Water management in the high mountain watersheds of the Sierra Nevada National Park (southern Spain). An example of ancestral Integrated Water Management

Abstract

Sierra Nevada is the main mountain range in the southern Iberian Peninsula and has been catalogued as a Biosphere Reserve (1986), a Natural Park (1989) and a National Park (1999). Apart from its ecological, geomorphological and landscape singularities, there are other remarkable hydrological, historical and cultural features, such as the ancestral water management performed at the headwaters of the rivers. A dense network channels excavated in the ground, the so-called acequias de careo, allows the derivation of melt water from of the river water head towards the higher zone of the hillsides, where it infiltrates. It slowly flows down through the weathered zone of the metamorphic rocks, until reaching the rivers and springs used for supply and irrigation. This water management system, implemented since the Muslim conquest of southern Spain (VIII century), has led to a remarkable transformation of the landscape, where agricultural terraces and pastures coexist with ecosystems of high ecological value. This paper describes the careos water-management technique in a pilot basin, the Bérchules watershed, recently studied during 2014 and 2015 by the Geological Survey of Spain. Migration, the abandonment of cultivated lands and, consequently, of the acequias de careo are affecting the dynamics of the rivers, endangering the delicate balance reached between man and nature in the Sierra Nevada, after many centuries of harmonious coexistence.