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Tolkning av georadarprofiler över grundvattenmagasinet Verveln - Gullringen i Kalmar län

Faraj, Haider LU (2019) In Examensarbeten i geologi vid Lunds universitet GEOL01 20191
Department of Geology
Abstract (Swedish)
I Sverige utgörs majoriteten av våra grundvattenresurser av isälvavlagringar i form av rullstensåsar och isälvsdeltan bestående av sand och grus. Isälvsavlagringarna är utan tvekan de mest betydelsefulla grundvattenförekomsterna för Sveriges dricksvattenförsörjning. Mer än 80% av landets alla vattenverk utnyttjar vatten från dessa resurser. En ojämn fördelning av grundvattenresurserna i kombination med pågående klimatförändringar kan leda till vattenbrist i landet. Risken för vattenbrist förekommer framförallt i områden som är belägna i Sydöstra Sverige där låga grundvattennivåer redan har konstaterats. Sveriges geologiska undersökning (SGU) har i uppdrag av regeringen tilldelats uppgiften att utöka kartläggningen och karaktäriseringen av... (More)
I Sverige utgörs majoriteten av våra grundvattenresurser av isälvavlagringar i form av rullstensåsar och isälvsdeltan bestående av sand och grus. Isälvsavlagringarna är utan tvekan de mest betydelsefulla grundvattenförekomsterna för Sveriges dricksvattenförsörjning. Mer än 80% av landets alla vattenverk utnyttjar vatten från dessa resurser. En ojämn fördelning av grundvattenresurserna i kombination med pågående klimatförändringar kan leda till vattenbrist i landet. Risken för vattenbrist förekommer framförallt i områden som är belägna i Sydöstra Sverige där låga grundvattennivåer redan har konstaterats. Sveriges geologiska undersökning (SGU) har i uppdrag av regeringen tilldelats uppgiften att utöka kartläggningen och karaktäriseringen av grundvattenresurser i särskilt utsatta områden. I samband med grundvattenkarteringen i Södra Östersjöns vattendistrikt (projekt-id:83–015) undersöktes grundvattenmagasinet Verveln – Gullringen i Kalmar län med hjälp av georadar. Georadar är en geofysisk undersökningsmetod där pulser av elektromagnetiska vågor inom frekvensintervallet 20 – 1000Mhz skickas ned i marken. En del av pulserna reflekteras tillbaka mot markytan när de stöter på variationer i markens magnetiska permeabilitet (µ) och elektriska permittivitet (ε). Reflektionerna detekteras av en mottagare vid markytan där resultatet visas i form av en georadarprofil. I georadarprofiler kan lagergränser, grundvattenytor och nedgrävda föremål identifieras. I detta arbete har georadarprofiler från SGU:s mätningar över Verveln – Gullringen tolkats i syfte att skapa ett bättre geologiskt underlag för att bedöma grundvattenförhållanden i magasinet. Syftet har även varit att bestämma jordlagrens mäktighet, berggrundens morfologi och att beräkna magasinet volym samt vattenmängd. Som stöd för tolkningsarbetet har jordartskartor, brunnsdata samt litteratur använts. Tolkade georadarprofiler användes som underlag för att skapa en mäktighetsmodell över området. Mäktighetsmodellen kan användas som underlag för framtida volymberäkningar av magasinet. I modellen framkommer att avlagringens jordlager har en mäktighet som varierar mellan 4m – 20m. Det framkommer även att majoriteten av sedimenten har mäktigheter inom intervallet 4m – 8m. Vidare har ett större samt sammanhängande område med mäktigheter inom intervallet 8m – 16m identifierats i magasinets centrala delar. För att få tillgång till stora vattenmängder och för att minska påverkan från yttre faktorer så rekommenderas att dricksvattenbrunnar placeras i dessa områden d.v.s. där jordmäktigheten är större. Under arbetets gång har även magasinets jordvolym bestämts till 79 miljoner m3 vilket motsvara en vattenkapacitet på ~12 miljoner m3 när jordlagrens porositet är approximerad till 15%. (Less)
Abstract
Most of Sweden’s groundwater resources are made up from glacifluvial deposits such as eskers and deltas that consist of sand and gravel. Glacifluvial deposits are certainly the most significant groundwater resources for drinking water supplies in Sweden. Groundwater resources are used to supply more than 80% of all the existing water plants nationwide. These important resources have an uneven distribution across the country, an uneven distribution in combination with recent climate changes can lead to water scarcity. High risk of water scarcity is already evident in areas such as Kalmar county in southeast Sweden where low groundwater levels have been noted. The Swedish government assigned the geological survey of Sweden (SGU) the task to... (More)
Most of Sweden’s groundwater resources are made up from glacifluvial deposits such as eskers and deltas that consist of sand and gravel. Glacifluvial deposits are certainly the most significant groundwater resources for drinking water supplies in Sweden. Groundwater resources are used to supply more than 80% of all the existing water plants nationwide. These important resources have an uneven distribution across the country, an uneven distribution in combination with recent climate changes can lead to water scarcity. High risk of water scarcity is already evident in areas such as Kalmar county in southeast Sweden where low groundwater levels have been noted. The Swedish government assigned the geological survey of Sweden (SGU) the task to expand the mapping and characterization of groundwater resources in high-risk areas. Within the assigned task, SGU performed a ground penetrating (GPR) survey on Verveln – Gullringen, a glacifluvial groundwater aquifer in Kalmar county. Ground penetrating radar (GPR) is a geophysical method that works by emitting electromagnetic pulses with frequencies in the range of 20 – 1000 MHz into the ground. Parts of the emitted EM – pulse is reflected towards the surface when it encounters changes in the magnetic permeability (µ) and electrical permittivity (ε) of the subsurface materials. The reflections are detected by a detecting device on the surface. The resulting reflection patterns are shown in a radargram, also known as a GPR-section. Subsurface boundaries, groundwater tables and other subsurface objects will usually show as reflections that can be determined in a GPR – section. In this thesis GPR - sections from SGU: s survey on Verveln – Gullringen were obtained and interpreted for the purpose to create improved geological material to assess the aquifer. The purpose with this thesis has also been to determine the thickness of the sediments that build up the aquifer, the morphology of the underlying bedrock and to estimate the volume of the aquifer and its water content. For this purpose, soil maps, information from water wells and literature was used to support the interpretation process. The interpreted sections were used to create a model where the thickness of the sediments in the area are displayed. The model shows that the sediments have a varying thickness from <4m – 20m but most of the sediments have a thickness that range from 4m – 8m. Further, a relatively large and continues area in the central parts of the aquifer was identified, in this area the sediments exhibited thicknesses in the range of 8m – 16m. It is recommended to locate water wells in these areas where large amounts of water can be obtained and where the risk of pollution is reduced. The volume of the aquifer was also determined to 79 million m3 and the total water capacity was determined to 12 million m3. The sediment thickness model can be used for future water content estimations. (Less)
Please use this url to cite or link to this publication:
author
Faraj, Haider LU
supervisor
organization
alternative title
Interpretation of GPR sections to gain insight into the groundwater aquifer Verveln - Gullringen in Kalmar county, Sweden
course
GEOL01 20191
year
type
M2 - Bachelor Degree
subject
keywords
grundvatten, grundvattenmagasin, hydrogeologi, dricksvattenförsörjning, Kalmar län, georadar, geofysik, isälvsavlagringar, Sveriges geologiska undersökning, SGU, klimatförändringar
publication/series
Examensarbeten i geologi vid Lunds universitet
report number
562
language
Swedish
additional info
Extern handledare: Mattias Gustafsson, Sveriges geologiska undersökning
id
8991091
date added to LUP
2019-07-29 14:30:56
date last changed
2019-07-29 14:30:56
@misc{8991091,
  abstract     = {Most of Sweden’s groundwater resources are made up from glacifluvial deposits such as eskers and deltas that consist of sand and gravel. Glacifluvial deposits are certainly the most significant groundwater resources for drinking water supplies in Sweden. Groundwater resources are used to supply more than 80% of all the existing water plants nationwide. These important resources have an uneven distribution across the country, an uneven distribution in combination with recent climate changes can lead to water scarcity. High risk of water scarcity is already evident in areas such as Kalmar county in southeast Sweden where low groundwater levels have been noted. The Swedish government assigned the geological survey of Sweden (SGU) the task to expand the mapping and characterization of groundwater resources in high-risk areas. Within the assigned task, SGU performed a ground penetrating (GPR) survey on Verveln – Gullringen, a glacifluvial groundwater aquifer in Kalmar county. Ground penetrating radar (GPR) is a geophysical method that works by emitting electromagnetic pulses with frequencies in the range of 20 – 1000 MHz into the ground. Parts of the emitted EM – pulse is reflected towards the surface when it encounters changes in the magnetic permeability (µ) and electrical permittivity (ε) of the subsurface materials. The reflections are detected by a detecting device on the surface. The resulting reflection patterns are shown in a radargram, also known as a GPR-section. Subsurface boundaries, groundwater tables and other subsurface objects will usually show as reflections that can be determined in a GPR – section. In this thesis GPR - sections from SGU: s survey on Verveln – Gullringen were obtained and interpreted for the purpose to create improved geological material to assess the aquifer. The purpose with this thesis has also been to determine the thickness of the sediments that build up the aquifer, the morphology of the underlying bedrock and to estimate the volume of the aquifer and its water content. For this purpose, soil maps, information from water wells and literature was used to support the interpretation process. The interpreted sections were used to create a model where the thickness of the sediments in the area are displayed. The model shows that the sediments have a varying thickness from <4m – 20m but most of the sediments have a thickness that range from 4m – 8m. Further, a relatively large and continues area in the central parts of the aquifer was identified, in this area the sediments exhibited thicknesses in the range of 8m – 16m. It is recommended to locate water wells in these areas where large amounts of water can be obtained and where the risk of pollution is reduced. The volume of the aquifer was also determined to 79 million m3 and the total water capacity was determined to 12 million m3. The sediment thickness model can be used for future water content estimations.},
  author       = {Faraj, Haider},
  keyword      = {grundvatten,grundvattenmagasin,hydrogeologi,dricksvattenförsörjning,Kalmar län,georadar,geofysik,isälvsavlagringar,Sveriges geologiska undersökning,SGU,klimatförändringar},
  language     = {swe},
  note         = {Student Paper},
  series       = {Examensarbeten i geologi vid Lunds universitet},
  title        = {Tolkning av georadarprofiler över grundvattenmagasinet Verveln - Gullringen i Kalmar län},
  year         = {2019},
}