Do Environmental Stream Classifications Support Flow Assessments in Mediterranean Basins?

The final publication is available at http://dx.doi.org/10.1007/s11269-012-0104-3Natural flow regimes are of primary interest in designing environmental flows and therefore essential for water management and planning. The present study discriminated natural hydrologic variation using two different environmental classifications (REC-Segura and WFD-ecotypes) and tested their agreement with an a posteriori (hydrologic) classification in a Spanish Mediterranean basin (the Segura River, SE Spain). The REC-Segura was developed as a two-level hierarchical classification based on environmental variables that influence hydrology (climate and source-of-flow). The WFD-ecotypes were developed by the Spanish Ministry for the Environment to implement the Water Framework Directive (WFD) using hierarchical hydrologic, morphologic and physicochemical variables. The climate level in the REC-Segura broadly described the hydrologic pattern observed along the NW-SE aridity gradient of the basin. However, source-of-flow (defined by karstic geology) was only able to discriminate variation in flow regimes within one climatic category. The WFD-ecotypes, despite incorporating hydrologic variables, did not fully discriminate hydrologic variation in the basin. Ecotypes in tributary streams located in dry or semiarid climates embrace different flow regimes (both perennial and intermittent). There was little agreement between environmental and hydrologic classifications. Therefore, the authors advise against the use of environmental classifications for the assessment of environmental flows without first testing their ability to discriminate hydrologic patterns.We would like to thank the University of Murcia for its financial support to Oscar Belmar through a pre-doctoral grant, the Hydrographic Confederation of the Segura for providing the precipitation data as well as the SIMPA model, and the Euromediterranean Institute of Water for its support to the project "Hydrological classification of the rivers and streams in the Segura Basin and associated macroinvertebrate communities".Belmar, O.; Velasco, J.; Martinez-Capel, F.; Peredo Parada, MM.; Snelder, T. (2012). Do Environmental Stream Classifications Support Flow Assessments in Mediterranean Basins?. Water Resources Management. 26(13):3803-3817. doi:10.1007/s11269-012-0104-3S38033817261