Geometric modeling of sea level elevation in Tagus Estuary Natural Reserve

Abstract

The Tagus Estuary Natural Reserve (TENR) is an area with approximately 14400 ha, with height no higher than 11m and includes an extensive surface of estuarine waters, atolls, saline and agricultural alluvial lands. Geomorphological features of this area as well as its ecological and economic relevance determine that climate change and the subsequent rise in sea level will produce significant negative effects. Geometric models, allowing the identification and monitoring the inherent problems to the water level rise, are relevant tools. Main objectives of the research were the rigorous altimetry definition of the area, the potential flooded areas registration and the identification of affected protection infrastructures resulting from the rise of the sea level until 2100. Geometric modeling was supported in the geo-referenced data collection with centimeter accuracy using the global satellite navigation system. Analyzed data allowed the tracing of terrain profiles in strategic sections, the analysis of water level rising and the identification of irreversible overflow in the defense infrastructures, considering the time horizon 2100. The conceptual model allowed to verify that about 90% of the non-estuarine area in the TERN will be affected by the rise of the sea level in some of the scenarios considered. The geometric model supported by real data could be a useful tool to support decision-making on mitigation and on adaptation measures of damaged areas to climate change.