Vietnam) - faced with multiple future challenges, namely: (i) the likely effect of climate change-driven sea level rise, (ii) an expected increase of river runoff due to climate change as estimated by the Vietnamese government, (iii) increased urban runoff driven by imperviousness, and (iv) enhancement of extreme rainfall due to urban growth-driven, microclimatic change (urban heat islands). A set of model simulations were used to construct future scenarios, combining these influences. Urban growth of the city was projected up to year 2100 based on historical growth patterns, using a land use simulation model (Dinamica EGO). A dynamic limited-area atmospheric model (WRF), coupled with a detailed land surface model with vegetation parameterization (Noah LSM), was employed in controlled numerical experiments to estimate the anticipated changes in extreme rainfall patterns due to urban heat island effect. Finally, a 1-D/2-D coupled urban-drainage/flooding model (SWMM-Brezo) was used to simulate storm-sewer surcharge and surface inundation to establish the increase in the flood hazard resulting from the changes. The results show that under the combined scenario of significant change in river level (due to climate-driven sea level rise and increase of flow in the Mekong) and "business as usual" urbanization, the flooding of Can Tho could increase significantly. The worst case may occur if a sea level rise of 100 cm and the flow from upstream happen together with high-development scenarios. The relative contribution of causes of flooding are significantly different at various locations; therefore, detailed research on adaptation are necessary for future investments to be effective. © Author(s) 2013.
Ramos M.H.,IRSTEA |
Van Andel S.J.,UNESCO-IHE Institute for Water Education |
Hydrology and Earth System Sciences | Year: 2013
The last decade has seen growing research in producing probabilistic hydro-meteorological forecasts and increasing their reliability. This followed the promise that, supplied with information about uncertainty, people would take better risk-based decisions. In recent years, therefore, research and operational developments have also started focusing attention on ways of communicating the probabilistic forecasts to decision-makers. Communicating probabilistic forecasts includes preparing tools and products for visualisation, but also requires understanding how decision-makers perceive and use uncertainty information in real time. At the EGU General Assembly 2012, we conducted a laboratory-style experiment in which several cases of flood forecasts and a choice of actions to take were presented as part of a game to participants, who acted as decision-makers. Answers were collected and analysed. In this paper, we present the results of this exercise and discuss if we indeed make better decisions on the basis of probabilistic forecasts. © Author(s) 2013.
Nancharaiah Y.V.,UNESCO-IHE Institute for Water Education |
Nancharaiah Y.V.,Bhabha Atomic Research Center |
Lens P.N.L.,UNESCO-IHE Institute for Water Education
Microbiology and Molecular Biology Reviews | Year: 2015
In nature, selenium is actively cycled between oxic and anoxic habitats, and this cycle plays an important role in carbon and nitrogen mineralization through bacterial anaerobic respiration. Selenium-respiring bacteria (SeRB) are found in geographically diverse, pristine or contaminated environments and play a pivotal role in the selenium cycle. Unlike its structural analogues oxygen and sulfur, the chalcogen selenium and its microbial cycling have received much less attention by the scientific community. This review focuses on microorganisms that use selenate and selenite as terminal electron acceptors, in parallel to the well-studied sulfate-reducing bacteria. It overviews the significant advancements made in recent years on the role of SeRB in the biological selenium cycle and their ecological role, phylogenetic characterization, and metabolism, as well as selenium biomineralization mechanisms and environmental biotechnological applications. Copyright © 2015, American Society for Microbiology. All Rights Reserved.
Montanari A.,University of Bologna |
Di Baldassarre G.,UNESCO-IHE Institute for Water Education
Advances in Water Resources | Year: 2013
Observation uncertainty is nowadays recognized as a serious issue undermining the reliability of hydrological studies. For instance, many recent contributions show that river flow observations are affected by errors that may reach 25% even when state-of-the-art measurement techniques are adopted. Yet, there is still little guidance by the literature on the most appropriate modelling strategies to be adopted under observation uncertainty. We carried out a series of simulation experiments and explored how the selection of appropriate model complexity can help reduce the impact of observation uncertainty. We found that model structure plays a relevant role and, in particular, a description of the relevant physical processes that come into play can effectively contribute to limit the impact of data errors and therefore significantly reduce overall uncertainty. © 2012 Elsevier Ltd.
McClain M.E.,UNESCO-IHE Institute for Water Education |
McClain M.E.,Technical University of Delft
Ambio | Year: 2013
Sustainable development in Africa is dependent on increasing use of the continent's water resources without significantly degrading ecosystem services that are also fundamental to human wellbeing. This is particularly challenging in Africa because of high spatial and temporal variability in the availability of water resources and limited amounts of total water availability across expansive semi-arid portions of the continent. The challenge is compounded by ambitious targets for increased water use and a rush of international funding to finance development activities. Balancing development with environmental sustainability requires (i) understanding the boundary conditions imposed by the continent's climate and hydrology today and into the future, (ii) estimating the magnitude and spatial distribution of water use needed to meet development goals, and (iii) understanding the environmental water requirements of affected ecosystems, their current status and potential consequences of increased water use. This article reviews recent advancements in each of these topics and highlights innovative approaches and tools available to support sustainable development. While much remains to be learned, scientific understanding and technology should not be viewed as impediments to sustainable development on the continent. © 2012 The Author(s).
Gupta J.,VU University Amsterdam |
Gupta J.,UNESCO-IHE Institute for Water Education
Current Opinion in Environmental Sustainability | Year: 2012
Global forest governance is moving incrementally forward. REDD+ is the latest forest instrument being promoted globally as a cost-effective mechanism. This paper addresses the question: Does a glocal (global to local to global) analysis of forest policies lead to the conclusion that REDD+ can deliver a win-win situation as proponents claim? Using a literature review and focusing on four countries, this paper argues that REDD+ can potentially address deforestation and climate change by mobilizing financial and human resources, and help developed countries through cost-effective measures and developing countries by channeling resources to them. However, there is a risk that REDD+ may become a 'lose-lose' instrument leading to irreversible commodification and tradeability of forests, exacerbating North-South conflicts, and marginalizing local communities. © 2012 Elsevier B.V.
Jonoski A.,UNESCO-IHE Institute for Water Education |
Popescu I.,UNESCO-IHE Institute for Water Education
Water Resources Management | Year: 2012
This paper presents the conceptualisation, design and implementation of an online course on the topic of Decision Support Systems in River Basin Management. The need for development of such a course has been recognised, as activities in the field of water resources planning and management increasingly depend on decision support methods such as simulation, optimisation and Multi Criteria Analysis (MCA). The online learning approach is particularly needed for continuous professional development and life-long learning of professionals active in this field, and especially for those coming from developing countries. The course was developed and implemented following the competence-based learning approach, supported by the EU FP 7 educational research project named TenCompetence, which also provided the learning platform for deploying and delivering the course. The paper presents the course design, implementation and evaluation by the course participants, with special focus on the course content and the developed learning resources. Participants' evaluations show high appreciation for the course, but they also highlight areas for future improvements. © 2011 Springer Science+Business Media B.V.
Kelderman P.,UNESCO-IHE Institute for Water Education
Water, Air, and Soil Pollution | Year: 2012
This paper presents an overview of a long-term study on sediment pollution in the city canals of Delft, the Netherlands. This pollution was most evident for the inner city canal system, with copper, lead, zinc, and polycyclic aromatic hydrocarbons (PAHs) as main pollutants. Sediments of the outer city canals generally had a much better quality. Pollution levels, mutual correlations, and spatial variations were investigated for the various sediment parameters. Also, heavy metal binding forms onto Delft sediments were assessed with the help of sequential extraction techniques; results were found to be in line with expected preferential physicochemical binding processes. Input of sediments into the Delft inner city canals was shown to be largely driven by busy shipping traffic on the main canal surrounding the inner city. Mass balances for the inner city were used to quantify internal and external pollution sources; 65-85 % of the heavy metal pollution can be attributed to sources outside the Delft area. As shown by factor and cluster analyses, it is highly probable that these external sources derive from the river Rhine. A gradual improvement of the sediment quality has set in; it is expected that, due to further pollution abatement measures, this improvement will continue over the years to come. With respect to the ship-induced sediment input into the inner city canals, it was estimated that a reduction of ship velocities to <1.5 m/s will bring down the sediment input mentioned above to about 85 %. © 2012 Springer Science+Business Media B.V.
Agency: GTR | Branch: NERC | Program: | Phase: Research Grant | Award Amount: 1.93M | Year: 2015
Adequate public water services are not provided in, or expanded to, informal unplanned urban areas in Sub-Saharan Africa (SSA). Explanations in the literature range from technical difficulties, weak institutional settings, and poor cadastral information. Also, urban poor tend to lack the political or economic resources to exercise power within the urban arena to change their situation; rather, they are subject to commercialisation, industrialisation and full cost recovery for water access. In such cases, groundwater is turned to as an alternative, mainly through private vendors, self-supply from own or shared wells, and/or NGO-run kiosks. However, groundwater of good and safe quality is scarce, either seasonally or at different locations throughout the urban area. Also, there is very little insight in the hydrologic cycle within the urban area, including surface water and groundwater flow patterns and interactions, associated transport velocities, dynamics of pollutant transport, and the presence of recharge and discharge areas in the urban area. Therefore, it is unknown if and how long natural groundwater reserves can sustain these increasing urban groundwater demands. Social, institutional, financial and environmental conditions make the dependence of urban poor on groundwater a challenge that may lead to reduction of the quality of living, income, and life expectancy of the urban poor. It can therefore be regarded a complex and persistent societal problem, which is highly uncertain in terms of future developments and hard to manage, since it is rooted in different societal domains. Also, these problems seem impossible to solve with traditional approaches and instruments or through existing institutions. What is lacking is information, integration, coherence, and systemic thinking. The solution to the problem is likewise complex and not straight-forward; it will involve different stakeholders, it requires social learning, and arriving at the solution is uncertain and will take a long time. Hosted by Local Transitioning Teams, and focusing on parts of Kampala (Uganda), Arusha (Tanzania), and Accra (Ghana), as examples of growing mixed urban areas in Sub-Saharan Africa, including poor people in slums, who depend on groundwater, T-GroUP will first firmly root itself in cutting edge demand-led interdisciplinary social and natural research. What are current and historic multi-scale groundwater use-regimes and multi-level governance arrangements, how were and are power structures and power dynamics present in these areas, and what is how do financial and economic factors come into play? These are the more social, governance, institutional and socio-economic type of question we ask ourselves. From the environmental and natural sciences point of view, we aim to unravel complex urban groundwater flow systems and patterns in pathogen distributions in aquifers using next generation DNA sequencing techniques and qPCR techniques we recently developed. Then, our project will turn into a socio-biophysical transition experiment. These areas described above become Urban Transitioning Laboratories in which we plan to implement a Transition Management Cycle (TMC), which is able to properly deal with the complex societal problem described above, and which can convert unsustainable water use into inclusive urban groundwater management, thereby focusing on the role and the needs of the urban poor. Key components of the TMC include multi-stakeholder platforms (Learning Alliances), strategic planning, and small scale demonstrations to show the promise in making the transition towards sustainable groundwater management. Being designed for development impact, the TMC is also subject of research: departing from a TMC we developed earlier, we aim to arrive at a TMC tailored to groundwater use in the complex context of our study areas, which can be replicated in other cities in Sub-Saharan Africa.
Alizadeh Tabatabai S.A.,UNESCO-IHE Institute for Water Education |
Schippers J.C.,UNESCO-IHE Institute for Water Education |
Kennedy M.D.,UNESCO-IHE Institute for Water Education
Water Research | Year: 2014
This paper investigated the effect of coagulation on fouling potential and removal of algal organic matter (AOM) in seawater ultrafiltration (UF) systems. AOM harvested from a strain of bloom forming marine diatom, Chaetoceros affinis, was coagulated with ferric chloride under different coagulation modes and conditions. The effect of coagulation on fouling potential was determined with the Modified Fouling Index-Ultrafiltration (MFI-UF). Removal of AOM was studied for three different modes of coagulation, namely, coagulation followed by sedimentation, coagulation followed by sedimentation and filtration through 0.45μm, and inline coagulation followed by filtration through 150kDa UF membranes. Liquid chromatography - organic carbon detection was used to determine the removal of AOM with particular emphasis on biopolymers.AOM (as biopolymers) had a high fouling potential as measured by MFI-UF, which strongly depended on filtration flux. Moreover, the developed cake/gel layer on the membrane was fairly compressible during filtration; manifested as higher fouling potential at higher filtration flux and non-linear development of pressure in filtration tests.Coagulation substantially reduced fouling potential and compressibility of the AOM cake/gel layer. The impact of coagulation was particularly significant at coagulant doses >1mg Fe/L. Coagulation also substantially reduced the flux-dependency of AOM fouling potential, resulting in linear development of pressure in filtration tests at constant flux. This was attributed to adsorption of biopolymers on precipitated iron hydroxide and formation of Fe-biopolymer aggregates, such that the fouling characteristics of iron hydroxide precipitates prevailed and AOM fouling characteristics diminished. At low coagulant dose, inline coagulation/UF was more effective in removing AOM than the other two coagulation modes tested. At high coagulant dose where sweep floc conditions prevailed, AOM removal was considerably higher and controlled by coagulant dose rather than coagulation mode. © 2014.