Impact of Interface Soil Layer on Groundwater Aquifer Behaviour
The geological environment where the groundwater is collected represents the most important element that affects the behaviour of groundwater aquifer. As groundwater is a worldwide vital resource, it requires knowing the parameters that affect this source accurately so that the conceptualized mathematical models would be acceptable to the broadest ranges. Therefore, groundwater models have recently become an effective and efficient tool to investigate groundwater aquifer behaviours. Groundwater aquifer may contain aquitards, aquicludes, or interfaces within its geological formations. Aquitards and aquicludes have geological formations that forced the modellers to include those formations within the conceptualized groundwater models, while interfaces are commonly neglected from the conceptualization process because the modellers believe that the interface has no effect on aquifer behaviour. The current research highlights the impact of an interface existing in a real unconfined groundwater aquifer called Dibdibba, located in Al-Najaf City, Iraq where it has a river called the Euphrates River that passes through the eastern part of this city. Dibdibba groundwater aquifer consists of two types of soil layers separated by an interface soil layer. A groundwater model is built for Al-Najaf City to explore the impact of this interface. Calibration process is done using PEST 'Parameter ESTimation' approach and the best Dibdibba groundwater model is obtained. When the soil interface is conceptualized, results show that the groundwater tables are significantly affected by that interface through appearing dry areas of 56.24 km² and 6.16 km² in the upper and lower layers of the aquifer, respectively. The Euphrates River will also leak water into the groundwater aquifer of 7359 m³/day. While these results are changed when the soil interface is neglected where the dry area became 0.16 km², the Euphrates River leakage became 6334 m³/day. In addition, the conceptualized models (with and without interface) reveal different responses for the change in the recharge rates applied on the aquifer through the uncertainty analysis test. The aquifer of Dibdibba in Al-Najaf City shows a slight deficit in the amount of water supplied by the current pumping scheme and also notices that the Euphrates River suffers from stresses applied to the aquifer. Ultimately, this study shows a crucial need to represent the interface soil layer in model conceptualization to be the intended and future predicted behaviours more reliable for consideration purposes.
Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1315788Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 470
 F. Abdulla, and T. Al-Assa'd, “Modelling of groundwater flow for Mujib aquifer, Jordan,”. Earth System Science J., vol. 115, pp. 289-298, 2006.
 A. Alcolea, J. Carrera, and A. Medina, “Pilot points method incorporating prior information for solving the groundwater flow inverse problem,” Advances in Water Resources J., vol. 29, no. 11, pp. 1678– 1689, 2006.
 S. W. Al-Muqdadi, Groundwater Investigation and Modeling-Western Desert of Iraq. PhD-Thesis, Freiberg-Germany, Technische Universität, 2012.
 T. H. Al-Salim, and M. F. A. Khattab, “Mathematical model of ground water flow of Bashiqa area, northern Iraq,” Iraqi National J. of Earth Sciences, vol. 4, no. 2, pp. 84-98, 2004.
 M. Al-Sibaʹai, “Modeling of groundwater movement (Euphrates lower basin),” Damascus University for Basic Sciences J., vol. 21, no. 2, pp. 91-114, 2005.
 M. P. Anderson, and W. W. Woessner, Applied Groundwater Modeling: Simulation of Flow and Advective Transport. San Diego, California: Academic Press Inc., 1992.
 M. P. Anderson, W. W. Woessner, and R. J. Hunt, Applied Groundwater Modeling, Simulation of Flow and Advective Transport. London: Academic Press, 2015.
 J. T. K. Blegen, Numerical and Analytical Modelling of Ground Water Flow in Delta Structures. University Of Oslo, 2005.
 H. Bouwer, Groundwater Hydrology. New York: McGraw-Hill, 1978, pp. 480.
 R. L. Cooley, “A method of estimating parameters and assessing reliability for models of steady state groundwater flow: 2. Application of statistical analysis,” Water Resources Research J., vol. 15, no. 3, pp. 603– 617, 1979.
 R. L. Cooley, and P. J. Sinclair, “Uniqueness of a model of steady-state groundwater flow,” Hydrology J., vol. 31, no. 3–4, pp. 245–269, 1976.
 H. Darcy, Les Fontains Publiques De La Ville De Dijon. Victor Dalmont: Paris, 1958.
 H. J. G. Diersch, FEFLOW 5.2 Finite Element Subsurface Flow and Transport Simulation System. User’s Manual. WASY GmbH Institute Water Resources Planning and System Research, Berlin: Germany, 2005.
 J. Doherty, “Ground water model calibration using pilot points and regularization,” Groundwater J., vol. 41, no. 2, pp. 170– 177, 2003.
 J. E. Doherty, M. N. Fienen, R. J. Hunt, Approaches to Highly Parameterized Inversion: Pilot-Point Theory, Guidelines, and Research Directions. U.S. Geological Survey, Scientific Investigations Report, no. 5168, 2010, pp. 36.
 GEOSURV, Geological and Hydrogeological Data of Al-Najaf Province. The Iraqi Ministry of Industry and Minerals, General Commission for Geological Survey and Mining, 2015.
 A. W. Harbaugh, “MODFLOW-2005, The U.S. geological survey modular groundwater model-the ground-water flow process,” in Modeling Techniques. USA: U.S. Department of the Interior and U.S. Geological Survey, 2005.
 A. J. Hemker, “Transient well flow in layered aquifers systems: the uniform well-face drawdown solution,” Hydrology J., vol. 225, pp. 19-44, 1999.
 A. Husam, “Fundamentals of groundwater modeling,” in Groundwater: Modelling, Management and Contamination, F. Luka, and L. W. Jonas. New York: Nova Publisher, 2011.
 S. Z. Igor, and G. E. Lorne, Groundwater Resources of The World and Their Use. The United Nations Educational, Scientific and Cultural Organization, Saint-Denis, 2004.
 S. Jakub, Examples of Determining The Hydraulic Conductivity of Soils: Theory and Applications of Selected Basic Methods. Faculty of the Environment, Handbook on Soil Hydraulics, Jan Evangelista Purkyně University, 2014.
 D. Jeff et al., Applications of Groundwater Modeling for Decision-Making in Water Management and Engineering With Water Supply and Remediation Case Studies. National Ground Water Association Press: U.S.A, 2017.
 L. F. Konikow, T. E. Reilly, P. M. Barlow, and C. I. Voss, “Groundwater modeling,” in The Handbook of Groundwater Engineering, J. W. Delleur, 2nd ed. USA: CRC press, 2006.
 G. P. Kruseman, N.A. de Ridder, and J.M. Verweij, Analysis and Evaluation of Pumping Test Data. Amsterdam: ILRI Publication 47, 2000.
 M. G. McDonald, and A. W. Harbaugh, A Modular Three-Dimension Finite-Difference Groundwater Flow Model. Techniques of Water Resources Investigations of the U.S. Geological Survey, USA, 1988.
 N. J. Middleton, and D. S. G. T. Arnold, World Atlas of Desertification. United Nations Environment Programme, 1997.
 MOTRANS (Ministry of Transportation, Iraq), Meteorological Data of Al-Najaf City Station. Ministry of Transportation – Iraqi meteorological organization and seismology – Iraq, 2015.
 MOWR (Ministry of Water Resources, Iraq), “Water crisis reasons,” Ministry of Water Resources. Al-Rafidain J., (Un-Published), 2015.
 R. J. Oosterbaan, and H. J. Nijland, “Determining the saturated hydraulic conductivity,” in Drainage Principles and Applications, H. P. Ritzema. International Institute for Land Reclamation and Improvement, ILRI Publication 16, 2006, pp. 1-38.
 A. M. Sefelnasr, Development of groundwater flow model for water resources management in the development areas of the western desert, Egypt. PhD Thesis, Martin Luther University, Germany. 2007
 Q. Shuwei, L. Xiujuan, X. Changlai, F. Zhang, and L. Fengchao, “Numerical simulation of groundwater flow in a river valley basin in Jilin urban area, China,” Water J. vol. 7, pp. 5768-5787, 2015.
 S. Siebert et al., “Groundwater Use for Irrigation – A Global Inventory,” Hydrology Earth System Sciences J., vol. 14, pp. 1863-1880, 2010.
 A. Spiliotopoulos, and C. B. Andrews, “Analysis of aquifer test data – MODFLOW and PEST,” Conference of Managing Ground-Water Systems J., pp. 569-573, 2006.
 A. W. Thornthwaite, “An approach toward a rational classification of climate,” Geographical Review J., vol. 38, no. 1, pp. 55-94, 1948.
 S. Vijai, and G. Rohit, “Development of conceptual groundwater flow model for Pali area, India,”. African J. of Environmental Science and Technology, vol. 5, no. 12, pp. 1085-1092, 2011.
 Y. A. S. Wa’il, and I. H. Randa, “Using MODFLOW and MT3D groundwater flow and transport models as a management tool for the Azraq groundwater system,” Jordan J. of Civil Engineering, vol. 1, no. 2, pp. 153-172, 2007.
 W. W. G. Yeh, and G. W. Tauxe, “Optimal identification of aquifer diffusivity using quasilinearization,” Water Resources Research J., vol. 7, no. 4, pp. 955–962, 1971.