Development and application of the River Health Index (RHI) with an integrated approach to assess the ecological status (Case study: Tajan River)

Mohajer Tabrizi, Lilian; Rahimi, Razieh; Zaeimdar, Mojgan; Rafati, Maryam

doi:10.22059/ije.2026.420638.1927

Development and application of the River Health Index (RHI) with an integrated approach to assess the ecological status (Case study: Tajan River)

Articles in Press

Document Type : Research Article

Authors

Lilian Mohajer Tabrizi ¹

Razieh Rahimi ²

Mojgan Zaeimdar ³

Maryam Rafati ³

¹ Department of Environment, , NTC, , Islamic Azad University, Tehran, Iran

² Department of Environmental Science and Engineering.West Tehran Branch.Islamic Azad University

³ Department of Environment, NTC,, Islamic Azad University, Tehran, Iran

10.22059/ije.2026.420638.1927

Abstract

Objective: This study aimed to develop and apply an integrated River Health Index (RHI) to assess the condition of the Tajan River by combining hydrological components, water quality, river reliability, resilience, and vulnerability (RRV), along with human and developmental pressures.

Methods: In this study, the river health index was assessed over a 10-year period (2014–2024) by integrating data from six hydrometric stations and nine water quality monitoring stations. The assessment components included hydrological characteristics, physicochemical parameters, RRV indicators, and GIS-based human pressures. After normalizing the components, the final river health index was calculated using Shannon entropy weighting. This comprehensive modeling provides a strategic tool for river ecosystem management and offers an accurate perspective on the overall health status of the basin, supporting informed decision-making in major water resource planning.

Results: Results indicate a gradual decline in Tajan River health from upstream to downstream. Water quality had the greatest influence on the final index, followed by RRV, hydrology, and human pressures. Spatial zoning showed that downstream reaches are in a more unfavorable condition.

Conclusion: The proposed integrated index can serve as a practical tool for river monitoring, identifying critical areas, and supporting management decisions in basins under pressure.

Keywords

Tajan

River

RRV

Water

Quality

Subjects