Estimativa da condutividade hidráulica pela curva de distribuição granulométrica do aquífero Plio-Quaternário da Bacia do Baixo Tejo em Berverde (Portugal)

The hydraulic conductivity (K) of the Plio-Quaternary multi-layered aquifer system at Belverde in the Tagus left river bank was estimated by grain-size distribution data picked between 12,77 and 130,15 m depth from a continuous borehole core. Using Breddin's method, three permeability classes were determined for the detritic material (classes 3, 4 and 5) with K value ranging from 85 m/d to 8 m/d. This study allowed to characterize a complex aquifer system formed by an unconfined and a confined aquifer with a thickness of 53 and 63 meters respectively. Between them there is an aquiclude with about 6 meters of thickness. The vertical and horizontal hydraulic conductivities of the unconfined aquifer were estimated kv = 53,0 m/d, kh = 62,9 m/d. In the confined aquifer the values were kv = 35,0 m/d, kh = 42,7 m/d.