Hydrological responses in equatorial watersheds indicated by Principal Components Analysis (PCA) – study case in Atrato River Basin (Colombia)

Author(s)

Sebastián Balbín Betancur ^[1] ; Didier Gastmans ^[2] ; Katherine Vásquez Vásquez ^[3] ; Lucas Vituri Santarosa ^[4] ; Vinícius dos Santos ^[5] ; Roberto Eduardo Kirchheim ^[6]

Affiliation

^[1] Universidade Estadual Paulista “Júlio de Mesquita Filho”. Centro de Estudos Ambientais - Brasil

^[2] Universidade Estadual Paulista “Júlio de Mesquita Filho”. Centro de Estudos Ambientais - Brasil

^[3] Universidade de São Paulo. Laboratório de Hidrologia Florestal - Brasil

^[4] Universidade Estadual Paulista “Júlio de Mesquita Filho”. Centro de Estudos Ambientais - Brasil

^[5] Universidade Estadual Paulista “Júlio de Mesquita Filho”. Centro de Estudos Ambientais - Brasil

^[6] Serviço Geológico do Brasil - Brasil

• Document type: Journal article
• Source: RBRH; v. 25, 2020-10-19.

Abstract

ABSTRACT The Atrato river basin is located in the Pacific fringe of Colombia, region with one of the highest precipitation rates in the world. The main purpose of this study is to determine the dominant processes in the hydrological responses along 17 sub-basins within the basin using principal component analysis. Watersheds located at the headwater presented a fast or medium response to the precipitation events, while higher flow homogeneity was observed in watersheds located at the lower portions of the basin. Three principal components were responsible for explaining 85.18% of the total variance. The component PC1 revealed the largest contributions for low flow behavior, being associated to precipitation, characteristic discharge values, compactness index, soil coverage and soil coarse textures. The component PC2 was assigned to the geological variables, fine and average texture soil and the average basin slope. Finally, the component PC3 has shown to be related to high flow patterns (maximum characteristic discharge values Q5 and Q1), igneous rocks and length of the basin. Highest specific discharge was associated to alluvial deposits and forest cover, whereas the slope was considered determinant for the run-off generation. (AU)

• FAPESP's process: 18/06666-4 - Isotopic tracers revealing the water movement in watersheds of the São Paulo State
• Grantee: Didier Gastmans
• Support Opportunities: Regular Research Grants