Do It Yourself Instrumentation for Extracting Satellite-Derived Bathymetry: The Case of the Ebro Delta

Coastal regions are areas of great socioeconomic and ecological value. Within them, deltas are particularly vulnerable, as they experience intense anthropogenic pressures and the effects of climate change, which are even more pronounced in the Mediterranean Sea. These environments face an increasing risk of coastal flooding, wetland loss, shoreline retreat, and infrastructure deterioration.

Therefore, it is essential to have high spatial and temporal resolution data for monitoring these areas. In this context, bathymetric information is crucial for marine environmental planning, navigation, fisheries management, and many other applications. However, both large- and small-scale bathymetric data are limited and expensive. In response to this limitation,cost-effective alternatives for bathymetric monitoring have been explored, with Satellite-Derived Bathymetry (SDB) emerging as a viable option to complement conventional techniques.

This research used a Do It Yourself (DIY) bathymetric sensor, specifically designed to obtain in situ data and extract Satellite-Derived Bathymetry (SDB) at the river mouth of the Ebro Delta (NW Mediterranean Sea), in order to analyze changes in the bathymetry between 2023 and 2025. For this purpose, four sampling campaigns were carried out at the mouth of the delta, combining the obtained data with images from the Sentinel-2A/B mission of the Copernicus Program. The Sentinel-2 images were processed using the ACOLITE processor to perform atmospheric and sunglint corrections. The objective of this research is to demonstrate the feasibility of using DIY technologies to obtain in situ bathymetric data in coastal areas, which can support the extraction of SDB. These technologies are especially useful for countries in the process of development and initiatives with open and collaborative science platforms (i.e. citizen science). Validating this methodology will contribute to providing access to bathymetric data essential for coastal zone management and mitigation of the future impacts of climate changes.