RefereraExporteraLink to record
Permanent link

Direct link
Referera
Referensformat
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
Groundwater resources in hard rock coastal terrains: Insights into heterogeneity and spatial variability
KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Vatten- och miljöteknik.ORCID-id: 0000-0002-9431-753X
2019 (engelsk)Doktoravhandling, med artikler (Annet vitenskapelig)
Abstract [en]

Challenges regarding water security in hard rock coastal regions with limited soil cover are: a seasonal absence of recharge during times of peak residency, heterogeneity and variability of the fracture network, close proximity to saline water sources and spatially inconsistent storage and extraction. In areas where it is not feasible to connect residents to municipal water systems, a better understanding of the resilience of reservoirs is needed. The purpose of this study is to investigate and describe the spatial nature of hydraulic data in these types of terrains and present several novel GIS-based groundwater tools with the intent of increasing local water security and aiding in sustainable water resources management. Methods used in this study include groundwater balance modelling and conceptual groundwater storage modelling, as well as a combination of parametric and non-parametric statistical methods such as ANOVA, PCA, correlation and semivariogram analyses. Specific capacity estimates from the Geological Survey of Sweden’s well archive grouped by age or rock type showed very little autocorrelation and in assumed homogeneous geological regions showed statistically significant differences when arbitrarily grouped along a lineament. Estimates of kinematic porosity based on surface fracture data were found have statistically significant correlations with the well data. A GIS-based multivariate prediction tool for assessing Groundwater Resources Potential (GRP) was found to have statistically significant correlations with well data. The GRP method was then combined with a conceptual groundwater storage model and was subsequently found to have statistically significant correlations with chloride concentrations in well quality tests. The storage model was found to have a spatially-dependent sensitivity, meaning that different assumptions within the model had varying effects on the model depending on the geological settings. Incorporating the storage model into a spatial groundwater balance model was then compared with groundwater level time series data over a period of two years, where it was found to have a good explanative capacity and RMSE values of the storage ratio (0.06 to 0.34). Additionally, a soil depth model was developed, tested and found to produce promising results in regions with frequent rock outcrops, where up to 86% of estimates were within 2 m of actual soil depths. Conclusions from this study illustrate the need for a spatial approach to groundwater resources in these types of terrains, and demonstrate a strong potential of several new tools for quantity, capacity and vulnerability estimates to increase water security in a changing climate.

Abstract [sv]

Utmaningar för grundvattenförsörjning i kustnära områden med litet jordtäcke inkluderar begränsad grundvattenbildning under sommarsäsongen när behoven av vatten är som störst, heterogenitet i vattenflöde, närhet till saltvattenkällor samt heterogen lagring och uttag. I områden där det inte är möjligt att ansluta boende till kommunala VA-system behövs en bättre förståelse av magasinens uthållighet för att tillgodose vattenbehoven under nuvarande och ändrade klimatförhållanden. Syftet med forskningen har varit att undersöka det rumsliga beteendet hos hydraulisk data och att öka kunskapen om grundvattnets sårbarhet i kustnära områden med kristallin berggrund och tunna jordlager samt att utveckla verktyg för att beräkna vattenuttag och användning i dylika områden. Projekten har bedrivits med hjälp av GIS-verktyg, parametriska och icke-parametriska statistiska metoder såsom ANOVA, PCA, variogramsanalyser och korrelationsanalyser, samt modellering med grundvattenbalanser och grundvattenlagring.

Brunnsdata från borrade brunnar, grupperade efter ålder och berggrundstyp visade på svag rumslig korrelation. I områden med en antagen geologisk homogenitet hittades statistiskt signifikanta skillnader i brunnkapacitetsdata vid slumpmässig gruppering längs ett lineament. Uppskattningar av kinematisk porositet baserad på ytliga sprickmätningar har visat statistiskt signifikanta korrelationer med brunnskapacitet. Ett multivariat prediktionsverktyg (GRP) för bedömning av områden med god utvinningskapacitet har utvecklats och visade statistiskt signifikanta korrelationer med kapaciteten från existerande brunnar.

GRP-metoden kombinerades sedan med en konceptuell grundvattenmagasinsmodell som visade statistiskt signifikanta korrelationer med kloridhalter tagna från ett brunnskemiarkiv. Magasinsmodellen visade sig ha en rumsligt beroende känslighet, vilket innebar att olika antaganden inom modellen, bland annat avseende geologiska egenskaper i terrängen, hade varierande effekt på modellresultaten. En grundvattenbalansmodell har också utvecklats i GIS och jämförts med verkliga tidserier av grundvattennivå över en tvåårsperiod, med RMSE-värden varierande mellan 0,06 till 0,34. Som hjälp för att beräkna magasineringen i jordlager har en jorddjupsmodell utvecklats och testats vilken visade god överensstämmelse med existerande borrhål i områden med kristallint berg och stor berghällfrekvens.

Slutsatserna från dessa studier ger stöd till behovet av att ta hänsyn till det rumsliga förhållandet hos grundvattenresurserna i områden med kristallin berggrund och visar hur den rumsliga variationen kan beskrivas. Ökad kunskap om den rumsliga variationen kan ge möjlighet att utveckla förbättrade uppskattningar av grundvattenresurserna vilket i sin tur kan leda till bättre användning av befintliga vattenresurser. Dessutom har ett flertal nya verktyg utvecklats för potentiella beräkningar av kvantitet, kapacitet och sårbarhetsanalyser för grundvattenresurserna vilka kan användas för att analysera vattensäkerheten vid olika klimat- och markanvändningsscenarier.

sted, utgiver, år, opplag, sider
Stockholm: KTH Royal Institute of Technology, 2019. , s. 45
Serie
TRITA-ABE-DLT ; 1932
Emneord [en]
Crystalline Rock, Groundwater Balance, Kinematic porosity, Groundwater Recharge, Water Security, Coastal Aquifer
HSV kategori
Forskningsprogram
Mark- och vattenteknik
Identifikatorer
URN: urn:nbn:se:kth:diva-256317ISBN: 978-91-7873-272-2 (tryckt)OAI: oai:DiVA.org:kth-256317DiVA, id: diva2:1346912
Disputas
2019-09-20, F3, Lindstedtsvägen 26, Stockholm, 14:00 (engelsk)
Opponent
Veileder
Forskningsfinansiär
The Geological Survey of Sweden (SGU), 60-1640/2007Swedish Research Council Formas, 2017-01504
Merknad

QC 20190830

Tilgjengelig fra: 2019-08-30 Laget: 2019-08-29 Sist oppdatert: 2019-08-30bibliografisk kontrollert
Delarbeid
1. Groundwater Resources Potential in Hard Rock Terrain: A Multivariate Approach
Åpne denne publikasjonen i ny fane eller vindu >>Groundwater Resources Potential in Hard Rock Terrain: A Multivariate Approach
2014 (engelsk)Inngår i: Ground Water, ISSN 0017-467X, E-ISSN 1745-6584Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Groundwater resources are limited and difficult to predict in crystalline bedrock due to heterogeneity and anisotropy in rock fracture systems. Municipal-level governments often lack the resources for traditional hydrogeological tests when planning for sustainable use of water resources. A new methodology for assessing groundwater resources potential (GRP) based on geological and topographical factors using principal component analysis (PCA) and analysis of variance (ANOVA) was developed and tested. ANOVA results demonstrated statistically significant differences in classed variable groups as well as in classed GRP scores with regard to hydrogeological indicators, such as specific capacity (SC) and transmissivity. Results of PCA were used to govern the weight of the variables used in the prediction maps. GRP scores were able to identify 79% of wells in a verification dataset, which had SC values less than the total dataset median. GRP values showed statistically significant correlations using both parametric (using transformed datasets) and non-parametric methods. The method shows promise for municipal or regional level planning in crystalline terrains with high levels of heterogeneity and anisotropy as a hydrogeologically and statistically based tool to assist in assessing groundwater resources. The methodology is executed in a geographic information systems environment, and uses often readily available data, such as geological maps, feature maps and topography, and thus does not require expensive and time-consuming aquifer tests.

sted, utgiver, år, opplag, sider
John Wiley & Sons, 2014
Emneord
Coastal aquifer, Crystalline rock, Fracture, Geographic information system (GIS), Principal Component Analysis (PCA)
HSV kategori
Identifikatorer
urn:nbn:se:kth:diva-151298 (URN)10.1111/gwat.12265 (DOI)000360758100009 ()2-s2.0-84940744630 (Scopus ID)
Merknad

Updated from Manuscript to published Article. QC 20150218

Tilgjengelig fra: 2014-09-17 Laget: 2014-09-17 Sist oppdatert: 2019-08-29bibliografisk kontrollert
2. Hydraulic heterogeneity and its impact on kinematic porosity in Swedish coastal terrains
Åpne denne publikasjonen i ny fane eller vindu >>Hydraulic heterogeneity and its impact on kinematic porosity in Swedish coastal terrains
2018 (engelsk)Inngår i: Engineering Geology, ISSN 0013-7952, E-ISSN 1872-6917, Vol. 245Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Hydrogeology in crystalline rock aquifers is often problematic due to the heterogeneity and anisotropy in thefracture network. Kinematic porosity of the host rock is exceedingly important for municipal decision makers inassessing sustainably extractable water supply volumes and assessing contaminant transport behavior within thematrix. This study explores heteroscedasticity in the hydrogeological characteristics of the fracture network andestimation of kinematic porosity from superficial fracture measurements. Estimates were based on the geometricalproperties of the fractures including: fracture frequency, aperture and orientation. The estimates wereadjusted for aperture changes with depth, connectivity of the fracture network, fracture continuity and measurementorientation bias. The results were compared with well archive data and correlations were found to besignificant with more than 95% confidence. Erratic behaviour of well data relative to fracture measurementsindicates that well orientation with respect to the fracture network gives incomplete hydrogeological data.Spatial heterogeneity of the bedrock was examined using spatial statistics and geographic information systems.The results from the spatial statistical analyses of well data showed that the heterogeneity within the bedrock issufficiently high that spatial correlations cease to exist in nearly all investigated rock types at distances greaterthan 500 m, and in some rocks, particularly sedimentary gneisses, no spatial correlations were observed.Arbitrarily grouped samples with similar geology and topography showed evidence of non-stationary variance.Results indicate that regional generalizations based on sparse point measurements are highly error prone andpotential exists in complementary field-based estimates.

sted, utgiver, år, opplag, sider
Elsevier, 2018
HSV kategori
Identifikatorer
urn:nbn:se:kth:diva-246195 (URN)10.1016/j.enggeo.2018.08.008 (DOI)000448494600006 ()2-s2.0-85051820071 (Scopus ID)
Forskningsfinansiär
The Geological Survey of Sweden (SGU), 60-1640/2007Swedish Research Council Formas, 2017-01504
Merknad

QC 20190318

Tilgjengelig fra: 2019-03-15 Laget: 2019-03-15 Sist oppdatert: 2019-08-29bibliografisk kontrollert
3. Comparison of methods for predicting regolith thickness in previously glaciated terrain, Stockholm, Sweden
Åpne denne publikasjonen i ny fane eller vindu >>Comparison of methods for predicting regolith thickness in previously glaciated terrain, Stockholm, Sweden
Vise andre…
2014 (engelsk)Inngår i: Geoderma, ISSN 0016-7061, E-ISSN 1872-6259, Vol. 226, s. 116-129Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Knowledge about regolith thickness is important in several civil and environmental engineering fields. However, subsurface characteristics such as regolith thickness are difficult to determine through surface investigations and maps at regional scales. This paper presents four methods for estimating regolith thickness in a GIS environment for previously glaciated terrain with high frequency of rock outcrops: linear regression (LR) using topographical covariates; inverse distance weighting (IOW) interpolation of regolith thickness point data from well drillings: a trigonometrical approach (TA) developed for this study which uses outcrop slopes and distance between outcrops; and a simplified regolith model (SRM). The SRM is a model modified from TA which estimates the regolith thickness based on outcrops, slopes and the distance to outcrops in eight directions. The methods were compared for three study areas (Tyreso, Vallentuna and Osteraker) in Stockholm County, Sweden. Based on the results in this paper, LR proved to be the most accurate method for regolith thickness estimation, measured through root mean square error values. Whereas IDW was the most accurate method in terms of error within 2 m, which would make it a suitable model if and when large datasets of regolith point data are available. When drilling data is scarce then both the TA and SRM methods can be used for regolith estimations. However, the SRM proved to be a more accurate regolith thickness model compared to TA. SRM shows promising results and could be used at a preliminary stage in engineering projects where little or no data is available prior to detailed field investigations in previously glaciated terrain.

HSV kategori
Identifikatorer
urn:nbn:se:kth:diva-147399 (URN)10.1016/j.geoderma.2014.03.003 (DOI)000336467500013 ()2-s2.0-84897441618 (Scopus ID)
Forskningsfinansiär
Formas, 2009-1285
Merknad

QC 20140702

Tilgjengelig fra: 2014-07-02 Laget: 2014-06-27 Sist oppdatert: 2019-08-29bibliografisk kontrollert
4. Integrating storage and spatial variability into regional groundwater balances: Moving towards water security in hard rock coastal areas
Åpne denne publikasjonen i ny fane eller vindu >>Integrating storage and spatial variability into regional groundwater balances: Moving towards water security in hard rock coastal areas
(engelsk)Manuskript (preprint) (Annet vitenskapelig)
Abstract [en]

In terrains with limited soil cover and groundwater storage, groundwater resource management is governed by the spatial nature of storage, recharge and extraction. Local soils may act as important groundwater reservoirs for residents which have no other feasible water supply. A novel groundwater balance methodology is presented which accounts for the spatial distribution of storage and extraction. Existing topographical and geological databases as well as well data were used to construct a conceptual model of the groundwater system, assuming stratigraphy based on typical geology. The method is implemented in a geographic information systems environment and allows for variable climate and land use scenarios.

Several scenarios were examined with this method, demonstrating that on a regional scale average reservoir volumes meet demand but at the local levels depletion of reservoirs may be experienced. Groundwater level drawdown in excess of 50% of the projected reservoir storage were seen, particularly near the coast. Soil-filled valleys may act as local hydraulic barriers, preventing contamination from saline water provided no direct hydraulic connection is present. The method demonstrates the importance of a spatial approach in managing groundwater resources, and shows promise as a tool for planners in increasing water security.

Emneord
crystalline rock, fractured rock, geographic information systems, groundwater recharge, water budget, water security
HSV kategori
Identifikatorer
urn:nbn:se:kth:diva-256323 (URN)
Forskningsfinansiär
Swedish Research Council Formas, 2017-01504The Geological Survey of Sweden (SGU), 60-1640/2007
Merknad

QCR 20190827

Tilgjengelig fra: 2019-08-21 Laget: 2019-08-21 Sist oppdatert: 2019-08-29bibliografisk kontrollert
5. The importance of a spatial approach to water resources management in heterogeneous regions
Åpne denne publikasjonen i ny fane eller vindu >>The importance of a spatial approach to water resources management in heterogeneous regions
(engelsk)Manuskript (preprint) (Annet vitenskapelig)
Abstract [en]

Limited groundwater storage in recently glaciated terrains with frequent hard, crystalline bedrock outcrops poses challenges for groundwater resources management. Due to often-limited economic resources allocated to groundwater investigations in areas where drinking water is primarily supplied by private wells, heuristic solutions such as groundwater balances with built-in limitations of storage may serve a vital role in improving water security. This study investigates the use of a conceptual groundwater balance model and the use of a conceptual-statistical reservoir vulnerability model with this aim. A limited storage, GIS-based groundwater balance model using existing databases was applied to an area outside of Stockholm, Sweden with existing groundwater level measurement data. The spatial model showed improved performance over existing S-Hype model estimates of groundwater levels currently used in groundwater resources management by the Geological Survey of Sweden, even without local calibration. Differences between two wells with time series data showed evidence of strong influence due to in-situ geological conditions. Groundwater vulnerability estimates correlated significantly with chloride measurements from an existing chemistry database. The performance of the conceptually-based spatial groundwater balance supports the use of the approach as an aid for municipal planners and decision-makers in moving towards sustainable groundwater resources planning and improving water security in areas with limited storage and a large number of dispersed, private wells.

Emneord
Coastal aquifer, crystalline rock, fracture flow, water balance, groundwater modelling, sustainable water use
HSV kategori
Identifikatorer
urn:nbn:se:kth:diva-256324 (URN)
Merknad

QC 20190827

Tilgjengelig fra: 2019-08-21 Laget: 2019-08-21 Sist oppdatert: 2019-08-29bibliografisk kontrollert

Open Access i DiVA

Earon_dissertation(11971 kB)52 nedlastinger
Filinformasjon
Fil FULLTEXT01.pdfFilstørrelse 11971 kBChecksum SHA-512
b0e0c6d6b528b2678b5b2fd729ce337065ce7dcfb237edcbcaeca6f3d43eff727d2db52ea172c43108794792ae2748994adc8a3519811e269fab429bb186c9b1
Type fulltextMimetype application/pdf

Søk i DiVA

Av forfatter/redaktør
Earon, Robert
Av organisasjonen

Søk utenfor DiVA

GoogleGoogle Scholar
Totalt: 52 nedlastinger
Antall nedlastinger er summen av alle nedlastinger av alle fulltekster. Det kan for eksempel være tidligere versjoner som er ikke lenger tilgjengelige

isbn
urn-nbn

Altmetric

isbn
urn-nbn
Totalt: 486 treff
RefereraExporteraLink to record
Permanent link

Direct link
Referera
Referensformat
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf