A multi-criteria analysis for Environmental Flow Assessment based on hydraulic modelling

Area of Science:

• River ecology
• Hydrology
• Conservation biology

Background:

• Environmental Flow (EF) assessment is vital for evaluating water withdrawal impacts on riverine habitats.
• Standardized methods for EF assessment are lacking, often requiring case-specific adaptations.
• Existing techniques are frequently tailored ad hoc, limiting broader applicability.

Purpose of the Study:

• To propose a novel multi-criteria approach for quantifying Environmental Flow (EF).
• To integrate hydraulic modeling and habitat viability for a target fish species.
• To quantify the uncertainty associated with EF estimations.

Main Methods:

• Developed a multi-criteria framework incorporating six distinct criteria.
• Utilized a hydraulic river model to simulate flow conditions.
• Assessed habitat viability based on geometric, biological, riverbed quality, and macro-benthos requirements.
• Generated a comparison table of optimal criteria values to determine a "globally viable" EF.

Main Results:

• The proposed approach quantifies Environmental Flow (EF) and its associated uncertainty.
• Six criteria were defined, encompassing geometric, biological, riverbed quality, and prey availability constraints.
• The method provides a structured way to compare optimal flow values for different criteria.

Conclusions:

• The multi-criteria approach offers a robust framework for Environmental Flow assessment.
• This method aids in selecting a "globally viable" EF that balances various ecological needs.
• It provides a more standardized and less case-specific method for river management decisions.