Artificial recharge by means of careo channels versus natural aquifer recharge in a semi-arid, high-mountain watershed (Sierra Nevada, Spain).

The acequias de careo are ancestral water channels excavated during the early Al-Andalus period (8th-10th centuries), which are used to recharge aquifers in the watersheds of the Sierra Nevada mountain range (Southeastern Spain). The water channels are maintained by local communities, and their main function is collecting snowmelt, but also runoff from rainfall from the headwaters of river basins and distributing it throughout the upper parts of the slopes. This method of aquifer artificial recharge extends the availability of water resources in the lowlands of the river basins during the dry season when there is almost no precipitation and water demand is higher. This study investigates the contribution of the careo channels in the watershed of Bérchules concerning the total aquifer recharge during the 2014-2015 hydrological year. Several channels were gauged, and the runoff data were compared with those obtained from a semi-distributed hydrological model applied to the same hydrological basin. The natural infiltration of meteoric waters accounted for 52% of the total recharge, while the remaining 48% corresponded to water transported and infiltrated by the careo channels. In other words, the careo recharge system enhances by 92% the natural recharge to the aquifer. Our results demonstrate the importance of this ancestral and efficient channel system for recharging slope aquifers developed in hard rocks. The acequias de careo are nature-based solutions for increasing water resources availability that have contributed to a prosperous life in the Sierra Nevada. Its long history (>1200 years) suggests that the system has remarkable resilience properties, which have allowed adaptation and permance for centuries in drastically changing climatic and socioeconomic conditions. This recharge system could also be applied to -or inspire similar adaptation measures in- semi-arid mountain areas around the world where it may help in mitigating climate change effects.

Treatment of massive subretinal hemorrhage from complications of scleral buckling procedures.

Vitrectomy techniques permit removal of subretinal hemorrhage, but the prognosis varies and depends principally on the cause of the hemorrhage. Nine consecutive patients undergoing pars plana vitrectomy with internal drainage of massive subretinal hemorrhage from complications of scleral buckling procedures were studied, to evaluate the long-term results. In all eyes, the final visual acuity was improved, compared with preoperative visual acuity, and was 20/80 or better in seven of nine cases. Recurrent retinal detachment secondary to proliferative vitreoretinopathy developed in two patients, but complete retinal reattachment was achieved after further procedures were performed. Patients with massive subretinal hemorrhage from complications of scleral buckling procedures comprise a subgroup of patients with subretinal hemorrhage in which internal drainage via pars plana vitrectomy is an acceptable alternative to observation only and may result in improved visual acuity outcomes.