Mapping aquifer recharge areas by Factorial Kriging on the basis of piezometric patterns

Abstract:

Factorial Kriging has been used so far to explore the structure of multivariable spatial hydrochemical information towards a discrimination of geological and antropogenic influences. Factorial Kriging is used to identify and to map preferential aquifer recharge areas based on groundwater flow patterns. Under natural flow conditions, the experimental variogram computed on the piezometric spatial data exhibits an idiosyncratic non stationary behaviour, which reflects the groundwater flow gradients. If an external process is the cause of modification of the shape of the variogram, particular spatial correlation can be detect at a specific scale. This is the case of a recharge phenomenon preferentially actuating in an aquifer region. Therefore two structures can be deduced: a short-range one, mostly reflecting the variability of the recharge action and a long-range one, more related with the regional groundwater flow. Factorial Kriging technique can be used to map on a regular grid and for various times the two regionalized factors, enhancing the relative extension of the recharge area, which can be analysed according to the precipitation temporal patterns (wet or dry years). This geostatistical study will provide important results for the investigation and decision making: the definition of protection perimeters in recharge zones, mostly vulnerable to the pollution. The area under study is the groundwater karstic system of Tor-Silves, located in Central Algarve, Portugal.

Año de publicación:

1999

Keywords:

Fuente:

scopus