Constraining the response of continental‐scale groundwater flow to climate change

Constraining the response of continental‐scale groundwater flow to climate change

Authors: Ben MatherDietmar MüllerCraig O’NeillAdam BeallWillem VervoortLouis Moresi

Uploaded by: Ben Mather

Upload date: August 28, 2023

Abstract

Numerical models of groundwater flow play a critical role for water management scenarios under climate extremes. Large-scale models play a key role in determining long range flow pathways from continental interiors to the oceans, yet struggle to simulate the local flow patterns ofered by small-scale models. We have developed a highly scalable numerical framework to model continental groundwater flow which capture the intricate flow pathways between deep aquifers and the near-surface. The coupled thermal-hydraulic basin structure is inferred from hydraulic head measurements, recharge estimates from geochemical proxies, and borehole temperature data using a Bayesian framework. We use it to model the deep groundwater flow beneath the Sydney–Gunnedah–Bowen Basin, part of Australia’s largest aquifer system. Coastal aquifers have flow rates of up to 0.3 m/ day, and a corresponding groundwater residence time of just 2,000 years. In contrast, our model predicts slow flow rates of 0.005 m/day for inland aquifers, resulting in a groundwater residence time of ∼400,000 years. Perturbing the model to account for a drop in borehole water levels since 2000, we fnd that lengthened inland flow pathways depart signifcantly from pre-2000 streamlines as groundwater is drawn further from recharge zones in a drying climate. Our results illustrate that progressively increasing water extraction from inland aquifers may permanently alter long-range flow pathways. Our open-source modelling approach can be extended to any basin and may help inform policies on the sustainable management of groundwater.

Publication

DOI10.1038/s41598-022-08384-w
Mather, B., Müller, R. D., O’Neill, C., Beall, A., Vervoort, R. W., & Moresi, L. (2022). Constraining the response of continental-scale groundwater flow to climate change. Scientific Reports, 12(1). DOI: 10.1038/s41598-022-08384-w

Tags

Climate ChangeDarcyPythonbasinsgroundwater

Graphic abstract

Graphic abstract | Constraining the response of continental‐scale groundwater flow to climate change