HESS Hydrology and Earth System Sciences HESS Hydrol. Earth Syst. Sci. 1607-7938 Copernicus Publications Göttingen, Germany 10.5194/hess-6-753-2002 Influence of the Yesa reservoir on floods of the Aragón River, central Spanish Pyrenees López-Moreno J. I. 2 1 Beguería S. 1 García-Ruiz J. M. 1 Instituto Pirenaico de Ecología, CSIC, Campus de Aula Dei, Apartado 202, 50080-Zaragoza, Spain Email for corresponding author: humberto@ipe.csic.es 31 08 2002 6 4 753 762 Copyright: © 2002 J. I. López-Moreno et al. 2002 This work is licensed under the Creative Commons Attribution-NonCommercial-ShareAlike 2.5 Generic License. To view a copy of this licence, visit https://creativecommons.org/licenses/by-nc-sa/2.5/ This article is available from https://hess.copernicus.org/articles/6/753/2002/hess-6-753-2002.html The full text article is available as a PDF file from https://hess.copernicus.org/articles/6/753/2002/hess-6-753-2002.pdf

The Yesa reservoir, the largest Pyrenean reservoir, was constructed in 1959 to supply water to new irrigated areas in the Ebro Depression, NE Spain. It is filled from October to May-June and then releases large quantities of water in the summer via the Bardenas Canal. The results confirm that the frequency of floods downstream of the dam decreased. The reduction mainly depends on two factors: i) the water storage level, and ii) the season of the year. Floods are very well controlled when the reservoir level is lower than 50%. Between 50 and 70%, only the highest floods are controlled. Finally, the reservoir retains mainly autumn and spring floods; most winter floods are released downstream to ensure the safety of the dam.</p> <p style="line-height: 20px;"><b>Keywords: </b>reservoir, flood control, flood seasonality, flood frequency, river regime, Pyrenees</p>