River Discharge Estimation by Using Altimetry Data and Simplified Flood Routing Modeling

Angelica Tarpanelli,Silvia Barbetta,Luca Brocca,Tommaso Moramarco

doi:10.3390/rs5094145

Angelica Tarpanelli, Silvia Barbetta + Show 2 more

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https://doi.org/10.3390/rs5094145

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Abstract

A methodology to estimate the discharge along rivers, even poorly gauged ones, taking advantage of water level measurements derived from satellite altimetry is proposed. The procedure is based on the application of the Rating Curve Model (RCM), a simple method allowing for the estimation of the flow conditions in a river section using only water levels recorded at that site and the discharges observed at another upstream section. The European Remote-Sensing Satellite 2, ERS-2, and the Environmental Satellite, ENVISAT, altimetry data are used to provide time series of water levels needed for the application of RCM. In order to evaluate the usefulness of the approach, the results are compared with the ones obtained by applying an empirical formula that allows discharge estimation from remotely sensed hydraulic information. To test the proposed procedure, the 236 km-reach of the Po River is investigated, for which five in situ stations and four satellite tracks are available. Results show that RCM is able to appropriately represent the discharge, and its performance is better than the empirical formula, although this latter does not require upstream hydrometric data. Given its simple formal structure, the proposed approach can be conveniently utilized in ungauged sites where only the survey of the cross-section is needed.

Highlights

River discharge is the variable of interest for many scientific and operational applications related to water resources management and flood risk mitigation
River discharge is estimated for two gauged sites on the Po River by using altimetry data from ERS-2 and ENVISAT satellites
The comparison between the satellite and in situ water level measurements has shown that the accuracy of the altimetry data depends on the satellite sensor

Summary

Introduction

River discharge is the variable of interest for many scientific and operational applications related to water resources management and flood risk mitigation. The highest values of discharge are obtained by extending the rating curve through extrapolation that could be affected by significant uncertainties [3] In addition to these inherent issues, the need to develop new procedures for river discharge estimation based on remote sensing technology is motivated by: (1) the recent decrease in the hydraulic monitoring network observed all over the world [4,5,6], (2) the inaccessibility of many remote areas and (3) the difficulties for data sharing among developing countries [7]. Satellite altimetry has been developed and optimized for open ocean and, only later, the capability of measuring water level change of continental surface reservoirs, such as inland seas and lakes, has been demonstrated [8,9,10]

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