Author: Phanumat Kullaboot
Kullaboot, Phanumat, 2025 Groundwater-Surface water interactions: models to improve understanding of processes and dynamics in Baroota Creek, SA, Flinders University, College of Science and Engineering
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Understanding streamflow generation in non-perennial rivers remains limited due to sparse data and the complexity of unsaturated and transient flow processes. This study contributes to address this gap by demonstrating how environmental flow released from the Baroota Reservoir influences groundwater and surface water (GW-SW) interactions in the Baroota Creek. Through a combination of field-based streamflow gauging and numerical modelling, the research characterised GW–SW interactions along a 3,450 m section of the creek. The study explored the efficiency of using a simplified surrogate model to accelerate simulation based on field hydrologic data collected at seven stream reaches. The results showed that there was high infiltration at the upstream reaches where coarse sediments, such as gravel and coarse sand, contribute to higher streambed hydraulic conductivity. In contrast, at the downstream reaches, which has finer sediments and lower creek bed elevation gradient, contributed to lower infiltration. The simplification of stream geometry and poorly constrained estimates of streambed hydraulic conductivity likely underestimate wetted perimeters and infiltration rates. Despite using a simplified conceptual model, the numerical model effectively captured spatial variability in surface water infiltration along the study reach. Overall, the study provides an initial step towards evaluating the success of managed flow releases intended to support riparian ecosystems. In particular, the benefits of environmental flows contributing to the River Red Gum woodland can reflect the biodiversity along these non-perennial river systems. Our findings have broader relevance for culturally inclusive water planning that aligns ecological restoration with First Nation values.
Keywords: Groundwater-surface water interaction, groundwater modelling, MODFLOW, ephemeral streams, groundwater recharge, infiltration
Subject: Hydrology thesis
Thesis type: Masters
Completed: 2025
School: College of Science and Engineering
Supervisor: Eddie Banks