Continuous Interannual Monitoring of Artificial and Natural Breachings of an Intermittently Open/Closed Estuary in Central Chile

Abstract We present the analysis of continuous remotely sensed data (hourly collections of high-resolution daytime videos) of the Nilahue Intermittently Open/Closed Estuary (IOCE) on the central Chilean Pacific seaboard (34.48°S, 72.00°W). Videos are automatically processed on-the-fly using state-of-the-art Artificial Intelligence algorithms to produce time series of river mouth metrics, which, in combination with measured and modeled hydrological (rainfall, river discharge, lagoon water level), oceanographic (tides and waves), and environmental (salinity) variables, provide unprecedented insights for understanding, diagnosing, and forecasting multi-scale processes in these fragile and rapidly evolving ecosystems. The initial analyses cover a time frame from April 2023 to November 2024, spanning two complete winter seasons and one summer. In particular, during 2023, significant rainfall associated with the El Niño/Southern Oscillation (ENSO) led to extreme flooding and a complete river mouth opening and reset, allowing us to track the subsequent morphodynamical processes and gradual closure of the mouth. In this talk, we also report on periods of artificial openings during spring-summer-autumn (December to April), summarizing the different conditions and outcomes. Based on the captured data and analysis, we discuss the possibilities of building physics-based and data-driven forecasting capabilities to understand lagoon functioning and, from there, provide guidance for IOCE management to ensure their ecological integrity amidst uncertain environmental changes.