Flood monitoring in Santa Fe using the Google Earth Engine platform

Abstract

Floods cause large losses for society. The frequency of these events has been increasing in recent decades in different regions of the world as a consequence of the global climate change. In Argentina, Santa Fe city is vulnerable to the flooding of two major rivers, i.e. the Paraná and the Salado-Juramento. For this reason, this paper aims to develop an online monitoring system for the metropolitan area of Santa Fe, in order to improve the response to a water risk. For this purpose, satellite information and the programming interface available on the Google Earth Engine (GEE) platform, were used here. The following indicators were evaluated to monitoring water excess: the normalized difference vegetation index (NDVI), the water ratio index (WRI), the modified normalized difference water index (MNDWI) and the radar signal thresholding technique of the Sentinel 1 mission. The spatial-temporal behaviour of the indicators was analysed for the period 2016-2021, including the 2016 Paraná River flood, to determine the monitoring capacity of the indicators studied. The results presented suggest that the proposed set of optical indices and the thresholding of the Sentinel 1 radar signal allow monitoring the evolution of flooded zones in the area of influence of the city of Santa Fe in near-real time.