Hydraulic Model Calibration Using Remote-Sensing Data: The Usefulness of ERS-2 and ENVISAT Water Surface Levels

Abstract

The calibration of hydrologic and hydraulic models usually relies on the availability of in-situ observations which may be limited, or absent, in vast areas of the globe. In this scenario of lack of data, the recent advances in radar-altimetry technology may represent a valid alternative for providing remotely sensed water level for lakes and rivers, even located in poorly-gauged area. The present analysis aims to investigate the usefulness of water surface elevation data provided by ERS-2 and ENVISAT satellites for the calibration of a hydraulic numerical model. Focusing on a 130 km reach of the middle-lower portion of the Po river, we investigate the opportunity of calibrating a quasi two-dimensional (quasi-2D) numerical model for intermediate streamflow conditions. Referring in turn to in-situ and remotely sensed water levels we calibrated the model comparing the results in terms of calibrated roughness coefficient. Despite the low frequency of satellite overpasses and the limited accuracy of remotely-sensed water surface levels, our analysis clearly points out that satellite times-series can effectively describe the hydrometric regime in a given cross-section and can integrate traditional data, improving the knowledge on the streamflow regime and enhancing the model calibration.