Satellite-based estimation of total suspended solids and chlorophyll-a concentrations for the Gold Coast Broadwater, Australia

• Published in: Marine pollution bulletin 2024-04, Vol.201, p.116217-116217, Article 116217
• Main Authors: Bertone, Edoardo, Ajmar, Andrea, Tonolo, Fabio Giulio, Dunn, Ryan J.K., Doriean, Nicholas J.C., Bennett, William W., Purandare, Jemma
• Format: Article
• Language: English
• Subjects: Chlorophyll-a; Empirical modelling; Remote sensing; Total suspended solids; Water quality
• ISSN: 0025-326X; 1879-3363
• DOI: 10.1016/j.marpolbul.2024.116217

Satellite retrieval of total suspended solids (TSS) and chlorophyll-a (chl-a) was performed for the Gold Coast Broadwater, a micro-tidal estuarine lagoon draining a highly developed urban catchment area with complex and competing land uses. Due to the different water quality properties of the rivers and creeks draining into the Broadwater, sampling sites were grouped in clusters, with cluster-specific empirical/semi-empirical prediction models developed and validated with a leave-one-out cross validation approach for robustness. For unsampled locations, a weighted-average approach, based on their proximity to sampled sites, was developed. Confidence intervals were also generated, with a bootstrapping approach and visualised through maps. Models yielded varying accuracies (R2 = 0.40–0.75). Results show that, for the most significant poor water quality event in the dataset, caused by summer rainfall events, elevated TSS concentrations originated in the northern rivers, slowly spreading southward. Conversely, high chl-a concentrations were first recorded in the southernmost regions of the Broadwater. •Chl-a and TSS predicted for large estuarine lagoon from satellite data•Empirical models for clusters of sampling sites•Distance-specific weighted average prediction for unsampled sites•Bootstrapping approach for confidence intervals generation and visualisation•TSS originating from Northern rivers, chl-a in southern region during wet periods