Regional flood analysis at the Atlantic coast of Galicia northwest of Spain

Abstract

This paper includes a regional flood frequency analysis within an area above 8,000 km2, located in the northwest of Spain, in the Atlantic coast of the Autonomous Community of Galicia, known as "Rías Baixas". The index flood method was used together with the General Extreme Value distribution adjusted to the region by the method of Probability Weighted Moments. The region's water homogeneity has been verified by measuring discharges of several regional rivers for the last three years. Homogeneity has also been demonstrated by applying the statistical regional homogeneity test. The basin area has proved a good variable to predict the mean annual flood in catchments where hydrologic information is scarce. The obtained regional flood frequency curve was compared with the curves developed for other humid worldwide regions with similar climatological characteristics. The developed method constituted a good tool for the estimation and analysis of frequency of extreme floods in the Galician region of Rías Baixas.