scholarly journals Stress-testing groundwater and baseflow drought responses to synthetic climate change-informed recharge scenarios

2020 ◽  
Author(s):  
Jost Hellwig ◽  
Michael Stoelzle ◽  
Kerstin Stahl

Abstract. Groundwater is the main source of freshwater and maintains streamflow during drought. Potential future groundwater and baseflow drought hazards depend on systems' sensitivity to altered recharge conditions. We performed groundwater model experiments using three different generic scenarios to estimate the groundwater- and baseflow drought sensitivity to changes in recharge. The scenarios stem from a stakeholder co-design process that specifically followed the idea of altering known drought events from the past, i.e. asking whether altered recharge could have made a particular event worse. Across Germany groundwater responses to the scenarios are highly heterogeneous with groundwater heads in the North more sensitive to long-term recharge and in the Central German Uplands to short-term recharge variations. Baseflow droughts are generally more sensitive to intra-annual dynamics and baseflow responses to the scenarios are smaller compared to the groundwater heads. The groundwater drought recovery time is mainly driven by the hydrogeological conditions with slow (fast) recovery in the porous (fractured rock) aquifers. In general, a seasonal shift of recharge (i.e. less summer recharge and more winter recharge) will therefore have low effects on groundwater and baseflow drought severity. A lengthening of dry spells might cause much stronger responses, especially in regions with slow groundwater response to precipitation. As climate models suggest such directional changes for Germany in the future, the results of the stress tests suggest that groundwater resources in Germany may not decrease in general, but water management may need to consider the potential for more severe groundwater droughts in the large porous aquifers following prolonged meteorological droughts.

2021 ◽  
Author(s):  
Jost Hellwig ◽  
Michael Stoelzle ◽  
Kerstin Stahl

<p>Groundwater is the main source of freshwater and maintains streamflow during drought. Potential future groundwater and baseflow drought hazards depend on the systems' sensitivity to altered recharge conditions. We performed groundwater model experiments using three different generic stress tests to estimate the groundwater- and baseflow drought sensitivity to changes in recharge. The stress tests stem from a stakeholder co-design process that specifically followed the idea of altering known drought events from the past, i.e. asking whether altered recharge could have made a particular event worse. Here we show that groundwater responses to the stress tests are highly heterogeneous across Germany with groundwater heads in the North more sensitive to long-term recharge and in the Central German Uplands to short-term recharge variations. Baseflow droughts are generally more sensitive to intra-annual dynamics and baseflow responses to the stress tests are smaller compared to the groundwater heads. The groundwater drought recovery time is mainly driven by the hydrogeological conditions with slow (fast) recovery in the porous (fractured rock) aquifers. In general, a seasonal shift of recharge (i.e., less summer recharge and more winter recharge) will therefore have low effects on groundwater and baseflow drought severity. A lengthening of dry spells might cause much stronger responses, especially in regions with slow groundwater response to precipitation. Water management may need to consider the spatially different sensitivities of the groundwater system and the potential for more severe groundwater droughts in the large porous aquifers following prolonged meteorological droughts, particularly in the context of climate change projections indicating stronger seasonality and more severe drought events.</p>


2021 ◽  
Vol 25 (2) ◽  
pp. 1053-1068
Author(s):  
Jost Hellwig ◽  
Michael Stoelzle ◽  
Kerstin Stahl

Abstract. Groundwater is the main source of freshwater and maintains streamflow during drought. Potential future groundwater and baseflow drought hazards depend on the systems' sensitivity to altered recharge conditions. We performed groundwater model experiments using three different generic stress tests to estimate the groundwater and baseflow drought sensitivity to changes in recharge. The stress tests stem from a stakeholder co-design process that specifically followed the idea of altering known drought events from the past, i.e. asking whether altered recharge could have made a particular event worse. Across Germany, groundwater responses to the stress tests are highly heterogeneous, with groundwater heads in the north more sensitive to long-term recharge and in the Central German Uplands to short-term recharge variations. Baseflow droughts are generally more sensitive to intra-annual dynamics, and baseflow responses to the stress tests are smaller compared to the groundwater heads. The groundwater drought recovery time is mainly driven by the hydrogeological conditions, with slow (fast) recovery in the porous (fractured rock) aquifers. In general, a seasonal shift of recharge (i.e. less summer recharge and more winter recharge) will have lesser effects on groundwater and baseflow drought severity. A lengthening of dry spells might cause much stronger responses, especially in regions with slow groundwater response to precipitation. Water management may need to consider the spatially different sensitivities of the groundwater system and the potential for more severe groundwater droughts in the large porous aquifers following prolonged meteorological droughts, particularly in the context of climate change projections indicating stronger seasonality and more severe drought events.


2019 ◽  
Author(s):  
William Rust ◽  
Ian Holman ◽  
John Bloomfield ◽  
Mark Cuthbert ◽  
Ron Corstanje

Abstract. Predicting the next major drought is of paramount interest to water managers, globally. Estimating the onset of groundwater drought is of particular importance, as groundwater resources are often assumed to be more resilient when surface water resources begin to fail. A potential source of long-term forecasting is offered by possible periodic controls on groundwater level via teleconnections with oscillatory ocean-atmosphere systems. However, relationships between large-scale climate systems and regional to local-scale rainfall, ET and groundwater are often complex and non-linear so that the influence of long-term climate cycles on groundwater drought remains poorly understood. Furthermore it is currently unknown whether the absolute contribution of multi-annual climate variability to total groundwater storage is significant. This study assesses the extent to which inter-annual variability in groundwater can be used to indicate the timing of groundwater droughts in the UK. Continuous wavelet transforms show how repeating teleconnection-driven 7-year and 16–32 year cycles in the majority of groundwater sites from all the UK's major aquifers can systematically control the recurrence of groundwater drought; and we provide evidence that these periodic modes are driven by teleconnections. Wavelet reconstructions demonstrate that multi-annual periodicities of the North Atlantic Oscillation, known to drive North Atlantic meteorology, comprise up to 40 % of the total groundwater storage variability. Furthermore, the majority of UK recorded droughts in recent history coincide with a minima phase in the 7-year NAO-driven cycles in groundwater level, allowing the estimation of future drought occurrences on a multi-annual timescale. Long-range groundwater drought forecasts via climate teleconnections present transformational opportunities to drought prediction and its management across the North Atlantic region.


2021 ◽  
Vol 21 (1) ◽  
pp. 39-51
Author(s):  
Buruk Kitachew Wossenyeleh ◽  
Kaleb Asnake Worku ◽  
Boud Verbeiren ◽  
Marijke Huysmans

Abstract. Drought can be described as a temporary decrease in water availability over a significant period that affects both surface and groundwater resources. Droughts propagate through the hydrological cycle and may impact vulnerable ecosystems. This paper investigates drought propagation in the hydrological cycle, focusing on assessing its impact on a groundwater-fed wetland ecosystem. Meteorological drought indices were used to analyze meteorological drought severity. Moreover, a method for assessing groundwater drought and its propagation in the aquifer was developed and applied. Groundwater drought was analyzed using the variable threshold method. Furthermore, meteorological drought and groundwater drought on recharge were compared to investigate drought propagation in the hydrological cycle. This research is carried out in the Doode Bemde wetland in central Belgium. The results of this research show that droughts are attenuated in the groundwater system. The number and severity of drought events on groundwater discharge were smaller than for groundwater recharge. However, the onset of both drought events occurred at the same time, indicating a quick response of the groundwater system to hydrological stresses. In addition, drought propagation in the hydrological cycle indicated that not all meteorological droughts result in groundwater drought. Furthermore, this drought propagation effect was observed in the wetland.


2021 ◽  
Vol 298 ◽  
pp. 05002
Author(s):  
Mohamed Jalal El Hamidi ◽  
Abdelkader Larabi ◽  
Mohamed Faouzi

The study area of Rmel-O. Ogbane aquifer, located in the north of Morocco, currently faces major water challenges related to the sustainable management of water resources. Climate change and Sea-Level-Rise can increase the risks and costs of water resources management and impact water resources' quantity and quality. Hence, for planning and management, an integrated approach is developed for linking climate models and groundwater models to investigate future impacts of climate change on groundwater resources. Climate projections show an increase in temperature of about 0.45 °C and a reduction in precipitation of 16.7% for 2016-2050. Simulations of seawater intrusion corresponding to various combinations of groundwater extraction predicted climate change and sea-level-rise show that the area will be contaminated on the NW sector of the coastal part. The toe would reach about 5.2 km inland and intrude on high salinity (15–25g/l). Beyond these zones, the contamination of the aquifer will be limited. Moreover, these results were confirmed by the application of the GALDIT method. They reveal that the fringe littoral areas of the aquifer are the most affected by seawater intrusion, with a high risk in the north-western part of the study area.


2020 ◽  
Author(s):  
Buruk Kitachew Wossenyeleh ◽  
Kaleb Asnake Worku ◽  
Boud Verbeiren ◽  
Marijke Huysmans

Abstract. Drought can be described as a temporary decrease in water availability over a significant period and affects both surface and groundwater resources. Droughts propagate through the hydrological cycle and may impact vulnerable ecosystems. This paper investigates drought propagation in the hydrological cycle, focusing on assessing its impact on a groundwater-fed wetland ecosystem. Meteorological drought indices were used to analyze meteorological drought severity. Besides, a method for assessing groundwater drought and its propagation in the aquifer was developed and applied. Groundwater drought was analyzed using the variable threshold method. Furthermore, meteorological drought and groundwater drought on recharge were compared to investigate drought propagation in the hydrological. This research is carried out in the Doode Bemde wetland in central Belgium. The results of this research show that droughts are strongly attenuated in the groundwater system. The number and severity of groundwater discharge drought events were smaller than for groundwater recharge drought. However, the onset of both drought events occurred at the same time, indicating a quick response of the groundwater system to hydrological stresses. In addition, drought propagation in the hydrological cycle indicated that not all meteorological droughts result in groundwater drought. Furthermore, this drought propagation effect was observed in the wetland.


2019 ◽  
Vol 23 (8) ◽  
pp. 3233-3245 ◽  
Author(s):  
William Rust ◽  
Ian Holman ◽  
John Bloomfield ◽  
Mark Cuthbert ◽  
Ron Corstanje

Abstract. Predicting the next major drought is of paramount interest to water managers globally. Estimating the onset of groundwater drought is of particular importance, as groundwater resources are often assumed to be more resilient when surface water resources begin to fail. A potential source of long-term forecasting is offered by possible periodic controls on groundwater level via teleconnections with oscillatory ocean–atmosphere systems. However, relationships between large-scale climate systems and regional to local-scale rainfall, evapotranspiration (ET) and groundwater are often complex and non-linear so that the influence of long-term climate cycles on groundwater drought remains poorly understood. Furthermore, it is currently unknown whether the absolute contribution of multi-annual climate variability to total groundwater storage is significant. This study assesses the extent to which multi-annual variability in groundwater can be used to indicate the timing of groundwater droughts in the UK. Continuous wavelet transforms show how repeating teleconnection-driven 7-year and 16–32-year cycles in the majority of groundwater sites from all the UK's major aquifers can systematically control the recurrence of groundwater drought; and we provide evidence that these periodic modes are driven by teleconnections. Wavelet reconstructions demonstrate that multi-annual periodicities of the North Atlantic Oscillation, known to drive North Atlantic meteorology, comprise up to 40 % of the total groundwater storage variability. Furthermore, the majority of UK recorded droughts in recent history coincide with a minimum phase in the 7-year NAO-driven cycles in groundwater level, providing insight into drought occurrences on a multi-annual timescale. Long-range groundwater drought forecasts via climate teleconnections present transformational opportunities to drought prediction and its management across the North Atlantic region.


2008 ◽  
Vol 22 (2) ◽  
pp. 85 ◽  
Author(s):  
William F. Humphreys

Over the last two decades, Australia has undergone a renaissance in studies of subterranean biology. This paper sets these recent developments into context from the perspective of groundwater fauna. Owing to its obligate subterranean life, typical local endemicity and the geological persistence of subterranean habitats, stygofauna is an excellent subject for biogeographic study. Groundwater containing diverse faunas range from freshwater to marine salinities in both coastal and continental locations. They occur in typical karst, alluvial, and fractured rock aquifers, but also in novel matrices formed during the hydrogeochemical evolution of groundwater (goethite pisolites and groundwater calcretes) in the Tertiary. This range of habitats, water quality and the diverse origins of the fauna (Gondwanan, Pangaean and Tethys) support a phylogenetically highly diverse fauna. Several taxa, notably among the Podocopida, Bathynellacea, Amphipoda, and Dytiscidae show remarkable species diversity. Typically there is fine spatial scale endemicity of species associated with local aquifers, but there are inexplicable regional differences, such as the change of fauna between the Yilgarn and Pilbara, contiguous areas on the long emergent Western Shield. The anchialine taxa representing higher taxa are highly disjunct from their congeners in the North Atlantic. The emerging species richness, the fine scale patchwork of endemicity, and the distinct regional differences, respectively, contribute to a substantial increase in α, β and γ diversity of the aquatic fauna, especially in arid Australia. This diversity is posing challenging issues for proponents and regulators of mineral development because much of this diversity has emerged in the two most mineraliferous provinces of Australia. The scientific capacity to respond is challenged by the sheer scale of the emerging issues.


2016 ◽  
Vol 41 ◽  
pp. 22-25 ◽  
Author(s):  
Vittorio Bonaria ◽  
Francesco Faccini ◽  
Ilaria Cinzia Galiano ◽  
Alessandro Sacchini

2019 ◽  
Author(s):  
Hamed D. Ibrahim

North and South Atlantic lateral volume exchange is a key component of the Atlantic Meridional Overturning Circulation (AMOC) embedded in Earth’s climate. Northward AMOC heat transport within this exchange mitigates the large heat loss to the atmosphere in the northern North Atlantic. Because of inadequate climate data, observational basin-scale studies of net interbasin exchange between the North and South Atlantic have been limited. Here ten independent climate datasets, five satellite-derived and five analyses, are synthesized to show that North and South Atlantic climatological net lateral volume exchange is partitioned into two seasonal regimes. From late-May to late-November, net lateral volume flux is from the North to the South Atlantic; whereas from late-November to late-May, net lateral volume flux is from the South to the North Atlantic. This climatological characterization offers a framework for assessing seasonal variations in these basins and provides a constraint for climate models that simulate AMOC dynamics.


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