Integrating Real-Time Monitoring and 3D Hydrodynamic Modeling to Assess Tidal Impacts on Water Quality in a Mangrove-Influenced Aquaculture Zone in Central Sulawesi, Indonesia

Understanding how tidal fluctuations affect water quality in estuarine and mangrove-influenced aquaculture zones is essential for healthy and productive ponds. This study investigated how key water quality parameters respond to tidal changes in the Tanah Mea estuary, Central Sulawesi, Indonesia. A PC-based real-time Water Quality Monitoring System (WQMS) and IoT sensors were deployed in situ to record high-frequency data, while OpenFlows Flood software was used to simulate the spatial distribution of temperature, salinity, nitrite, and dissolved oxygen (DO) during the tidal cycles. Correlation analyses (Pearson and Spearman, corrected for autocorrelation) were employed to quantify the relationship between water level and each measured parameter. Continuous monitoring from March to April 2025 yielded 9,537 valid observations. The results showed strong inverse correlations between tidal height and both pH and DO, with weaker relationships for nitrite, temperature, and salinity, while EC exhibited minimal correlation with tides. Spatial simulations indicated clear gradients of DO and salinity from upstream to open waters, with dilution and oxygenation improving further from the estuary. However, DO values from WQMS did not fully align with modeled patterns. Tidal dynamics play a key role in shaping estuarine water quality. Integrating real-time monitoring and 3D modeling provides complementary insights and supports practical recommendations for sustainable aquaculture, specifically scheduling pond water intake shortly after low tide to maximize DO and minimize nitrite levels.