A Heuristic Approach to Estimating Spatial Variability of Vertical Leakage in the Recharge Zone of the Gambier Basin Tertiary Confined Sand Aquifer, South Australia

Nara  Somaratne; Jeff  Lawson; Saad  Mustafa

doi:10.4236/jwarp.2016.82015

Nara Somaratne¹^*, Jeff Lawson², Saad Mustafa²

Abstract: The vertical leakage to confined aquifers is rarely quantified in complex settings, where the recharge zone is characterized by both diffuse and preferential flows. In such setting, conventional hydraulic or tracer based estimation of recharge or vertical leakage is problematic, unless the effects of duality of flow regimes are considered. A water balance approach by the use of calibrated groundwater models can be used, as the mass balance is independent of the particular mode of recharge and vertical leakage processes. Here, we adopt a water balance approach to provide a first order assessment of recharge to the unconfined Tertiary limestone aquifer (TLA) and vertical leakage to the Tertiary confined sand aquifer (TCSA) within the Glencoe-Nangwarry-Nagwarry (GNN) recharge zone of the Gambier Basin in South Australia. Despite many studies expressing concern about the impact of land use on recharge to the TLA and vertical leakage to the TCSA, no estimates have been made to quantify the vertical leakage within the GNN recharge zone. In the GNN recharge zone, relatively high recharge to the unconfined aquifer and vertical leakage to the confined aquifer occurs as a result of both diffuse and preferential flow processes. This is due to presence of structural faults and thin or absent aquitard. Within the Hundred of Nangwarry, where 83% of the area is covered with plantation forest, the model calculated recharge to the TLA of 80 mm·year^-1, about 44% reduction compared to adjacent non-forested area (144 mm·year^-1). Vertical leakage to the TCSA within the Hundred of Nangwarry area is higher (84.5 mm·year^-1) than recharge to the TLA. Higher vertical leakage combined with the reduced recharge to TLA resulted in depletion of the TLA storage, as evidenced by drying of the TLA at one locality. In contrast, in plantation forest areas where diffuse recharge is the dominant process (Hundred of Penola), recharge to the TLA is about 19 mm·year^-1, a 78% reduction compared to the non-forested areas, a mix of irrigation and dryland pasture. In these areas, vertical leakage to the TCSA is much smaller: 8 mm·year^-1 through a thick aquitard. Simulation of a management scenario in which plantation forest is replaced by dryland pasture in the Hundred of Nangwarry results in 135 mm·year^-1 recharge to TLA and a 98 mm·year^-1 vertical leakage to the TCSA.

Keywords: Gambier Basin, Confined Aquifer, Preferential Flows, Vertical Leakage, Groundwater Models, Groundwater Management

Cite this paper: Somaratne, N. , Lawson, J. and Mustafa, S. (2016) A Heuristic Approach to Estimating Spatial Variability of Vertical Leakage in the Recharge Zone of the Gambier Basin Tertiary Confined Sand Aquifer, South Australia. Journal of Water Resource and Protection, 8, 183-200. doi: 10.4236/jwarp.2016.82015.

References

[1] Sukjija, B.S., Reddy, D.V., Nagabhushanam, P., Hussain, S., Giri, V.Y. and Patil, D.J. (1996) Environmental and Injected Tracers Methodology to Estimate Direct Precipitation Recharge to a Confined Aquifer. Journal of Hydrology, 77, 77-97.
http://dx.doi.org/10.1016/0022-1694(95)02788-2

[2] Jones, B.F., Hanor, J.S. and Evans, R.W. (1994) Sources of Dissolved Salts in the Central Murray Basin, Australia. Chemical Geology, 111, 135-154.
http://dx.doi.org/10.1016/0009-2541(94)90087-6

[3] Hendry, M.J., Wassenaar, L.I. and Kotzer, T. (2000) Chloride and Chlorine Isotopes (36Cl and δ37Cl) as Tracers of Solute Migration in a Thick, Clay-Rich Aquitard System. Water Resources Research, 36, 285-296.
http://dx.doi.org/10.1029/1999WR900278

[4] Love, A., Herczeg, A.L. and Walker, G. (1995) Transport of Water and Solutes across a Regional Aquitard Inferred from Porewater Deuterium and Chloride Profiles Otway Basin, Australia. In: IAEA (Ed.), Proceedings of a Symposium on Isotopes in Water Resources Management, Vienna, 20-24 March 1995, Vol. 1: 73-86.

[5] Harrington, G.A., Walker, G.R., Love, A.J. and Narayan, K.A. (1999) A Compartmental Mixing-Cell Approach for the Quantitative Assessment of Groundwater Dynamics in the Otway Basin, South Australia. Journal of Hydrology, 214, 49-63.
http://dx.doi.org/10.1016/S0022-1694(98)00243-1

[6] Motz, L.H. (1998) Vertical Leakage and Vertically Averaged Vertical Conductance for Karst Lakes in Florida. Water Resources Research, 34, 159-167.
http://dx.doi.org/10.1029/97WR03134

[7] Ruhl, J., Kanivetsky, R. and Shmagin, B. (2002) Estimates of Recharge to Unconfined Aquifers and Leakage to Confined Aquifers in the Seven-County Metropolitan Area of Minneapolis-St. Paul, Minnesota. Water Resources Investigation Report 2002-4092, US Geological Survey, Minnesota.

[8] Chen, C. and Jiao, J.J. (1999) Numerical Simulation of Pumping Tests in Multilayer Wells with Non-Darcian Flow in the Wellbore. Groundwater, 37, 465-474.
http://dx.doi.org/10.1111/j.1745-6584.1999.tb01126.x

[9] Neuman, S.P. and Witherspoon, P.A. (1968) Theory of Flow in Aquicludes Adjacent to Slightly Leaky Aquifers. Journal of Water Resources Research, 4, 103-112.

[10] Cihan, A., Zhou, Q. and Birkhlzer, J.T. (2011) Analytical Solutions for Pressure Perturbations and Fluid Leakage through Aquitards and Wells in Multi Layered Aquifer Systems. Water Resources Research, 47, WR10504.
http://dx.doi.org/10.1029/2011WR010721

[11] Somaratne, N. (2014) Characteristics of Point Recharge in Karst Aquifers. Water, 6, 2782-2807.

[12] Somaratne, N. (2015) Pitfalls in Application of the Conventional Chloride Mass Balance (CMB) in Karst Aquifers and Use of the Generalized CMB Method. Environmental Earth Sciences, 74, 337-349.

[13] Brown, K.G., Love, A.J. and Harrington, G.A. (2001) Vertical Groundwater Recharge to the Tertiary Confined Sand Aquifer, South East, South Australia. Report DWR 2001/002, Department for Water Resources, Adelaide.

[14] Somaratne, N., Lawson, J. and Mustafa, S. (2015) Study of Characteristics of the Recharge Zone and Groundwater Movement in the Tertiary Confined Sand Aquifer for the Establishment of Bool Lagoon Wellfield. Technical Report, South Australian Water Corporation, Adelaide.

[15] Gerber, R.E. and Howard, K. (2000) Recharge through a Regional Till Aquitard: Three-Dimensional Flow Model Water Balance Approach. Ground Water, 38, 410-422.
http://dx.doi.org/10.1111/j.1745-6584.2000.tb00227.x

[16] Weiss, M. and Gvirtzman, H. (2007) Estimating Ground Water Recharge Using Flow Models of Perched Karstic Aquifers. Ground Water, 45, 761-773.
http://dx.doi.org/10.1111/j.1745-6584.2007.00360.x

[17] Brown, K. (2000) A Groundwater Flow Model of the Tertiary Confined Sand Aquifer in South East South Australia and South West Victoria. Report Book 2000/00016, Department for Water Resources, Primary Industries and Resources, Adelaide.

[18] Harrington, N. and Lamontagne, S., Eds. (2013) Framework for a Regional Water Balance Model for the South Australian Limestone Coast Region. Technical Report Series No. 13/14, Goyder Institute for Water Research, Adelaide.

[19] Harrington, N.M., Chambers, K. and Lawson, J. (2007) Primary Production to Mitigate Water Quality Threats Project, Zone 1A Numerical Modelling Study: Conceptual Model Development. DWLBC Report 2008/12, Government of South Australia through Department of Water, Land and Biodiversity Conservation, Adelaide.

[20] Konikow, L.F. and Bredehoeft, J.D. (1992) Ground-Water Models Cannot Be Validated. Advances in Water Resources, 15, 75-83.
http://dx.doi.org/10.1016/0309-1708(92)90033-X

[21] Beven, K. (1993) Prophecy, Reality and Uncertainty in Distributed Hydrological Modelling. Advances in Water Resources, 16, 41-51.
http://dx.doi.org/10.1016/0309-1708(93)90028-E

[22] Oreskes, N., Shrader-Frechette, K. and Belitz, K. (1994) Verification and Confirmation of Numerical Models in Earth Sciences. Science, 263, 641-646.
http://dx.doi.org/10.1126/science.263.5147.641

[23] Gupta, H., Sorooshian, S. and Yapo, P. (1999) Status of Automatic Calibration for Hydrologic Models: Comparison with Multilevel Expert Calibration. Journal of Hydrologic Engineering, 4, 135-143.
http://dx.doi.org/10.1061/(ASCE)1084-0699(1999)4:2(135)

[24] Hendricks Franssen, H.J., Alcolea, A., Riva, M., Bakr, M., van der Wier, N., Stauffer, F. and Guadagnini, A. (2009) A Comparison of Seven Methods for the Inverse Modelling of Groundwater Flow. Application to the Characterization of Well Catchments. Advances in Water Resources, 32, 851-872.
http://dx.doi.org/10.1016/j.advwatres.2009.02.011

[25] Boyle, D.P., Gupta, H. and Sorooshian, S. (2000) Towards Improved Calibration of Hydrologic Models: Combining the Strengths of Manual and Automatic Methods. Water Resources Research, 6, 3663-3674.
http://dx.doi.org/10.1029/2000WR900207

[26] Saiers, J.E., Genereux, D.P. and Bolster, C.H. (2004) Influence of Calibration Methodology on Groundwater Flow Predictions. Ground Water, 42, 32-44.
http://dx.doi.org/10.1111/j.1745-6584.2004.tb02448.x

[27] Eckhardt, K., Fohrer, N. and Frede, H. (2005) Automatic Model Calibration. Hydrological Processes, 19, 651-658.
http://dx.doi.org/10.1002/hyp.5613

[28] Moore, C. and Doherty, J. (2006) The Cost of Uniqueness in Groundwater Model Calibration. Advances in Water Resources, 29, 605-623.
http://dx.doi.org/10.1016/j.advwatres.2005.07.003

[29] Yeh, T.J., Mao, D., Zha, Y., Wen, J., Wan, L., Hsu, K. and Lee, C. (2015) Uniqueness, Scale and Resolution Issues in Groundwater Model Parameter Identification. Water Science and Engineering, 8, 175-194.
http://dx.doi.org/10.1016/j.wse.2015.08.002

[30] Holmes, J.W. and Colville, J.S. (1970) Grassland Hydrology in a Karstic Region of South Australia. Journal of Hydrology, 10, 38-58.
http://dx.doi.org/10.1016/0022-1694(70)90053-3

[31] Holmes, J.W. and Colville, J.S. (1970) Forest Hydrology in a Karstic Region of Southern Australia. Journal of Hydrology, 10, 59-74.
http://dx.doi.org/10.1016/0022-1694(70)90054-5

[32] Colville, J.S. and Holmes, J.W. (1972) Water Table Fluctuations under Forest and Pasture in a Karstic Region of Southern Australia. Journal of Hydrology, 17, 61-80.
http://dx.doi.org/10.1016/0022-1694(72)90066-2

[33] Allison, G.B. and Hughes, M.W. (1978) The Use of Environmental Chloride and Tritium to Estimate Total Recharge to an Unconfined Aquifer. Australian Journal of Soil Research, 16, 181-195.
http://dx.doi.org/10.1071/SR9780181

[34] Leaney, F.W. and Herczeg, A.L. (1995) Regional Recharge to a Karst Aquifer Estimated from Chemical and Isotopic Composition of Diffuse and Localized Recharge, South Australia. Journal of Hydrology, 164, 363-387.
http://dx.doi.org/10.1016/0022-1694(94)02488-W

[35] Department of Environment, Water and Natural Resources (2014) Prescribed Wells Areas of the South East Confined Aquifer: 2014 Groundwater Level and Salinity Status Report. Department of Environment, Water and Natural Resources, Adelaide.

[36] Love, A.J. (1991) Groundwater Flow Systems: Past and Present, Gambier Embayment, Otway Basin, South Australia. Master’s Thesis, Flinders University of South Australia, Adelaide, 261.

[37] Harbough, A.W., Banta, E.R., Hill, M.C. and McDonald, M.G. (2000) MODFLOW-2000, The US Geological Survey Modular Ground-Water Model-User Guide to Modularization Concepts and the Ground-Water Flow Process. US Department of Interior, US Geological Survey, Open-File Report 00-92, Reston, VA.

[38] Chiang, W.-H. and Kinzelbach, W. (1998) Processing MODFLOW—A Simulation System for Modelling Groundwater Flow and Pollution. Hamburg, 342 p.
www.pmwin.net

[39] Mustafa, S. and Lawson, J.S. (2002) Review of Tertiary Gambier Limestone Aquifer Properties, Lower South East, South Australia. Report DWLBC 2002/24, Department of Water, Land and Biodiversity Conservation, Adelaide.

[40] ROSETTA V1, USDA-ARS Salinity Laboratory, Riverside, US, 1999.

[41] Mustafa, S. and Lawson, J. (2012) South Australia-Victoria Border Zone Groundwater Investigation: Results of the Pumping Test Program. Technical Report DFW 2011/2, Department for Water, Adelaide.

[42] Benyon, R.G. and Doody, T.M. (2004) Water Use by Tree Plantations in South East South Australia. CSIRO Forestry and Forest Products Technical Report Number 148, CSIRO Mount Gambier SA, Australia.

[43] Hanson, R.T., Li, Z. and Faunt, C.C. (2004) Documentation of Santa Clara Valley Regional Groundwater Model, Santa Clara, California. Scientific Investigation Report 2004-5231, US Department of the Interior, US Geological Survey, Reston, VA.

[44] Leijnse, A., Pastoors, M.J.H. and Roelofsen, F.J. (2002) The Effect of Weighting the Observations on Parameter Estimates in Groundwater Modelling. In: Calibration and Reliability in Groundwater Modelling: A Few Steps Closer to Reality (Proceedings of ModelCARE 2002), IAH Publication No. 277, Czech Republic, 204-211.

[45] Carrera, J. and Neuman, S.P. (1986) Estimation of Aquifer Parameters under Transient and Steady State Conditions I: Maximum Likelihood Method Incorporating Prior Information. Water Resources Research, 22, 199-210.
http://dx.doi.org/10.1029/WR022i002p00199

[46] Waterloo Hydrogeologic (2015) Visual MODFLOW 2011.1 User’s Manual. Waterloo Hydrogeologic, Waterloo, ON.

[47] Loucks, D.P., van Beek, E., Stedinger, J.R., Dijkman, J.P.M. and Villars, M.T. (2005) Water Resources Systems Planning and Management. An Introduction to Methods, Models and Applications. UNNESCO, Paris and Delft Hydraulics, The Netherlands.

[48] Brown, K., Harrington, G. and Lawson, J. (2006) Review of Groundwater Resource Condition and Management Principles for the Tertiary Limestone Aquifer in the South East of South Australia. DWLBC Report 2006/2, Department of Water, Land and Bio Diversity Conservation, Adelaide.

[49] Allison, G.B. and Hughes, M.W. (1972) Comparison of Recharge to Groundwater under Pasture and Forest Using Environ Mental Tritium. Journal of Hydrology, 17, 81-95.
http://dx.doi.org/10.1016/0022-1694(72)90067-4

[50] Benyon, R., Thieveyanathan, T. and Doody, T.M. (2006) Impacts of Plantations on Groundwater in South-Eastern Australia. Australian Journal of Botany, 54, 181-192.
http://dx.doi.org/10.1071/BT05046

[51] Benyon, R., Doody, T.M., Thieveyanathan, S. and Koul, V. (2008) Plantations Forest Water Use in Southwest Victoria. CSIRO Water for a Healthy Country Research Flagship, CSIRO, Canberra.

[52] Bevan, K.J. and Young, P. (2013) A Guide in Modelling Scenarios for Authors and Referees. Water Resources Research, 49, 5092-5098.
http://dx.doi.org/10.1002/wrcr.20393

[53] Huntush, M.S. (1960) Modification of the Theory of Leaky Aquifers. Journal of Geophysical Research, 65, 3713-3726.
http://dx.doi.org/10.1029/JZ065i011p03713

[54] Harrington, G. and Cook, P. (2011) Mechanical Loading and Unloading of Confined Aquifers: Implications for the Assessment of Long-Term Trends in Potentiometric Levels. Waterlines Report Series No. 51, National Water Commission, Canberra.