Water resource management in karstic catchments: the case of the Asso Torrent basin (Southern Italy)

In karstic endhoreic basins the hydraulic works for runoff regulation, marshland reclaiming and defence from inundations usually consist of channels tributary to sinkholes vertically connected to aquifers through karstic conduits and fractures. The drainage capacity of such basins reduces as conduits and fractures are progressively clogged by sediments, thus floodings may occur during heavy rains. The sinks may also be utilized to inject treated wastewater underground. This note concerns the management issues of the Asso Torrent basin (Italy), where the recharge through water sinks preserves the deep aquifer from saltwater intrusion. The basin represents a controversial case for which the sequence of infrastructures produced a critical system and nowadays it is difficult to find a compromise among mitigation of flood hazard, safeguard of groundwater resources and preservation of human health. The hydrogeological framework and the hydraulic works executed in the basin are described, followed by considerations on the environmental effects of the decision-making process. Finally, statements concerning alternative measures for the management of the water resources are given. Management actions conforming to the Integrated Water Resources Management recommendations fail in the studied case because there is an intrinsic difficulty to transform the related concepts to practical and robust solutions.