Nature-Human-River Relationships at the Ebro River and its Delta (Spain)

Abstract

The Ebro is one of the largest river basins in Southern Europe, with an area of 85,000 km2, a river length of 930 km, and a population of more than three million people. Since ancient times, it has not only been a resource, but also a channel for communication, commerce and the settlement of great civilizations along its course. The Ebro Basin has always been rich in cultural heritage and blessed with a diverse biology. It hosts a wide variety of endemic species, some of which are now endangered by human-induced threats. Spain is one of the most vulnerable countries in Europe concerning climate change. It also has a long history of human-water relationships, evident from Roman (after 197 BC) and Umayyad-Muslim (after 711 AD) influences; both cultures are famous for their water management technologies. The Ebro River waters, coming from the Pyrenees mountain range with which it flows almost in parallel southwards, have always been coveted. Over the centuries, land and water exploitation have progressively intensified, and the most recent transformations have resulted in the Ebro now being one of the most stressed rivers in the world. A great number of large reservoirs produce a big amount of energy but have significantly changed the river's flow and sediment regimes. This regulation, combined with excessive water extraction for irrigation and drinking water in its thirsty surroundings, has been detrimental to almost all aspects of the river ecosystem. The highest impact is visible at the delta, which suffers from compaction, subsidence, and regression, today receiving less than 5% of the river's original sediment load. Despite being administered by one of the oldest hydrographic management organizations worldwide, the increasing overall water locations and subsequent environmental and social problems in the Ebro Basin area are a source of considerable on-going conflict and debate. This situation has given rise to one of the most powerful social movements in defense of the Ebro River. Several initiatives are underway to reverse the detrimental losses of natural geodiversity and functionality, by maintaining flows that sustain ecological health, giving natural space back to the river and improving human flood defense systems. Nevertheless, much remains to be done, and ongoing challenges can only be effectively tackled through well-directed (and previously-lacking) institutional will, backed by broad public consensus. If not, what has taken countless centuries to create will be lost in less than one.