Using multicriteria analysis to develop environmental flow scenarios for rivers targeted for water resource management

Abstract

DRIFT is an interactive, holistic approach for advising on environmental flows for rivers. The DRIFT methodology, together with multicriteria analysis (MCA), can be used to provide flow scenarios and descriptive summaries of their consequences in terms of the condition of the river ecosystem, for examination and comparison by decision-makers. The essential features of DRIFT, the output of workshops where it is applied, and the development of the DRIFT database are described. Modules within the database include DRIFTSOLVER and DRIFT CATEGORY. DRIFTSOLVER contains an integer linear programming MCA method, which generates optimally distributed flow scenarios for different total annual volumes of water. DRIFT CATEGORY facilitates evaluation of these in terms of river condition. These two modules are explained in detail and illustrated with examples. Water SA Vol.29(4): 365-374