Article
Estimation of annual maximum and minimum flow trends in a data-scarce basin. Case study of the Allipén river watershed, Chile
Estimación de Flujos Máximos y Mínimos Anuales en una Cuenca de Datos Escasos. Estudio de Caso de la Cuenca del Río Allipén, Chile
Autor
Medina, Yelena
Muñoz, Enrique
Resumen
Data on historical extreme events provides information not only for water resources
planning and management but also for the design of disaster-prevention measures. However, most
basins around the globe lack long-term hydro-meteorological information to derive the trend of
hydrological extremes. This study aims to investigate a method to estimate maximum and minimum
flow trends in basins with limited streamflow records. To carry out this study, data from the Allipén
River watershed (Chile), the Hydrologiska Byråns Vattenbalansavdelning (HBV) hydrological model
at a daily time step, and an uncertainty analysis were used. Through a calibration using only five
years of records, 21-year mean daily flow series were generated and the extreme values derived.
To analyze the effect of the length of data availability, 2, 5, and 10 years of flows were eliminated from
the analyses. The results show that in the case of 11 years of simulated flows, the annual maximum
and minimum flow trends present greater uncertainty than in the cases of 16 and 19 years of simulated
flows. Simulating 16 years, however, proved to properly simulate the observed long-term trends.
Therefore, in data-scarce areas, the use of a hydrological model to simulate extreme mean daily flows
and estimate long-term trends with at least 16 years of meteorological data could be a valid option.