Hydrological Characterization of Watering Ponds in Rangeland Farms in the Southwest Iberian Peninsula

Watering ponds are an important source of drinking water supply for livestock in semi-arid rangelands. Understanding the hydrological functioning of this kind of infrastructures is crucial for efficient water management in areas where water resources are often scarce. In this line, we have analyzed temporal patterns of water availability in a set of watering ponds located in Iberian rangelands and their relationship with temporal rainfall variability. In addition, the effectiveness of the ponds for conserving stored water during dry periods and some influencing factors (pond size and catchment area) have also been assessed. The results showed a high correlation between water availability and precedent rainfall, confirming, on the one hand, the capacity of storage of these infrastructures and, on the other hand, the importance of temporal rainfall patterns in their hydrological behavior. Our findings point to a minimum pond area of 2000 m(2) and a catchment area/storage capacity ratio around 100 m(-1) in order for watering ponds can face the dry summer period with certain guarantees, at least in regular hydrological years. Nonetheless, the vulnerability shown by the majority of the watering ponds in times of drought limits their usefulness as unique sources of water supply in many farms.