Development of an environmental flow approach applied to the Piabanha River watershed

Abstract

Although in Brazil the science of environmental flows is still little explored, the structure of water resources management of the country presents a great opportunity for its implementation through the engagement of watershed committees during the construction of Water Resources Plans. This study proposed an adaptation of the Ecological Limits of Hydrologic Alteration (ELOHA) framework to the context of Brazilian watershed committees. The adaptation includes the addition of new steps: engage/consult the watershed committee through workshops, surveys, and participatory mapping; classification of the hydrological alterations; proposal of the inclusion of an ecological foundation; and propose different e-flows recommendations based on the different state legislations and the Tennant method. The workshops, surveys, and participatory mapping were able to facilitate the watershed members to participate and communicate their needs. The basin does not have significant hydrological alteration on its rivers when classified the rivers fall in the category of un-impacted and low impact condition. The flow ecology hypothesis pointed out a link between the hydrological alterations and the fish species richness. These links need to be further investigated. Outstanding and Excellent categories from Tennant method presented the highest values for instream flow protection compared with the current Brazilian methods. This study was able to propose and apply an environmental flow approach adapted to the context of Brazilian watershed committees.