Comparison of stage/discharge rating curves derived from different recording systems: Consequences for streamflow data and water management in a Mediterranean island

Obtaining representative hydrometric values is essential for characterizing extreme events, hydrological dynamics and detecting possible changes on the long-term hydrology. Reliability of streamflow data requires a temporal continuity and a maintenance of the gauging stations, which data are affected by epistemic and random sources of error. An assessment of discharge meterings' and stage-discharge rating curves' uncertainties were carried out by comparing the accuracy of the measuring instruments of two different hydrometric networks (i.e., one analogical and one digital) established in the same river location at the Mediterranean island of Mallorca. Furthermore, the effects of such uncertainties were assessed on the hydrological dynamics, considering the significant global change impacts beset this island. Evaluation was developed at four representative gauging stations of the hydrographic network with analogic (≈40 years) and digital (≈10 years) data series. The study revealed that the largest source of uncertainty in the analogical (28 to 274%) and in the digital (17–37%) networks were the stage-discharge rating curves. Their impact on the water resources was also evaluated at the event and annual scales, resulting in an average difference of water yields of 183% and 142% respectively. Such improvement on the comprehension of hydrometric networks uncertainties will dramatically benefit the interpretation of the long-term streamflow by providing better insights into the hydrologic and flood hazard planning, management and modelling. © 2019This work was supported by a research contract funded in 2014 by the Directorate-General of Water Resources (Department of Environment, Agriculture, and Fishery of the Balearic Autonomous Government) and the research project CGL2012-32446 “Assessing hydrological and sediment connectivity in contrasting Mediterranean catchments. Impacts of Global Change-MEDhyCON” funded by the Ministry of Economy and Competitiveness of the Spanish Government. The contribution of Jérôme Latron was supported by the research project PCIN-2017-061/AEI also funded by the Ministry of Economy and Competitiveness of the Spanish Government. Josep Fortesa has a contract funded by Ministry of Innovation, Research and Tourism of the Autonomous Government of the Balearic Islands (FPI/2048/2017). He also acknowledges the support from “la Caixa” Foundation through a mobility grant for young researchers at the Universitat de les Illes Balears with announcement reference number 3111. Julián García-Comendador is in receipt of a pre-doctoral contract (FPU15/05239) funded by the Spanish Ministry of Education and Culture. Aleix Calsamiglia acknowledges the support from the Spanish Ministry of Economy and Competitiveness through a pre-doctoral contract (BES-2013-062887). José Andrés López-Tarazón is in receipt of a Vicenç Mut postdoctoral fellowship (CAIB PD/038/2016) funded by the Vice-presidency and Ministry of Innovation, Research and Tourism of the Autonomous Government of the Balearic Islands. Meteorological data were facilitated by the Spanish Meteorological Agency (AEMET). Authors thank the three anonymous reviewers and the Guest Editor, Prof. Axel Bronstert, for their constructive comments and suggestions that significantly improved the final version of the paper.Peer reviewe