DOCSLIB.ORG

Hydraulic Relationships Between Buried Valley Sediments and Adjacent Bedrock Formations

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Hydraulic Relationships Between Buried Valley Sediments and Adjacent Bedrock Formations HYDRAULIC RELATIONSHIPS BETWEEN BURIED VALLEY SEDIMENTS AND ADJACENT BEDROCK FORMATIONS A Thesis submitted to Kent State University in partial fulfillment of the requirements for the Degree of Master of Sciences By Wondwosen Mekonnen Seyoum August 2012 Thesis written by Wondwosen Mekonnen Seyoum B. Sc. Addis Ababa University, 1999 M. Sc. Addis Ababa University, 2005 M. Sc. Kent State University, 2012 Approved by Dr. Yoram Eckstein ________________________________________, Advisor Dr. Daniel Holm ________________________________________, Chair, Department of Geology Dr. Timothy Moerland ________________________________________, Dean, College of Arts and Sciences Dedicated to My Beloved Mom SHEWAYE TILAHUN (1957-2007) & My Father-in-law NIGUSSIE WOLDEYOHANNES (1931-2005) TABLE OF CONTENTS LIST OF FIGURES .................................................................................................................. VII LIST OF TABLES ...................................................................................................................... X ACKNOWLEDGEMENT .......................................................................................................... XI CHAPTER 1 INTRODUCTION ................................................................................................... 1 1.1. Introduction ............................................................................................................... 1 1.2. Earlier research .......................................................................................................... 5 1.3. Objective of the study .............................................................................................. 11 1.4. Description of the study area ................................................................................... 12 1.5. Geology and hydrogeology ...................................................................................... 14 1.5.1. Glacial deposits ........................................................................................... 15 1.5.2. Bedrock geology .......................................................................................... 19 CHAPTER 2 METHODOLOGY ................................................................................................. 25 2.1. Introduction ............................................................................................................. 25 2.2. Data ......................................................................................................................... 26 2.3. Conceptual model development .............................................................................. 28 2.3.1. Hydrostratigraphic units .............................................................................. 29 2.3.2. Hydraulic parameters .................................................................................. 31 2.3.3. Groundwater recharge and discharge ......................................................... 37 2.3.4. Groundwater levels and flow directions ...................................................... 39 iv 2.4. Numerical Model Construction ................................................................................ 39 2.4.1. Introduction ................................................................................................ 39 2.4.2. Finite difference approximation .................................................................. 42 2.4.3. Model design and model layers ................................................................... 45 2.4.4. Hydraulic conductivity and anisotropy ........................................................ 47 2.4.5. Boundary conditions ................................................................................... 49 2.4.6. Drain boundary ........................................................................................... 53 2.4.7. Recharge boundary ..................................................................................... 55 2.4.8. Calibration .................................................................................................. 58 2.4.9. Mass balance .............................................................................................. 63 CHAPTER 3 RESULTS ............................................................................................................. 64 3.1. Stratigraphy and hydrostratigraphic units ................................................................ 64 3.2. Hydraulic parameter estimation of the buried valley sediments (Outwash) ............. 70 3.2.1. Correction for partial penetration ............................................................... 71 3.2.2. Transmissivity and hydraulic conductivity analysis ...................................... 72 3.2.3. Spatial distribution of hydraulic parameters ................................................ 73 3.3. Conceptual groundwater model............................................................................... 74 3.4. Numerical Model Calibration ................................................................................... 79 3.5. Numerical Model results .......................................................................................... 82 3.5.1. Simulated hydraulic parameters.................................................................. 83 3.5.2. Simulated hydraulic heads .......................................................................... 85 v 3.5.3. Model mass balance.................................................................................... 89 CHAPTER 4 DISCUSSION ....................................................................................................... 94 4.1. Hydraulic characteristics of the buried valley sediments ...................................................... 94 4.2. Numerical model ................................................................................................................. 96 CHAPTER 5 SUMMARY AND CONCLUSION......................................................................... 102 REFERENCES ....................................................................................................................... 105 APPENDIX........................................................................................................................... 112 I. Cross-sections across the buried valley showing the various stratigraphic units ....... 112 II. 2D conceptual model................................................................................................ 116 III. Inflow-outflow estimation using Darcy’s Law ............................................................ 117 IV. Calculation of the hydraulic parameters for the buried valley sediments .................. 118 V. Observed (field measured) Vs model computed head data....................................... 127 VI. Mass balance of each major aquifer layers ............................................................... 128 VII. Estimation of rate of flow contribution from bedrock aquifers along several across the buried valley ....................................................................................................... 129 vi LIST OF FIGURES Figure 1.1 An example of the possible hydraulic relationships in a section across a hypothetical buried valley ...................................................................................................... 3 Figure 1.2 Location map of the study area ............................................................................ 13 Figure 1.3 Digital Elevation Model (DEM) showing topography of the study area ................. 14 Figure 1.4 A stratigraphic column in Cuyahoga Valley (from Corbett et al, 1988) .................. 16 Figure 1.5 Isopach map of the glacial sediments (both the till and outwash) of the study area ...................................................................................................................................... 17 Figure 1.6 Networks of buried valleys in Geauga County (Modified from ODC, 1971) ........... 19 Figure 1.7 Bedrock geologic map, with bedrock topographic contours of the area (modified from Eberts, Bair, and De Roche, 1990) ................................................................ 22 Figure 1.8 Stratigraphic and hydrogeologic description of the study area (Richards, 1981) .................................................................................................................................... 24 Figure 2.1 Sample driller’s log and report (information are circled) ...................................... 27 Figure 2.2 Methodology chart showing steps in developing the conceptual model ............... 29 Figure 2.3 Cells showing nodes and cell notations ................................................................ 43 Figure 2.4 A given cell i,j,k with six surrounding cells (Modified from McDonald and Harbaugh, 1988) ................................................................................................................... 44 vii Figure 2.5 Published values of hydraulic conductivities from Halford and Kuniansky (2002) and Domenico and Schwartz (1990) .......................................................................... 49 Figure 2.6 Schematic map view representation of boundary conditions in the bedrock units and buried valley sediments of the glacial drift ............................................................ 51 Figure 2.7 Schematic representation of a drain in a single cell .............................................
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]