Toward the return to the historical natural flow regime in highly managed rivers: a pilot experience in the South of Spain

In highly managed rivers where the presence of reservoirs has completely altered the natural regime of the river, returning to the historical natural flow regime is an increasingly distant option. However, managers and water authorities must establish criteria to ensure the ecological status of water bodies following the recommendations of the Water Framework Directive (WFD). Often integrating this objective competes with the rest of water uses, making maintaining a balance that brings on both human development and environmental conservation a challenge. This issue is especially crucial in unmonitored basins in which the natural hydrological regime conditions prior to alteration are unknown. 

To face this challenge, interdisciplinary collaborations connecting stakeholders and research arise for both improving operational hydrology services and achieving science-informed policies. This work brings an example of that science-policy-practice nexus through a collaboration between university and business. The pilot area to host the experience is the Rivera de Huelva basin, located in the South of Spain, where a state-owned water company manages the three reservoirs which spatially and temporally allocate water resources in the basin. An approach combining historical streamflow and operation data and hydrological modelling will allow us to assess natural hydrological conditions in this unmonitored and regulated basin, as well as the definition of an environmental flow regime in drought and/or scarcity situations. Our outcomes will help reservoir managers to set the basis for the design of new minimum environmental flow rates which are founded on the principles of the natural flow regime paradigm.

 

Acknowledgments: This work has been funded by the project CONV 39-27 UCO-EMASESA, in the framework of the TED/934/2022-PCAU00006, funded by MITECO and by European Union NextGenerationEU/PTR.