A New Method for Environmental Flow Assessment Based on Basin Geology: Application to the Ebro Basin.

  The determination of environmental flows is one of the commonest practical actions implemented on European rivers to promote their good ecological status. In Mediterranean rivers, groundwater inflows are a decisive factor in streamflow maintenance. This work examines the relationship between the lithological composition of the Ebro basin (Spain) and dry-season flows, in order to establish a model that can assist in the calculation of environmental flow rates. The explanatory variable used in the proposed model is easy to calculate and is sufficiently powerful to take into account all the required characteristics. The model has a high coefficient of determination, indicating that it is accurate for the intended purpose. The advantage of this method is that it requires very little data and provides a simple estimate of environmental flow. The results of this research also contribute to knowledge of the variables that influence low-flow periods on rivers in the Ebro basin.