ORCID Profile
0000-0002-7411-6562
Current Organisations
Utrecht University
,
Deltares
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Publisher: Copernicus GmbH
Date: 18-04-2017
DOI: 10.5194/ESD-2017-38
Abstract: Abstract. In our globalised world, food security and water security are inextricably intertwined. Food production accounts for approximately 70 % of global freshwater use, with variability in agricultural production impacting water resources and vice versa. Trade is central to determining water resource use, because when we trade food, we also trade the water embedded in the production of that food. As the world becomes more globalised and more urbanised, our dependence on trade for food and water security increases. Managing food and water security under globalisation is a complex challenge owing to the increased interdependency among regions and sectors. Given the unprecedented pressure on water resources in the 21st century, there is an urgent need for new models to assist in developing water management policies that capture these complexities. We present a new framework for modelling the complexities of food and water security under globalisation. The framework sets out a method to capture agency, cross-scale socioenvironmental feedbacks and interdependency brought about by globalisation and urbanisation. The approach unifies and extends the existing fields of hydrology, Integrated Assessment Modelling and agent-based modelling. The core of our framework is a multi-agent network of city nodes and infrastructural trade links. This network captures the important role of cities as centres of food and water demand. In addition, it captures the infrastructural networks that constrain our ability to extract water resources from the environment and redistribute them to meet demand. We believe that this framework can form the basis for a new wave of models that capture cross-scale socioenvironmental feedbacks within our globalised world.
Publisher: Copernicus GmbH
Date: 11-07-2017
DOI: 10.5194/HESS-21-3427-2017
Abstract: Abstract. The ersity in hydrologic models has historically led to great controversy on the correct approach to process-based hydrologic modeling, with debates centered on the adequacy of process parameterizations, data limitations and uncertainty, and computational constraints on model analysis. In this paper, we revisit key modeling challenges on requirements to (1) define suitable model equations, (2) define adequate model parameters, and (3) cope with limitations in computing power. We outline the historical modeling challenges, provide ex les of modeling advances that address these challenges, and define outstanding research needs. We illustrate how modeling advances have been made by groups using models of different type and complexity, and we argue for the need to more effectively use our ersity of modeling approaches in order to advance our collective quest for physically realistic hydrologic models.
Publisher: Copernicus GmbH
Date: 23-08-2017
DOI: 10.5194/HESS-21-4169-2017
Abstract: Abstract. Over recent decades, the global population has been rapidly increasing and human activities have altered terrestrial water fluxes to an unprecedented extent. The phenomenal growth of the human footprint has significantly modified hydrological processes in various ways (e.g. irrigation, artificial dams, and water ersion) and at various scales (from a watershed to the globe). During the early 1990s, awareness of the potential for increased water scarcity led to the first detailed global water resource assessments. Shortly thereafter, in order to analyse the human perturbation on terrestrial water resources, the first generation of large-scale hydrological models (LHMs) was produced. However, at this early stage few models considered the interaction between terrestrial water fluxes and human activities, including water use and reservoir regulation, and even fewer models distinguished water use from surface water and groundwater resources. Since the early 2000s, a growing number of LHMs have incorporated human impacts on the hydrological cycle, yet the representation of human activities in hydrological models remains challenging. In this paper we provide a synthesis of progress in the development and application of human impact modelling in LHMs. We highlight a number of key challenges and discuss possible improvements in order to better represent the human–water interface in hydrological models.
Publisher: Copernicus GmbH
Date: 04-05-2017
Abstract: Abstract. Over the last decades, the global population has been rapidly increasing and human activities have altered terrestrial water fluxes at an unprecedented scale. The phenomenal growth of the human footprint has significantly modified hydrological processes in various ways (e.g., irrigation, artificial dams, and water ersion) and at various scales (from a watershed to the globe). During the early 1990s, awareness of the potential water scarcity led to the first detailed global water resource assessments. Shortly thereafter, in order to analyse the human perturbation on terrestrial water resources, the first generation of large-scale hydrological models (LHMs) was produced. However, at this early stage few models considered the interaction between terrestrial water fluxes and human activities, including water use and reservoir regulation, and even fewer models distinguished water use from surface water and groundwater resources. Since the early 2000s, a growing number of LHMs are incorporating human impacts on hydrological cycle, yet human representations in hydrological models remain challenging. In this paper we provide a synthesis of progress in the development and application of human impact modeling in LHMs. We highlight a number of key challenges and discuss possible improvements in order to better represent the human-water interface in hydrological models.
Publisher: American Meteorological Society
Date: 07-2013
DOI: 10.1175/JCLI-D-12-00319.1
Abstract: Confidence in projections of global-mean sea level rise (GMSLR) depends on an ability to account for GMSLR during the twentieth century. There are contributions from ocean thermal expansion, mass loss from glaciers and ice sheets, groundwater extraction, and reservoir impoundment. Progress has been made toward solving the “enigma” of twentieth-century GMSLR, which is that the observed GMSLR has previously been found to exceed the sum of estimated contributions, especially for the earlier decades. The authors propose the following: thermal expansion simulated by climate models may previously have been underestimated because of their not including volcanic forcing in their control state the rate of glacier mass loss was larger than previously estimated and was not smaller in the first half than in the second half of the century the Greenland ice sheet could have made a positive contribution throughout the century and groundwater depletion and reservoir impoundment, which are of opposite sign, may have been approximately equal in magnitude. It is possible to reconstruct the time series of GMSLR from the quantified contributions, apart from a constant residual term, which is small enough to be explained as a long-term contribution from the Antarctic ice sheet. The reconstructions account for the observation that the rate of GMSLR was not much larger during the last 50 years than during the twentieth century as a whole, despite the increasing anthropogenic forcing. Semiempirical methods for projecting GMSLR depend on the existence of a relationship between global climate change and the rate of GMSLR, but the implication of the authors' closure of the budget is that such a relationship is weak or absent during the twentieth century.
Publisher: Springer Science and Business Media LLC
Date: 25-11-2012
DOI: 10.1038/NCLIMATE1744
Publisher: Copernicus GmbH
Date: 20-05-2011
DOI: 10.5194/HESS-15-1537-2011
Abstract: Abstract. Climate change is likely to have significant effects on the hydrology. The Ganges-Brahmaputra river basin is one of the most vulnerable areas in the world as it is subject to the combined effects of glacier melt, extreme monsoon rainfall and sea level rise. To what extent climate change will impact river flow in the Brahmaputra basin is yet unclear, as climate model studies show ambiguous results. In this study we investigate the effect of climate change on both low and high flows of the lower Brahmaputra. We apply a novel method of discharge-weighted ensemble modeling using model outputs from a global hydrological models forced with 12 different global climate models (GCMs). Our analysis shows that only a limited number of GCMs are required to reconstruct observed discharge. Based on the GCM outputs and long-term records of observed flow at Bahadurabad station, our method results in a multi-model weighted ensemble of transient stream flow for the period 1961–2100. Using the constructed transients, we subsequently project future trends in low and high river flow. The analysis shows that extreme low flow conditions are likely to occur less frequent in the future. However a very strong increase in peak flows is projected, which may, in combination with projected sea level change, have devastating effects for Bangladesh. The methods presented in this study are more widely applicable, in that existing multi-model streamflow simulations from global hydrological models can be weighted against observed streamflow data to assess at first order the effects of climate change for specific river basins.
Publisher: Elsevier BV
Date: 04-2017
Publisher: Copernicus GmbH
Date: 16-01-2017
Abstract: Abstract. The ersity in hydrologic models has historically led to great controversy on the “correct” approach to process-based hydrologic modeling, with debates centered on the adequacy of process parameterizations, data limitations and uncertainty, and computational constraints on model analysis. In this paper we revisit key modeling challenges, outlined by Freeze and Harlan nearly 50 years ago, on requirements to (1) define suitable model equations, (2) define adequate model parameters, and (3) cope with limitations in computing power. We outline the historical modeling challenges, summarize modeling advances that address these challenges, and define outstanding research needs. We illustrate how modeling advances have been made by groups using models of different type and complexity, and we argue for the need to more effectively use our ersity of modeling approaches in order to advance our collective quest for physically realistic hydrologic models.
Publisher: Copernicus GmbH
Date: 16-03-2016
Abstract: Abstract. Groundwater is the world's largest accessible source of freshwater to satisfy human water needs. Moreover, groundwater buffers variable precipitation rates over time, thereby effectively sustaining river flows in times of droughts as well as evaporation in areas with shallow water tables. Lateral flows between basins can be a significant part of the basins water budget, but most global-scale hydrological models do not consider surface water-groundwater interactions and do not include a lateral groundwater flow component. In this study we simulate groundwater head fluctuation and groundwater storage changes in both confined and unconfined aquifer systems using a global-scale high-resolution (5 arc-minutes) groundwater model by deriving new estimates of the distribution and thickness of confining layers. Inclusion of confined aquifer systems (estimated 6 % to 20 % of the total aquifer area) changes timing and litude of head fluctuations, as well as flow paths and groundwater-surface water interactions rates. Also, timing and magnitude of groundwater head fluctuations are better estimated when confining layers are included. Groundwater flow paths within confining layers are shorter then paths in the underlying aquifer, while flows within the confined aquifer can get disconnected from the local drainage system due to the low conductivity of the confining layer. Lateral groundwater flows between basins are significant in the model, especially for areas with (partially) confined aquifers were long flow paths are simulated crossing catchment boundaries, thereby supporting water budgets of neighboring catchments or aquifer systems. The two-layer transient groundwater model is used to identify hotspots of groundwater depletion resulting in an estimated global groundwater depletion of 6700 km3 over the 1960–2010, consistent with estimates of previous studies.
Publisher: Copernicus GmbH
Date: 25-07-2017
DOI: 10.5194/HESS-21-3777-2017
Abstract: Abstract. Recent research in large-scale hydroclimatic variability is surveyed, focusing on five topics: (i) variability in general, (ii) droughts, (iii) floods, (iv) land–atmosphere coupling, and (v) hydroclimatic prediction. Each surveyed topic is supplemented by illustrative ex les of recent research, as presented at a 2016 symposium honoring the career of Professor Eric Wood. Taken together, the recent literature and the illustrative ex les clearly show that current research into hydroclimatic variability is strong, vibrant, and multifaceted.
Publisher: Authorea, Inc.
Date: 11-06-2023
DOI: 10.22541/ESSOAR.168652289.91346805/V1
Abstract: Fresh submarine groundwater discharge (SGD) and seawater intrusion (SWI) are complementary processes at the interface of coastal groundwater and oceans. Multiple common drivers enable or limit SGD and SWI. However, we find that SGD and SWI are rarely studied simultaneously. In this meta-analysis, we synthesize 1298 publications, examining drivers of SGD and SWI, where and why they are studied, and at which scales they are impacted by their drivers. Studies of SGD and SWI accumulate in urban coastal basins with high gross domestic product (GDP), and high permeabilities, where measurable groundwater fluxes are expected. We find, that studies investigate various drivers, but rarely assess the scales they act at. Effects of temporally recurring processes (e.g., tides) are studied more often and are better known than effects of spatial variability (e.g., permeability). Future studies should investigate SGD and SWI simultaneously, report impact scales of drivers explicitly and explore unchartered coastlines.
Publisher: Copernicus GmbH
Date: 19-02-2014
Abstract: Abstract. Throughout its historical development, hydrology as an earth science, but especially as a problem-centred engineering discipline has largely relied (quite successfully) on the assumption of stationarity. This includes assuming time invariance of boundary conditions such as climate, system configurations such as land use, topography and morphology, and dynamics such as flow regimes and flood recurrence at different spatio-temporal aggregation scales. The justification for this assumption was often that when compared with the temporal, spatial, or topical extent of the questions posed to hydrology, such conditions could indeed be considered stationary, and therefore the neglect of certain long-term non-stationarities or feedback effects (even if they were known) would not introduce a large error.
Publisher: Copernicus GmbH
Date: 31-01-2018
Abstract: Abstract. We present a new framework for modelling the complexities of food and water security under globalisation. The framework sets out a method to capture regional and sectoral interdependencies and cross-scale feedbacks within the global food system that contribute to emergent water use patterns. The framework integrates aspects of existing models and approaches in the fields of hydrology and integrated assessment modelling. The core of the framework is a multi-agent network of city agents connected by infrastructural trade networks. Agents receive socio-economic and environmental constraint information from integrated assessment models and hydrological models respectively and simulate complex, socio-environmental dynamics that operate within those constraints. The emergent changes in food and water resources are aggregated and fed back to the original models with minimal modification of the structure of those models. It is our conviction that the framework presented can form the basis for a new wave of decision tools that capture complex socio-environmental change within our globalised world. In doing so they will contribute to illuminating pathways towards a sustainable future for humans, ecosystems and the water they share.
Publisher: American Meteorological Society
Date: 06-2013
DOI: 10.1175/BAMS-D-11-00176.1
Abstract: Drought is a global problem that has far-reaching impacts, especially on vulnerable populations in developing regions. This paper highlights the need for a Global Drought Early Warning System (GDEWS), the elements that constitute its underlying framework (GDEWF), and the recent progress made toward its development. Many countries lack drought monitoring systems, as well as the capacity to respond via appropriate political, institutional, and technological frameworks, and these have inhibited the development of integrated drought management plans or early warning systems. The GDEWS will provide a source of drought tools and products via the GDEWF for countries and regions to develop tailored drought early warning systems for their own users. A key goal of a GDEWS is to maximize the lead time for early warning, allowing drought managers and disaster coordinators more time to put mitigation measures in place to reduce the vulnerability to drought. To address this, the GDEWF will take both a top-down approach to provide global realtime drought monitoring and seasonal forecasting, and a bottom-up approach that builds upon existing national and regional systems to provide continental-to-global coverage. A number of challenges must be overcome, however, before a GDEWS can become a reality, including the lack of in situ measurement networks and modest seasonal forecast skill in many regions, and the lack of infrastructure to translate data into useable information. A set of international partners, through a series of recent workshops and evolving collaborations, has made progress toward meeting these challenges and developing a global system.
Publisher: Copernicus GmbH
Date: 15-03-2017
Abstract: Abstract. Recent research in large-scale hydroclimatic variability is surveyed, focusing on five topics: (i) variability in general, (ii) droughts, (iii) floods, (iv) land-atmosphere interactions, and (v) hydroclimatic prediction. Each surveyed topic is supplemented by illustrative ex les of recent research, as presented at a 2016 symposium honoring the career of Professor Eric Wood. Taken together, the recent literature and the illustrative ex les clearly show that research into hydroclimatic variability continues to be strong, vibrant, and multifaceted.
Location: Netherlands
No related grants have been discovered for Marc F.P. Bierkens.