Assessment of Potential Tsunami Inundation Under High-Tide Conditions Along the Saurashtra Coast, Gujarat: A Delft3d-Based Case Study of the 1945 Makran Tsunami

Natural disasters, particularly tsunamis, often cause devastating losses to the environment and economy. This study focuses on the impacts of the Makran tsunami of November 28, 1945, which claimed over 4,000 lives and severely affected the western Indian coast. The Saurashtra coastal belt, a vital region within Gujarat's 1,600 km coastline, holds considerable economic significance due to its ports, refineries, chemical industries, and salt-processing units. Using the Okada model within the Delft Dashboard and Delft3D, the present study simulated an Mw 8.1 tsunami event. The simulation produced an initial wave height of approximately 4 m at the source, followed by waves of 1–1.5 m along the Saurashtra coast. To assess the potential impact under high-tide conditions, a 4 m high-tide level was combined with the simulated 1.5 m tsunami wave height, resulting in a 5.5 m combined water-level scenario. The resulting inundation assessment indicates potential inland water penetration of approximately 350–450 m in some coastal stretches, particularly near Dwarka and Shivrajpur Beach. High velocity waves (1.2 m/s) pose additional risks of coastal erosion, highlighting the need for proactive hazard assessment. Inundation mapping highlights vulnerabilities in areas like Shivrajpur beach and the Dwarka beach, emphasizing the need for comprehensive hazard assessments to mitigate risks Beyond hazard characterization, the study provides indicative guidance for tsunami risk reduction by identifying potential zones suitable for nature-based measures such as mangrove and dune restoration, as well as elevated inland areas that may serve as evacuation and assembly points. These recommendations, derived from inundation and flow characteristics, can support local authorities in planning strategies aimed at minimizing coastal erosion and reducing damage in vulnerable coastal stretches.