An ecosystem service approach to understand conflicts on river flows: local views on the Ter River (Catalonia)

Claims for a global agenda addressing the need to protect environmental flows are increasing. In the context of frequent conflicts related to unsustainable exploitation of rivers, instream flow policies may result in very different outcomes and involve different beneficiaries. We propose and test an innovative local knowledge-based methodology that uses the ecosystem services approach to disentangle the links within the river-society system. In particular, network analysis is employed to identify potential tradeoffs caused by the river flow management. Our empirical evidence relies on a thorough scrutiny of key stakeholders' positions in the Ter River basin (Catalonia, Spain). As in other Northern Mediterranean contexts, multiple weirs interrupt the water flow in the upper course, diverting water for hydropower. Meanwhile, in the middle course, the bulk of water flow is transferred to the metropolitan Barcelona contributing to water scarcity in the Lower Ter, where farmers and other users claim against imposed restrictions on access to water flows. Our results point out that (1) in contexts such as the analyzed one, the 'ecosystem services' (ES) notion enhances communication among stakeholders; (2) ground-up exercises are essential for identifying river benefits at local scale and characterizing the related ES; and (3) network analysis helps to make explicit tradeoffs between river uses, in which recognition is crucial to understand how conflicts on river flows emerge and how can be managed, (4) management of instream flows should be informed by the complex interaction, herein outlined, between hydrological alterations, components of river ecosystems and the benefits they provide.