Rainfall behavior regionalization to provide design values for infraestructure : case of study in a binational basin of South America

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Julio Isaac Montenegro Gambini

Wednesday 1 july 2015

11:00 - 11:15h at North America (level 0)

Themes: (T) Extreme events, natural variability and climate change, (ST) Hydrological extremes: floods and droughts

Parallel session: 9I. Extreme events - Flood Drought

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This research aims to make a Hydrological regionalization in the binational basin of Catamayo-Chira river, one of the most affected basins in south america due to El Niño Phenomenom. We explored the most of existing information, seeking to estimate hydrological variables in lacking data sites where existing information is insufficient in quantity or quality, on the other hand it's very important we have design values such as rainfall to propose hydraulic insfraestructure . This technique allows better exploring in samples and, consequently, improving the estimates of variables checking the consistency of hydrological series and identifying the lack of observation using daily rainfall data provided by governmental institutions of Perú and Ecuador. With the use of statistical methods, hydrological regions are analogous to areal classes. In this present study, we applied to Catamayo-Chira river in order to analyses the patterns of variation and to delimit regions of uniform behavior and making comparisons with the maximum values of rainfall and runoff data using different methods. Regional homogeneity characteristics were evaluated following the Multidimensional strokes method by Andrews (1972) and index-flood method, described by Dalrymple (1960). We perform theoretical probability distributions obtaining the most representative maximum daily rainfall values and to assess several return periods, additionally within each region, the relationship between rainfall and El Niño phenomenom is examined. The comparison of results between the maximum rainfall values obtained by frequency analysis in each of the rainfall gauges and by regionalization shows that the methodology is reliable and useful with very good correlation between the Real and the Regionalized values, in order to obtain design values for hydraulic infrastructure. Based on hydrometeorological analysis have been developed isohyets maps and 3D surfaces to assess the spatial distribution of rainfall regions.