scholarly journals HESS Opinions "Integration of groundwater and surface water research: an interdisciplinary problem?"

2014 ◽  
Vol 11 (2) ◽  
pp. 2011-2044
Author(s):  
R. Barthel

Abstract. Today there is a great consensus that water resources research needs to become more holistic, integrating perspectives of a large variety of disciplines. Groundwater and surface water (hereafter: GW and SW) are typically identified as different compartments of the hydrological cycle and were traditionally often studied and managed separately. However, despite this separation, these respective fields of study are usually not considered to be different disciplines. They are often seen as different specialisations of hydrology with different focus, yet similar theory, concepts, methodology. The present article discusses how this notion may form a substantial obstacle in the further integration of GW and SW research and management. The article focusses on the regional scale (areas of approx. 103 to 106 km2), which is identified as the scale where integration is most greatly needed, but ironically the least amount of fully integrated research seems to be undertaken. The state of research on integrating GW and SW research is briefly reviewed and the most essential differences between GW hydrology (or hydrogeology, geohydrology) and SW hydrology are presented. Groundwater recharge and baseflow are used as examples to illustrate different perspectives on similar phenomena that can cause severe misunderstandings and errors in the conceptualisation of integration schemes. It is also discussed that integration of GW and SW research on the regional scale necessarily must move beyond the hydrological aspects, by collaborating with social sciences and increasing the interaction between science and the society in general. The typical elements of an ideal interdisciplinary workflow are presented and their relevance with respect to integration of GW and SW is discussed. The overall conclusions are that GW hydrology and SW hydrogeology study rather different objects of interest, using different types of observation, working on different problem settings. They have thus developed different theory, methodology and terminology. Yet, there seems to be a widespread lack of awareness of these differences which hinders the detection of the existing interdisciplinary aspects of GW and SW integration and consequently the development of truly unifying, interdisciplinary theory and methodology. Thus, despite having the ultimate goal of creating a more holistic approach, we should start integration by analysing potential disciplinary differences. Improved understanding among hydrologists of what interdisciplinary means and how it works is needed. Hydrologists, despite frequently being involved in multidisciplinary projects, are not sufficiently involved in developing interdisciplinary strategies and do usually not regard the process of integration as such as a research topic of its own. There seems to be a general reluctance to apply (truly) interdisciplinary methodology because this is tedious and few, immediate incentives are experienced.

2014 ◽  
Vol 18 (7) ◽  
pp. 2615-2628 ◽  
Author(s):  
R. Barthel

Abstract. Today there is a great consensus that water resource research needs to become more holistic, integrating perspectives of a large variety of disciplines. Groundwater and surface water (hereafter: GW and SW) are typically identified as different compartments of the hydrological cycle and were traditionally often studied and managed separately. However, despite this separation, these respective fields of study are usually not considered to be different disciplines. They are often seen as different specializations of hydrology with a different focus yet similar theory, concepts, and methodology. The present article discusses how this notion may form a substantial obstacle in the further integration of GW and SW research and management. The article focuses on the regional scale (areas of approximately 103 to 106 km2), which is identified as the scale where integration is most greatly needed, but ironically where the least amount of fully integrated research seems to be undertaken. The state of research on integrating GW and SW research is briefly reviewed and the most essential differences between GW hydrology (or hydrogeology, geohydrology) and SW hydrology are presented. Groundwater recharge and baseflow are used as examples to illustrate different perspectives on similar phenomena that can cause severe misunderstandings and errors in the conceptualization of integration schemes. The fact that integration of GW and SW research on the regional scale necessarily must move beyond the hydrological aspects, by collaborating with the social sciences and increasing the interaction between science and society in general, is also discussed. The typical elements of an ideal interdisciplinary workflow are presented and their relevance with respect to the integration of GW and SW is discussed. The overall conclusions are that GW hydrology and SW hydrogeology study rather different objects of interest, using different types of observation, working on different problem settings. They have thus developed a different theory, methodology and terminology. However, there seems to be a widespread lack of awareness of these differences, which hinders the detection of the existing interdisciplinary aspects of GW and SW integration and consequently the development of a truly unifying interdisciplinary theory and methodology. Thus, despite having the ultimate goal of creating a more holistic approach, we may have to start integration by analyzing potential disciplinary differences. Improved understanding among hydrologists of what interdisciplinary means and how it works is needed. Hydrologists, despite frequently being involved in multidisciplinary projects, are not sufficiently involved in developing interdisciplinary strategies and do usually not regard the process of integration as such as a research topic of its own. There seems to be a general reluctance to apply a (truly) interdisciplinary methodology because this is tedious and few immediate incentives are experienced. The objective of the present opinion paper is to stimulate a discussion rather than to provide recipes on how to integrate GW and SW research or to explain how specific problems of GW–SW interaction should be solved on a technical level. For that purpose it presents complicated topics in a rather simplified, bold way, ignoring to some degree subtleties and potentially controversial issues.


2021 ◽  
Author(s):  
Sly Wongchuig ◽  
Jhan Carlo Espinoza ◽  
Thomas Condom ◽  
Hans Segura ◽  
Josyane Ronchail ◽  
...  

<p>Linking the Amazonian deforestation to changes in the hydrological cycle remains a puzzling question, addressed here through the use of recent global databases analyzing the relations between key hydro-climate variables (Precipitation (P), potential and actual evapotranspiration (PET and AET, respectively)), the surface water-energy balance and indices of forest cover change (regional forest loss ratio -RFL and regional non-forest vegetation ratio -RNF) for Southern Amazon (south of 8°S) and over the 1981-2018 period. The Southern Amazon constitutes a peculiar region due to specific climatic characteristics and shows a higher significant deforestation rate in comparison with the Northern Amazon. We further subdivided the study region into three subregions called Southern Bolivian Amazon (15° S‒21° S, 57° W‒70° W), Southern Peruvian Amazon (8° S‒15° S, 77° W‒65° W) and Southern Brazilian Amazon (8° S‒15° S, 65° W‒50° W). The surface water-energy balance is analyzed using a pixel-based Budyko-like theoretical framework approach, which discriminates energy-limited regions from water-limited regions. Southern Bolivian Amazon is shown to have undergone the strongest forest transition, becoming water-limited in conjunction with high forest loss. In this region, there is a significant relation between RFL values above 40%, P decrease, PET increases and AET decrease. These results suggest that areas with RNF values higher than 40% are prone to shift from an energy-limited to a water-limited state and remain trapped in this new state. Regions further north remain energy-limited due to minor P changes and even though significant increases in PET and decreases in AET are observed, associated with deforestation (high values RFL). This is typically the case in the ‘Arc of Deforestation’. In the Southern Bolivian Amazon, land use transition is associated with much larger changes from closed forest to a low-tree cover state as compared to regions further north - by at least a factor three as a proportion of area. Our findings indicate a clear link between hydro-climatic changes and deforestation, providing a new perspective on their spatial variability on a regional scale.</p><p> </p><p>This research is part of the French AMANECER-MOPGA project.</p>


2021 ◽  
Author(s):  
Dario Ruggiu ◽  
Salvatore Urru ◽  
Roberto Deidda ◽  
Francesco Viola

<p>The assessment of climate change and land use modifications effects on hydrological cycle is challenging. We propose an approach based on Budyko theory to investigate the relative importance of natural and anthropogenic drivers on water resources availability. As an example of application, the proposed approach is implemented in the island of Sardinia (Italy), which is affected by important processes of both climate and land use modifications. In details, the proposed methodology assumes the Fu’s equation to describe the mechanisms of water partitioning at regional scale and uses the probability distributions of annual runoff (Q) in a closed form. The latter is parametrized by considering simple long-term climatic info (namely first orders statistics of annual rainfall and potential evapotranspiration) and land use properties of basins.</p><p>In order to investigate the possible near future water availability of Sardinia, several climate and land use scenarios have been considered, referring to 2006-2050 and 2051-2100 periods. Climate scenarios have been generated considering fourteen bias corrected outputs of climatic models from EUROCORDEX’s project (RCP 8.5), while three land use scenarios have been created following the last century tendencies.</p><p>Results show that the distribution of annual runoff in Sardinia could be significantly affected by both climate and land use change. The near future distribution of Q generally displayed a decrease in mean and variance compared to the baseline.   </p><p>The reduction of  Q is more critical moving from 2006-2050 to 2051-2100 period, according with climatic trends, namely due to the reduction of annual rainfall and the increase of potential evapotranspiration. The effect of LU change on Q distribution is weaker than the climatic one, but not negligible.</p>


2012 ◽  
Vol 16 (3) ◽  
pp. 649-669 ◽  
Author(s):  
G. H. de Rooij

Abstract. The increasing importance of catchment-scale and basin-scale models of the hydrological cycle makes it desirable to have a simple, yet physically realistic model for lateral subsurface water flow. As a first building block towards such a model, analytical solutions are presented for horizontal groundwater flow to surface waters held at prescribed water levels for aquifers with parallel and radial flow. The solutions are valid for a wide array of initial and boundary conditions and additions or withdrawals of water, and can handle discharge into as well as lateral infiltration from the surface water. Expressions for the average hydraulic head, the flux to or from the surface water, and the aquifer-scale hydraulic conductivity are developed to provide output at the scale of the modelled system rather than just point-scale values. The upscaled conductivity is time-variant. It does not depend on the magnitude of the flux but is determined by medium properties as well as the external forcings that drive the flow. For the systems studied, with lateral travel distances not exceeding 10 m, the circular aquifers respond very differently from the infinite-strip aquifers. The modelled fluxes are sensitive to the magnitude of the storage coefficient. For phreatic aquifers a value of 0.2 is argued to be representative, but considerable variations are likely. The effect of varying distributions over the day of recharge damps out rapidly; a soil water model that can provide accurate daily totals is preferable over a less accurate model hat correctly estimates the timing of recharge peaks.


2021 ◽  
Author(s):  
Michiel Maertens ◽  
Veerle Vanacker ◽  
Gabriëlle De Lannoy ◽  
Frederike Vincent ◽  
Raul Giménez ◽  
...  

<p>The South-American Dry Chaco is a unique ecoregion as it is one of the largest sedimentary plains in the world hosting the planet’s largest dry forest. The 787.000 km² region covers parts of Argentina, Paraguay, and Bolivia and is characterized by a negative climatic water balance as a consequence of limited rainfall inputs (800 mm/year) and high temperatures (21°C). In combination with the region’s extreme flat topography (slopes < 0.1%) and shallow groundwater tables, saline soils are expected in substantial parts of the region. In addition, it is expected that large-scale deforestation processes disrupt the hydrological cycle resulting in rising groundwater tables and further increase the risk for soil salinization.</p><p>In this study, we identified the regional-scale patterns of subsurface soil salinity in the Dry Chaco.  Field data were obtained during a two-month field campaign in the dry season of 2019. A total of 492 surface- and 142 subsurface-samples were collected along East-West transects to determine soil electric conductivity, pH, bulk density and humidity. Spatial regression techniques were used to reveal the topographic and ecohydrological variables that are associated with subsurface soil salinity over the Dry Chaco. The hydrological information was obtained from a state-of-the-art land surface model with an improved set of satellite-derived vegetation and land cover parameters.</p><p>In the presentation, we will present a subsurface soil salinity map for a part of the Argentinean Dry Chaco and provide relevant insights into the driving mechanisms behind it.</p>


2019 ◽  
Vol 11 (24) ◽  
pp. 7189
Author(s):  
Wiktor Halecki ◽  
Tomasz Kowalik ◽  
Andrzej Bogdał

The anthropogenic problems in richly sculpted areas (mountain and submontane) are mainly related to agricultural activity, which shapes the quality of surface waters. This paper presents an analysis of the results of the hydrochemical tests carried out in the years 2007–2018 at check-control spots. The heavy metal pollution index (HPI < 100) indicated a low risk for aquatic organisms. The statistical calculations obtained by means of multivariate adaptive regression splines (MARS) designated that the hazard quotient (HQ) index can be combined with the electrical conductivity (EC) and total dissolved substances (TDS) parameters used in the assessment of water erosion. The HQ index showed that the concentration of individual heavy metals is lower than their value in the 0.5 percentile of the value. In subsequent studies, it should be assessed whether the size of arable land has an impact on the increased concentration of heavy metals in the surface water. We recommend small retention reservoirs as a potential management measure to improve the quality of the surface water at a regional scale. This study has great potential to mitigate the degradation processes related to the insufficient storage capacity, and to promote natural water retention.


2005 ◽  
Vol 36 (4-5) ◽  
pp. 321-333 ◽  
Author(s):  
Valentina Krysanova ◽  
Fred Hattermann ◽  
Anja Habeck

Reliable modelling of climate–water interactions at the river basin and regional scale requires development of advanced modelling approaches at scales relevant for assessing the potential effects of climate change on the hydrological cycle. These approaches should represent the atmospheric, surface and subsurface hydrological processes and take into account their characteristic temporal and spatial scales of occurrence. The paper presents a climate change impact assessment performed for the Elbe River basin in Germany (about 100 000 km2). The method used for the study combines: (a) a statistical downscaling method driven by GCM-predicted temperature trend for producing climate scenarios, and (b) a simulation technique based on an ecohydrological semi-distributed river basin model, which was thoroughly validated in advance. The overall result of the climate impact study for the basin is that the mean water discharge and the mean groundwater recharge in the Elbe basin will be most likely decreased under the expected climate change and diffuse source pollution will be diminished. Our study confirms that the uncertainty in hydrological and water quality responses to changing climate is generally higher than the uncertainty in climate input. The method is transferable to other basins in the temperate zone.


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