References

HESS

Hydrology and Earth System Sciences

HESS

Hydrol. Earth Syst. Sci.

1607-7938

Copernicus Publications

Göttingen, Germany

10.5194/hess-19-2315-2015

Identifying flood recharge and inter-aquifer connectivity using multiple isotopes in subtropical Australia

King

A. C.

¹ ² Raiber

¹ ² ³ Cendón

D. I.

https://orcid.org/0000-0002-3275-1939

⁴ ⁵ Cox

M. E.

¹ ² Hollins

S. E.

⁴

School of Earth, Environmental and Biological Sciences, Queensland University of Technology (QUT), Brisbane, QLD 4001, Australia

National Centre for Groundwater Research and Training (NCGRT), Adelaine, Australia

CSIRO Land and Water, Dutton Park, Brisbane, QLD 4102, Australia

Australian Nuclear Science and Technology Organisation (ANSTO), Menai, Sydney, NSW 2234, Australia

Connected Water Initiative, School of Biological, Earth and Environmental Sciences, University of New South Wales (UNSW), Sydney, NSW 2052, Australia

19 05 2015

19 5 2315 2335

2015

This work is licensed under the Creative Commons Attribution 3.0 Unported License. To view a copy of this licence, visit https://creativecommons.org/licenses/by/3.0/

This article is available from https://hess.copernicus.org/articles/19/2315/2015/hess-19-2315-2015.html

The full text article is available as a PDF file from https://hess.copernicus.org/articles/19/2315/2015/hess-19-2315-2015.pdf

An understanding of hydrological processes is vital for the sustainable management of groundwater resources, especially in areas where an aquifer interacts with surface water systems or where aquifer interconnectivity occurs. This is particularly important in areas that are subjected to frequent drought/flood cycles, such as the Cressbrook Creek catchment in Southeast Queensland, Australia. In order to understand the hydrological response to flooding and to identify inter-aquifer connectivity, multiple isotopes (δ2H, δ18O, 87Sr/86Sr, 3H and 14C) were used in this study in conjunction with a comprehensive hydrochemical assessment, based on data collected 6 months after severe flooding in 2011. The relatively depleted stable isotope signatures of the flood-generating rainfall (δ2H: −30.2 to −27.8&permil;, δ18O: −5.34 to −5.13&permil; VSMOW) were evident in surface water samples (δ2H: −25.2 to −23.2&permil;, δ18O: −3.9 to −3.6&permil; VSMOW), indicating that these extreme events were a major source of recharge to the dam in the catchment headwaters. Furthermore, stable isotopes confirmed that the flood generated significant recharge to the alluvium in the lower part of the catchment, particularly in areas where interactions between surface waters and groundwater were identified and where diffuse aquifer recharge is normally limited by a thick (approximately 10 m) and relatively impermeable unsaturated zone. However, in the upper parts of the catchment where recharge generally occurs more rapidly due to the dominance of coarse-grained sediments in the unsaturated zone, the stable isotope signature of groundwater resembles the longer-term average rainfall values (δ2H: −12.6, δ18O: −3.4&permil; VSMOW), highlighting that recharge was sourced from smaller rainfall events that occurred subsequent to the flooding. Interactions between the bedrock aquifers and the alluvium were identified at several sites in the lower part of the catchment based on 87Sr/86Sr ratios; this was also supported by the hydrochemical assessment, which included the modelling of evaporation trends and saturation indices. The integrated approach used in this study facilitated the identification of hydrological processes over different spatial and temporal scales, and the method can be applied to other complex geological settings with variable climatic conditions.

References 1

Anibas, C., Verbeiren, B., Buis, K., Chorma\'nski, J., De Doncker, L., Okruszko, T., Meire, P., and Batelaan, O.: A hierarchical approach on groundwater-surface water interaction in wetlands along the upper Biebrza River, Poland, Hydrol. Earth Syst. Sci., 16, 2329–2346, <a href="http://dx.doi.org/10.5194/hess-16-2329-2012">https://doi.org/10.5194/hess-16-2329-2012</a>, 2012.

Appelo, C. A. J. and Postma, D.: Geochemistry, Groundwater and Pollution, 2nd Edn, A. A. Balkema Publishers, Leiden, the Netherlands, 2005.

Arnell, N. W. and Gosling, S. N.: The impacts of climate change on river flow regimes at the global scale, J. Hydrol., 486, 351–364, <a href="http://dx.doi.org/10.1016/j.jhydrol.2013.02.010">https://doi.org/10.1016/j.jhydrol.2013.02.010</a>, 2013.

Babister, M. and Retallick, M.: Brisbane River 2011 flood event – flood frequency analysis, final report, Project number 111024, Queensland Floods Commission of Inquiry, WMA Water, Brisbane, Australia, 2011.

Baudron, P., Barbecot, F., Aróstegui, J. L. G., Leduc, Y. T., Travi, Y., and Martinez-Vicente, D.: Impacts of human activities on recharge in a multilayer semiarid aquifer (Campo de Cartagena, SE Spain), Hydrol. Process., 28, 2223–2236, 2014.

Barrett, M. H., Hiscock, K. M., Pedley, S., Lerner, D. N., Tellam, J. H., and French, M. J.: Marker species for identifying urban groundwater recharge sources: a review and case study in Nottingham, UK, Water Res., 33, 3083–3097, <a href="http://dx.doi.org/10.1016/s0043-1354(99)00021-4">https://doi.org/10.1016/s0043-1354(99)00021-4</a>, 1999.

Barron, O. V., Crosbie, R. S., Dawes, W. R., Charles, S. P., Pickett, T., and Donn, M. J.: Climatic controls on diffuse groundwater recharge across Australia, Hydrol. Earth Syst. Sci., 16, 4557–4570, <a href="http://dx.doi.org/10.5194/hess-16-4557-2012">https://doi.org/10.5194/hess-16-4557-2012</a>, 2012.

Boulton, A. J., Findlay, S., Marmonier, P., Stanley, E. H., and Valett, H. M.: The functional significance of the hyporheic zone in streams and rivers, Annu. Rev. Ecol. Syst., 29, 59–81, <a href="http://dx.doi.org/10.1146/annurev.ecolsys.29.1.59">https://doi.org/10.1146/annurev.ecolsys.29.1.59</a>, 1998.

Boulton, A. J., Datry, T., Kasahara, T., Mutz, M., and Stanford, J. A.: Ecology and management of the hyporheic zone: stream-groundwater interactions of running waters and their floodplains, J. N. Am. Benthol. Soc., 29, 26–40, <a href="http://dx.doi.org/10.1899/08-017.1">https://doi.org/10.1899/08-017.1</a>, 2010.

Bureau of Meteorology – BOM: Commonwealth of Australia Bureau of Meteorology, available at: <a href="http://www.bom.gov.au/climate/data/">http://www.bom.gov.au/climate/data/</a>, last access: 15 July 2012.

Cartwright, I. and Morgenstern, U.: Constraining groundwater recharge and the rate of geochemical processes using tritium and major ion geochemistry: Ovens catchment, southeast Australia, J. Hydrol., 475, 137–149, <a href="http://dx.doi.org/10.1016/j.jhydrol.2012.09.037">https://doi.org/10.1016/j.jhydrol.2012.09.037</a>, 2012.

Cartwright, I., Weaver, T., Cendón, D. I., and Swane, I.: Environmental isotopes as indicators of inter-aquifer mixing, Wimmera region, Murray Basin, Southeast Australia, Chem. Geol., 277, 214–226, <a href="http://dx.doi.org/10.1016/j.chemgeo.2010.08.002">https://doi.org/10.1016/j.chemgeo.2010.08.002</a>, 2010a.

Cartwright, I., Weaver, T. R., Simmons, C. T., Fifield, L. K., Lawrence, C. R., Chisari, R., and Varley, S.: Physical hydrogeology and environmental isotopes to constrain the age, origins, and stability of a low-salinity groundwater lens formed by periodic river recharge, J. Hydrol., 380, 203–221, 2010b.

Cartwright, I., Weaver, T. R., Cendón, D. I., Fifield, L. K., Tweed, S. O., Petrides, B., and Swane, I.: Constraining groundwater flow, residence times, inter-aquifer mixing, and aquifer properties using environmental isotopes in the southeast Murray Basin, Australia, Appl. Geochem., 27, 1698–1709, <a href="http://dx.doi.org/10.1016/j.apgeochem.2012.02.006">https://doi.org/10.1016/j.apgeochem.2012.02.006</a>, 2012.

Cendón, D. I., Larsen, J. R., Jones, B. G., Nanson, G. C., Rickleman, D., Hankin, S. I., Pueyo, J. J., and Maroulis, J.: Freshwater recharge into a shallow saline groundwater system, Cooper Creek floodplain, Queensland, Australia, J. Hydrol., 392, 150–163, 2010.

Cendón, D. I., Hankin, S. I., Williams, J. P., van der Ley, M., Peterson, M., Hughes, C. E., Meredith, K. T., Hollins, S. E., Graham, I. T., Chisari, R., Wong, H., and Levchenko, V.: Groundwater residence time in a dissected and weathered sandstone plateau: Kulnura – Mangrove Mountain aquifer, NSW, Australia: Aust. J. Earth Sci., 61, 475–499, 2014.

Clark, I. D. and Fritz, P.: Environmental Isotopes in Hydrogeology, Lewis Publishers, New York, USA, 1997.

Costelloe, J. F., Irvine, E. C., Western, A. W., and Tyler, M.: Identifying fluvial recharge and artesian upwards leakage contributions to arid zone shallow, unconfined groundwater, Chem. Geol., 326–327, 189–200, <a href="http://dx.doi.org/10.1016/j.chemgeo.2012.08.014">https://doi.org/10.1016/j.chemgeo.2012.08.014</a>, 2012.

Cox, M. E., James, A., Hawke, A., and Raiber, M.: Groundwater Visualisation System (GVS): a software framework for integrated display and interrogation of conceptual hydrogeological models, data and time-series animation, J. Hydrol., 491, 56–72, <a href="http://dx.doi.org/10.1016/j.jhydrol.2013.03.023">https://doi.org/10.1016/j.jhydrol.2013.03.023</a>, 2013.

Cranfield, L. C., Donchak, P. J. T., Randall, R. E., and Crosby, G. C.: Yarraman Special 1: 250 000 Geology, Queensland, Department of Natural Resources and Mines, Brisbane, Australia, 2001.

Crosbie, R. S., Morrow, D., Cresswell, R. G., Leaney, F. W., Lamontagne, S., and Lefournour, M.: New insights into the chemical and isotopic composition of rainfall across Australia, CSIRO Water for a Healthy Country Flagship, Australia, 2012.

Dawes, W., Ali, R., Varma, S., Emelyanova, I., Hodgson, G., and McFarlane, D.: Modelling the effects of climate and land cover change on groundwater recharge in south-west Western Australia, Hydrol. Earth Syst. Sci., 16, 2709–2722, <a href="http://dx.doi.org/10.5194/hess-16-2709-2012">https://doi.org/10.5194/hess-16-2709-2012</a>, 2012.

Department of Natural Resources and Mines – DNRM: Department of Natural Resources and Mines, Groundwater Database, Brisbane, Australia, 2012.

Department of Natural Resources and Mines, available at: <a href="http://watermonitoring.derm.qld.gov.au/host.htm">http://watermonitoring.derm.qld.gov.au/host.htm</a>, last access: 8 October 2013.

Dia, A. N., Cohen, A. S., O'Nions, R. K., and Shackleton, N. J.: Seawater Sr isotope variation over the past 300 kyr and influence of global climate cycles, Nature, 356, 786–788, <a href="http://dx.doi.org/10.1038/356786a0">https://doi.org/10.1038/356786a0</a>, 1992.

Dogramaci, S. S. and Herczeg, A. L.: Strontium and carbon isotope constraints on carbonate-solution interactions and inter-aquifer mixing in groundwaters of the semi-arid Murray Basin, Australia, J. Hydrol., 262, 50–67, <a href="http://dx.doi.org/10.1016/s0022-1694(02)00021-5">https://doi.org/10.1016/s0022-1694(02)00021-5</a>, 2002.

Dogramaci, S. S., Skrzypek, G., Dodson, W., and Grierson, P. F.: Stable isotope and hydrochemical evolution of groundwater in the semi-arid Hamersley Basin of subtropical northwest Australia, J. Hydrol., 475, 281–293, <a href="http://dx.doi.org/10.1016/j.jhydrol.2012.10.004">https://doi.org/10.1016/j.jhydrol.2012.10.004</a>, 2012.

Douglas, G., Palmer, M., Caitcheon, G., and Orr, P.: Identification of sediment sources to LakeWivenhoe, south-east Queensland, Australia, Mar. Freshwater Res., 58, 793–810, 2007.

Drever, J. I.: The geochemistry of natural waters, surface and groundwaterenvironments, 3rd Edn., Prentice-Hall Inc., New Jersey, USA, 1997.

Fink, D., Hotchkis, M., Hua, Q., Jacobsen, G., Smith, A. M., Zoppi, U., Child, D., Mifsud, C., van der Gaast, H., Williams, A., and Williams, M.: The ANTARES AMS facility at ANSTO, Nucl. Instrum. Meth. B, 223, 109–115, <a href="http://dx.doi.org/10.1016/j.nimb.2004.04.025">https://doi.org/10.1016/j.nimb.2004.04.025</a>, 2004.

Fritz, B., Richard, L., and McNutt, R. H.: Geochemical modeling of Sr isotopic signatures in the interaction between granitic-rocks and natural solutions, in: Water-Rock Interaction, Rotterdam, the Netherlands, 927–930, 1992.

Geological Survey of Queensland and Irrigation and Water Supply Commission (GSQ and IWSC): Groundwater Resources of Queensland: Explanatory Notes, 1:2 500 000 Map, 1973.

Gleeson, T., Novakowski, K., and Kyser, K.: Extremely rapid and localized recharge to a fractured rock aquifer, J. Hydrol., 376, 496–509, 2009.

Green, T. R., Taniguchi, M., Kooi, H., Gurdak, J. J., Allen, D. M., Hiscock, K. M., Treidel, H., and Aureli, A.: Beneath the surface of global change: impacts of climate change on groundwater, J. Hydrol., 405, 532–560, <a href="http://dx.doi.org/10.1016/j.jhydrol.2011.05.002">https://doi.org/10.1016/j.jhydrol.2011.05.002</a>, 2011.

Hagedorn, B., Cartwright, I., Raveggi, M., and Maas, R.: Rare earth element and strontium geochemistry of the Australian Victorian Alps drainage system: evaluating the dominance of carbonate vs. aluminosilicate weathering under varying runoff, Chem. Geol., 284, 105–126, <a href="http://dx.doi.org/10.1016/j.chemgeo.2011.02.013">https://doi.org/10.1016/j.chemgeo.2011.02.013</a>, 2011.

Hancock, P. J., Boulton, A. J., and Humphreys, W. F.: Aquifers and hyporheic zones: towards an ecological understanding of groundwater, Hydrogeol. J., 13, 98–111, <a href="http://dx.doi.org/10.1007/s10040-004-0421-6">https://doi.org/10.1007/s10040-004-0421-6</a>, 2005.

Harms, B. P. and Pointon, S. M.: Land resource assessment of the Brisbane Valley, Queensland, Department of Natural Resources, Brisbane, Australia, 1999.

Hattersley, P. W.: The distribution of C3 and C4 grasses in Australia in relation to climate, Oceologia (Berlin), 57, 113–128, 1983.

Hrachowitz, M., Bohte, R., Mul, M. L., Bogaard, T. A., Savenije, H. H. G., and Uhlenbrook, S.: On the value of combined event runoff and tracer analysis to improve understanding of catchment functioning in a data-scarce semi-arid area, Hydrol. Earth Syst. Sci., 15, 2007–2024, <a href="http://dx.doi.org/10.5194/hess-15-2007-2011">https://doi.org/10.5194/hess-15-2007-2011</a>, 2011.

Hughes, C. E. and Crawford, J.: A new precipitation weighted method for determining the meteoric water line for hydrological applications demonstrated using Australian and global GNIP data, J. Hydrol., 464–465, 344–351, 2012.

Hughes, C. E. and Crawford, J.: Spatial and temporal variation in precipication isotopes in the Sydney Basin, Australia, J. Hydrol. 489, 42–55, 2013.

Hughes, C. E., Cendón, D. I., Johansen, M. P., and Meredith, K. T.: Climate change and groundwater, sustaining groundwater resources, in: Sustaining Groundwater Resources, edited by: Jones, J. J. A., Springer Netherlands, 2011.

Hvorslev, M. J.: Time lag and soil permeability in ground water observations, US Army Corps of Engineers Waterways EXP. STa. Bulletin 36, 1951.

International Atomic Energy Agency and the World Meteorological Organization (IAEA/WMO): Global Network of Isotopes in Precipitation, available at: <a href="http://www-naweb.iaea.org/napc/ih/IHS_resources_gnip.html">http://www-naweb.iaea.org/napc/ih/IHS_resources_gnip.html</a>, last access: 2014.

King, A., Raiber, M., and Cox, M.: Multivariate statistical analysis of hydrochemical data to assess stream-alluvial aquifer connectivity during flood and drought: Cressbrook Creek, southeast Queensland, Australia, Hydrogeol. J., 22, 481–500, <a href="http://dx.doi.org/10.1007/s10040-013-1057-1">https://doi.org/10.1007/s10040-013-1057-1</a>, 2014.

Kirchner, J. W., Tetzlaff, D., and Soulsby, C.: Comparing chloride and water isotopes as hydrological tracers in two Scottish catchments, Hydrol. Process., 24, 1631–1645, <a href="http://dx.doi.org/10.1002/hyp.7676">https://doi.org/10.1002/hyp.7676</a>, 2010.

Knighton, A. D. and Nanson, G. C.: Waterhole form and process in the anastomosing channel system of Cooper Creek, Australia, Geomorphology, 35, 101–117, <a href="http://dx.doi.org/10.1016/s0169-555x(00)00026-x">https://doi.org/10.1016/s0169-555x(00)00026-x</a>, 2000.

Kumar, U. S., Sharma, S., Navada, S. V., and Deodhar, A. S.: Environmental isotopes investigation on recharge processes and hydrodynamics of the coastal sedimentary aquifers of Tiruvadanai, Tamilnadu State, India, J. Hydrol., 364, 23–39, <a href="http://dx.doi.org/10.1016/j.jhydrol.2008.10.004">https://doi.org/10.1016/j.jhydrol.2008.10.004</a>, 2009.

Lange, J.: Dynamics of transmission losses in a large and stream channel, J. Hydrol., 306, 112–126, <a href="http://dx.doi.org/10.1016/j.jhydrol.2004.09.016">https://doi.org/10.1016/j.jhydrol.2004.09.016</a>, 2005.

Leybourne, M. I., Clark, I. D., and Goodfellow, W. D.: Stable isotope geochemistry of ground and surface waters associated with undisturbed massive sulfide deposits; constraints on origin of waters and water–rock reactions, Chem. Geol., 231, 300–325, 2006.

Lis, G., Wassenaar, L. I., and Hendry, M. J.: High-precision laser spectroscopy D/H and 18O/16O measurements of microliter natural water samples, Anal. Chem., 80, 287–293, <a href="http://dx.doi.org/10.1021/ac701716q">https://doi.org/10.1021/ac701716q</a>, 2008.

Liu, J., Fu, G., Song, X., Charles, S. P., Zhang, Y., Han, D., and Wang, S.: Stable isotopic compositions in Australian precipitation, J. Geophys. Res., 115, D23307, <a href="http://dx.doi.org/10.1029/2010JD014403">https://doi.org/10.1029/2010JD014403</a>, 2010.

Made, B. and Fritz, B.: Simulation of granite dissolution at 25, 60 and 100 degrees C based on thermodynamic potential and kinetic laws, in: Water-Rock Interaction, Edmonton, 461–464, 1989.

Mandal, A. K., Zhang, J., and Asai, K.: Stable isotopic and geochemical data for inferring sources of recharge and groundwater flow on the volcanic island of Rishiri, Japan, Appl. Geochem., 26, 1741–1751, 2011.

Maroulis, J. C., Nanson, G. C., Price, D. M., and Pietsch, T.: Aeolian-fluvial interaction and climate change: source-bordering dune development over the past similar to 100 ka on Cooper Creek, central Australia, Quaternary Sci. Rev., 26, 386–404, <a href="http://dx.doi.org/10.1016/j.quascirev.2006.08.010">https://doi.org/10.1016/j.quascirev.2006.08.010</a>, 2007.

Mast, M. A., Drever, J. I., and Baron, J. S.: Chemical weathering in the Loch Vale Watershed, Rocky Mountain National Park, Colorado, Water Resour. Res., 26, 2971–2978, 1990.

McNutt, R. H.: Strontium isotopes, in: Environmental Tracers in Subsurface Hydrology, edited by: Cook, P. G. and Herczeg, A. L., Kluwer Academic Publishers, Boston, MA, USA, 233–261, 2000.

Morgenstern, U. and Daughney, C. J.: Groundwater age for identification of baseline groundwater quality and impacts of land-use intensification – the National Groundwater Monitoring Programme of New Zealand, J. Hydrol., 456, 79–93, <a href="http://dx.doi.org/10.1016/j.jhydrol.2012.06.010">https://doi.org/10.1016/j.jhydrol.2012.06.010</a>, 2012.

Morgenstern, U., Stewart, M. K., and Stenger, R.: Dating of streamwater using tritium in a post nuclear bomb pulse world: continuous variation of mean transit time with streamflow, Hydrol. Earth Syst. Sci., 14, 2289–2301, <a href="http://dx.doi.org/10.5194/hess-14-2289-2010">https://doi.org/10.5194/hess-14-2289-2010</a>, 2010.

Nanson, G. C., Price, D. M., Jones, B. G., Maroulis, J. C., Coleman, M., Bowman, H., Cohen, T. J., Pietsch, T. J., and Larsen, J. R.: Alluvial evidence for major climate and flow regime changes during the middle and late Quaternary in eastern central Australia, Geomorphology, 101, 109–129, <a href="http://dx.doi.org/10.1016/j.geomorph.2008.05.032">https://doi.org/10.1016/j.geomorph.2008.05.032</a>, 2008.

Négrel, P. and Petelet-Giraud, E.: Strontium isotopes as tracers of groundwater-induced floods: the Somme case study (France), J. Hydrol., 305, 99–119, 2005.

Parkhurst, D. L. and Appelo, C. A. J.: User's guide to PHREEQC (version 2); a computer program for speciation, batch-reaction, one-dimensional transport, and inverse geochemical calculations, Water-Resources Investigations – US Geological Survey, US Geological Survey, Reston, VA, USA, 312 pp., 1999.

Parry, M. L., Canziani, O. F., Palutikof, J. P., van der Linden, P. J., and Hanson, C. E. (Eds.): Contribution of Working Group II to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Cambridge University Press, Cambridge, UK and New York, NY, USA, 2007.

Plummer, L. N. and Glynn, P. D.: Radiocarbon dating in groundwater systems, in: Isotope Methods for Dating Old Groundwater, International Atomic Energy Agency (IAEA), Vienna, 33–90, 2013.

Praamsma, T., Novakowski, K., Kyser, K., and Hall, K.: Using stable isotopes and hydraulic head data to investigate groundwater recharge and discharge in a fractured rock aquifer, J. Hydrol., 366, 35–45, 2009.

Raiber, M., Webb, J. A., and Bennetts, D. A.: Strontium isotopes as tracers to delineate aquifer interactions and the influence of rainfall in the basalt plains of southeastern Australia, J. Hydrol., 367, 188–199, 2009.

Richards, H. G., Savage, D., and Andrews, J. N.: Granite water reactions in an experimental hot dry rock geothermal reservoir, Rosemanowes test site, Cornwall, UK, Appl. Geochem., 7, 193–222, <a href="http://dx.doi.org/10.1016/0883-2927(92)90038-5">https://doi.org/10.1016/0883-2927(92)90038-5</a>, 1992.

Rozanski, K., Araguas-Araguas, L., and Gonfiantini, R.: Isotopic patterns in modern global precipitation, Climate Change in Continental Isotopic Records, edited by: Swart, P. K., Lohmann, J., McKenzie, J., and Savin, S., American Geophysical Union, Geophysical Monograph 78, 1993.

Rushton, K. R. and Tomlinson, L. M.: Possible mechanisms for leakage between aquifers and rivers, J. Hydrol., 40, 49–65, 1979.

Scholl, M. Christenson, S., Cozzarelli, I. Ferree, D., and Jaeschke, J.: Recharge Processes in an Alluvial Aquifer Riparian Zone, Norman Landfill, Norman, Oklahoma, 1998–2000, Scientific Investigations Report 2004-5238, US Department of the Interior, US Geological Survey, 2004.

Simpson, S. C. and Meixner, T.: Modeling effects of floods on streambed hydraulic conductivity and groundwater-surface water interactions, Water Resour. Res., 48, W02515, <a href="http://dx.doi.org/10.1029/2011wr011022">https://doi.org/10.1029/2011wr011022</a>, 2012.

Simpson, S. C., Meixner, T., and Hogan, J. F.: The role of flood size and duration on streamflow and riparian ground water composition in a semi-arid basin, J. Hydrol., 488, 126–135, <a href="http://dx.doi.org/10.1016/j.jhydrol.2013.02.049">https://doi.org/10.1016/j.jhydrol.2013.02.049</a>, 2013.

Siwek, J. P., Zelazny, M., and Chemicki, W.: Influence of catchment characteristics and flood type on relationship between streamwater chemistry and streamflow: case study from Carpathian foothills in Poland, Water Air Soil Poll., 214, 547–563, <a href="http://dx.doi.org/10.1007/s11270-010-0445-6">https://doi.org/10.1007/s11270-010-0445-6</a>, 2011.

Soulsby, C., Tetzlaff, D., van den Bedem, N., Malcolm, I. A., Bacon, P. J., Youngson, A. F.: Inferring groundwater influences on surface water in montane catchments from hydrochemical surveys of springs and streamwaters, J. Hydrol., 333, 199–213, 2007.

Stuiver, M. and Polach, A.: Reporting of 14C data, Radiocarbon, 19, 355–363, 1977.

Tadros, C. V., Hughes, C. E., Crawford, J., Hollins, S. E., and Chisari, R.: Tritium in Australian precipitation: A 50 year record, J. Hydrol., 513, 262–273, 2014.

Toowoomba Regional Council: Unpublished Data, c/o David Frizzell, July 2012, 2012.

Toowoomba Regional Council, Cressbrook Dam: <a href="http://www.toowoombarc.qld.gov.au/environment-and-waste/water-supply-and-dams/dams-a-bores/toowoomba-bulk-water/5311-cressbrook-dam">http://www.toowoombarc.qld.gov.au/environment-and-waste/water-supply-and-dams/dams-a-bores/toowoomba-bulk-water/5311-cressbrook-dam</a>, last access: 8 January 2014.

Ullman, W. J. and Collerson, K. D.: The Sr-isotope record of late quaternary hydrologic changes around Lake Frome, South Australia, J. Earth Sci., 41, 37–45, 2014.

Vanderzalm, J. L., Jeuken, B. M., Wischusen, J. D. H., Pavelic, P., Le Gal La Salle, C., Knapton, A., and Dillon, P. J.: Recharge sources and hydrogeochemical evolution of groundwater in alluvial basins in arid central Australia, J. Hydrol., 397, 71–82, <a href="http://dx.doi.org/10.1016/j.jhydrol.2010.11.035">https://doi.org/10.1016/j.jhydrol.2010.11.035</a>, 2011.

Winter, T. C., Harvey, J. W., Franke, O. L., and Alley, W. M.: Ground water and surface water, a single resource, US Geological Survey Circular 1139, US Geological Survey, Denver, USA, 1998.

Workman, S. R. and Serrano, S. E.: Recharge to alluvial valley aquifers from overbank flow and excess infiltration, J. Am. Water Resour. As., 35, 425–432, <a href="http://dx.doi.org/10.1111/j.1752-1688.1999.tb03600.x">https://doi.org/10.1111/j.1752-1688.1999.tb03600.x</a>, 1999.

Zahawi, Z.: Cressbrook Creek Damsites, Record 1972/33, Department of Mines, Geological Survey of Queensland, 1972.

Zhu, G. F., Li, Z. Z., Su, Y. H., Ma, J. Z., and Zhang, Y. Y.: Hydrogeochemical and isotope evidence of groundwater evolution and recharge in Minqin Basin, Northwest China, J. Hydrol. 333, 239–251, 2007.