Lars Marklund - Academia.edu (original) (raw)
Papers by Lars Marklund
Geological Control of Fractal Groundwater Residence Times
ABSTRACT Groundwater transports and distributes heat, particles and solutes both in the subsurfac... more ABSTRACT Groundwater transports and distributes heat, particles and solutes both in the subsurface and to and from surficial ecosystems. Therefore, understanding groundwater circulation is a key issue for biogeochemical cycles, water resource management and CO2 sequestration. Fractal scaling relationships have been found in distributions of both land surface topography and solute efflux from watersheds and it have been shown that the fractal nature of the land surface produces fractal distributions of recharge, discharge, and associated subsurface flow patterns in humid regions with low-permeability rock, where the groundwater flow is controlled by landscape topography. In this paper, we relate the groundwater circulation to extensive topographic and geological data sets from Scandinavia and North America using spectral analysis. Especially, we have systematized the spatial distribution of groundwater flow utilizing an exact solution for 3D groundwater flow based on spectral analysis of the topography. This approach is an efficient way to analyze multi-scaled topography-controlled groundwater flow, because the impact of individual topographic scales on the groundwater flow can be analyzed separately. The fractal nature of topography yields a single scale-independent distribution of subsurface water residence times for both near-surface fluvial systems and deeper hydrogeological flows. Large-scale topography mainly controls deeper and larger flow cells and small-scale topography controls smaller and shallower flow cells. This scaling behavior holds at all scales, from small fluvial bedforms (tens of centimeters) to the continental landscape (hundreds of kilometers). However, the geological conditions within a specific region modify the topographic control of the groundwater circulation pattern. For instance, layers of Quaternary deposits and decaying permeability with depth increase the importance of smaller topographic scales. At the groundwater surface, the water flux is proportional to to lambda-2/3 (where lambda is the topographic scale) when the geology consist of Quaternary deposits and depth-decaying permeability rock. To be compared to lambda0.31 for homogeneous rock. Both a layer of Quaternary deposits and depth-decaying permeability rock create groundwater flow fields where a larger portion of the water occupies smaller and shallower circulation cells. In frequently occurring conditions of depth-decaying rock permeability, only 0.1% of the groundwater reaches deeper than 700 m. At ~700 m depth, the impact of topographic scales larger than ~60 km is practically negligible.
The effect of topography and quaternary deposits on circulation of groundwater and discharge area distribution
Implication of physical and chemical retention on radioactive land-area in the biosphere
Application of a Regulatory Performance Assessment Approach for Comparison with the Proponent’s Calculations
Scaling of surface water-subsurface water interaction with implication to hydrogeological site evaluations
Field Study on Discharge of Natural Isotopes from the 238U and 232Th Series through Quaternary Deposit
Impact of landscape topography and quaternary overburden on the performance of a geological repository of nuclear waste
Nuclear …, 2008
Résumé/Abstract The topographical driving forces for groundwater on different spatial scales in s... more Résumé/Abstract The topographical driving forces for groundwater on different spatial scales in several ways influence the performance of a repository for nuclear waste located at large depth in crystalline bedrock. We show that the relation between local topographical ...
Landscape topography is the most important driving force for groundwater flow and all scales of t... more Landscape topography is the most important driving force for groundwater flow and all scales of topography contribute to groundwater movement. Here we present results of how different scales of topography affect the groundwater flow at different depths. The study is based on a spectral analysis of the topography and a couple of exact 3-D solutions of the groundwater flow. We are also analyzing how different heterogeneities of the subsurface hydraulic conductivity impact the groundwater flow at different depths and alter the relative importance of different topographic scales on the groundwater flow. Quaternary deposits are extremely important for the infiltration at the ground surface, but the effect is primarily constrained to the deposit strata. Depth dependent hydraulic conductivity has a major impact on the size and depth of the groundwater flow cells, but it also affects the infiltration at the surface. Depth dependent hydraulic conductivity tends to counteract the effect of the large-scale topography on the groundwater flow more effectively than the smaller landscape scales.
Fractal scaling for surface water-subsurface water interaction through the Earths crust
AGU Fall Meeting Abstracts, Dec 1, 2007
Landscape topography from mountain ranges to the smallest hills induces the pressure boundary con... more Landscape topography from mountain ranges to the smallest hills induces the pressure boundary condition at ground surface that controls groundwater circulation. This interplay between surface water and groundwater controls the circulation patterns of deep groundwater in the Earth's crust, the water balance in watersheds, as well as solute transport from the continents to the oceans. Separating the topography in a Fourier spectrum both represents the fractal ground surface topography in fluvial and glacial landscapes and ...
The Use of Spectral Analysis to Characterize Topography-Controlled Groundwater Flow
Unbounded, Exact Solution for 3-D Topography Driven Groundwater Flow
ABSTRACT An exact analytical solution is presented for saturated groundwater flow to provide impr... more ABSTRACT An exact analytical solution is presented for saturated groundwater flow to provide improved understanding of the renewal rate of deep and shallow groundwater and the long-term management of groundwater resources. The solution is derived under the assumptions that the hydraulic potential of the groundwater surface follows the topography and imposes a steady boundary condition for driving the groundwater flow. This assumption is justified in most areas of humid climate. The solution is applicable on a wide range of spatial scales and accounts for decaying permeability with depth, stratified aquifers as well as anisotropy. The flow problem is solved by representing the topography with a three-dimensional spectral scaling solution based on harmonic functions that are independent in x- and y-directions. In most areas the Fourier-series, representing the topography, give a nearly perfect image of the ground surface elevation. The topography is found to be fractal and this imposes a fractal nature of the groundwater flow that is altered by the additional geometrical scales. The groundwater flow solution, based on the Fourier-spectrum, depends on the decay with depth and anisotropy in hydraulic conductivity and stratifications due to quaternary deposits, layered sediments etc. Prior analytical solutions are limited to either two-dimensional flows or harmonic functions uniform in the x- and y- directions, hence making them unable to predict three-dimensional subsurface flows beneath a realistic landscape. However, the most important advantage of this new method is the ability to analyse the impact of different geometrical scales on the groundwater flow. Analyses indicate that in a homogeneous subsurface, shallow groundwater flows would be approximately equally controlled by all scales of topography. Although shorter topographical wavelengths control the surface water flux, their impact decreases faster with depth in relation to longer wavelengths. This induces an increasing importance of large-scale topography with depth. However, the hydraulic conductivity tends to decay with depth and this counteracts the effect of the large-scale topography on the groundwater flow more effectively than the smaller landscape scales. For the depth-dependent hydraulic conductivity applicable to the Fennoscandian bedrock, we find a depth-limitation of the flow cells that tends to reduce the importance of the larger wavelengths on the fluxes at all depths.
A regulatory modelling strategy for review of dose calculations
Accumulation in the overburden of radionuclides from a leaking nuclear waste repository
Accidental leakage through embankment dams caused by internal erosion, differential settlements o... more Accidental leakage through embankment dams caused by internal erosion, differential settlements or both can lead to heavy throughflow and instabilities of the downstream dam slope. This study concerns seepage analyses for Trängslet embankment dam, Sweden, performed for an assumed erosion pipe through the central moraine core as well as for a scenario in which the core and sand filters is hypothetically removed and replaced with shoulder material. Information of the seepage can be used as design values for erosion protection of the Toe revetment placed on the downstream slope. When the diameter of an erosion pipe exceeded a few centimetres the leakage is larger than compared to a reference case when the moraine core section is completely replaced with the rockfill material. An exact solution is derived for the through flow arising due to the erosion pipe.
Topographic and Geological controls of Groundwater Renewal
Developing a Regulatory Performance Assessment Approach for Final Disposal of Spent Nuclear Fuel
Denna rapport beskriver en databas som täcker hela Sveriges yta med avseende på olika geografiska... more Denna rapport beskriver en databas som täcker hela Sveriges yta med avseende på olika geografiska parametrar av betydelse för simulering av grundvattenströmning på en regional skala och i hela kontinentalplattan. Databasen innehåller topografi, vattendragen definierade i nätverk, markanvändning och vattenkemi i grundvattnet på begränsade områden.
IFIP Advances in Information and Communication Technology, 2011
The CryoLand project implements and validates a standardized and sustainable service on snow and ... more The CryoLand project implements and validates a standardized and sustainable service on snow and land ice monitoring as a Downstream Service of GMES. It will provide geospatial product coverages of seasonal snow (snow extent, snow mass, melt state), glaciers (area, snow / ice extent, ice velocities, glacier dammed lakes), and lake / river ice (extent, temporal variations, snow burden) derived from Earth observation (EO) satellite data. Processing lines and a service infrastructure will be developed on top of existing Web service environments supporting the publication, provision and chaining of involved geospatial data services. The CryoLand service architecture commits INSPIRE, OGC, and OASIS standards specifically respecting HMA and GENESIS frameworks. User information services offering discovery, view and download functions will be provided.
Hydrogeology Journal, 2011
Spectral analysis enhances the ability to analyze groundwater flow at a steady state by separatin... more Spectral analysis enhances the ability to analyze groundwater flow at a steady state by separating the top boundary condition into its periodic forms. Specifically, spectral analysis enables comparisons of the impact of individual spatial scales on the total flow field. New exact spectral solutions are presented for analyzing 3D groundwater flow with an arbitrarily shaped top boundary. These solutions account for depth-decaying, anisotropic and layered permeability while utilizing groundwater flux or the phreatic surface as a top boundary condition. Under certain conditions, groundwater flow is controlled by topography. In areas where the groundwater flow is controlled by the topography, the unknown water table is often approximated by the topography. This approximation induces a systematic error. Here, the optimal resolution of digital elevation models (DEMs) is assessed for use as a top boundary in groundwater flow models. According to the analysis, the water-table undulation is smoother than the topography; therefore, there is an upper limit to the resolution of DEMs that should be used to represent the groundwater surface. The ability to represent DEMs of various spectral solutions was compared and the results indicate that the fit is strongly dependent on the number of harmonics in the spectral solution.
Geophysical Research Letters, 2011
Geological Control of Fractal Groundwater Residence Times
ABSTRACT Groundwater transports and distributes heat, particles and solutes both in the subsurfac... more ABSTRACT Groundwater transports and distributes heat, particles and solutes both in the subsurface and to and from surficial ecosystems. Therefore, understanding groundwater circulation is a key issue for biogeochemical cycles, water resource management and CO2 sequestration. Fractal scaling relationships have been found in distributions of both land surface topography and solute efflux from watersheds and it have been shown that the fractal nature of the land surface produces fractal distributions of recharge, discharge, and associated subsurface flow patterns in humid regions with low-permeability rock, where the groundwater flow is controlled by landscape topography. In this paper, we relate the groundwater circulation to extensive topographic and geological data sets from Scandinavia and North America using spectral analysis. Especially, we have systematized the spatial distribution of groundwater flow utilizing an exact solution for 3D groundwater flow based on spectral analysis of the topography. This approach is an efficient way to analyze multi-scaled topography-controlled groundwater flow, because the impact of individual topographic scales on the groundwater flow can be analyzed separately. The fractal nature of topography yields a single scale-independent distribution of subsurface water residence times for both near-surface fluvial systems and deeper hydrogeological flows. Large-scale topography mainly controls deeper and larger flow cells and small-scale topography controls smaller and shallower flow cells. This scaling behavior holds at all scales, from small fluvial bedforms (tens of centimeters) to the continental landscape (hundreds of kilometers). However, the geological conditions within a specific region modify the topographic control of the groundwater circulation pattern. For instance, layers of Quaternary deposits and decaying permeability with depth increase the importance of smaller topographic scales. At the groundwater surface, the water flux is proportional to to lambda-2/3 (where lambda is the topographic scale) when the geology consist of Quaternary deposits and depth-decaying permeability rock. To be compared to lambda0.31 for homogeneous rock. Both a layer of Quaternary deposits and depth-decaying permeability rock create groundwater flow fields where a larger portion of the water occupies smaller and shallower circulation cells. In frequently occurring conditions of depth-decaying rock permeability, only 0.1% of the groundwater reaches deeper than 700 m. At ~700 m depth, the impact of topographic scales larger than ~60 km is practically negligible.
The effect of topography and quaternary deposits on circulation of groundwater and discharge area distribution
Implication of physical and chemical retention on radioactive land-area in the biosphere
Application of a Regulatory Performance Assessment Approach for Comparison with the Proponent’s Calculations
Scaling of surface water-subsurface water interaction with implication to hydrogeological site evaluations
Field Study on Discharge of Natural Isotopes from the 238U and 232Th Series through Quaternary Deposit
Impact of landscape topography and quaternary overburden on the performance of a geological repository of nuclear waste
Nuclear …, 2008
Résumé/Abstract The topographical driving forces for groundwater on different spatial scales in s... more Résumé/Abstract The topographical driving forces for groundwater on different spatial scales in several ways influence the performance of a repository for nuclear waste located at large depth in crystalline bedrock. We show that the relation between local topographical ...
Landscape topography is the most important driving force for groundwater flow and all scales of t... more Landscape topography is the most important driving force for groundwater flow and all scales of topography contribute to groundwater movement. Here we present results of how different scales of topography affect the groundwater flow at different depths. The study is based on a spectral analysis of the topography and a couple of exact 3-D solutions of the groundwater flow. We are also analyzing how different heterogeneities of the subsurface hydraulic conductivity impact the groundwater flow at different depths and alter the relative importance of different topographic scales on the groundwater flow. Quaternary deposits are extremely important for the infiltration at the ground surface, but the effect is primarily constrained to the deposit strata. Depth dependent hydraulic conductivity has a major impact on the size and depth of the groundwater flow cells, but it also affects the infiltration at the surface. Depth dependent hydraulic conductivity tends to counteract the effect of the large-scale topography on the groundwater flow more effectively than the smaller landscape scales.
Fractal scaling for surface water-subsurface water interaction through the Earths crust
AGU Fall Meeting Abstracts, Dec 1, 2007
Landscape topography from mountain ranges to the smallest hills induces the pressure boundary con... more Landscape topography from mountain ranges to the smallest hills induces the pressure boundary condition at ground surface that controls groundwater circulation. This interplay between surface water and groundwater controls the circulation patterns of deep groundwater in the Earth's crust, the water balance in watersheds, as well as solute transport from the continents to the oceans. Separating the topography in a Fourier spectrum both represents the fractal ground surface topography in fluvial and glacial landscapes and ...
The Use of Spectral Analysis to Characterize Topography-Controlled Groundwater Flow
Unbounded, Exact Solution for 3-D Topography Driven Groundwater Flow
ABSTRACT An exact analytical solution is presented for saturated groundwater flow to provide impr... more ABSTRACT An exact analytical solution is presented for saturated groundwater flow to provide improved understanding of the renewal rate of deep and shallow groundwater and the long-term management of groundwater resources. The solution is derived under the assumptions that the hydraulic potential of the groundwater surface follows the topography and imposes a steady boundary condition for driving the groundwater flow. This assumption is justified in most areas of humid climate. The solution is applicable on a wide range of spatial scales and accounts for decaying permeability with depth, stratified aquifers as well as anisotropy. The flow problem is solved by representing the topography with a three-dimensional spectral scaling solution based on harmonic functions that are independent in x- and y-directions. In most areas the Fourier-series, representing the topography, give a nearly perfect image of the ground surface elevation. The topography is found to be fractal and this imposes a fractal nature of the groundwater flow that is altered by the additional geometrical scales. The groundwater flow solution, based on the Fourier-spectrum, depends on the decay with depth and anisotropy in hydraulic conductivity and stratifications due to quaternary deposits, layered sediments etc. Prior analytical solutions are limited to either two-dimensional flows or harmonic functions uniform in the x- and y- directions, hence making them unable to predict three-dimensional subsurface flows beneath a realistic landscape. However, the most important advantage of this new method is the ability to analyse the impact of different geometrical scales on the groundwater flow. Analyses indicate that in a homogeneous subsurface, shallow groundwater flows would be approximately equally controlled by all scales of topography. Although shorter topographical wavelengths control the surface water flux, their impact decreases faster with depth in relation to longer wavelengths. This induces an increasing importance of large-scale topography with depth. However, the hydraulic conductivity tends to decay with depth and this counteracts the effect of the large-scale topography on the groundwater flow more effectively than the smaller landscape scales. For the depth-dependent hydraulic conductivity applicable to the Fennoscandian bedrock, we find a depth-limitation of the flow cells that tends to reduce the importance of the larger wavelengths on the fluxes at all depths.
A regulatory modelling strategy for review of dose calculations
Accumulation in the overburden of radionuclides from a leaking nuclear waste repository
Accidental leakage through embankment dams caused by internal erosion, differential settlements o... more Accidental leakage through embankment dams caused by internal erosion, differential settlements or both can lead to heavy throughflow and instabilities of the downstream dam slope. This study concerns seepage analyses for Trängslet embankment dam, Sweden, performed for an assumed erosion pipe through the central moraine core as well as for a scenario in which the core and sand filters is hypothetically removed and replaced with shoulder material. Information of the seepage can be used as design values for erosion protection of the Toe revetment placed on the downstream slope. When the diameter of an erosion pipe exceeded a few centimetres the leakage is larger than compared to a reference case when the moraine core section is completely replaced with the rockfill material. An exact solution is derived for the through flow arising due to the erosion pipe.
Topographic and Geological controls of Groundwater Renewal
Developing a Regulatory Performance Assessment Approach for Final Disposal of Spent Nuclear Fuel
Denna rapport beskriver en databas som täcker hela Sveriges yta med avseende på olika geografiska... more Denna rapport beskriver en databas som täcker hela Sveriges yta med avseende på olika geografiska parametrar av betydelse för simulering av grundvattenströmning på en regional skala och i hela kontinentalplattan. Databasen innehåller topografi, vattendragen definierade i nätverk, markanvändning och vattenkemi i grundvattnet på begränsade områden.
IFIP Advances in Information and Communication Technology, 2011
The CryoLand project implements and validates a standardized and sustainable service on snow and ... more The CryoLand project implements and validates a standardized and sustainable service on snow and land ice monitoring as a Downstream Service of GMES. It will provide geospatial product coverages of seasonal snow (snow extent, snow mass, melt state), glaciers (area, snow / ice extent, ice velocities, glacier dammed lakes), and lake / river ice (extent, temporal variations, snow burden) derived from Earth observation (EO) satellite data. Processing lines and a service infrastructure will be developed on top of existing Web service environments supporting the publication, provision and chaining of involved geospatial data services. The CryoLand service architecture commits INSPIRE, OGC, and OASIS standards specifically respecting HMA and GENESIS frameworks. User information services offering discovery, view and download functions will be provided.
Hydrogeology Journal, 2011
Spectral analysis enhances the ability to analyze groundwater flow at a steady state by separatin... more Spectral analysis enhances the ability to analyze groundwater flow at a steady state by separating the top boundary condition into its periodic forms. Specifically, spectral analysis enables comparisons of the impact of individual spatial scales on the total flow field. New exact spectral solutions are presented for analyzing 3D groundwater flow with an arbitrarily shaped top boundary. These solutions account for depth-decaying, anisotropic and layered permeability while utilizing groundwater flux or the phreatic surface as a top boundary condition. Under certain conditions, groundwater flow is controlled by topography. In areas where the groundwater flow is controlled by the topography, the unknown water table is often approximated by the topography. This approximation induces a systematic error. Here, the optimal resolution of digital elevation models (DEMs) is assessed for use as a top boundary in groundwater flow models. According to the analysis, the water-table undulation is smoother than the topography; therefore, there is an upper limit to the resolution of DEMs that should be used to represent the groundwater surface. The ability to represent DEMs of various spectral solutions was compared and the results indicate that the fit is strongly dependent on the number of harmonics in the spectral solution.
Geophysical Research Letters, 2011