Characterising the discharge of hillslope karstic aquifers from hydrodynamic and physicochemical data (Sierra Seca, SE Spain)Caractérisation du débit des aquifères karstiques de pente à partir des données hydrodynamiques et physicochimiques (Sierra Seca, SE Espagne)Caracterización de la descarga de acuíferos kársticos a partir de datos hidrodinámicos y fisicoquímicos (Sierra Seca, SE de España)从水动力和物理化学数据对西班牙东南部Sierra Seca山坡喀斯特含水层的排泄特征进行表征Caracterização da descarga de aquíferos cársicos de encosta a partir de dados hidrodinâmicos e físico-químicos (Sierra Seca, SE Espanha)

Groundwater flow has been investigated in the Sierra Seca, Spain. Maximum recharge to the central core of the mountain occurs at high elevations, which provides recharge to two overlapping karst aquifers constituting a groundwater storage zone at a lower elevation break in slope. Both karst aquifers are associated with three springs arising from the upper part of the permeable formations. The climate is characterized by long and intense periods of drought and short periods of rainfall, which trigger discharges from the springs. Spring flow recession curve analysis, cross-correlation and monitoring of groundwater temperature and electrical conductivity have demonstrated contrasts observed in the hydrodynamic and physicochemical response of the three springs during flood events. One spring records floods with narrow and short peaks of high discharge accompanied by sharp drops in temperature and electrical conductivity. Another spring records floods with somewhat wider peaks and sharp increases in temperature and electrical conductivity (piston effect), whereas the third spring shows great consistency in all monitored characteristics. It is concluded that the absence of a piston effect in the spring with the highest flow rates is due to the contribution of rapidly circulating water that is expelled by semi-active karst networks (overflow) before reaching the saturated zone, which does not occur in the other springs due to the absence of overflow hydrological pathways. The most regular spring owes its functioning to the contribution of infiltrated water in the bed of an upstream riverbed, which explains this regularity.