DOCSLIB.ORG

Geophysical, Geological and Hydrogeological Characterization of a Tributary Buried Bedrock Valley in Southern Ontario

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Geophysical, Geological and Hydrogeological Characterization of a Tributary Buried Bedrock Valley in Southern Ontario Canadian Journal of Earth Sciences Geophysical, geological and hydrogeological characterization of a tributary buried bedrock valley in southern Ontario Journal: Canadian Journal of Earth Sciences Manuscript ID cjes-2016-0120.R2 Manuscript Type: Article Date Submitted by the Author: 05-Dec-2016 Complete List of Authors: Steelman, Colby; University of Guelph, School of Engineering Arnaud, Emmanuelle;Draft University of Guelph, Pehme, Peeter; University of Guelph Parker, Beth; University of Guelph, School of Engineering buried bedrock valley, electrical resistivity tomography, karst, water Keyword: supply, Silurian dolostone https://mc06.manuscriptcentral.com/cjes-pubs Page 1 of 59 Canadian Journal of Earth Sciences TITLE : Geophysical, geological and hydrogeological characterization of a tributary buried bedrock valley in southern Ontario AUTHORS : Colby M. Steelman 1,2 , Emmanuelle Arnaud 1,3 , Peeter Pehme 1,2 and Beth L. Parker 1,2 AFFILIATIONS : [1] G360 Centre for Applied Groundwater Research, University of Guelph, Guelph ON Canada [2] School of Engineering, University of Guelph, Guelph ON, Canada [3] School of Environmental Sciences, University of Guelph, Guelph ON, Canada *Correspondence to: C. M. Steelman ([email protected]) and B. L. Parker ([email protected]) Draft 1 https://mc06.manuscriptcentral.com/cjes-pubs Canadian Journal of Earth Sciences Page 2 of 59 1 ABSTRACT 2 Buried bedrock valleys infilled with Quaternary-aged sediment have the potential to become productive 3 aquifers due to prevalent sand and gravel deposits often associated with these topographic lows. In 4 areas where groundwater is drawn from the underlying bedrock aquifer, buried bedrock channels may 5 significantly affect the spatial distribution of recharge and localized contaminant pathways. Therefore, 6 understanding the form, distribution and the nature of Quaternary infill sediments within these buried 7 bedrock river valleys, and their relationship to hydraulically-transmissive bedrock features is an important 8 aspect of groundwater resource management. Here, we evaluate the effectiveness of electrical resistivity 9 and seismic refraction collected over a partially urbanized 150 ha area with variable vegetation, roads, 10 and structures, to map the spatial distribution of sediments and delineation of a channel segment 11 associated with a regional bedrock valley. Electrical resistivity and seismic refraction was performed 12 along 13 (covering ~11.6 km) and 7 transects (coverDrafting ~0.9 km), respectively, to map and characterize 13 the bedrock surface morphology beneath a variable thickness of unconsolidated deposits. Three 14 continuously cored holes and downhole geophysical logs, supplemented with four nearby water well 15 records captured the in-channel as well as adjacent Quaternary stratigraphy (~15-40 m). Cores recorded 16 multiple glacial till deposits and ice marginal processes associated with ice advances and retreats. 17 Hydraulic transmissivity of the bedrock around the valley feature was evaluated using a FLUTe™ hydraulic 18 transmissivity profiling technique. This study demonstrates the potential of combining several surface 19 geophysical methods with sedimentological analysis of continuous cores and hydraulic data for 20 characterizing tributary bedrock channel morphology and Quaternary infill at a scale relevant to localized 21 studies of municipal production well recharge zones and contaminant transport and fate. 22 23 KEY WORDS : buried bedrock valley; electrical resistivity tomography; karst; water supply; Silurian dolostone 2 https://mc06.manuscriptcentral.com/cjes-pubs Page 3 of 59 Canadian Journal of Earth Sciences 24 1.0 INTRODUCTION 25 Buried bedrock valleys (BBVs) represent an important component of the hydrogeologic conceptual 26 model of southern Ontario and other previously glaciated terrains such as the Canadian Prairies, northern 27 United States, and Europe (e.g., Kehew and Boettger 1986; Sandersen and Jørgensen 2003; Russell et al. 28 2004; Cummings et al. 2012; Sharpe et al. 2013). In southern Ontario, these complex and variably 29 distributed features comprise an extensive network of bedrock valleys that formed through, or were 30 enhanced by, intense glacial and glaciofluvial erosion during the Pleistocene (Karrow 1979; Eyles et al. 31 1997; Kor and Cowell 1998; Gao 2011), and were subsequently infilled with Quaternary-age glacial and 32 interglacial sediment (Karrow 1968; Barnett 1992). Although province-wide mapping (Gao et al. 2006) 33 and regional mapping of some specific areas (e.g., Marich et al. 2011; Burt 2011; Bajc et al. 2012) have 34 been carried out, the location and geometry ofDraft these BBVs and their tributaries is not well constrained in 35 many parts of Ontario. 36 Source water protection has become an integral component of a community’s groundwater 37 management plan since the introduction of the Clean Water Act (2006), S.O. 2006, c.22. This has led to 38 significant investments in three-dimensional sediment and bedrock surface mapping across Ontario both 39 by the geological surveys (e.g., Sharpe and Russell, 2006; Bajc 2008; Davies et al. 2008; Bajc and Rainsford 40 2010; Gao et al. 2006; Bajc et al. 2012; Burt 2012; Bajc et al. 2014) and municipalities and conservation 41 authorities that were tasked with creating source water protection plans (e.g., Gartner Lee 2004; Golder 42 Associates 2006; AquaResource 2010). These activities have supported the conceptualization of aquifer 43 and aquitard units and the delineation of regional-scale groundwater flow systems within and around 44 BBVs. 45 In some cases, here in Ontario and elsewhere, thick successions of sand and gravel deposits have 46 infilled these valleys resulting in highly-productive aquifers (Kehew and Boettger 1986; Russell et al. 2004; 3 https://mc06.manuscriptcentral.com/cjes-pubs Canadian Journal of Earth Sciences Page 4 of 59 47 Wiederhold 2009). Alternatively, buried valleys can be infilled or covered by low-permeable Quaternary- 48 age diamicton or a combination of sediment types with complex geometries and very different hydraulic 49 properties (Meyer and Eyles 2007; Jørgensen et al. 2003a; Cummings et al. 2012), further complicating 50 hydrogeologic conceptualizations (van der Kamp and Maathuis 2012, Cummings et al. 2012). Therefore, 51 these environments require more detailed characterization of both form and infill to ensure accurate 52 quantitative analysis of local groundwater flow system geometries. 53 The underlying sedimentary bedrock across southern Ontario contains ubiquitous interconnected 54 fractures with variable lengths and apertures (Johnson et al. 1992; Kennel 2008; Munn 2012). In addition 55 to these fractures, the Silurian dolostone aquifer – a prolific aquifer for private and municipal water 56 across southern Ontario – contains dissolution enhanced features (e.g., fractures or vugs) and conduits 57 that increase its groundwater resource potential,Draft but also its susceptibility to surface contamination (e.g., 58 Perrin et al. 2011). Many communities across southern Ontario rely almost exclusively on these fractured 59 and dissolution enhanced bedrock aquifers for their drinking water supply. The complex interdependent 60 relationship between Quaternary deposits and these fractured sedimentary rocks has become an 61 important component in the development of effective groundwater management strategies for these 62 communities (e.g., Gartner Lee 2004; AquaResource 2010). Given the potential association between 63 BBVs and increased recharge and transmissivity of bedrock aquifers (Cole et al. 2009), successful 64 groundwater management strategies will depend on sufficiently high-resolution (spatial and temporal) 65 quantitative information, enabling accurate and well-constrained geologic and hydrogeologic 66 conceptualizations of buried valley features (e.g., Shaver and Pusc 1992; Smerdon et al. 2005). 67 Geophysical methods have the capacity to unravel complex geologic relationships and can play a 68 critical role in advancing our understanding of shallow groundwater flow systems in these settings (van 69 Dam 2012). Studies utilizing multiple geophysical methods combined with geologic and hydrogeologic 4 https://mc06.manuscriptcentral.com/cjes-pubs Page 5 of 59 Canadian Journal of Earth Sciences 70 data are particularly effective for three-dimensional mapping of hydrostratigraphic units (e.g., Gabriel et 71 al. 2003; Jørgensen et al. 2003a and 2003b; Steuer et al. 2009; Stumpf and Ismail 2013; Cassidy et al. 72 2014; Sapia et al. 2014). In Ontario, shallow seismic reflection, gravity and electromagnetic surveys have 73 been used at mostly regional scales to delineate the nature of the infilled sediment and bedrock valley 74 geometry (e.g., Greenhouse and Monier-Williams 1985; Greenhouse and Karrow 1994; Zweirs et al. 75 2008; Burt 2011; Bajc et al. 2012; Pugin et al. 2013). Elsewhere, airborne transient electromagnetic 76 (TEM) methods are mostly used (e.g., Sandersen and Jørgensen 2003; Jørgensen et al. 2003a and 2003b; 77 Sørensen and Auken 2004; Sapia et al. 2015). 78 This paper focuses on a local-scale high-resolution electrical resistivity study conducted within the 79 City of Guelph, Canada, with a primary goal of demonstrating the capability and limitations of the 80 technique for mapping a buried bedrock valleyDraft at a relatively local scale. Surface electrical resistivity and 81 seismic refraction results are combined with sedimentological analysis of cores, downhole geophysical
Load more

Recommended publications
  • Sulphate Balance of Lakes and Shallow Groundwater in the Vasavere Buried Valley, Northeast Estonia
    SULPHATE BALANCE OF LAKES AND SHALLOW GROUNDWATER IN THE VASAVERE BURIED VALLEY, NORTHEAST ESTONIA K. ERG Department of Mining Tallinn Technical University 82 Kopli St., 10412 Tallinn Estonia Phone: 620 38 53 Fax: 620 36 96 E-mail:[email protected] Groundwater constitutes an important component of many water resource systems, supplying water for domestic use, for industry, and for agriculture. Management of a groundwater system, an aquifer, means making such decisions as to the total quantity of water to be withdrawn annually, the location of wells for pumping and for artificial recharge and their rates, and control conditions at aquifer boundaries. Not less important are decisions related to groundwater quality. In fact, the quantity and quality problems cannot be separated. In many parts of country, with the increased withdrawal of groundwater, the quality of groundwater has been continuously deteriorating. In recent years the attention has been focused on groundwater contamination by mine water. A most important part of modelling procedure is a thorough understanding of the system, and the processes that take place in it. It is important to identify those parts of the system’s behaviour that are relevant to the considered problem, while other parts may be neglected. On the basis of this understanding, summarised as a conceptual model of the given problem, a numerical model is constructed. A groundwater flow model of the Quaternary aquifer, in eastern part of oil shale deposit area, in Vasavere buried valley, was constructed by using the conceptual model. The infiltration of contaminants grows and the Quaternary aquifer is polluted by sulphate in a large area of Vasavere buried valley.
    [Show full text]
  • On the Breccia Gashes of the Durham Coast. Lebour.G.A
    Durham E-Theses Some aspects of the geomorphology of the Durham coast Westgate, W. A. How to cite: Westgate, W. A. (1957) Some aspects of the geomorphology of the Durham coast, Durham theses, Durham University. Available at Durham E-Theses Online: http://etheses.dur.ac.uk/8519/ Use policy The full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that: • a full bibliographic reference is made to the original source • a link is made to the metadata record in Durham E-Theses • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders. Please consult the full Durham E-Theses policy for further details. Academic Support Oce, Durham University, University Oce, Old Elvet, Durham DH1 3HP e-mail: [email protected] Tel: +44 0191 334 6107 http://etheses.dur.ac.uk The copyright of this thesis rests with the author. No quotation from it should be published without his prior written consent and information derived from it should be acknowledged. SOME ASPECTS OF THE G-EOMQRPHOLO GY OP THE DUHHAM COAST W.A. Westgate, B.Sc. Submitted for the Degree of Ph.D. in the University of Durham. February, 1957. Itmm?, not ** > \ i3i (i) This research was carried out whilst I was in receipt of a Nature Conservancy Research Studentship "between July 1953 and July 1955.
    [Show full text]
  • Bedrock Valleys of the New England Coast As Related to Fluctuations of Sea Level
    Bedrock Valleys of the New England Coast as Related to Fluctuations of Sea Level By JOSEPH E. UPSON and CHARLES W. SPENCER SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY GEOLOGICAL SURVEY PROFESSIONAL PAPER 454-M Depths to bedrock in coastal valleys of New England, and nature of sedimentary Jill resulting from sea-level fluctuations in Pleistocene and Recent time UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1964 UNITED STATES DEPARTMENT OF THE INTERIOR STEWART L. UDALL, Secretary GEOLOGICAL SURVEY Thomas B. Nolan, Director The U.S. Geological Survey Library has cataloged this publication, as follows: Upson, Joseph Edwin, 1910- Bedrock valleys of the New England coast as related to fluctuations of sea level, by Joseph E. Upson and Charles W. Spencer. Washington, U.S. Govt. Print. Off., 1964. iv, 42 p. illus., maps, diagrs., tables. 29 cm. (U.S. Geological Survey. Professional paper 454-M) Shorter contributions to general geology. Bibliography: p. 39-41. (Continued on next card) Upson, Joseph Edwin, 1910- Bedrock valleys of the New England coast as related to fluctuations of sea level. 1964. (Card 2) l.Geology, Stratigraphic Pleistocene. 2.Geology, Stratigraphic Recent. S.Geology New England. I.Spencer, Charles Winthrop, 1930-joint author. ILTitle. (Series) For sale by the Superintendent of Documents, U.S. Government Printing Office Washington, D.C. 20402 CONTENTS Page Configuration and depth of bedrock valleys, etc. Con. Page Abstract.__________________________________________ Ml Buried valleys of the Boston area. _ _______________
    [Show full text]
  • Lithostratigraphic Characterization of a Buried Bedrock Valley Using Airborne and Surface Geophysics
    Lithostratigraphic Characterization of a Buried Bedrock Valley Using Airborne and Surface Geophysics by Oliver Conway-White A Thesis presented to The University of Guelph In partial fulfilment of the requirements for the degree of Master of Applied Science in Engineering Guelph, Ontario, Canada © Oliver R. Conway-White, May, 2020 ABSTRACT LITHOSTRATIGRAPHIC CHARACTERIZATION OF A BURIED BEDROCK VALLEY USING AIRBORNE AND SURFACE GEOPHYSICS Oliver Conway-White Advisor: University of Guelph, 2020 Dr. Beth Parker A helicopter-borne frequency-domain electromagnetic instrument was used to investigate the lithostratigraphic architecture of a buried bedrock valley near Elora, Ontario. The resulting airborne electrical resistivity model was evaluated against co-located high-resolution ground- based electrical resistivity, seismic refraction, and gravity surveys across two sections of the valley. Results were interpreted using published geological datasets including continuous core, geophysical logs, and an existing regional Quaternary geologic model. A comparison between the local geophysically-based model and the regional Quaternary model shows that an airborne electromagnetic survey can markedly improve characterization of bedrock valley morphology and Quaternary architecture. These results provide confidence in regional-scale interpretations of airborne electromagnetic data for the purpose of delineating lithostratigraphic boundaries. Such data would provide valuable insight into the placement of boreholes for additional and complementary characterization at the borehole scale, leading to delineation of hydrostratigraphic boundaries. In combination, these data will inform 3-D groundwater flow models. iii ACKNOWLEDGEMENTS First, I would like to thank Dr. Colby Steelman who was the lead on assisting me with this thesis. While paperwork may have prevented him from being officially on my committee, we all know he went above and beyond as my ‘scientific’ advisor.
    [Show full text]
  • Evidence for Multiple Glacial Advances and Ice Loading from a Buried Valley in Southern Manhattan INTRODUCTION DRILLING PROCEDUR
    Evidence for Multiple Glacial Advances and Ice Loading From a Buried Valley in Southern Manhattan Cheryl J. Moss, Mueser Rutledge Consulting Engineers, 14 Penn Plaza, New York, NY 10122 ([email protected]) Charles Merguerian, Geology Department, 114 Hofstra University, Hempstead, NY 11549 ([email protected]; [email protected]) INTRODUCTION Our field and subsurface studies of glacial strata from construction sites and borings indicate that the glacial history of the New York City area is complex. The Ronkonkoma and Harbor Hill terminal moraines are evidence that the area has experienced more than one glacial advance. There is more to the story, however, than simply ice advance, retreat, repeat. Many locations in New York City display seemingly simple stratigraphy, such as thick layers of till over bedrock or 100’ of outwash sands. Most sites aren’t as obviously complex as one offering multiple tills intercalated with outwash and varved strata. When characteristics other than soil type are taken into consideration, however, stratigraphic differences sometimes appear. A change in color or mineralogy, for instance, might indicate ice coming from another direction. A change in engineering properties can also contribute to the art of unraveling glacial history. A site in lower Manhattan near the Brooklyn Bridge occupies a bedrock valley filled with a variety of interlayered glacial drift. These varied strata mandate that multiple waves of ice have passed over the area. Changes in the compactness of the soil with depth, as measured by the Standard Penetration Test, provide additional evidence of ice loading. This paper will demonstrate that patterns in strata and SPT values can be used to determine which layers at a site have been ice loaded.
    [Show full text]
  • Morphological Analysis and Evolution of Buried Tunnel Valleys in Northeast Alberta, Canada
    Quaternary Science Reviews 65 (2013) 53e72 Contents lists available at SciVerse ScienceDirect Quaternary Science Reviews journal homepage: www.elsevier.com/locate/quascirev Morphological analysis and evolution of buried tunnel valleys in northeast Alberta, Canada N. Atkinson*, L.D. Andriashek, S.R. Slattery Alberta Geological Survey, Energy Resources Conservation Board, Twin Atria Building, 4th Floor, 4999-98 Ave. Edmonton, Alberta T6B 2X3, Canada article info abstract Article history: Tunnel valleys are large elongated depressions eroded into unconsolidated sediments and bedrock. Received 9 August 2012 Tunnel valleys are believed to have been efficient drainage pathways for large volumes of subglacial Received in revised form meltwater, and reflect the interplay between groundwater flow and variations in the hydraulic con- 26 November 2012 ductivity of the substrate, and basal meltwater production and associated water pressure variations at Accepted 28 November 2012 the ice-bed interface. Tunnel valleys are therefore an important component of the subglacial hydrological Available online 12 February 2013 system. Three-dimensional modelling of geophysical and lithological data has revealed numerous buried Keywords: Tunnel valleys valleys eroded into the bedrock unconformity in northeast Alberta, many of which are interpreted to be Subglacial drainage tunnel valleys. Due to the very high data density used in this modelling, the morphology, orientation and Sedimentary architecture internal architecture of several of these tunnel valleys have been determined. The northeast Alberta buried tunnel valleys are similar to the open tunnel valleys described along the former margins of the southern Laurentide Ice Sheet. They have high depth to width ratios, with un- dulating, low gradient longitudinal profiles. Many valleys start and end abruptly, and occur as solitary, straight to slightly sinuous incisions, or form widespread anastomosing networks.
    [Show full text]
  • Hydrogeologic Setting and Ground-Water Flow Simulations of the Great Miami River Basin Regional Study Area, Ohio
    Hydrogeologic Setting and Ground-Water Flow Simulations of the Great Miami River Basin Regional Study Area, Ohio By Rodney A. Sheets Section 7 of Hydrogeologic Settings and Ground-Water Flow Simulations for Regional Studies of the Transport of Anthropogenic and Natural Contaminants to Public-Supply Wells—Studies Begun in 2001 Edited by Suzanne S. Paschke Professional Paper 1737–A U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior DIRK KEMPTHORNE, SECRETARY U.S. Geological Survey Mark D. Myers, Director U.S. Geological Survey, Reston, Virginia: 2007 For product and ordering information: World Wide Web: http://www.usgs.gov/pubprod Telephone: 1-888-ASK-USGS For more information on the USGS--the Federal source for science about the Earth, its natural and living resources, natural hazards, and the environment: World Wide Web: http://www.usgs.gov Telephone: 1-888-ASK-USGS Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this report is in the public domain, permission must be secured from the individual copyright owners to reproduce any copyrighted materials contained within this report. Suggested citation: Sheets, R.A., 2007, Hydrogeologic setting and ground-water flow simulations of the Great Miami Basin Regional Study Area, Ohio, section 7 of Paschke, S.S., ed., THydrogeologic settings and ground-water flow simulations for regional studies of the transport of anthropogenic and natural contaminants to public-supply wells—studies begun in 2001: Reston, Va., U.S. Geological Survey Professional Paper 1737–A, pp.
    [Show full text]
  • Examining the Geometry, Age and Genesis of Buried Quaternary Valley Systems in the Midland Valley of Scotland, UK
    bs_bs_banner Examining the geometry, age and genesis of buried Quaternary valley systems in the Midland Valley of Scotland, UK TIMOTHY I. KEARSEY , JONATHAN R. LEE, ANDREW FINLAYSON, MARIETA GARCIA-BAJO AND ANTHONY A. M. IRVING Kearsey, T.I., Lee, J.R., Finlayson, A., Garcia-Bajo, M. & Irving, A. A. M. 2019 (July): Examining the geometry, age and genesis of buried Quaternary valley systems in the Midland Valleyof Scotland, UK. Boreas, Vol.48, pp. 658–677. https://doi.org/10.1111/bor.12364. ISSN 0300-9483. Buried palaeo-valley systems havebeen identifiedwidely beneath lowland parts of the UK including eastern England, centralEngland,southWalesandtheNorthSea.IntheMidlandValleyofScotlandpalaeo-valleyshavebeenidentified yet the age and genesis of these enigmatic features remain poorly understood. This study utilizes a digital data set of over 100 000 boreholes that penetrate the full thickness of deposits in the Midland Valleyof Scotland. It identified 18 buried palaeo-valleys, which range from 4 to 36 km in length and 24 to 162 m in depth. Geometric analysis has revealed four distinct valley morphologies, which were formed by different subglacial and subaerial processes. Some palaeo-valleys cross-cut each other with the deepest features aligning east–west. These east–west features align with thereconstructedice-flowdirectionunder maximumconditionsoftheMainLateDevensianglaciation.Theshallower features appear more aligned to ice-flow direction during ice-sheet retreat, and were therefore probably incised under more restricted ice-sheet configurations. The bedrock lithology influences and enhances the position and depth of palaeo-valleys in this lowland glacial terrain. Faults have juxtaposed Palaeozoic sedimentary and igneous rocks and the deepest palaeo-valleys occur immediately down-ice of knick-points in the more resistant igneous bedrock.
    [Show full text]
  • Dubois County Unconsolidated Aquifer Systems
    Unconsolidated Aquifer Systems of Dubois County, Indiana by Glenn E. Grove and William C. Herring Division of Water, Resource Assessment Section March 2003 Five unconsolidated aquifer systems have been mapped in Dubois County: the Dissected Till and Residuum/Unglaciated Southern Hills and Lowlands; the Alluvial, Lacustrine, and Backwater Deposits; the White River and Tributaries Outwash; the Buried Valley; and the Coal Mine Spoil. The first four aquifer systems comprise sediments that were deposited by glaciers and their meltwaters, or are thin, eroded residuum (a product of bedrock weathering). Boundaries of these aquifer systems are commonly gradational and individual aquifers may extend across aquifer system boundaries. The Coal Mine Spoil Aquifer System is man-made and most boundaries are well defined. In northwestern and central portions of the county, there is as much as 160 feet of unconsolidated material overlying the bedrock. This contrasts with most other areas in the county, especially in the eastern and southern parts, which have 20 feet or less of unconsolidated material overlying bedrock. In places, sand and gravel aquifers are located immediately above the bedrock surface. Sand and gravel aquifers occur in the main valley of the East Fork White River, in a deeply buried bedrock valley in northwestern Dubois County, and in some smaller buried bedrock valleys that commonly coincide with present-day valleys. Dissected Till and Residuum/Unglaciated Southern Hills and Lowlands Aquifer System The Dissected Till and Residuum/Unglaciated Southern Hills and Lowlands Aquifer System, which covers much of the southern and eastern portions of Dubois County, has the most limited groundwater resources of the unconsolidated aquifer systems in the county.
    [Show full text]
  • Aqueous Geochemistry of the Cambrian–Vendian Aquifer System in the Tallinn Intake, Northern Estonia
    GEOLOGIJA. 2005. Nr. 51. P. 50–56 ©50 Lietuvos mokslø akademija, 2005 Robert Mokrik, Lehte Savitskaja, Leonid Savitski © Lietuvos mokslø akademijos leidykla, 2005 Hidrogeologija • Hydrogeology • Ãèäðîãåîëîãèÿ Aqueous geochemistry of the Cambrian–Vendian aquifer system in the Tallinn intake, northern Estonia Robert Mokrik, Mokrik R., Savitskaja L., Savitski L. Aqueous geochemistry of the Cam- brian–Vendian aquifer system in the Tallinn intake, northern Estonia. Lehte Savitskaja, Geologija. Vilnius. 2005. No. 51. P. 50–56. ISSN 1392-110X. Identification of seawater intrusion is based on intake observation Leonid Savitski results in the groundwater chemistry and isotopes. Indications of the sa- line front of marine origin can be obtained from the cation exchange process which is reflected in the groundwater chemical composition by Ca–Cl and Na–HCO3 types of groundwater. The Na–Ca exchange evi- dences are accompanied by sulfate reduction reaction, dissolution and deposition of carbonates, which are also confirmed by the distribution and evolution of content of stable and radioisotopes in the groundwater of the Cambrian–Vendian aquifer system on the Tallinn intake, northern Estonia. Key words: groundwater chemistry, seawater intrusion, cation exchange, chloride and bromide ratio, stable isotopes, Baltic Basin Received 29 March 2005, accepted 16 May 2005 Robert Mokrik. Department of Hydrogeology and Engineering Geology of Vilnius University, M. K. Èiurlionio 21, LT-2009, Vilnius, Lithuania. E- mail: robert. [email protected] Lehte Savitskaja and Leonid Savitski. Geological Survey of Estonia, Ka- daka tee 82, 12618, Tallinn, Estonia. E-mail: [email protected] INTRODUCTION exploitation of the Tallinn intake resulted in saliniza- tion not only in the Cambrian–Vendian sandstones As a result of intensive exploitation, a vast depres- but also in the basement water, which kept brackish sion cone exceeding 100 km has formed at the Tal- groundwater because of seawater intrusion.
    [Show full text]
  • Estimation of Effective Porosity in Large-Scale Groundwater Models
    Hydrol. Earth Syst. Sci. Discuss., https://doi.org/10.5194/hess-2018-99 Manuscript under review for journal Hydrol. Earth Syst. Sci. Discussion started: 23 March 2018 c Author(s) 2018. CC BY 4.0 License. Estimation of effective porosity in large-scale groundwater models by combining particle tracking, auto-calibration and 14C dating Rena Meyer1, Peter Engesgaard1, Klaus Hinsby2, Jan A. Piotrowski3, and Torben O. Sonnenborg2 1University of Copenhagen 2Geological Survey of Denmark and Greenland 3Aarhus University Correspondence: Rena Meyer ([email protected]) Abstract. Effective porosity plays an important role in contaminant management. However, the effective porosity is often assumed constant in space and hence either neglected or simplified in transport model calibration. Based on a calibrated highly parametrized flow model, a three-dimensional advective transport model (MODPATH) of a 1300 km2-large coastal area of southern Denmark and northern Germany is presented. A detailed voxel model represents the highly heterogeneous 5 geological composition of the area. Inverse modelling of advective transport is used to estimate seven, spatially distributed, effective porosity units based on apparent groundwater ages inferred from 11 14C measurements in Pleistocene and Miocene aquifers, corrected for the effects of diffusion and geochemical reactions. The match between the observed and simulated ages is improved significantly by the calibration of seven porosity units by a reduction of ME of 99% and RMS of 82% compared to a uniform porosity approach. Groundwater ages range from a few hundred years in the Pleistocene to several thousand years 10 in Miocene aquifers. The advective age distributions derived from particle tracking at each sampling well show unimodal (for younger ages) to multimodal (for older ages) shapes and thus reflect the heterogeneity that particles encounter along their travel path.
    [Show full text]
  • Water Resources Report for the Great Miami River Watershed
    2011-29 2011 WATER RESOURCES REPORT FOR THE GREAT MIAMI RIVER WATERSHED Summary This report summarizes the overall state of water resources in the Great Miami River Watershed for 2011, with an emphasis on the buried valley aquifer and water quantity and quality data. The Miami Conservancy District (MCD) operates and maintains an extensive hydrologic monitoring system. By tracking trends in precipitation, runoff, and groundwater levels, changes to the balance of the hydrologic system of the watershed are assessed. Water quality data also is collected in both surface and groundwater to track annual trends, establish a baseline for future studies, and verify nutrient reductions from landowner incentive programs. WATER QUANTITY The year 2011 was a record setting year with regards to annual precipitation. In 2011 MCD recorded record high annual precipitation within the Great Miami River Watershed. The 2011 mean annual precipitation was 58.89 inches, 19.84 inches above the long-term mean annual precipitation. The above normal precipitation contributed to above normal runoff in the Great Miami River and its tributary streams. The total annual runoff for the Great Miami River Watershed upstream of Hamilton was 29.83 inches, 16.61 inches above the long-term mean annual runoff. The year 2011 was an above normal year for groundwater storage in the Great Miami River buried valley aquifer system. The annual groundwater recharge to aquifers is estimated from stream gaging records for the Great Miami River Watershed. Groundwater recharge in 2011 was estimated to be 15.54 inches, 7.46 inches above the long-term mean annual groundwater recharge.
    [Show full text]