Coastal lagoons host important values and provide irreplaceable services to society. Communication areas with the sea (gullets, 'golas' in Spanish) are dynamic environments with a key role in their overall functioning, often representing also strongholds of biodiversity, which increases their conservation value and social demand for nature-based activities. In 2013 the Regional Assembly of the Autonomous Community of Murcia adopted unanimously the creation of a pedestrian walkway to promote ecotourism, environmental education and research in the area of the 'Encanizadas del Mar Menor' (EMM, thereafter), a space between the aforementioned lagoon and the Mediterranean Sea. The agreement was conditioned upon the completion of an environmental feasibility study which was commissioned to the University of Murcia. The area affected concentrates several habitats and species of community importance listed in EU Habitat and Bird Directives, including habitat 1140 (Mudflats and sandflats not covered by seawater at low tide) and many seabird and waterbirds. Traditional fishing has not only preserved its ecological uniqueness but increased cultural value. The multi-criteria evaluation developed by a multidisciplinary team has combined the basic information available with specific models of response to the presence of the infrastructure and its use by visitors, especially regarding hydrological and sediment dynamics, and biodiversity (birds and habitats). Although constrained by the complex regulatory and administrative framework, and by the quality of the environmental information available, the design and development of this study provides a model for the evaluation of projects with strong public demand in ecologically sensitive areas of Mediterranean coastal lagoons. The assessment was made on the basis of four groups of viability criteria (socioeconomic, environmental, administrative and legal, technical), weighted by expert panels to rate the alternatives previously drafted. A specific social consultation provided information on the preferences and attitudes of actual users and the regional public on the intervention and its alternatives. A combined analysis of socioeconomic (positive) and environmental (negative) impacts was used to select the alternative that concurrently maximized social preferences and environmental integration. Although the possibility of building a footbridge was rejected, the selected alternative (peripheral boat itinerary) still had good social acceptance, was consistent with ecotourism policies and matched experiences carried out elsewhere. Additional utilities of such multidisciplinary assessments are their performance as public information and participation processes, and the possibility to use them as a basis for drafting initiatives for the valorisation or restoration of other sections of lagoon complexes.
