“Unflushed: The Hidden Flow That’s Killing Our Coastline”
White Paper: “Coastal Collapse: The Engineering Hypothesis We Can’t Ignore”
Nutrient Overload, Ocean Physics, and Environmental Risk in South Australia
Executive Summary
South Australia's coastal ecosystems may be subject to a significant environmental transport mechanism that is currently under-acknowledged in marine planning. This white paper presents a technically grounded engineering hypothesis — that dense, nutrient-rich outflows from Spencer Gulf are not dispersing freely into the Southern Ocean but are being redirected by regional current structures and topography into a concentrated coastal transport pathway.
Drawing from core fluid dynamics principles, ocean current data, and regional bathymetry, the paper explores how the interaction between the Spencer Gulf Outflow (SGO), the Leeuwin Current (LC), and Kangaroo Island may result in nutrient accumulation in downstream systems such as Gulf St Vincent and the Murray Mouth. Observed environmental events, including the June 2025 marine die-offs and toxic algal blooms, are consistent with the outcomes predicted by this mechanism.
This document does not assert definitive causality but identifies a scientifically plausible process that warrants further investigation through hydrodynamic modelling and empirical validation.