Evidence-based risk assessment of ecological damage due to groundwater abstraction; the case of Doñana Natural Space, Spain

Many regions of the world are facing mounting water stress as competition increases for this vital resource that may become scarcer under future climates. More water is being allocated to our needs for food, public supply, hydro-electric power and industrial goods to support growing populations and mounting life-style expectations. To achieve this, less water is often being retained for water-dependent ecosystems. Environmental protection agencies and conservation organisations have highlighted the resulting threat to freshwater biodiversity and associated ecosystem services that support human livelihoods and well-being. Careful assessments are therefore required to advise on the optimum allocation of water and to determine the risk of developments that require redistribution of water resources. Along the northern fringes of the Guadalquivir River delta and estuary in southern Spain about 40% of all jobs derive from agriculture. The production of olives, fruit trees, rice and berries is a major component of the local economy producing large exports, but it requires significant water from local rivers and the underlying aquifers. The economy is also reliant on tourism that brings many thousands of people to the area in the summer for which groundwater abstraction is augmented. The delta is the location of the Doñana wetland complex of lagoons, marshlands, fixed and mobile dunes that was designated as a Biosphere Reserve by UNESCO in 1980, as wetland of international importance (Ramsar Site) under the Convention on Wetlands in 1982 and as a World Heritage Site by UNESCO in 1994. Fears have been expressed that increasing human water use is putting the wetlands at risk of drying out, despite efforts by the river basin authority to limit abstraction to sustainable levels. This paper reports on a methodology that analyses best available eco-hydrological scientific knowledge together with information on the likely success of abstraction control measures to determine the risk to the wetland ecosystem of current and future planned water allocation. The method was applied to Doñana by the joint UNESCO/IUCN/Ramsar Reactive Monitoring mission to in 2020. The results are also provided in the paper, which raised many important scientific and related political, legal and social issues concerning the impacts of water withdrawals on the ecology of the wetlands. The methodology has wide application to environmental water allocation assessments