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Wörman, A., Mojarrad, B. B. & Riml, J. (2019). Fragmentation of the Hyporheic Zone Due to Regional Groundwater Circulation. Water resources research, 55(2), 1-21
Open this publication in new window or tab >>Fragmentation of the Hyporheic Zone Due to Regional Groundwater Circulation
2019 (English)In: Water resources research, ISSN 0043-1397, E-ISSN 1944-7973, Vol. 55, no 2, p. 1-21Article in journal (Refereed) Published
Abstract [en]

By use of numerical modeling and field observations, this work quantified the effects of catchment-scale upwelling groundwater on the hyporheic (below stream) fluxes over a wide range of spatial scales. A groundwater flow model was developed that specifically accounted for the hydrostatic and dynamic head fluctuations induced by the streambed topography. Although the magnitudes and relative importance of these streambed-induced fluxes were found to be highly sensitive to site-specific hydromorphological properties, we showed that streambed topographic structures exert a predominant control on the magnitude of hyporheic exchange fluxes in a Swedish boreal catchment. The magnitude of the exchange intensity evaluated at the streambed interface was found to be dominated by the streambed-induced hydraulic head across stream order. However, the catchment-scale groundwater flow field substantially affected the distribution of groundwater discharge points and thus decreased the fragmentation of the hyporheic zone, specifically by shifting the cumulative density function toward larger areas of coherent upwelling at the streambed interface. This work highlights the spectrum of spatial scales affecting the surface water-groundwater exchange patterns and resolves the roles of key mechanisms in controlling the fragmentation of the hyporheic zone.

Place, publisher, year, edition, pages
American Geophysical Union (AGU), 2019
National Category
Earth and Related Environmental Sciences
Identifiers
urn:nbn:se:kth:diva-244783 (URN)10.1029/2018WR024609 (DOI)000461858900020 ()2-s2.0-85061595295 (Scopus ID)
Note

QC 20190304

Available from: 2019-02-25 Created: 2019-02-25 Last updated: 2020-03-09Bibliographically approved
Hamisi, R., Renman, G., Renman, A. & Wörman, A. (2019). Modelling Phosphorus Sorption Kinetics and the Longevity of Reactive Filter Materials Used for On-site Wastewater Treatment. Water, 11(4), Article ID 811.
Open this publication in new window or tab >>Modelling Phosphorus Sorption Kinetics and the Longevity of Reactive Filter Materials Used for On-site Wastewater Treatment
2019 (English)In: Water, Vol. 11, no 4, article id 811Article in journal (Refereed) Published
Abstract [en]

Use of reactive filter media (RFM) is an emerging technology in small-scale wastewater treatment to improve phosphorus (P) removal and filter material longevity for making this technology sustainable. In this study, long-term sorption kinetics and the spatial dynamics of sorbed P distribution were simulated in replaceable P-filter bags filled with 700 L of reactive material and used in real on-site treatment systems. The input data for model calibration were obtained in laboratory trials with Filtralite P®, Polonite® and Top16. The P concentration breakthrough threshold value was set at an effluent/influent (C/C0) ratio of 1 and simulations were performed with P concentrations varying from 1 to 25 mg L−1. The simulation results showed that influent P concentration was important for the breakthrough and longevity, and that Polonite performed best, followed by Top16 and Filtralite P. A 100-day break in simulated intermittent flow allowed the materials to recover, which for Polonite involved slight retardation of P saturation. The simulated spatial distribution of P accumulated in the filter bags showed large differences between the filter materials. The modelling insights from this study can be applied in design and operation of on-site treatment systems using reactive filter materials

National Category
Civil Engineering
Research subject
Land and Water Resources Engineering
Identifiers
urn:nbn:se:kth:diva-256497 (URN)10.3390/w11040811 (DOI)000473105700181 ()2-s2.0-85065037122 (Scopus ID)
Note

QC 20190903

Available from: 2019-08-26 Created: 2019-08-26 Last updated: 2019-09-03Bibliographically approved
Hamisi, R., Renman, G., Renman, A. & Wörman, A. (2019). Modelling phosphorus sorption kinetics and the longevity of reactive filter materials used for on-sitewastewater treatment. Water, 11(4), Article ID 811.
Open this publication in new window or tab >>Modelling phosphorus sorption kinetics and the longevity of reactive filter materials used for on-sitewastewater treatment
2019 (English)In: Water, ISSN 2073-4441, E-ISSN 2073-4441, Vol. 11, no 4, article id 811Article in journal (Refereed) Published
Abstract [en]

Use of reactive filter media (RFM) is an emerging technology in small-scale wastewater treatment to improve phosphorus (P) removal and filter material longevity for making this technology sustainable. In this study, long-term sorption kinetics and the spatial dynamics of sorbed P distribution were simulated in replaceable P-filter bags filled with 700 L of reactive material and used in real on-site treatment systems. The input data for model calibration were obtained in laboratory trials with Filtralite P®, Polonite® and Top16. The P concentration breakthrough threshold value was set at an effluent/influent (C/C 0 ) ratio of 1 and simulations were performed with P concentrations varying from 1 to 25 mg L -1 . The simulation results showed that influent P concentration was important for the breakthrough and longevity, and that Polonite performed best, followed by Top16 and Filtralite P. A 100-day break in simulated intermittent flow allowed the materials to recover, which for Polonite involved slight retardation of P saturation. The simulated spatial distribution of P accumulated in the filter bags showed large differences between the filter materials. The modelling insights from this study can be applied in design and operation of on-site treatment systems using reactive filter materials.

Place, publisher, year, edition, pages
MDPI AG, 2019
Keywords
Breakthrough, COMSOL modelling, P-filter bags, Phosphorus saturation, Solute transport, Effluents, Filtration, Phosphorus, Wastewater treatment, Design and operations, Emerging technologies, Filter bags, Phosphorus sorption, Reactive materials, Small scale wastewater treatment, Passive filters
National Category
Water Treatment
Identifiers
urn:nbn:se:kth:diva-255943 (URN)10.3390/w11040811 (DOI)000473105700181 ()2-s2.0-85065037122 (Scopus ID)
Note

QC 20190815

Available from: 2019-08-15 Created: 2019-08-15 Last updated: 2020-02-19Bibliographically approved
Refsgaard, J. C., Hansen, A. L., Hojberg, A. L., Olesen, J. E., Hashemi, F., Wachniew, P., . . . Chubarenko, B. (2019). Spatially differentiated regulation: Can it save the Baltic Sea from excessive N-loads?. Ambio, 48(11), 1278-1289
Open this publication in new window or tab >>Spatially differentiated regulation: Can it save the Baltic Sea from excessive N-loads?
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2019 (English)In: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 48, no 11, p. 1278-1289Article in journal (Refereed) Published
Abstract [en]

The Baltic Sea Action Plan and the EU Water Framework Directive both require substantial additional reductions of nutrient loads (N and P) to the marine environment. Focusing on nitrogen, we present a widely applicable concept for spatially differentiated regulation, exploiting the large spatial variations in the natural removal of nitrate in groundwater and surface water. By targeting mitigation measures towards areas where nature's own capacity for removal is low, spatially differentiated regulation can be more cost-effective than the traditional uniform regulation. We present a methodology for upscaling local modelling results on targeted measures at field scale to Baltic Sea drainage basin scale. The paper assesses the potential gain and discusses key challenges related to implementation of spatially differentiated regulation, including the need for more scientific knowledge, handling of uncertainties, practical constraints related to agricultural practice and introduction of co-governance regimes.

Place, publisher, year, edition, pages
SPRINGER, 2019
Keywords
Baltic Sea drainage basin, Co-governance, EU Water Framework Directive, N-loads from agriculture, Spatially differentiated regulation
National Category
Earth and Related Environmental Sciences
Identifiers
urn:nbn:se:kth:diva-264163 (URN)10.1007/s13280-019-01195-w (DOI)000492594700005 ()31187428 (PubMedID)2-s2.0-85067395150 (Scopus ID)
Note

QC 20191210

Available from: 2019-12-10 Created: 2019-12-10 Last updated: 2019-12-10Bibliographically approved
Wang, J.-Z. & Wörman, A. (2019). Spectral Analysis of River Resistance and Aquifer Diffusivity in a River-Confined Aquifer System. Water resources research, 55(10), 8046-8060
Open this publication in new window or tab >>Spectral Analysis of River Resistance and Aquifer Diffusivity in a River-Confined Aquifer System
2019 (English)In: Water resources research, ISSN 0043-1397, E-ISSN 1944-7973, Vol. 55, no 10, p. 8046-8060Article in journal (Refereed) Published
Abstract [en]

Hydraulic connections between a river and an adjacent aquifer are controlled by the river resistance and aquifer diffusivity. In this paper, we derive a spectral solution linking the power spectrum of river stage fluctuations to that of the hydraulic head of a confined aquifer by means of a physical scaling factor. The physical scaling factor represents an algebraic expression of the river resistance and aquifer diffusivity and is included in an exact spectral solution derived herein. Statistical measures of the aquifer diffusivity and river resistance are provided by fitting the solution versus observed groundwater hydraulic head obtained at several distances and/or frequencies. At a study site in the middle reach of the Yangtze River and downstream of the Three Gorges Dam in China, we find systematic damping of the hydraulic head variations with distance from the river, which follows a fractal pattern driven by the river stage. In general, the estimated parameters are consistent with results reported in the literature, which supports the validity of the proposed spectral approach, although the paper discusses advantages and limitations due to application conditions.

Place, publisher, year, edition, pages
AMER GEOPHYSICAL UNION, 2019
Keywords
spectral solutions, river resistance spectrum, aquifer diffusivity spectrum, groundwater and surface water interaction, the Yangtze River
National Category
Ocean and River Engineering
Identifiers
urn:nbn:se:kth:diva-266508 (URN)10.1029/2018WR024639 (DOI)000501356200007 ()2-s2.0-85074257757 (Scopus ID)
Note

QC 20200406

Available from: 2020-04-06 Created: 2020-04-06 Last updated: 2020-04-06Bibliographically approved
Mojarrad, B. B., Betterle, A., Singh, T., Olid, C. & Wörman, A. (2019). The Effect of Stream Discharge on Hyporheic Exchange. Water, 11(7), Article ID 1436.
Open this publication in new window or tab >>The Effect of Stream Discharge on Hyporheic Exchange
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2019 (English)In: Water, ISSN 2073-4441, E-ISSN 2073-4441, Vol. 11, no 7, article id 1436Article in journal (Refereed) Published
Abstract [en]

Streambed morphology, streamflow dynamics, and the heterogeneity of streambed sediments critically controls the interaction between surface water and groundwater. The present study investigated the impact of different flow regimes on hyporheic exchange in a boreal stream in northern Sweden using experimental and numerical approaches. Low-, base-, and high-flow discharges were simulated by regulating the streamflow upstream in the study area, and temperature was used as the natural tracer to monitor the impact of the different flow discharges on hyporheic exchange fluxes in stretches of stream featuring gaining and losing conditions. A numerical model was developed using geomorphological and hydrological properties of the stream and was then used to perform a detailed analysis of the subsurface water flow. Additionally, the impact of heterogeneity in sediment permeability on hyporheic exchange fluxes was investigated. Both the experimental and modelling results show that temporally increasing flow resulted in a larger (deeper) extent of the hyporheic zone as well as longer hyporheic flow residence times. However, the result of the numerical analysis is strongly controlled by heterogeneity in sediment permeability. In particular, for homogeneous sediments, the fragmentation of upwelling length substantially varies with streamflow dynamics due to the contribution of deeper fluxes.

Place, publisher, year, edition, pages
MDPI, 2019
Keywords
hyporheic zone, transient flow discharge, groundwater-surface water interaction, experimental-modeling study, temperature measurement, depth decaying permeability
National Category
Oceanography, Hydrology and Water Resources
Identifiers
urn:nbn:se:kth:diva-257467 (URN)10.3390/w11071436 (DOI)000480632300121 ()2-s2.0-85073891965 (Scopus ID)
Note

QC 20190830

Available from: 2019-08-30 Created: 2019-08-30 Last updated: 2020-03-09Bibliographically approved
Wu, L., Singh, T., Gomez-Velez, J., Nutzmann, G., Wörman, A., Krause, S. & Lewandowski, J. (2018). Impact of Dynamically Changing Discharge on Hyporheic Exchange Processes Under Gaining and Losing Groundwater Conditions. Water resources research, 54(12), 10076-10093
Open this publication in new window or tab >>Impact of Dynamically Changing Discharge on Hyporheic Exchange Processes Under Gaining and Losing Groundwater Conditions
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2018 (English)In: Water resources research, ISSN 0043-1397, E-ISSN 1944-7973, Vol. 54, no 12, p. 10076-10093Article in journal (Refereed) Published
Abstract [en]

Channel discharge, geomorphological setting, and regional groundwater flow determine the spatiotemporal variability of bedform-induced hyporheic exchange and the emergence of biogeochemical hot spots and hot moments that it drives. Of particular interest, and significantly understudied, is the role that dynamically changing discharge has on the hyporheic exchange process and how regional groundwater flow modulates the effects of transience. In this study, we use a reduced-complexity model to systematically explore the bedform-induced hyporheic responses to dynamically changing discharge events in systems with different bedform geometries exposed to varying degrees of groundwater flow (under both upwelling and downwelling conditions). With this in mind, we define metrics to quantify the effects of transience: spatial extent of the hyporheic zone, net hyporheic flux, mean residence time, and denitrification efficiency. We find that regional groundwater flow and geomorphological settings greatly modulate the temporal evolution of bedform-induced hyporheic responses driven by a single-peak discharge event. Effects of transience diminish with increasing groundwater upwelling or downwelling fluxes, decreasing bedform aspect ratios, and decreasing channel slopes. Additionally, we notice that increasing discharge intensities can reduce the modulating impacts of regional groundwater flow on the effects of transience but hardly overcomes the geomorphological controls. These findings highlight the necessities of evaluating hyporheic exchange processes in a more comprehensive framework.

Place, publisher, year, edition, pages
AMER GEOPHYSICAL UNION, 2018
National Category
Earth and Related Environmental Sciences
Identifiers
urn:nbn:se:kth:diva-244144 (URN)10.1029/2018WR023185 (DOI)000456949300004 ()2-s2.0-85058717748 (Scopus ID)
Note

QC 20190218

Available from: 2019-02-18 Created: 2019-02-18 Last updated: 2019-03-18Bibliographically approved
Morén, I., Wörman, A. & Riml, J. (2017). Design of Remediation Actions for Nutrient Mitigation in the Hyporheic Zone. Water resources research, 53(11), 8872-8899
Open this publication in new window or tab >>Design of Remediation Actions for Nutrient Mitigation in the Hyporheic Zone
2017 (English)In: Water resources research, ISSN 0043-1397, E-ISSN 1944-7973, Vol. 53, no 11, p. 8872-8899Article in journal (Refereed) Published
Abstract [en]

Although hyporheic exchange has been shown to be of great importance for the overall water quality of streams, it is rarely considered quantitatively in stream remediation projects. A main driver of hyporheic exchange is the hydraulic head fluctuation along the streambed, which can be enhanced by modifications of the streambed topography. Here we present an analytical 2-D spectral subsurface flow model to estimate the hyporheic exchange associated with streambed topographies over a wide range of spatial scales; a model that was validated using tracer-test-results and measurements of hydraulic conductivity. Specifically, engineered steps in the stream were shown to induce a larger hyporheic exchange velocity and shorter hyporheic residence times compared to the observed topography in Tullstorps Brook, Sweden. Hyporheic properties were used to parameterize a longitudinal transport model that accounted for reactions in terms of first-order decay and instantaneous adsorption. Theoretical analyses of the mitigation effect for nitrate due to denitrification in the hyporheic zone show that there is a Damkohler number of the hyporheic zone, associated with several different stream geomorphologies, that optimizes nitrate mass removal on stream reach scale. This optimum can be limited by the available hydraulic head gradient given by the slope of the stream and the geological constraints of the streambed. The model illustrates the complex interactions between design strategies for nutrient mitigation, hyporheic flow patterns, and stream biogeochemistry and highlights the importance to diagnose a stream prior remediation, specifically to evaluate if remediation targets are transport or reaction controlled.

Place, publisher, year, edition, pages
American Geophysical Union (AGU), 2017
National Category
Water Engineering
Identifiers
urn:nbn:se:kth:diva-221034 (URN)10.1002/2016WR020127 (DOI)000418736700013 ()2-s2.0-85033605629 (Scopus ID)
Funder
EU, FP7, Seventh Framework ProgrammeSwedish Research Council FormasSwedish Environmental Protection Agency
Note

QC 20180112

Available from: 2018-01-12 Created: 2018-01-12 Last updated: 2018-01-12Bibliographically approved
Wörman, A., Lindstrom, G. & Riml, J. (2017). The power of runoff. Journal of Hydrology, 548, 784-793
Open this publication in new window or tab >>The power of runoff
2017 (English)In: Journal of Hydrology, ISSN 0022-1694, E-ISSN 1879-2707, Vol. 548, p. 784-793Article in journal (Refereed) Published
Abstract [en]

Although the potential energy of surface water is a small part of Earth's energy budget, this highly variable physical property is a key component in the terrestrial hydrologic cycle empowering geomorphological and hydrological processes throughout the hydrosphere. By downscaling of the daily hydrometeorological data acquired in Sweden over the last half-century this study quantifies the spatial and temporal distribution of the dominating energy components in terrestrial hydrology, including the frictional resistance in surface water and groundwater as well as hydropower. The energy consumed in groundwater circulation was found to be 34.6 TWh/fy or a heat production of approximately 13% of the geothermal heat flux. Significant climate driven, periodic fluctuations in the power of runoff, stream flows and groundwater circulation were revealed that have not previously been documented. We found that the runoff power ranged from 173 to 260 TWh/y even when averaged over the entire surface of Sweden in a five-year moving window. We separated short-term fluctuations in runoff due to precipitation filtered through the watershed from longer-term seasonal and climate driven modes. Strong climate driven correlations between the power of runoff and climate indices, wind and solar intensity were found over periods of 3.6 and 8 years. The high covariance that we found between the potential energy of surface water and wind energy implies significant challenges for the combination of these renewable energy sources.

Place, publisher, year, edition, pages
ELSEVIER SCIENCE BV, 2017
Keywords
Energy components of terrestrial hydrology, Climate driven fluctuations in the power of runoff, Groundwater energy, Surface water energy, Hydropower
National Category
Ocean and River Engineering
Identifiers
urn:nbn:se:kth:diva-210938 (URN)10.1016/j.jhydrol.2017.03.041 (DOI)000403739000059 ()2-s2.0-85018523561 (Scopus ID)
Note

QC 20170714

Available from: 2017-07-14 Created: 2017-07-14 Last updated: 2017-07-14Bibliographically approved
Ahmad, N., Wörman, A., Sanchez-Vila, X., Jarsjö, J., Bottacin-Busolin, A. & Hellevang, H. (2016). Injection of CO2-saturated brine in geological reservoir: A way to enhanced storage safety. International Journal of Greenhouse Gas Control, 54, 129-144
Open this publication in new window or tab >>Injection of CO2-saturated brine in geological reservoir: A way to enhanced storage safety
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2016 (English)In: International Journal of Greenhouse Gas Control, ISSN 1750-5836, E-ISSN 1878-0148, Vol. 54, p. 129-144Article in journal (Refereed) Published
Abstract [en]

Injection of free-phase supercritical CO2 into deep geological reservoirs is associated with risk of considerable return flows towards the land surface due to the buoyancy of CO2, which is lighter than the resident brine in the reservoir. Such upward movements can be avoided if CO2 is injected in the dissolved phase (CO2aq). In this work, injection of CO2-saturated brine in a subsurface carbonate reservoir was modelled. Physical and geochemical interactions of injected low-pH CO2-saturated brine with the carbonate minerals (calcite, dolomite and siderite) were investigated in the reactive transport modelling. CO2-saturated brine, being low in pH, showed high reactivity with the reservoir minerals, resulting in a significant mineral dissolution and CO2 conversion in reactions. Over the injection period of 10 yr, up to 16% of the injected CO2 was found consumed in geochemical reactions. Sorption included in the transport analysis resulted in additional quantities of CO2 mass stored. However, for the considered carbonate minerals, the consumption of injected CO2aq was found mainly in the form of ionic trapping.

Place, publisher, year, edition, pages
Elsevier, 2016
Keywords
Carbonate mineral reactions, Carbonate reservoir, Enhanced storage safety, Geological storage, Injection of CO2-saturated brine, Ionic trapping, Carbonate minerals, Carbonation, Geochemistry, Geology, Minerals, Petroleum reservoirs, Safety engineering, Enhanced storage, Saturated brines, Carbon dioxide
National Category
Earth and Related Environmental Sciences
Identifiers
urn:nbn:se:kth:diva-195213 (URN)10.1016/j.ijggc.2016.08.028 (DOI)000387781500010 ()2-s2.0-84990212585 (Scopus ID)
Note

QC 20161118

Available from: 2016-11-18 Created: 2016-11-02 Last updated: 2019-02-08Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0003-2726-6821

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