W. Martín-Rosales

Conditioning factors in flooding of karstic poljes—the case of the Zafarraya polje (South Spain)

Abstract The Zafarraya polje undergoes periodical flooding, of which the last episode (1996–1997) was analysed in detail on this paper. On the basis of the retention curves of the two lakes that formed in the northwestern and southwestern sectors, we calculated the total infiltration capacity of the polje to have a maximum value of 3–3.5 m3/s and so we infer that when the flow of the Arroyo de la Madre exceeds this figure, there will be a risk of flooding in the polje. We also propose a model for the 1996 flood that can be extended to other similar occurrences in this and other poljes where we can establish the role played by groundwater and surface water during this flood. In response to the heavy precipitation, the flow of the Arroyo de la Madre rose abruptly, exceeding the infiltration capacity of the main swallow holes on the polje, causing first the northern lake and then the southern lake to form with only surface water supply. The water table of the karst aquifer rose sharply, reaching a situation of equilibrium between the level in the lakes and the water table in this sector of the karst aquifer that prevented infiltration through the swallow holes. In the case of the southern lake, there were even cases of swallow holes that began to operate as estavelles. During this phase of maximum flooding, one single lake was present, which was divided into two once more when the water table of the karst aquifer in the polje sector began to fall and surface supply also began to decrease.

Groundwater contamination in caves: four case studies in Spain

INTRODUCTION Soil and vadose zone of aquifers act as protective covers to groundwater (Mudry et al., 2003), so specific studies of subsurface water flow and solute transport that could be contaminants in both environments are necessary. These studies are essential for a better understanding of the attenuation factors affecting the contaminants before their arrival to the underground resource. The methodology applied to the study of porous aquifers is different from that applied to carbonate (karstic) aquifers (Stephens, 1����� Selker et al., 1���). The reason for this difference is

Climate-driven trends in the streamflow records of a reference hydrologic network in Southern Spain

Abstract Monthly streamflow records from a set of gauging stations, selected to form a reference hydrologic network, are analyzed together with precipitation and temperature data to establish whether the streamflows in the Guadalquivir River Basin have experienced changes during the last half of the 20th century that can be attributed to hydrological forcing. The observed seasonal and annual streamflows in the reference network have undergone generalized and significant decreases during the study period. Annual rainfall did not experienced statistically significant changes. The observed trends in streamflows may be attributed to either land-use changes, or to the statistically significant changes exhibited both by yearly potential evapotranspiration values and by the seasonal redistribution of precipitation. In the attribution work conducted using both data-based and simulation-based methods, the intra-annual redistribution of precipitation is shown to be the main statistically significant climate-driver of streamflow change. The contributions of other non-climate factors, such as changes in land cover, to the reduction in annual streamflows are shown to be minor in comparison.