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  • 1.
    Asokan, Shilpa M.
    et al.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Dutta, Dushmanta
    Analysis of water resources in the Mahanadi River Basin, India under projected climate conditions2008In: Hydrological Processes, ISSN 0885-6087, E-ISSN 1099-1085, Vol. 22, no 18, p. 3589-3603Article in journal (Refereed)
    Abstract [en]

    The paper presents the outcomes of a study conducted to analyse water resources availability and demand in the Mahanadi River Basin in India under climate change conditions. Climate change impact analysis was carried out for the years 2000, 2025, 2050, 2075 and 2100, for the months of September and April (representing wet and dry months), at a sub-catchment level. A physically based distributed hydrologic model (DHM) was used for estimation of the present water availability. For future scenarios under climate change conditions, precipitation output of Canadian Centre for Climate Modelling and Analysis General Circulation Model (CGCM2) was used as the input data for the DHM. The model results show that the highest increase in peak runoff (38%) in the Mahanadi River outlet will occur during September, for the period 2075-2100 and the maximum decrease in average runoff (32·5%) will be in April, for the period 2050-2075. The outcomes indicate that the Mahanadi River Basin is expected to experience progressively increasing intensities of flood in September and drought in April over the considered years. The sectors of domestic, irrigation and industry were considered for water demand estimation. The outcomes of the analysis on present water use indicated a high water abstraction by the irrigation sector. Future water demand shows an increasing trend until 2050, beyond which the demand will decrease owing to the assumed regulation of population explosion. From the simulated future water availability and projected water demand, water stress was computed. Among the six sub-catchments, the sub-catchment six shows the peak water demand. This study hence emphasizes on the need for re-defining water management policies, by incorporating hydrological response of the basin to the long-term climate change, which will help in developing appropriate flood and drought mitigation measures at the basin level.

  • 2. Bishop, K.
    et al.
    Seibert, J.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Nyberg, L.
    Rodhe, A.
    Water storage in a till catchment. II: Implications of transmissivity feedback for flow paths and turnover times2011In: Hydrological Processes, ISSN 0885-6087, E-ISSN 1099-1085, Vol. 25, no 25, p. 3950-3959Article in journal (Refereed)
    Abstract [en]

    This paper explores the flow paths and turnover times within a catchment characterized by the transmissivity feedback mechanism where there is a strong increase in the saturated hydraulic conductivity towards the soil surface and precipitation inputs saturate progressively more superficial layers of the soil profile. The analysis is facilitated by the correlation between catchment water storage and groundwater levels, which made it possible to model the daily spatial distribution of water storage, both vertically in different soil horizons and horizontally across a 6300-m2 till catchment. Soil properties and episodic precipitation input dynamics, combined with the influence of topographic features, concentrate flow in the horizontal, vertical, and temporal dimensions. Within the soil profile, there was a vertical concentration of lateral flow to superficial soil horizons (upper 30?cm of the soil), where much of the annual flow occurred during runoff episodes. Overland flow from a limited portion of the catchment can contribute to peak flows but is not a necessary condition for runoff episodes. The spatial concentration of flow, and the episodic nature of runoff events, resulted in a strong and spatially structured differentiation of local flow velocities within the catchment. There were large differences in the time spent by the laterally flowing water at different depths, with turnover times of lateral flow across a 1-m-wide soil pedon ranging from under 1?h at 10- to 20-cm depth to a month at 70- to 80-cm depth. In many regards, the hydrology of this catchment appears typical of the hydrology in till soils, which are widespread in Fenno-Scandia. Copyright (c) 2011 John Wiley & Sons, Ltd.

  • 3. Carey, Sean K.
    et al.
    Tetzlaff, Doerthe
    Seibert, Jan
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology (INK).
    Soulsby, Chris
    Buttle, Jim
    Laudon, Hjalmar
    McDonnell, Jeff
    McGuire, Kevin
    Caissie, Daniel
    Shanley, Jamie
    Kennedy, Mike
    Devito, Kevin
    Pomeroy, John W.
    Inter-comparison of hydro-climatic regimes across northern catchments: synchronicity, resistance and resilience2010In: Hydrological Processes, ISSN 0885-6087, E-ISSN 1099-1085, Vol. 24, no 24, p. 3591-3602Article in journal (Refereed)
    Abstract [en]

    The higher mid-latitudes of the Northern Hemisphere are particularly sensitive to climate change as small differences in temperature determine frozen ground status, precipitation phase, and the magnitude and timing of snow accumulation and melt. An international inter-catchment comparison program, North-Watch, seeks to improve our understanding of the sensitivity of northern catchments to climate change by examining their hydrological and biogeochemical responses. The catchments are located in Sweden (Krycklan), Scotland (Mharcaidh, Girnock and Strontian), the United States (Sleepers River, Hubbard Brook and HJ Andrews) and Canada (Catamaran, Dorset and Wolf Creek). This briefing presents the initial stage of the North-Watch program, which focuses on how these catchments collect, store and release water and identify 'types' of hydro-climatic catchment response. At most sites, a 10-year data of daily precipitation, discharge and temperature were compiled and evaporation and storage were calculated. Inter-annual and seasonal patterns of hydrological processes were assessed via normalized fluxes and standard flow metrics. At the annual-scale, relations between temperature, precipitation and discharge were compared, highlighting the role of seasonality, wetness and snow/frozen ground. The seasonal pattern and synchronicity of fluxes at the monthly scale provided insight into system memory and the role of storage. We identified types of catchments that rapidly translate precipitation into runoff and others that more readily store water for delayed release. Synchronicity and variance of rainfall-runoff patterns were characterized by the coefficient of variation (cv) of monthly fluxes and correlation coefficients. Principal component analysis (PCA) revealed clustering among like catchments in terms of functioning, largely controlled by two components that (i) reflect temperature and precipitation gradients and the correlation of monthly precipitation and discharge and (ii) the seasonality of precipitation and storage. By advancing the ecological concepts of resistance and resilience for catchment functioning, results provided a conceptual framework for understanding susceptibility to hydrological change across northern catchments.

  • 4.
    Dahlke, Helen E.
    et al.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Lyon, Steve W.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Jansson, Peter
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Karlin, Torbjörn
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Rosqvist, Gunhild
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Isotopic investigation of runoff generation in a glacierized catchment in northern Sweden2014In: Hydrological Processes, ISSN 0885-6087, E-ISSN 1099-1085, Vol. 28, no 3, p. 1383-1398Article in journal (Refereed)
    Abstract [en]

    In this study, summer rainfall contributions to streamflow were quantified in the sub-arctic, 30% glacierized Tarfala (21.7km(2)) catchment in northern Sweden for two non-consecutive summer sampling seasons (2004 and 2011). We used two-component hydrograph separation along with isotope ratios (O-18 and D) of rainwater and daily streamwater samplings to estimate relative fraction and uncertainties (because of laboratory instrumentation, temporal variability and spatial gradients) of source water contributions. We hypothesized that the glacier influence on how rainfall becomes runoff is temporally variable and largely dependent on a combination of the timing of decreasing snow cover on glaciers and the relative moisture storage condition within the catchment. The results indicate that the majority of storm runoff was dominated by pre-event water. However, the average event water contribution during storm events differed slightly between both years with 11% reached in 2004 and 22% in 2011. Event water contributions to runoff generally increased over 2011 the sampling season in both the main stream of Tarfala catchment and in the two pro-glacial streams that drain Storglaciaren (the largest glacier in Tarfala catchment covering 2.9km(2)). We credit both the inter-annual and intra-annual differences in event water contributions to large rainfall events late in the summer melt season, low glacier snow cover and elevated soil moisture due to large antecedent precipitation. Together amplification of these two mechanisms under a warming climate might influence the timing and magnitude of floods, the sediment budget and nutrient cycling in glacierized catchments.

  • 5. Dahlke, Helen E.
    et al.
    Williamson, Andrew G.
    Georgakakos, Christine
    Leung, Selene
    Sharma, Asha N.
    Lyon, Steve W.
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Walter, M. Todd
    Using concurrent DNA tracer injections to infer glacial flow pathways2015In: Hydrological Processes, ISSN 0885-6087, E-ISSN 1099-1085, Vol. 29, no 25, p. 5257-5274Article in journal (Refereed)
    Abstract [en]

    Catchment hydrology has become replete with flow pathway characterizations obtained via combinations of physical hydrologic measurements (e.g. streamflow hydrographs) and natural tracer signals (e.g. stable water isotopes and geochemistry). In this study, we explored how our understanding of hydrologic flow pathways can be improved and expanded in both space and time by the simultaneous application of engineered synthetic DNA tracers. In this study, we compared the advective-dispersive transport properties and mass recovery rates of two types of synthetic DNA tracers, one consisting of synthetic DNA strands encapsulated into biodegradable microspheres and another consisting of `free' DNA, i.e. not encapsulated. The DNA tracers were also compared with a conservative fluorescent dye. All tracers were injected into a small (3.2-km(2)) valley glacier, Storglaciaren, in northern Sweden. Seven of the nine DNA tracers showed clear recovery during the sampling period and similar peak arrival times and dispersion coefficients as the conservative fluorescent dye. However, recovered DNA tracer mass ranged only from 1% to 66%, while recovered fluorescent dye mass was 99%. Resulting from the cold and opaque subglacial environment provided by the glacier, mass loss associated with microbial activity and photochemical degradation of the DNA is likely negligible, leaving sorption of DNA tracers onto suspended particles and loss of microtracer particles to sediment storage as probable explanations. Despite the difference in mass recovery, the advection and dispersion information derived from the DNA tracer breakthrough curves provided spatially explicit information that allowed inferring a theoretical model of the flow pathways that water takes through the glacier.

  • 6.
    Darracq, Amelie
    et al.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Destouni, Georgia
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Persson, Klas
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Prieto, Carmen
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Jarsjö, Jerker
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Scale and model resolution effects on the distributions of advective solute travel times in catchments2010In: Hydrological Processes, ISSN 0885-6087, E-ISSN 1099-1085, Vol. 24, no 12, p. 1697-1710Article in journal (Refereed)
    Abstract [en]

    Advective solute travel times and their distributions in hydrological catchments are useful descriptors of the dynamics and variation of the physical mass transport among and along the different source-to-recipient pathways of solute transport through the catchments. This article investigates the scale dependence and the effects of model and data resolution on the quantification of advective travel times and their distributions in the Swedish catchment areas of Norrström and Forsmark. In the surface water networks of the investigated (sub)catchments, the mean advective travel time increases with (sub)catchment scale, whereas the relative travel time variability around the mean value (coefficient of variation, CV) is scale-invariant and insensitive to model resolution. In the groundwater and for the whole (sub)catchments, both the mean value and the CV of travel times are scale-invariant, but sensitive to model resolution and accuracy. Such quantifications and results of advective travel times constitute important steps in the development of improved understanding and modelling of nutrient, pollutant and tracer transport through catchments.

  • 7. Divine, D. V.
    et al.
    Sjolte, J.
    Isaksson, E.
    Meijer, H. A. J.
    van de Wal, R. S. W.
    Martma, T.
    Pohjola, V.
    Sturm, Christophe
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Godtliebsen, F.
    Modelling the regional climate and isotopic composition of Svalbard precipitation using REMOiso: a comparison with available GNIP and ice core data2011In: Hydrological Processes, ISSN 0885-6087, E-ISSN 1099-1085, Vol. 25, no 24, p. 3748-3759Article in journal (Refereed)
    Abstract [en]

    Simulations of a regional (approx. 50 km resolution) circulation model REMOiso with embedded stable water isotope module covering the period 1958-2001 are compared with the two instrumental climate and four isotope series (d18O) from western Svalbard. We examine the data from ice cores drilled on Svalbard ice caps in 1997 (Lomonosovfonna, 1250 m asl) and 2005 (Holtedahlfonna, 1150 m asl) and the GNIP series from Ny-angstrom lesund and Isfjord Radio. The surface air temperature (SAT) and precipitation data from Longyearbyen and Ny-angstrom lesund are used to assess the skill of the model in reproducing the local climate. The model successfully captures the climate variations on the daily to multidecadal times scales although it tends to systematically underestimate the winter SAT. Analysis suggests that REMOiso performs better at simulating isotope compositions of precipitation in the winter than summer. The simulated and measured Holtedahlfonna d18O series agree reasonably well, whereas no significant correlation has been observed between the modelled and measured Lomonosovfonna ice core isotopic series. It is shown that sporadic nature as well as variability in the amount inherent in precipitation process potentially limits the accuracy of the past SAT reconstruction from the ice core data. This effect in the study area is, however, diminished by the role of other factors controlling d18O in precipitation, most likely sea ice extent, which is directly related with the SAT anomalies.

  • 8. Garg, Kaushal K.
    et al.
    Wani, Suhas P.
    Barron, Jennie
    Stockholm University, Stockholm Resilience Centre, Stockholm Environment Institute.
    Karlberg, Louise
    Stockholm University, Stockholm Resilience Centre, Stockholm Environment Institute.
    Rockström, Johan
    Stockholm University, Stockholm Resilience Centre, Stockholm Environment Institute.
    Up-scaling potential impacts on water flows from agricultural water interventions: opportunities and trade-offs in the Osman Sagar catchment, Musi sub-basin, India2013In: Hydrological Processes, ISSN 0885-6087, E-ISSN 1099-1085, Vol. 27, no 26, p. 3905-3921Article in journal (Refereed)
    Abstract [en]

    Agricultural water management (AWM) has been shown to improve and secure yields in the tropics and has been suggested as an important way to combat poverty in the region. In this paper, we describe potential impacts on upstream and downstream flows of extensive AWM interventions, using the watershed development programme of the Osman Sagar catchment of Musi sub-basin, Andhra Pradesh semi-arid India, as an example. Various AWM interventions are compared with a non-intervention state and the current state of the study area, using 31 years of data by application of the calibrated and validated ARCSWAT 2005 (Version 2.1.4a) modelling tool. Different AWM interventions contribute to improved livelihoods of upstream smallholder farmers by increasing soil moisture availability and groundwater recharge, which can subsequently be used for irrigation. The result is higher crop production and hence larger incomes. Moreover, lower flow intensities and sediment losses reduced by 30-50%, reducing the risk of flooding and sediment accumulation in the Osman Sagar drinking water reservoir. On the other hand, AWM interventions are predicted to result in reduced total water inflows to the Osman Sagar reservoir from 11% of the total annual rainfall (754mm) recorded at present, to 8% if AWM interventions were implemented at large scale throughout the catchment. A cost-benefit analysis of AWM interventions showed that the highest net economic returns were achieved at intermediate intervention levels (only in-situ AWM).

  • 9. Garg, K.K.
    et al.
    Karlberg, Louise
    Stockholm University, Stockholm Resilience Centre, Stockholm Environment Institute.
    Barron, Jennie
    Stockholm Environment Institute, York, UK.
    Wani, S.P.
    Rockström, Johan
    Stockholm University, Stockholm Resilience Centre, Stockholm Environment Institute.
    Assessing impacts of agricultural water interventions in the Kothapally watershed, Southern India2012In: Hydrological Processes, ISSN 0885-6087, E-ISSN 1099-1085, Vol. 26, no 3, p. 387-404Article in journal (Refereed)
  • 10. Garg, K.L.
    et al.
    Wani, S.P.
    Barron, J.
    Karlberg, Louise
    Stockholm University, Stockholm Environment Institute.
    Rockström, Johan
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Reply to comment on ‘Up-scaling potential impacts on water flows from agricultural water interventions: opportunities and trade-offs in the Osman Sagar catchment, Musi sub-basin, India’2014In: Hydrological Processes, ISSN 0885-6087, E-ISSN 1099-1085, Vol. 28, no 8, p. 3352-3355Article in journal (Refereed)
  • 11.
    Lyon, S. W.
    et al.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Laudon, H.
    Seibert, Jan
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Morth, M.
    Tetzlaff, D.
    Bishop, K. H.
    Controls on snowmelt water mean transit times in northern boreal catchments2010In: Hydrological Processes, ISSN 0885-6087, E-ISSN 1099-1085, Vol. 24, no 12, p. 1672-1684Article in journal (Refereed)
    Abstract [en]

    Catchment-scale transit times for water are increasingly being recognized as an important control on geochemical processes. In this study, snowmelt water mean transit times (MTTs) were estimated for the 15 Krycklan research catchments in northern boreal Sweden. The snowmelt water MTTs were assumed to be representative of the catchment-scale hydrologic response during the spring thaw period and, as such, may be considered to be a component of the catchment's overall MTT. These snowmelt water MTTs were empirically related to catchment characteristics and landscape structure represented by using different indices of soil cover, topography and catchment similarity. Mire wetlands were shown to be significantly correlated to snowmelt MTTs for the studied catchments. In these wetlands, shallow ice layers form that have been shown to serve as impervious boundaries to vertical infiltration during snowmelt periods and, thus, alter the flow pathways of water in the landscape. Using a simple thought experiment, we could estimate the potential effect of thawing of ice layers on snowmelt hydrologic response using the empirical relationship between landscape structure (represented using a catchment-scale Pe number) and hydrologic response. The result of this thought experiment was that there could be a potential increase of 20-45% in catchment snowmelt water MTTs for the Krycklan experimental catchments. It is therefore possible that climatic changes present competing influences on the hydrologic response of northern boreal catchments that need to be considered. For example, MTTs may tend to decrease during some times of the year due to an acceleration in the hydrologic cycle, while they tend to increase MTTs during other times of the year due to shifts in hydrologic flow pathways. The balance between the competing influences on a catchment's MTT has consequences on climatic feedbacks as it could influence hydrological and biogeochemical cycles at the catchment scale for northern latitude boreal catchments. Copyright (C) 2010 John Wiley & Sons, Ltd.

  • 12.
    Lyon, Steve
    et al.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Desilets, S
    Troch, P
    A tale of two isotopes: differences in hydrograph separation fora runoff event when using δD versus δ18O2009In: Hydrological Processes, ISSN 0885-6087, E-ISSN 1099-1085, Vol. 23, no 14, p. 2095-2101Article in journal (Refereed)
    Abstract [en]

    It is often assumed that stable water isotopes (dD and d18O) provide redundant information for a given sample of water. In this note we illustrate  that the choice of isotope used may influence the resultant hydrograph separation. This is especially true in light of the spatial and temporal variability in the isotopic composition of rainfall water at the catchment scale. We present several possible hydrograph separations based on both dD and d18O observed in rainfall for a single runoff event occurring in the southwest USA. This study demonstrates the potential of using both stable water isotopes by showing that dD and d18O may provide unique information for catchment hydrologists. We also report on the utility of new technology capable of simultaneous measurements of both dD and d18O using off-axis integrated cavity output spectroscopy (OA-ICOS) methods. This may be of interest to catchment hydrologists seeking to incorporate this type of equipment into their laboratory.

  • 13.
    Lyon, Steve W.
    et al.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Koutsouris, Alexander
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Scheibler, Friedemann
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Jarsjö, Jerker
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Mbanguka, Rene
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Tumbo, Madaka
    Robert, Keven K.
    Sharma, Asha N.
    van der Velde, Ype
    Interpreting characteristic drainage timescale variability across Kilombero Valley, Tanzania2015In: Hydrological Processes, ISSN 0885-6087, E-ISSN 1099-1085, Vol. 29, no 8, p. 1912-1924Article in journal (Refereed)
    Abstract [en]

    We explore seasonal variability and spatiotemporal patterns in characteristic drainage timescale (K) estimated from river discharge records across the Kilombero Valley in central Tanzania. K values were determined using streamflow recession analysis with a Brutsaert-Nieber solution to the linearized Boussinesq equation. Estimated K values were variable, comparing between wet and dry seasons for the relatively small catchments draining upland positions. For the larger catchments draining through valley bottoms, K values were typically longer and more consistent across seasons. Variations in K were compared with long-term averaged, Moderate-resolution Imaging Spectroradiometer-derived monthly evapotranspiration. Although the variations in K were potentially related to evapotranspiration, the influence of data quality and analysis procedure could not be discounted. As such, even though recession analysis offers a potential approach to explore aquifer release timescales and thereby gain insight to a region's hydrology to inform water resources management, care must be taken when interpreting spatiotemporal shifts in K in connection with process representation in regions like the Kilombero Valley.

  • 14. Matti, Bettina
    et al.
    Dahlke, Helen E.
    Dieppois, Bastien
    Lawler, Damian M.
    Lyon, Steve W.
    Stockholm University, Faculty of Science, Department of Physical Geography. The Nature Conservancy, USA.
    Flood seasonality across Scandinavia—Evidence of a shifting hydrograph?2017In: Hydrological Processes, ISSN 0885-6087, E-ISSN 1099-1085, Vol. 31, no 24, p. 4354-4370Article in journal (Refereed)
    Abstract [en]

    Fluvial flood events have substantial impacts on humans, both socially and economically, as well as on ecosystems (e.g., hydroecology and pollutant transport). Concurrent with climate change, the seasonality of flooding in cold environments is expected to shift from a snowmelt-dominated to a rainfall-dominated flow regime. This would have profound impacts on water management strategies, that is, flood risk mitigation, drinking water supply, and hydro power. In addition, cold climate hydrological systems exhibit complex interactions with catchment properties and large-scale climate fluctuations making the manifestation of changes difficult to detect and predict. Understanding a possible change in flood seasonality and defining related key drivers therefore is essential to mitigate risk and to keep management strategies viable under a changing climate. This study explores changes in flood seasonality across near-natural catchments in Scandinavia using circular statistics and trend tests. Results indicate strong seasonality in flooding for snowmelt-dominated catchments with a single peak occurring in spring and early summer (March through June), whereas flood peaks are more equally distributed throughout the year for catchments located close to the Atlantic coast and in the south of the study area. Flood seasonality has changed over the past century seen as decreasing trends in summer maximum daily flows and increasing winter and spring maximum daily flows with 5-35% of the catchments showing significant changes at the 5% significance level. Seasonal mean daily flows corroborate those findings with higher percentages (5-60%) of the catchments showing statistically significant changes. Alterations in annual flood occurrence also point towards a shift in flow regime from snowmelt-dominated to rainfall-dominated with consistent changes towards earlier timing of the flood peak (significant for 25% of the catchments). Regionally consistent patterns suggest a first-order climate control as well as a local second-order catchment control, which causes inter-seasonal variability in the streamflow response.

  • 15. McDonnell, J. J.
    et al.
    McGuire, K.
    Aggarwal, P.
    Beven, K. J.
    Biondi, D.
    Destouni, G.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology (INK).
    Dunn, S.
    James, A.
    Kirchner, J.
    Kraft, P.
    Lyon, S.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology (INK).
    Maloszewski, P.
    Newman, B.
    Pfister, L.
    Rinaldo, A.
    Rodhe, A.
    Sayama, T.
    Seibert, J.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology (INK).
    Solomon, K.
    Soulsby, C.
    Stewart, M.
    Tetzlaff, D.
    Tobin, C.
    Troch, P.
    Weiler, M.
    Western, A.
    Worman, A.
    Wrede, S.
    How old is streamwater? Open questions in catchment transit time conceptualization, modelling and analysis2010In: Hydrological Processes, ISSN 0885-6087, E-ISSN 1099-1085, Vol. 24, no 12, p. 1745-1754Article in journal (Refereed)
  • 16.
    Nathanson, Marcus
    et al.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Kean, Jason
    Grabs, Thomas
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology. Uppsala University, Sweden.
    Seibert, Jan
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology. Uppsala University, Sweden; University of Zurich, Switzerland.
    Laudon, Hjalmar
    Lyon, Steve
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Modelling rating curves using remotely sensed LiDAR data2012In: Hydrological Processes, ISSN 0885-6087, E-ISSN 1099-1085, Vol. 26, no 9, p. 1427-1434Article in journal (Refereed)
    Abstract [en]

    Accurate stream discharge measurements are important for many hydrological studies. In remote locations, however, it is often difficult to obtain stream flow information because of the difficulty in making the discharge measurements necessary to define stage-discharge relationships (rating curves). This study investigates the feasibility of defining rating curves by using a fluid mechanics-based model constrained with topographic data from an airborne LiDAR scanning. The study was carried out for an 8m-wide channel in the boreal landscape of northern Sweden. LiDAR data were used to define channel geometry above a low flow water surface along the 90-m surveyed reach. The channel topography below the water surface was estimated using the simple assumption of a flat streambed. The roughness for the modelled reach was back calculated from a single measurment of discharge. The topographic and roughness information was then used to model a rating curve. To isolate the potential influence of the flat bed assumption, a ‘hybrid model’ rating curve was developed on the basis of data combined from the LiDAR scan and a detailed ground survey. Whereas this hybrid model rating curve was in agreement with the direct measurements of discharge, the LiDAR model rating curve was equally in agreement with the medium and high flow measurements based on confidence intervals calculated from the direct measurements. The discrepancy between the LiDAR model rating curve and the low flow measurements was likely due to reduced roughness associated with unresolved submerged bed topography. Scanning during periods of low flow can help minimize this deficiency. These results suggest that combined ground surveys and LiDAR scans or multifrequency LiDAR scans that see ‘below’ the water surface (bathymetric LiDAR) could be useful in generating data needed to run such a fluid mechanics-based model. This opens a realm of possibility to remotely sense and monitor stream flows in channels in remote locations.

  • 17.
    Pietroń, Jan
    et al.
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Nittrouer, Jeffrey A.
    Chalov, Sergey R.
    Dong, Tian Y.
    Kasimov, Nikolay
    Shinkareva, Galina
    Jarsjö, Jerker
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Sedimentation patterns in the Selenga River delta under changing hydroclimatic conditions2018In: Hydrological Processes, ISSN 0885-6087, E-ISSN 1099-1085, Vol. 32, no 2, p. 278-292Article in journal (Refereed)
    Abstract [en]

    The Selenga River delta (Russia) is a large (>600km(2)) fluvially dominated fresh water system that transfers water and sediment from an undammed drainage basin into Lake Baikal, a United Nations Educational, Scientific, and Cultural Organization World Heritage Site. Through sedimentation processes, the delta and its wetlands provide important environmental services, such as storage of sediment-bound pollutants (e.g., metals), thereby reducing their input to Lake Baikal. However, in the Selenga River delta and many other deltas of the world, there is a lack of knowledge regarding impacts of potential shifts in the flow regime (e.g., due to climate change and other anthropogenic impacts) on sedimentation processes, including sediment exchanges between deltaic channels and adjacent wetlands. This study uses field measurements of water velocities and sediment characteristics in the Selenga River delta, investigating conditions of moderate discharge, which have become more frequent over the past decades (at the expense of peak flows, Q>1,350m(3)s(-1)). The aims are to determine if the river system under moderate flow conditions is capable of supporting sediment export from the main distributary channels of the delta to the adjacent wetlands. The results show that most of the deposited sediment outside of the deltaic channels is characterized by a large proportion of silt and clay material (i.e., <63m). For example, floodplain lakes function as sinks of very fine sediment (e.g., 97% of sediment by weight<63m). Additionally, bed material sediment is found to be transported outside of the channel margins during conditions of moderate and high water discharge conditions (Q1,000m(3)s(-1)). Submerged banks and marshlands located in the backwater zone of the delta accumulate sediment during such discharges, supporting wetland development. Thus, these regions likely sequester various metals bound to Selenga River sediment.

  • 18. Rinderer, Michael
    et al.
    Kollegger, Andrea
    Fischer, Benjamin M. C.
    Staehli, Manfred
    Seibert, Jan
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Sensing with boots and trousers qualitative field observations of shallow soil moisture patterns2012In: Hydrological Processes, ISSN 0885-6087, E-ISSN 1099-1085, Vol. 26, no 26, p. 4112-4120Article in journal (Refereed)
    Abstract [en]

    While soil moisture patterns can be interesting traits to investigate spatio-temporal heterogeneity of catchments relevant for various physical processes of soilatmosphere interaction and soil water redistribution, many of the existing methods to capture spatial patterns are time consuming, expensive or need site-specific calibration. In this study we present a quick and inexpensive supplementary field method for classifying soil wetness in wet environments. The seven wetness classes are based on qualitative indicators, which one can touch, hear or see on the soil surface. To counter critics that such qualitative methods are considerably affected by subjectivity, we performed systematic testing of the method by taking qualitative measurements in the field with 20 non-expert raters. We then analyzed these in terms of degree of agreement and assessed the results against gravimetric sampling and time domain reflectometry measurements. In 70% of all classifications raters agreed on the wetness class assigned to the marked sampling locations and in 95% they were not off by more than one wetness class. The seven quantitative wetness classes agreed with gravimetric and time domain reflectometry measurements, although intermediate to wet classes showed an overlap of their range whereas the driest classes showed considerable spread. Despite some potential to optimize the method, it has been shown to be a reliable supplement to existing quantitative techniques for assessing soil moisture patterns in wet environments.

  • 19. Rodhe, Allan
    et al.
    Seibert, Jan
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Groundwater dynamics in a till hillslope: flow directions, gradients and delay2011In: Hydrological Processes, ISSN 0885-6087, E-ISSN 1099-1085, Vol. 25, no 12, p. 1899-1909Article in journal (Refereed)
    Abstract [en]

    Knowledge of groundwater dynamics is important for the understanding of hydrological controls on chemical processes along the water flow pathways. To increase our knowledge of groundwater dynamics in areas with shallow groundwater, the groundwater dynamics along a hillslope were studied in a boreal catchment in Southern Sweden. The forested hillslope had a 1- to 2-m deep layer of sandy till above bedrock. The groundwater flow direction and slope were calculated under the assumption that the flow followed the slope of the groundwater table, which was computed for different triangles, each defined by three groundwater wells. The flow direction showed considerable variations over time, with a maximum variation of 75 degrees. During periods of high groundwater levels the flow was almost perpendicular to the stream, but as the groundwater level fell, the flow direction became gradually more parallel to the stream, directed in the downstream direction. These findings are of importance for the interpretation of results from hillslope transects, where the flow direction usually is assumed to be invariable and always in the direction of the hillslope. The variations in the groundwater flow direction may also cause an apparent dispersion for groundwater-based transport. In contrast to findings in several other studies, the groundwater level was most responsive to rainfall and snowmelt in the upper part of the hillslope, while the lower parts of the slope reached their highest groundwater level up to 40 h after the upper parts. This can be explained by the topography with a wetter hollow area in the upper part.

  • 20.
    Seibert, J.
    et al.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Bishop, K.
    Nyberg, L.
    Rodhe, A.
    Water storage in a till catchment. I: Distributed modelling and relationship to runoff2011In: Hydrological Processes, ISSN 0885-6087, E-ISSN 1099-1085, Vol. 25, no 25, p. 3937-3949Article in journal (Refereed)
    Abstract [en]

    Although water storage is an important variable to understand the hydrological functioning of a catchment, it is challenging to estimate the total water storage in a catchment. Catchment water storage can be estimated on the basis of water balance, but this approach is prone to errors in the different water balance terms. Here, an approach is presented to estimate the daily dynamics of catchment-wide soil water and groundwater storage on the basis of groundwater-level observations, soil properties and an assumption of hydrological equilibrium above the water table. This approach was applied to a 6300-m2 till catchment in Southwest Sweden. The predicted mean catchment water storage between April 1991 and June 1992 was 210mm and ranged from 190 to 260mm. The estimated water storage followed runoff rates closely especially during recession periods. On average, 79% of the water storage was held in the unsaturated zone, and the remaining 21% was groundwater, but this proportion varied strongly with runoff and total storage. During dry conditions, unsaturated storage accounted for at maximum 95% of the water storage; during wet conditions, this number dropped to 40%. Copyright (c) 2011 John Wiley & Sons, Ltd.

  • 21.
    Seibert, Jan
    et al.
    Stockholm University, Faculty of Science, Department of Physical Geography. Uppsala University, Sweden; University of Zurich, Switzerland.
    Vis, Marc J. P.
    How informative are stream level observations in different geographic regions?2016In: Hydrological Processes, ISSN 0885-6087, E-ISSN 1099-1085, Vol. 30, no 14, p. 2498-2508Article in journal (Refereed)
    Abstract [en]

    Simple runoff models with a low number of model parameters are generally able to simulate catchment runoff reasonably well, but they rely on model calibration, which makes their use in ungauged basins challenging. In a previous study it has been shown that a limited number of streamflow measurements can be quite informative for constraining runoff models. In practice, however, instead of performing such repeated flow measurements, it might be easier to install a stream level logger. Here, a dataset of 600+ gauged basins in the USA was used to study how well models perform when only stream level data, rather than streamflow data, are available. A runoff model (the HBV model) was calibrated assuming that only stream level observations were available, and the simulations were evaluated on the full observed streamflow record. The results indicate that stream level data alone can already provide surprisingly good model simulation results in humid catchments, whereas in arid catchments some form of quantitative information (e.g. a streamflow observation or a regional average value) is needed to obtain good results. These results are encouraging for hydrological observations in data scarce regions as level observations are much easier to obtain than streamflow measurements. Based on runoff modelling, it might even be possible to derive streamflow time series from the level data obtained from loggers, satellites or community-based approaches.

  • 22.
    Selroos, Jan-Olof
    et al.
    Stockholm University, Faculty of Science, Department of Physical Geography. Swedish Nuclear Fuel and Waste Management Company, Sweden.
    Destouni, Georgia
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Influence of spatial and temporal flow variability on solute transport in catchments2015In: Hydrological Processes, ISSN 0885-6087, E-ISSN 1099-1085, Vol. 29, no 16, p. 3592-3603Article in journal (Refereed)
    Abstract [en]

    This study quantifies the separate and combined effects of spatial and temporal variability for waterborne solute transport through catchments. The questions addressed regard whether, when and why the different types of variability may dominate catchment-scale transport. We utilize a versatile numerical solute transport code with a particle-based Monte Carlo time-domain random walk method to simulate waterborne transport through a generic catchment. Simulations are concretized and exemplified using data on spatiotemporal flow-transport variability from direct stream discharge observations and independently calculated advective solute travel time distributions for catchments within the water management district Northern Baltic Proper in Mid-Eastern Sweden. A main conclusion is that the projections of catchment mass loading based on spatial variability alone are robust estimates of long-term average solute transport development. This is especially true when annually aggregated mass load rather than finer temporal resolution of mass flux is considered. Temporal variability yields short-term fluctuations around the long-term average solute breakthrough development, and earlier or later arrival than the latter, depending on the timing and duration of solute input relative to the temporal flow variability. The exact temporal characteristics of future solute breakthrough are thus fundamentally uncertain, but their statistical expectation may be well quantified by accounting only for spatial variability.

  • 23. Soulsby, C.
    et al.
    Piegat, K.
    Seibert, J.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Tetzlaff, D.
    Catchment-scale estimates of flow path partitioning and water storage based on transit time and runoff modelling2011In: Hydrological Processes, ISSN 0885-6087, E-ISSN 1099-1085, Vol. 25, no 25, p. 3960-3976Article in journal (Refereed)
    Abstract [en]

    Tracer-derived mean transit times (MTT) and rainfallrunoff modelling were used to explore stream flow generation in 14 Scottish catchments. Both approaches conceptualise the partitioning, storage, and release of water at the catchment scale. The study catchments were predominantly upland and ranged from 0.5 to 1800?km2. Lumped convolution integral models using tracer inputoutput relationships generally provided well-constrained MTT estimates using a gamma function as the transit time distribution. These ranged from 60?days to >10?years and are mainly controlled by catchment soil cover and drainage density. The HBV model was calibrated using upper and lower storage layers to conceptualise rapidly responding near-surface flow paths and slower groundwater contributions to runoff. Calibrated parameters that regulate groundwater recharge and partitioning between the two storages were reasonably well-identified and correlations with MTTs. The most clearly identified parameters and those with the strongest correlations with MTT and landscape controls (particularly soil cover) were the recession coefficients which control the release of water from the upper and lower storage layers. There was also strong correlation between the dynamic storage estimated by HBV and the total catchment storage inferred by tracer damping, although the latter was usually two orders of magnitude greater. This is explained by the different storages estimated: while the total storage inferred by tracers also includes the passive storage involved in mixing, the model estimates dynamic storage from water balance considerations. The former can be interpreted as relating to total porosity, whereas the latter rather corresponds to the drainable porosity. As MTTs for Scottish the uplands can be estimated from catchment characteristics, landscape analysis can be used to constrain sensitive model parameters when modelling in ungauged basins. Furthermore, the dynamic storage inferred by HBV may also be used to provide a first approximation of minimum total catchment storage. Copyright (c) 2011 John Wiley & Sons, Ltd.

  • 24. van der Velde, Ype
    et al.
    Heidbuechel, Ingo
    Lyon, Steve W.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Nyberg, Lars
    Rodhe, Allan
    Bishop, Kevin
    Troch, Peter A.
    Consequences of mixing assumptions for time-variable travel time distributions2015In: Hydrological Processes, ISSN 0885-6087, E-ISSN 1099-1085, Vol. 29, no 16, p. 3460-3474Article in journal (Refereed)
    Abstract [en]

    The current generation of catchment travel time distribution (TTD) research, integrating nearly three decades of work since publication of Water's Journey from Rain to Stream, seeks to represent the full distribution in catchment travel times and its temporal variability. Here, we compare conceptualizations of increasing complexity with regards to mixing of water storages and evaluate how these assumptions influence time-variable TTD estimates for two catchments with contrasting climates: the Gardsjon catchment in Sweden and the Marshall Gulch catchment in Arizona, USA. Our results highlight that, as long as catchment TTDs cannot be measured directly but need to be inferred from input-output signals of catchments, the inferred catchment TTDs depend strongly on the underlying assumptions of mixing within a catchment. Furthermore, we found that the conceptualization of the evapotranspiration flux strongly influences the inferred travel times of stream discharge. For the wet and forested Gardsjon catchment in Sweden, we inferred that evapotranspiration most likely resembles a completely mixed sample of the water stored in the catchment; however, for the drier Marshall Gulch catchment in Arizona, evapotranspiration predominantly contained the younger water stored in the catchment. For the Marshall Gulch catchment, this higher probability for young water in evapotranspiration resulted in older water in the stream compared to travel times inferred with assumptions of complete mixing. New observations that focus on the TTD of the evapotranspiration flux and the actual travel time of water through a catchment are necessary to improve identification of mixing and consequently travel times of stream water.

  • 25.
    van der Velde, Ype
    et al.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology. University of Utrecht, Netherlands.
    Vercauteren, Nikki
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Jaramillo, Fernando
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Dekker, Stefan C.
    Destouni, Georgia
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Lyon, Steve W.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Exploring hydroclimatic change disparity via the Budyko framework2014In: Hydrological Processes, ISSN 0885-6087, E-ISSN 1099-1085, Vol. 28, no 13, p. 4110-4118Article in journal (Refereed)
    Abstract [en]

    The Budyko framework characterizes landscape water cycles as a function of climate. We used this framework to identify regions with contrasting hydroclimatic change during the past 50years in Sweden. This analysis revealed three distinct regions: the mountains, the forests, and the areas with agriculture. Each region responded markedly different to recent climate and anthropogenic changes, and within each region, we identified the most sensitive subregions. These results highlight the need for regional differentiation in climate change adaptation strategies to protect vulnerable ecosystems and freshwater resources. Further, the Budyko curve moved systematically towards its water and energy limits, indicating augmentation of the water cycle driven by changing vegetation, climate and human interactions. This finding challenges the steady state assumption of the Budyko curve and therefore its ability to predict future water cycles.

  • 26. Westerberg, I.
    et al.
    Guerrero, J. -L
    Seibert, Jan
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Beven, K. J.
    Halldin, S.
    Stage-discharge uncertainty derived with a non-stationary rating curve in the Choluteca River, Honduras2011In: Hydrological Processes, ISSN 0885-6087, E-ISSN 1099-1085, Vol. 25, no 4, p. 603-613Article in journal (Refereed)
    Abstract [en]

    Uncertainty in discharge data must be critically assessed before data can be used in, e. g. water resources estimation or hydrological modelling. In the alluvial Choluteca River in Honduras, the river-bed characteristics change over time as fill, scour and other processes occur in the channel, leading to a non-stationary stage-discharge relationship and difficulties in deriving consistent rating curves. Few studies have investigated the uncertainties related to non-stationarity in the stage-discharge relationship. We calculated discharge and the associated uncertainty with a weighted fuzzy regression of rating curves applied within a moving time window, based on estimated uncertainties in the observed rating data. An 18-year-long dataset with unusually frequent ratings (1268 in total) was the basis of this study. A large temporal variability in the stage-discharge relationship was found especially for low flows. The time-variable rating curve resulted in discharge estimate differences of -60 to +90% for low flows and +/- 20% for medium to high flows when compared to a constant rating curve. The final estimated uncertainty in discharge was substantial and the uncertainty limits varied between -43 to +73% of the best discharge estimate.

1 - 26 of 26
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