Use of reclaimed water in the recreation and restoration of aquatic ecosystems: practical experience in the Costa Brava region (Girona, Spain)

Abstract

Where there is water scarcity, the situation is dramatic for aquatic ecosystems. In many Mediterranean basins the exploitation of water resources has gone clearly beyond renewable level and affects aquatic ecosystems. Thus, they may benefit from the recycling of high-quality effluents that can be used to cope with environmental water demands instead of being discharged. Their reclamation with natural technologies produces an improvement in quality based on the development of trophic webs built upon nutrients still dissolved in the reclaimed water. The main project in the Costa Brava area is that of the Empuriabrava constructed wetland system, where nitrified effluent is further treated to reduce the concentration of nutrients in the water and is reused for environmental enhancement. This facility is also an interesting site for bird-watching. Other projects where water recycling produces indirect benefits on the aquatic ecosystems are those in Tossa de Mar, affecting the “temporary” Tossa Creek (a watercourse which flows on temporary basis according to rainfall patterns), and in the Aro Valley, affecting the also “temporary”, but slightly bigger, Ridaura River. This document summarizes these projects and proposes practical recommendations for the use of treated effluents in the recreation and restoration of aquatic ecosystems.