## 1 Introduction
### Applications of the HEC-RAS Model  
HEC-RAS 2D (version 6.6), developed by the U.S. Army Corps of Engineers Hydroologic Engineering Center [24], is widely recognized as a robust tool for hydrodynamic modeling. This software has gained significant traction in simulating various surface flow conditions, ranging from riverine channel flows to floodplain inundation, rainfall-runoff processes in catchment areas, and even tsunami propagation [25]. Its numerical capabilities, including both full momentum and diffusion wave formulations of the shallow water equations, allow for the accurate representation of flow complexities in diverse hydraulic environments [26].  
The application of HEC-RAS 2D in riverine channel flow modeling is well established, particularly in steady and unsteady flow simulations, flood hazard mapping, and urban drainage system analysis [27; 28]. Studies have demonstrated its effectiveness in flood risk assessments, such as in Palembang [29] and the Oueme Basin [30], where the model has been instrumental in predicting inundation extents and hydrodynamic behavior. Its capabilities extend to simulating rainfall-runoff interactions in small basins, as seen in Scuropasso, Italy, where the model was validated for discharge hydrograph computation [26]. Beyond riverine applications, HEC-RAS 2D has proven to be effective in simulating floodplain dynamics and extreme hydrological events. Floodplain mapping applications, such as those in Wajo Regency and the Veseocica River [31; 32], have demonstrated its ability to capture complex flow interactions in urban and rural settings. The model has also been used to integrate hydrological and hydraulic processes in extreme rainfall events, facilitating early warning and mitigation strategies [33].  
HEC-RAS has been successfully utilized to simulate tsunami propagation, demonstrating its ability to accurately compute wave elevation and velocity in two different locations, namely Hilo Bay, Hawaii, and Tauranga Harbor, New Zealand [25]. The model has also been applied to wind-driven hydrodynamic studies, though to a significantly lesser extent. Some investigations have explored its suitability for modeling hydrodynamics in regulated logoons and tidal-influenced systems [34; 35]. However, its application to wind-induced surges in coastal and semi-enclosed water bodies, such as logoons, bays, and estuaries, remains uncommon. The hydrodynamics of the Vistula Lagoon, a semi-enclosed coastal water body in the Baltic Sea, is primarily driven by wind forcing and fluctuations in the Gulf of Gdarsk water levels [11]. The lack of extensive research on HEC-RAS 2D's suitability for wind-induced surge modeling necessitates an in-depth evaluation of its capabilities in this context.  
Given the model's proven reliability in various hydrodynamic applications but its limited verification for wind-driven flows, this study aims to assess the feasibility of using HEC-RAS 2D for simulating wind-induced surges in the Vistula Lagoon. The findings will contribute to evaluating its suitability for lagoon hydrodynamics and potentially expanding its application beyond traditional riverine and floodplain scenarios.