Informations et ressources scientifiques
sur le développement des zones arides et semi-arides

Accueil du site → Doctorat → Australie → Hydrogeology, Conceptual Model and Groundwater Flow Within Alluvial Aquifers of the Tenthill and Ma Ma Catchments, Lockyer Valley, Queensland

Queensland University of Technology (2005)

Hydrogeology, Conceptual Model and Groundwater Flow Within Alluvial Aquifers of the Tenthill and Ma Ma Catchments, Lockyer Valley, Queensland

Wilson, Andrew Scott

Titre : Hydrogeology, Conceptual Model and Groundwater Flow Within Alluvial Aquifers of the Tenthill and Ma Ma Catchments, Lockyer Valley, Queensland

Auteur : Wilson, Andrew Scott

Université de soutenance : Queensland University of Technology.

Grade : Doctor of Philosophy PhD 2005

Résumé partiel
The study focuses on the adjacent Tenthill and Ma Ma catchments which converge onto the heavily cultivated alluvial plain of Lockyer Creek. Groundwater extracted from the alluvial aquifers is the primary source of water for intensive irrigation. Within the study the hydrogeology is investigated, a conceptual groundwater model produced and a numerical groundwater flow model is developed from this. The hydrochemistry and stable isotope character of groundwater are also investigated to determine processes such as recharge and evaporation. Examination of bore logs confirms the Quaternary alluvium comprises a laterally continuous gravel aquifer with an average thickness of 4.5 m, overlain by mixed sands and clays which form a semi-confining layer with an average thickness of 22 m. Variations in long term groundwater hydrographs indicate the aquifer changes from confined to unconfined in some locations as water levels drop, while bores adjacent to creek banks display a rapid response to a flood event. Pump testing of bores screened in the gravel produces estimates of hydraulic conductivity ranging from 50-80 m/day and storativity of 0.00166 which are both within realistic bounds for this aquifer material. Major ion chemistry of surface water collected during a flood is Mgdominated, similar to alluvial groundwater in the Tenthill catchment and the Lockyer plain, suggesting a strong connection between surface and groundwater in these locations. Alluvial groundwater salinity in Tenthill catchment is typically less than 3500 ìS/cm but may approach 6000ìS/cm on the Lockyer plain. By contrast Ma Ma catchment alluvial groundwater is Na-dominated with conductivity up to 12000 ìS/cm and more associated with groundwater from the underlying sandstone bedrock. Stable isotope analyses of alluvial groundwater from throughout both catchments and the Lockyer plain are compared with basalt and sandstone groundwater.

Mots clés : hydrogeology • conceptual model • groundwater • alluvial aquifers • Lockyer Valley • Queensland

Présentation

Texte intégral

Page publiée le 5 mars 2006, mise à jour le 16 juillet 2017