Integrating physical hydrogeology, hydrochemistry, and environmental isotopes to constrain regional groundwater flow: southern Riverine Province, Murray Basin, Australia
Cartwright, Ian, Weaver, Tamie R., and Tweed, Sarah O. (2008) Integrating physical hydrogeology, hydrochemistry, and environmental isotopes to constrain regional groundwater flow: southern Riverine Province, Murray Basin, Australia. In: Carrillo-Rivera, J. Joel, and Ortega-Guerrero, M. Adrian, (eds.) Groundwater Flow Understanding: from local to regional scale. IAH - Selected Papers on Hydrogeology, 12 . Taylor & Francis, London, UK, pp. 105-133.
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The hydrochemistry of groundwater in the southern Riverine Province orthe Murray Basin is controlled largely by evapotranspiration with minor halite, silicate, carbonate, and gypsum dissolution. Groundwater salinity is highly variable (total dissovled solids, TDS, contents < 100 to - 50, 000 mgL -1) and controlled by recharge rates. In the palaeovalleys of past streams ("deep leads") more rapid recharge through coarser-grained sediments of the unconfined Shepparton Formation produces lower salinity groundwater in both shallow and deeper aquifers. Away from the deep leads, recharge rates are slower through the more clay-rich Shepparton Fonnation sediments. The distribution of salinity, trends in major ion and stable isotope ratios, and the distribution of percent modern carbon contents imply that groundwater now in the southern Riverine Province is locally complex. Vertical flow occurs within the Shepparton Formation. In the deep leads, there is significant lateral flow in the deeper Calivil-Renmark Formation, while in the intennediatc areas, there is much greater relative vertical leakage through the Shepparton Fonnation into the Calivil-Renmark Formation. Despite nearsuriace processes largely controlling groundwater chemistry, and climate in southeast Australia varying over the last 25-30 ka, there is little difference in chemistry between the older deeper groundwater of the Calivil-Rerunark Formation and younger shallower groundwater from the Shepparton Formation. Recent land clearing has increased recharge causing the water table to rise. Long term this may result in the groundwater in the Murray Basin becoming less saline, although in the short-term the rise of pre-existing saline water towards lhe surface represents a major envirorunental problem.
|Item Type:||Book Chapter (Research - B1)|
|Keywords:||groundwater; geochemistry; Murray Basin; environmental isotopes; 14-C|
|Date Deposited:||08 May 2010 02:43|
|FoR Codes:||04 EARTH SCIENCES > 0406 Physical Geography and Environmental Geoscience > 040603 Hydrogeology @ 100%|
|SEO Codes:||96 ENVIRONMENT > 9609 Land and Water Management > 960999 Land and Water Management of Environments not elsewhere classified @ 100%|