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.