Hybrid approaches to model salinity in Gatun Lake

Gatun Lake, located in central Panama, is the main source of freshwater for the operations of the Panama Canal. It also provides drinking water for nearly 600,000 people which is about 15% of Panama’s population. Historically, the lake has maintained a salinity well below 0.1 PSU, but since the inauguration of the Neo-Panamax locks in 2016, salinity in the lake has rapidly increased. This is a concern not only for drinking water supply and human health but for biodiversity as well. Accurately modelling salinity concentration and transport mechanisms in Gatun Lake is crucial for understanding its response to climate change and anthropogenic activities and to design effective management and mitigation strategies. However, current modelling techniques, both process-based (PB) and data-driven (DD), are limited in their ability to provide fast and accurate results with small amounts of data, especially in situations when boundary conditions are unknown or uncertain. Therefore, hybrid models have emerged as a potential solution to bridge the gap between these two approaches. The work presented here explores hybrid modelling approaches to estimate the magnitude of saltwater intrusion through the Neo-Panamax locks and calculate a salinity mass balance for Gatun Lake. Understanding these processes is useful for personnel at the Panama Canal Authority as it will inform their decision-making regarding management of Gatun Lake’s water quality and quantity.