Abstract

VILLANUEVA DIAZ, José et al. Reconstructed volumes in dams of the Valle del Yaqui with annual rings of conifers. Rev. Mex. Cienc. Agríc [online]. 2014, vol.5, n.spe10, pp.1977-1991. ISSN 2007-0934.

A dendrochronological network ofearly and late-wood and full ring of Pseudotusga menziesii was developed for the upper basin oftheYaqui river (CRY) to explain the historical runoffvolumes recorded in the basin and sub-basins feeding three of the largest dams (Angostura, Novillo, Oviachic) in the State of Sonora, which supply water annually for about 250 000 ha. The chronologies showed an inter-annual and multi-annual climate variability (r >0.60, p< 0.01), suggesting the influence of common weather phenomena; situation that allowed them within a regional chronology of 479 years (1534-2012) in length. The regional chronology of earlywood responded to the accumulated rainfall from February to May and runoff volumes from October to June, representing 43% of the annually registered in the CRY. Both variables were correlated (r= 0.83, p< 0.01, n= 479), suggesting that the annual runoff has high influence of the winter-spring precipitation. At sub-basin level, the dendrochronological series showed a significant association with the volumes recorded in the respective dams, but the limited number ofseries prevented a more complete analysis ofthe hydroclimatic variability, so it is important to expand it. ENSO was the phenomenon that affected the most the variability in rainfall and runoff ofthe winter-spring period.

The association between regional chronology ofearly-wood and the Southern Oscillation Index (SOI) was negative, but significant in the winter (r= -0.59, p< 0.01), implying high influence of the warm phase of this phenomenon in the natural climate variability.

Keywords : Pseudotsuga menziesii; dendrochronology; ENSO; runoff.