DOCSLIB.ORG

Determination of Groundwater Flow Velocity in the Capulin Canyon Drainage, Molycorp, Inc

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Determination of Groundwater Flow Velocity in the Capulin Canyon Drainage, Molycorp, Inc Technical Memorandum: Determination of Groundwater Flow Velocity in the Capulin Canyon Drainage, Molycorp, Inc. Site A groundwater flow velocity was calculated for the upper reach of Capulin Canyon from near MMW-23A to MMW-2 located in the lower portion of the canyon. The calculation was performed to determine the transit time for a water particle to travel from the lower catchment pond (pumpback), located approximately 3,600 feet from the toe of the Capulin rock pile to MMW-2. This distance is approximately 5,775 feet. The catchment pond was installed in 1992 and later upgraded in 2006 to prevent overflowing of the ponds during storm events. Assuming by 2006, no further downgradient migration of leachate from the Capulin rock pile, the transit time calculation was made to determine if residual contaminants are still traveling down canyon in the flowpath to the lower portions of Capulin Canyon. Results Summary of Transit Time Calculations The resulting seepage velocity ranges from 0.06 foot per day (ft/d) to 1.79 feet per day (ft/d) based on a Darcy’s Law calculation. The transit time for a water molecule to travel this distance would range from approximately 8.8 years to 247 years. Using the geomean hydraulic conductivity (K) value (0.7 ft/d), the transit time would take 35 years. However, using the yield analysis, the velocity is 30.2 ft/d and the transit time would take 0.5 year for groundwater to travel between the pumpback pond and MMW-2. If the K value from the yield analysis is included in the geomean (not included in the RI), it would reduce the transit time from 35 to 23 years. Given the limitations of both calculations and assumptions, the transit time (23 years), based on the recalculated geomean K value (1.04 ft/d), most likely represents a realistic permeability of the drainage. Assuming that capture of seepage from the Capulin rock pile did not occur until 1992 or later, it is entirely possible that contaminant migration could be occurring in the lower portions of the canyon for years to come. Supporting Information Hydraulic Parameter and Calculation Assumptions The upper reach of the Capulin Canyon drainage has a gradient that is approximated by the slope of the land surface, or 0.16 (Final RI Report, July 2009). The hydraulic properties of the Capulin Canyon colluvium have been measured in the upper reach at MMW-23A and near the mouth at MMW-2. At MMW-23A, 10 slug tests have been performed resulting in hydraulic conductivity (K) values ranging from 0.1 to 2.8 ft/d, with a geometric mean of 0.7 ft/d (Final RI Report, July 2009). Near the mouth of the canyon, the hydraulic conductivity of the colluvium has been calculated for MMW-2 during single-well pumping (0.1 ft/d) and recovery (0.06 ft/d) tests, or an average of 0.08 1 CAPULIN GW TRANSIT TIME CALCULATION RV6 7-06-10.DOC 020412 ft/d. The pumping test was conducted at a rate of 1.5 gallons per minute (gpm) for nearly 4 hours and the drawdown was 29 feet at the end of the test, which was near the bottom of the well. The low hydraulic conductivity of the colluvium is supported by the fact that the well had almost pumped dry at the low pumping rate. The resulting seepage velocity is much less than 1 ft/d, using the measured gradient of 0.11 and assumed porosity of 0.25. The calculation assumes that neither chemical reaction nor retardation of contaminants due partitioning of metals to solid phases is occurring. Partitioning of metals such as aluminum could result in much slower transit times. Instead of using the pump test data from MMW-23A, the hydraulic conductivity and seepage velocity were also calculated using the flow (Q) value (51 gpm) derived from the RI yield analysis. The back calculation was based on the hydraulic gradient (0.16), a cross-sectional area of 1,300 square feet (ft2), and an effective porosity of 0.25. The cross-sectional area value is also from the RI Report (July 2009). The yield analysis value in the RI Report for the entire reach of Capulin Canyon is 102 gpm. Although the Capulin rock pile covers approximately 30 percent of the Capulin drainage, Chevron Mining Inc (CMI) assumed in the RI Report that 50 percent of the yield of the total drainage derives from the rock pile because it is located at the head of canyon at the highest elevations. On this basis, 50 percent or 51 gpm potentially may be exiting the canyon into the Red River. The K value was calculated to be 47.2 ft/d with a seepage velocity of 30 ft/d. Limitations and Uncertainty Based on the K values, hydraulic gradients, and effective porosity values stated above, a discharge calculation was performed and included in the RI Report for Capulin Canyon. The results of this calculation indicate that less than 1 gpm is discharging from the mouth of Capulin Canyon into the Red River. This value is believed to be unreasonably low and considerably lower than groundwater discharge (51 gpm) from the canyon estimated from the yield analysis in the RI Report. The discrepancy may be attributable to several factors, one of which includes an inaccurate representation of the hydraulic characteristics at MMW-2 due to a poor choice of well placement. As acknowledged in the RI Report, the well is drilled in clayey gravel and may not have been located along the central axis of the of the colluvial drainage in coarser and more permeable material. As such, the pump test values are most likely not indicative of the actual hydraulic conductivity (K) and flow (Q) in the drainage. However, while flow from the yield analysis may appear to be reasonable, the hydraulic conductivity value and seepage velocity that were back calculated from Q (51 gpm) are believed to be unrealistically high. Although the discharge value (51 gpm) from the lower portion of Capulin Canyon below the rock pile appears to be a reasonable percentage (17 percent) of the yield estimate (293 gpm) of available groundwater leaving the mine site, the K value of 47.2 ft/d (1.66 x 10-2 centimeters per second [cm/sec]) is unrealistically high for the type of geological environment where it is located. The value corresponds to a clean sand (Freeze and Cherry 1979) and appears to be incongruous 2 CAPULIN GW TRANSIT TIME CALCULATION RV6 7-06-10.DOC 020413 given that the canyon is a result of colluvial processes with a predominately poorly sorted mixture of fine- and coarse-grained, clastic materials. One possible explanation for this inconsistency is that some of the flow (51 gpm) within Capulin Canyon drains into the underlying bedrock thus, reducing the outflow from the canyon. A lower Q would translate proportionally into a lower K and velocity values. Another less plausible explanation may be that the cross-sectional area value is too low. Despite these limitations, the K value from the yield analysis was used to calculate an upper bound to the seepage velocity and lower bound to transit times. Under these conditions, it would take a molecule of water approximately 0.5 years to travel down Capulin Canyon to MMW-2. 3 CAPULIN GW TRANSIT TIME CALCULATION RV6 7-06-10.DOC 020414 2010 -----JANUARy~--- S M T W TH F S 1 2 CDM 3 4 5 6 7 8 9 consulting. engineering. construction· operations 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24/31 25 26 27 28 29 30 -----FEBRUARy----- S M T W TH F S 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 ---'---MARCH---- S M T WTH F S 1 2 3 456 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 ---:--- APRIL ---- S M T WTH F S 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 ----MAy---- S M T WTH F S 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 2%0 24/31 25 26 27 28 29 -------JUNE------- S M T W ~ S 1 2 345 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 ----JULy---- S M T WTH F S 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 -----AUGUST---­ S M T WTH F S 1 2 34567 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 SEPTEMBER-- S MT W TH F S 1 2 3 4 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 1/ 26 27 28 29 30 -----OCTOBER----- S M T W TH S ( 1 2 3 4 5 6 789 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24/31 25 26 27 28 29 30 NOVEMBER-- S M T W TH S 1 2 3 4 5 6 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 DECEMBER-- S M T W TH F S 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 listen.
Load more

Recommended publications
  • Characterization of Groundwater Flow for Near Surface Disposal Facilities Iaea, Vienna, 2001 Iaea-Tecdoc-1199 Issn 1011–4289
    IAEA-TECDOC-1199 Characterization of groundwater flow for near surface disposal facilities February 2001 The originating Section of this publication in the IAEA was: Waste Technology Section International Atomic Energy Agency Wagramer Strasse 5 P.O. Box 100 A-1400 Vienna, Austria CHARACTERIZATION OF GROUNDWATER FLOW FOR NEAR SURFACE DISPOSAL FACILITIES IAEA, VIENNA, 2001 IAEA-TECDOC-1199 ISSN 1011–4289 © IAEA, 2001 Printed by the IAEA in Austria February 2001 FOREWORD The objective of adioactive waste disposal is to provide long term isolation of waste to protect humans and the environment while not imposing any undue burden on future generations. To meet this objective, establishment of a disposal system takes into account the characteristics of the waste and site concerned. In practice, low and intermediate level radioactive waste (LILW) with limited amounts of long lived radionuclides is disposed of at near surface disposal facilities for which disposal units are constructed above or below the ground surface up to several tens of meters in depth. Extensive experience in near surface disposal has been gained in Member States where a large number of such facilities have been constructed. The experience needs to be shared effectively by Member States which have limited resources for developing and/or operating near surface repositories. A set of technical reports is being prepared by the IAEA to provide Member States, especially developing countries, with technical guidance and current information on how to achieve the objective of near surface disposal through siting, design, operation, closure and post-closure controls. These publications are intended to address specific technical issues, which are important for the aforementioned disposal activities, such as waste package inspection and verification, monitoring, and long-term maintenance of records.
    [Show full text]
  • Hydrological Controls on Salinity Exposure and the Effects on Plants in Lowland Polders
    Hydrological controls on salinity exposure and the effects on plants in lowland polders Sija F. Stofberg Thesis committee Promotors Prof. Dr S.E.A.T.M. van der Zee Personal chair Ecohydrology Wageningen University & Research Prof. Dr J.P.M. Witte Extraordinary Professor, Faculty of Earth and Life Sciences, Department of Ecological Science VU Amsterdam and Principal Scientist at KWR Nieuwegein Other members Prof. Dr A.H. Weerts, Wageningen University & Research Dr G. van Wirdum Dr K.T. Rebel, Utrecht University Dr R.P. Bartholomeus, KWR Water, Nieuwegein This research was conducted under the auspices of the Research School for Socio- Economic and Natural Sciences of the Environment (SENSE) Hydrological controls on salinity exposure and the effects on plants in lowland polders Sija F. Stofberg Thesis submitted in fulfilment of the requirements for the degree of doctor at Wageningen University by the authority of the Rector Magnificus Prof. Dr A.P.J. Mol in the presence of the Thesis Committee appointed by the Academic Board to be defended in public on Wednesday 07 June 2017 at 4 p.m. in the Aula. Sija F. Stofberg Hydrological controls on salinity exposure and the effects on plants in lowland polders, 172 pages. PhD thesis, Wageningen University, Wageningen, the Netherlands (2017) With references, with summary in English ISBN: 978-94-6343-187-3 DOI: 10.18174/413397 Table of contents Chapter 1 General introduction .......................................................................................... 7 Chapter 2 Fresh water lens persistence and root zone salinization hazard under temperate climate ............................................................................................ 17 Chapter 3 Effects of root mat buoyancy and heterogeneity on floating fen hydrology ..
    [Show full text]
  • 1.72, Groundwater Hydrology Prof. Charles Harvey Lecture Packet #1: Course Introduction, Water Balance Equation
    1.72, Groundwater Hydrology Prof. Charles Harvey Lecture Packet #1: Course Introduction, Water Balance Equation Where does water come from? It cycles. The total supply doesn’t change much. 39 Moisture over 100 land Precipitation on land 385 Precipitation on ocean 61 424 Evaporation Evaporation from from the land the ocean Surface runoff Infiltration Evapotranspiration and evaporation Groundwater 38 surface recharge discharge Groundwater flow 1 Groundwater discharge Low permeability strata Hydrologic cycle with yearly flow volumes based on annual surface precipitation on earth, ~119,000 km3/year. 3000 BC – Ecclesiastes 1:7 (Solomon) “All the rivers run into the sea; yet the sea is not full; unto the place from whence the rivers come, thither they return again.” Greek Philosophers (Plato, Aristotle) embraced the concept, but mechanisms were not understood. 17th Century – Pierre Perrault showed that rainfall was sufficient to explain flow of the Seine. 1.72, Groundwater Hydrology Lecture Packet 1 Prof. Charles Harvey Page 1 of 15 The earth’s energy (radiation) cycle Solar (shortwave) radiation Terrestrial (long-wave) radiation Reflected Outgoing Space Incoming 99.998 6 18 6 4 39 27 Backscattering by air Net radiant emission by greenhouse Reflection gases by clouds Net radiant Atmosphere emission by 11 Net clouds 4 absorption by Absorption greenhouse by clouds gasses & 20 clouds Absorption by Reflection atmosphere Net radiant Net by surface Net latent emission by sensible heat flux surface heat flux 46 15 7 24 Ocean and Absorption by Land surface Heating of surface 46 0.002 Circulation redistributes energy /yr) 2 20 0 cal cm 1 -20 -60 4.0 3.0 Total Flux Net radiation flux (10 flux Net radiation 2.0 Latent 1.0 Heat cal/yr) 22 0 Ocean -1.0 Currents Sensible Heat -2.0 Energy Transfer (10 Energy Transfer -3.0 -4.0 900 N 600 300 00 300 600 900 S Latitude 1.72, Groundwater Hydrology Lecture Packet 1 Prof.
    [Show full text]
  • A Study on Water and Salt Transport, and Balance Analysis in Sand Dune–Wasteland–Lake Systems of Hetao Oases, Upper Reaches of the Yellow River Basin
    water Article A Study on Water and Salt Transport, and Balance Analysis in Sand Dune–Wasteland–Lake Systems of Hetao Oases, Upper Reaches of the Yellow River Basin Guoshuai Wang 1,2, Haibin Shi 1,2,*, Xianyue Li 1,2, Jianwen Yan 1,2, Qingfeng Miao 1,2, Zhen Li 1,2 and Takeo Akae 3 1 College of Water Conservancy and Civil Engineering, Inner Mongolia Agricultural University, Hohhot 010018, China; [email protected] (G.W.); [email protected] (X.L.); [email protected] (J.Y.); [email protected] (Q.M.); [email protected] (Z.L.) 2 High Efficiency Water-saving Technology and Equipment and Soil Water Environment Engineering Research Center of Inner Mongolia Autonomous Region, Hohhot 010018, China 3 Faculty of Environmental Science and Technology, Okayama University, Okayama 700-8530, Japan; [email protected] * Correspondence: [email protected]; Tel.: +86-13500613853 or +86-04714300177 Received: 1 November 2020; Accepted: 4 December 2020; Published: 9 December 2020 Abstract: Desert oases are important parts of maintaining ecohydrology. However, irrigation water diverted from the Yellow River carries a large amount of salt into the desert oases in the Hetao plain. It is of the utmost importance to determine the characteristics of water and salt transport. Research was carried out in the Hetao plain of Inner Mongolia. Three methods, i.e., water-table fluctuation (WTF), soil hydrodynamics, and solute dynamics, were combined to build a water and salt balance model to reveal the relationship of water and salt transport in sand dune–wasteland–lake systems. Results showed that groundwater level had a typical seasonal-fluctuation pattern, and the groundwater transport direction in the sand dune–wasteland–lake system changed during different periods.
    [Show full text]
  • The Exact Groundwater Divide on Water Table Between Two Rivers: a Fundamental Model Investigation
    Article The Exact Groundwater Divide on Water Table between Two Rivers: A Fundamental Model Investigation Peng-Fei Han, Xu-Sheng Wang *, Li Wan, Xiao-Wei Jiang and Fu-Sheng Hu Ministry of Education Key Laboratory of Groundwater Circulation and Environmental Evolution, China University of Geosciences, Beijing 100083, China; [email protected] (P.-F.H.); [email protected] (L.W.); [email protected] (X.-W.J.); [email protected] (F.-S.H.) * Correspondence: [email protected]; Tel.: +86-010-82322008 Received: 13 March 2019; Accepted: 1 April 2019; Published: 2 April 2019 Abstract: The groundwater divide within a plane has long been delineated as a water table ridge composed of the local top points of a water table. This definition has not been examined well for river basins. We developed a fundamental model of a two-dimensional unsaturated–saturated flow in a profile between two rivers. The exact groundwater divide can be identified from the boundary between two local flow systems and compared with the top of a water table. It is closer to the river of a higher water level than the top of a water table. The catchment area would be overestimated (up to ~50%) for a high river and underestimated (up to ~15%) for a low river by using the top of the water table. Furthermore, a pass-through flow from one river to another would be developed below two local flow systems when the groundwater divide is significantly close to a high river. Keywords: groundwater divide; water table; unsaturated–saturated flow; catchment area; pass- through flow 1.
    [Show full text]
  • The Hydrogeology Challenge: Water for the World TEACHER’S GUIDE
    The Hydrogeology Challenge: Water for the World TEACHER’S GUIDE Why is learning about groundwater important? • 95% of the water used in the United States comes from groundwater. • About half of the people in the United States get their drinking water from groundwater. In the future, the water industry will need leaders that can understand, interpret and manipulate groundwater models to make informed decisions. Geologists, agricultural scientists, petroleum engineers, civil engineers, and environmental engineers play an important role in deciding how to use and protect groundwater. The Hydrogeology Challenge introduces students to groundwater modeling and the role it plays in groundwater management. It challenges students to use an interactive computer model to think critically about groundwater resources. The Hydrogeology Challenge has been successfully utilized in educational settings including as a Division C Science Olympiad event and a complement to standard lessons. INTRODUCTION The Hydrogeology Challenge introduces groundwater characteristics in a fun and easy to understand way. It leads students step-by-step through a series of simple calculations that reveal information about how groundwater moves. The Hydrogeology Challenge can be used in a variety of ways in the classroom: • a teacher-led activity • an independent student activity • a team activity This instruction guide demonstrates key principles of the computer program so you can comfortably use the Hydrogeology Challenge in your classroom. Additional features to enhance student learning are available (information on page 6). KEY TOPICS: Aquifer, Contamination/pollution prevention, Earth science/geology, Groundwater, Water use GRADE LEVEL: High School, Undergraduate DURATION: 20 consecutive minutes to complete the challenge, variable for application OBJECTIVES: Understand basic groundwater modeling | Determine groundwater characteristics through basic calculations | Understand assumptions of the computer model.
    [Show full text]
  • The Groundwater Hydraulics of the Garmsar Alluvial Fan, Iran, Assessed with the Sahysmod Model
    The groundwater hydraulics of the Garmsar alluvial fan, Iran, assessed with the SahysMod model. R.J. Oosterbaan, 20-10-2019 On www.waterlog.info public domain Abstract The Garmsar alluvial fan is located approximately 120 km southeast of Tehran, at the southern fringe of the Alburz mountain range, where the Hableh Rud River emerges and where the Dasht-e-Kavir desert begins. The elevation of the area ranges between 800 to 900 m above sea level. The radius of the fan from top to bottom is some 20 km. The area is intensively irrigated. At the apex the water table is deep and the percolation losses of the irrigation water are carried downslope through a deep aquifer. At the bottom of the fan, the aquifer is less deep and its permeability for water is reduced, so that the water table becomes shallow and it gets at a depth from which capillary rise and evaporation of the groundwater occurs. As the salts remain behind, the soil salinizes here. In this article, the groundwater hydraulics of the fan, that play an important role in the use of pumped wells for irrigation and the depth of the water table at the foot of the fan in relation to salinization of the soils, will be assessed using the spatial (polygonal) agro-hydro-soil-salinity model SahysMod. Contents 1. Introduction 2. Geo-morphology, depth of the water table 3. Water resources 4. Geo-hydrology, hydraulic conductivity 5. Groundwater flow 6. Salinity of the groundwater 7. Subsurface drainage 8. Conclusion 9. References 1. Introduction Figure 1 shows a picture of the Garmsar alluvial fan from space.
    [Show full text]
  • Basic Concepts of Groundwater Hydrology
    PUBLICATION 8083 FWQP REFERENCE SHEET 11.1 Reference: Basic Concepts of Groundwater Hydrology THOMAS HARTER is UC Cooperative Extension Hydrogeology Specialist, University of California, Davis, and Kearney Agricultural Center. UNIVERSITY OF Life depends on water. Our entire living world—plants, animals, and humans—is CALIFORNIA unthinkable without abundant water. Human cultures and societies have rallied around water resources for tens of thousands of years—for drinking, for food produc- Division of Agriculture tion, for transportation, and for recreation, as well as for inspiration. and Natural Resources http://anrcatalog.ucdavis.edu Worldwide, more than a third of all water used by humans comes from ground water. In rural areas the percentage is even higher: more than half of all drinking In partnership with water worldwide is supplied from ground water. In California, rural areas’ dependence on ground water is even greater. California has 8,700 public water supply systems. Of these, 7,800 rely on ground water, drawing from more than 15,000 wells. In addition, there are tens of thousands of privately owned wells used for domestic water supply within the state. Although sufficient aquifers for this sort of use underlie much of California (Figure 1), the large metro- politan areas in Southern California and the San Francisco Bay Area rely primarily on http://www.nrcs.usda.gov surface water for their drinking water supplies. Overall, ground water supplies one- third of the water used in California in a typical year, in drought years as much as Farm Water one-half. Quality Planning WHAT IS GROUND WATER? A Water Quality and Technical Assistance Program Despite our heavy reliance on ground water, its nature remains a mystery to many for California Agriculture people.
    [Show full text]
  • Estimation of Groundwater Recharge Using Water Balance Coupled with Base-Flow-Record Estimation and Stable-Base-Flow Analysis
    Environ Geol (2006) 51: 73–82 DOI 10.1007/s00254-006-0305-2 ORIGINAL ARTICLE Cheng-Haw Lee Estimation of groundwater recharge using Wei-Ping Chen Ru-Huang Lee water balance coupled with base-flow-record estimation and stable-base-flow analysis Abstract In this paper, the long- complex hydrogeologic modeling or Received: 14 February 2006 Accepted: 12 April 2006 term mean annual groundwater re- detailed knowledge of soil charac- Published online: 11 May 2006 charge of Taiwan is estimated with teristics, vegetation cover, or land- Ó Springer-Verlag 2006 the help of a water-balance ap- use practices. Contours of the proach coupled with the base-flow- resulting long-term mean annual P, record estimation and stable-base- BFI, runoff, groundwater recharge, flow analysis. Long-term mean an- and recharge rates fields are well nual groundwater recharge was de- matched with the topographical rived by determining the product of distribution of Taiwan, which estimated long-term mean annual extends from mountain range runoff (the difference between pre- toward the alluvial plains of the C.-H. Lee (&) Æ W.-P. Chen Department of Resources Engineering, cipitation and evapotranspiration) island. The total groundwater National Cheng Kung University, and the base-flow index (BFI). The recharge of Taiwan obtained by the Tainan, Taiwan BFI was calculated from daily employed method is about 18 billion E-mail: [email protected] streamflow data obtained from tons per year. Tel.: +886-6-2757575 Fax: +886-6-2380421 streamflow gauging stations in Tai- wan. Mapping was achieved by Keywords Groundwater recharge Æ R.-H.
    [Show full text]
  • The Significance of Groundwater Flow Modeling Study for Simulation Of
    water Article The Significance of Groundwater Flow Modeling Study for Simulation of Opencast Mine Dewatering, Flooding, and the Environmental Impact Jacek Szczepi ´nski Poltegor-Institute, Institute of Opencast Mining, 51-616 Wrocław, Poland; [email protected] Received: 21 January 2019; Accepted: 18 April 2019; Published: 23 April 2019 Abstract: Simulations of open pit mines dewatering, their flooding, and environmental impact assessment are performed using groundwater flow models. They must take into consideration both regional groundwater conditions and the specificity of mine dewatering operations. This method has been used to a great extent in Polish opencast mines since the 1970s. However, the use of numerical models in mining hydrogeology has certain limitations resulting from existing uncertainties as to the assumed hydrogeological parameters and boundary conditions. They include shortcomings in the identification of hydrogeological conditions, cyclic changes of precipitation and evaporation, changes resulting from land management due to mining activity, changes in mining work schedules, and post-mining void flooding. Even though groundwater flow models used in mining hydrogeology have numerous limitations, they still provide the most comprehensive information concerning the mine dewatering and flooding processes and their influence on the environment. However, they will always require periodical verification based on new information on the actual response of the aquifer system to the mine drainage and the actual climate conditions, as well as up-to-date schedules of deposit extraction and mine closure. Keywords: open pit; dewatering; flooding; groundwater modeling; Poland 1. Introduction In the mining industry, water-related problems are among the most important aspects which can decide whether a new mine development will be reasonable or even feasible.
    [Show full text]
  • Spatial Modelling and Prediction of Soil Salinization Using Saltmod in a Gis Environment
    SPATIAL MODELLING AND PREDICTION OF SOIL SALINIZATION USING SALTMOD IN A GIS ENVIRONMENT M. MADYAKA February, 2008 SPATIAL MODELLING AND PREDICTION OF SOIL SALINIZATION USING SALTMOD IN A GIS ENVIRONMENT Spatial Modelling and Prediction of Soil Salinization Using SaltMod in a GIS Environment by Mthuthuzeli Madyaka Thesis submitted to the International Institute for Geo-information Science and Earth Observation in partial fulfilment of the requirements for the degree of Master of Science in Geo-information Science and Earth Observation, Specialisation: (Natural Resource Management – Soil Information Systems for Sustainable Land Management: NRM-SISLM) Thesis Assessment Board Prof. Dr. V.G.Jetten: Chairperson Prof. Dr.Ir. A. Veldkamp: External Examiner B. (Bas) Wesselman: Internal Examiner Dr. A. (Abbas) Farshad: First Supervisor Dr. D.B. (Dhruba) Pikha Shrestha: Second Supervisor INTERNATIONAL INSTITUTE FOR GEO-INFORMATION SCIENCE AND EARTH OBSERVATION ENSCHEDE, THE NETHERLANDS Disclaimer This document describes work undertaken as part of a programme of study at the International Institute for Geo-information Science and Earth Observation. All views and opinions expressed therein remain the sole responsibility of the author, and do not necessarily represent those of the institute. Abstract One of the problems commonly associated with agricultural development in semi-arid and arid lands is accumulation of soluble salts in the plant root-zone of the soil profile. The salt accumulation usually reaches toxic levels that impose growth stress to crops leading to low yields or even complete crop failure. This research utilizes integrated approach of remote sensing, modelling and geographic information systems (GIS) to monitor and track down salinization in the Nung Suang district of Nakhon Ratchasima province in Thailand.
    [Show full text]
  • GW Flow Equations
    1 SUMMARY OF DIFFERENTIAL EQUATIONS FOR GROUNDWATER FLOW All equations are derived by combining Darcy's Law with an equation of continuity (mass balance.) Symbols used: b aquifer thickness hpiezometric head K hydraulic conductivity S storage coefficient Ss specific storage Sya apparent specific yield T transmissibility t time x y orthogonal coordinate directions z ∂2 ∂ 2 ∂ 2 ∇2 Laplacian operator = + + ∂x2 ∂y2 ∂z2 Relations: S = bSs T = bK 1. CONFINED FLOW a. INHOMOGENEOUS ANISOTROPIC CONFINED AQUIFER ∂ ∂h ∂ ∂h ∂ ∂h ∂h Kx + Ky + Kz = Ss (1) ∂x ∂x ∂y ∂y ∂z ∂z ∂t Coordinate system must be selected so that axes are collinear with principal axes of hydraulic conductivity. If the medium is homogeneous, equation (1) reduces to: b. HOMOGENEOUS ANISOTROPIC CONFINED AQUIFER 2 2 2 ∂ h ∂ h ∂ h ∂h . ∂h Kx + Ky + Kz = Ss or K ∇2 h = Ss (2) ∂x2 ∂y2 ∂z2 ∂t ∂t Again, the coordinate axes must be chosen to coincide with the hydraulic conductivity axes. c. HOMOGENEOUS ISOTROPIC CONFINED AQUIFER (DIFFUSION EQUATION) ∂2h ∂2h ∂2h S ∂h S ∂h + + = s or ∇2 h = s (3) ∂x2 ∂y2 ∂z2 K ∂t K ∂t For an aquifer of constant thickness, b, this can be written: ∂2h ∂2h ∂2h S ∂h S ∂h + + = or ∇2 h = (4) ∂x2 ∂y2 ∂z2 T ∂t T ∂t Note that because the medium is isotropic, the selection of coordinate axes is arbitrary -- they may be placed in any convenient orientation. 2 d. HORIZONTAL FLOW IN HOMOGENEOUS ISOTROPIC CONFINED AQUIFER OF CONSTANT THICKNESS ∂h If flow is horizontal, = 0, and thus ∂z ∂2h ∂2h S ∂h + = (5) ∂x2 ∂y2 T ∂t In this equation piezometric head does not vary with elevation.
    [Show full text]