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Groundwater chemistry evaluation and a GIS-based approach for determining groundwater potential in Mörbylånga, Sweden

Benavides Höglund, Nikolas LU (2018) In Dissertations in Geology at Lund University GEOR02 20171
Department of Geology
Abstract
Recently, several regions in southern Sweden suffered extremely low groundwater levels following a long-term infrequency in rainfall. In response, irrigation was banned in many of the affected municipalities during 2016–2017, amongst which Mörbylånga municipality was one. Because nearly half of the nation’s drinking water is extracted from groundwater, protecting and managing this vital resource in a sustainable manner is essential. The public sector, spearheaded by the Geological Survey of Sweden (SGU), is now increasing their efforts in the search for additional groundwater resources, as well as in the management of existing ones.
The aim of this thesis, which is written in collaboration with SGU, is to evaluate the groundwater quality... (More)
Recently, several regions in southern Sweden suffered extremely low groundwater levels following a long-term infrequency in rainfall. In response, irrigation was banned in many of the affected municipalities during 2016–2017, amongst which Mörbylånga municipality was one. Because nearly half of the nation’s drinking water is extracted from groundwater, protecting and managing this vital resource in a sustainable manner is essential. The public sector, spearheaded by the Geological Survey of Sweden (SGU), is now increasing their efforts in the search for additional groundwater resources, as well as in the management of existing ones.
The aim of this thesis, which is written in collaboration with SGU, is to evaluate the groundwater quality of Mörbylånga municipality. The evaluation is based on more than 1400 groundwater analyses, sampled from private and municipal wells over the last 8–10 year period. The samples, analyzed for physiochemical and microbiological content, are compared to guideline values elaborated by SGU and the National Food Agency (Livsmedelsverket). In addition, 26 maps were created based on georeferenced data from private wells, showing the spatial distribution of the analyzed parameters. Furthermore, an estimation of the groundwater potential in the municipality was per-formed, using a GIS-based approach. By integrating spatial geodata in a multi-criteria analysis, three additional maps were created, which, together with other material, can be used as a base for future groundwater exploration. Results of the evaluation show, for the studied period, a better groundwater quality in municipal wells, compared to private wells. Significant concentrations of nutrients and microorganisms were detected in private wells, especially in the northern and eastern parts of the municipality. High concentrations of lead were in a few occasions encoun-tered in both municipal and private wells and a cyclical variation in concentrations of sodium, sulfate and calcium in one of the municipal wells could possibly be linked to saltwater intrusion. The source for these observations, and suggested measures, are discussed. Furthermore, the GIS-analyses undertaken in this study reveal an area of ap-proximately 2.5 km2 with higher than average groundwater potential. The area is conveniently located with regards to users and infrastructure. Suggestions for how to proceed the work with the GIS results are discussed as well. (Less)
Popular Abstract (Swedish)
Till följd av ovanligt låg nederbörd drabbades stora delar av södra Sverige av extremt låga grundvattennivåer under 2016–2017. För att undvika problem med vattenförsörjningen införde flera kommuner, inklusive Mörbylånga kommun, ett bevattningsförbud. Eftersom grundvatten utgör ungefär hälften av Sveriges dricksvatten är det viktigt att skydda och förvalta denna grundläggande resurs på ett hållbart sätt. Sveriges Geologiska Undersökning (SGU), tillsammans med berörda kommuner, undersöker nu olika möjligheter för att finna nya grundvattentillgångar, samt arbetar fram underlag för en bättre förvaltning av befintliga tillgångar.
Syftet med denna studie, som utförts i samarbete med SGU i Lund, är att utvärdera den kemiska grundvattenkvaliteten... (More)
Till följd av ovanligt låg nederbörd drabbades stora delar av södra Sverige av extremt låga grundvattennivåer under 2016–2017. För att undvika problem med vattenförsörjningen införde flera kommuner, inklusive Mörbylånga kommun, ett bevattningsförbud. Eftersom grundvatten utgör ungefär hälften av Sveriges dricksvatten är det viktigt att skydda och förvalta denna grundläggande resurs på ett hållbart sätt. Sveriges Geologiska Undersökning (SGU), tillsammans med berörda kommuner, undersöker nu olika möjligheter för att finna nya grundvattentillgångar, samt arbetar fram underlag för en bättre förvaltning av befintliga tillgångar.
Syftet med denna studie, som utförts i samarbete med SGU i Lund, är att utvärdera den kemiska grundvattenkvaliteten i Mörbylånga kommun. Denna utvärdering är baserad på mer än 1400 vattenanalyser utförda på kommunala och privata brunnar de senaste 8–10 åren. Proverna, som är analyserade för kemiska och mikrobiologiska parametrar, har jämförts med riktvärden utfärdade av SGU och Livsmedelsverket. Utöver detta har 26 stycken haltkartor skapats, baserat på georefererad vattenkemidata från privata brunnar. Dessa kartor visar halter (i enlighet med SGUs gränsvärden) samt den geografiska spridningen för de parametrar som analyserats i kommunen. Vidare har en GIS-baserad analys tillämpats för att göra en uppskattning av grundvattenpotentialen i Mörbylånga kommun. Genom att integrera rumsliga geodata i en multikriterieanalys skapades ytterligare tre kartor som, tillsammans med annat material, kan ligga till grund för sökandet efter framtida grundvattentillgångar. De resultat som arbetats fram visar att grundvattenkvaliteten är högre i kommunala brunnar jämfört med privata brunnar. Höga halter av näringsämnen och mikroorganismer uppmättes i de privata brunnarna, särskilt i de norra och östra delarna av kommunen. Periodvis uppmättes även höga halter av bly i både kommunala och privata brunnar. I en av de kommunala brunnarna upptäcktes ett cykliskt mönster vid en jämförelse av natrium-, sulfat- och kalciumkoncentrationer, eventuellt orsakat av saltvatteninträngning. Vidare visar resultat från GIS-analysen ett område på ca 2,5 km2 där grundvattenpotentialen förväntas vara högre än den genomsnittliga för kommunen. Detta område ligger nära både användare och infrastruktur. Ytterligare observationer, samt förslag till åtgärder diskuteras vidare i denna studie. (Less)
Please use this url to cite or link to this publication:
author
Benavides Höglund, Nikolas LU
supervisor
organization
course
GEOR02 20171
year
type
H2 - Master's Degree (Two Years)
subject
keywords
Groundwater chemistry, Groundwater potential, Mörbylånga, Öland, Chemical analysis, Hydrogeology, GIS, Multi-criteria analysis, Water quality guidelines, Groundwater deficit, Water shortage
publication/series
Dissertations in Geology at Lund University
report number
531
language
English
additional info
External supervisors: Peter Dahlqvist and Mattias Gustafsson, Sveriges geologiska undersökning
id
8944985
date added to LUP
2018-06-05 09:06:50
date last changed
2018-06-05 09:06:50
@misc{8944985,
  abstract     = {Recently, several regions in southern Sweden suffered extremely low groundwater levels following a long-term infrequency in rainfall. In response, irrigation was banned in many of the affected municipalities during 2016–2017, amongst which Mörbylånga municipality was one. Because nearly half of the nation’s drinking water is extracted from groundwater, protecting and managing this vital resource in a sustainable manner is essential. The public sector, spearheaded by the Geological Survey of Sweden (SGU), is now increasing their efforts in the search for additional groundwater resources, as well as in the management of existing ones.
The aim of this thesis, which is written in collaboration with SGU, is to evaluate the groundwater quality of Mörbylånga municipality. The evaluation is based on more than 1400 groundwater analyses, sampled from private and municipal wells over the last 8–10 year period. The samples, analyzed for physiochemical and microbiological content, are compared to guideline values elaborated by SGU and the National Food Agency (Livsmedelsverket). In addition, 26 maps were created based on georeferenced data from private wells, showing the spatial distribution of the analyzed parameters. Furthermore, an estimation of the groundwater potential in the municipality was per-formed, using a GIS-based approach. By integrating spatial geodata in a multi-criteria analysis, three additional maps were created, which, together with other material, can be used as a base for future groundwater exploration. Results of the evaluation show, for the studied period, a better groundwater quality in municipal wells, compared to private wells. Significant concentrations of nutrients and microorganisms were detected in private wells, especially in the northern and eastern parts of the municipality. High concentrations of lead were in a few occasions encoun-tered in both municipal and private wells and a cyclical variation in concentrations of sodium, sulfate and calcium in one of the municipal wells could possibly be linked to saltwater intrusion. The source for these observations, and suggested measures, are discussed. Furthermore, the GIS-analyses undertaken in this study reveal an area of ap-proximately 2.5 km2 with higher than average groundwater potential. The area is conveniently located with regards to users and infrastructure. Suggestions for how to proceed the work with the GIS results are discussed as well.},
  author       = {Benavides Höglund, Nikolas},
  keyword      = {Groundwater chemistry,Groundwater potential,Mörbylånga,Öland,Chemical analysis,Hydrogeology,GIS,Multi-criteria analysis,Water quality guidelines,Groundwater deficit,Water shortage},
  language     = {eng},
  note         = {Student Paper},
  series       = {Dissertations in Geology at Lund University},
  title        = {Groundwater chemistry evaluation and a GIS-based approach for determining groundwater potential in Mörbylånga, Sweden},
  year         = {2018},
}