Geological permeability controls streamflow generation in a remote, ungauged, semi-arid drainage system

A semi-arid drainage system overlying a thick (12 km) sedimentary sequence on the Dampier Peninsula in northwestern Australia. In this study we combine aerial geophysics, geological mapping, hydrometry and hydrochemistry with aerial image analysis and stream mass balance modeling to delineate the ke...

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Bibliographic Details
Published in:	Journal of hydrology. Regional studies Vol. 38; p. 100956
Main Authors:	Bourke, Sarah A., Degens, Bradley, Searle, Josephine, de Castro Tayer, Thiaggo, Rothery, Jasmin
Format:	Journal Article
Language:	English
Published:	Elsevier B.V 01-12-2021 Elsevier
Subjects:	Ephemeral stream Intermittent river Non-perennial streams Spring mechanisms Surface water - groundwater interaction Surface water - groundwater interaction Spring mechanisms Ephemeral stream Intermittent river Non-perennial streams
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Summary:	A semi-arid drainage system overlying a thick (12 km) sedimentary sequence on the Dampier Peninsula in northwestern Australia. In this study we combine aerial geophysics, geological mapping, hydrometry and hydrochemistry with aerial image analysis and stream mass balance modeling to delineate the key hydrogeological structures and processes that control streamflow generation within a remote ungauged semi-arid watershed. Four distinct processes of streamflow generation were identified, each dependent on the spatial distribution of lithological permeability; (1) ephemeral rainfall runoff over low-permeability surface lithologies, (2) intermittent flow generated by seasonal groundwater discharge from the unconfined aquifer above a newly mapped clay layer, (3) persistent flow from contact springs via interbedded high- and low-permeability layers, and (4) perennial flow associated with regional groundwater discharge at headwater springs. This study highlights the importance of geological permeability and the resultant hydrogeological processes as controls on streamflow generation, particularly in low-relief and arid regions where topography is less likely to determine the distribution of streamflow. •Streamflow generation is controlled by geological permeability.•Four streamflow generation mechanisms exist across spatiotemporal scales.•Ephemeral, intermittent, persistent and perennial flow are identified.•Hydrogeological system determines the distribution and sources of streamflow.
ISSN:	2214-5818 2214-5818
DOI:	10.1016/j.ejrh.2021.100956