A long-period assessment of climate change impact on river water quality in the central region of Iran

Abstract

Considering the detrimental impact of climate change on water quality, regional studies can prove invaluable in reducing financial losses and enhancing the efficacy of local water management strategies, thereby mitigating the potential adverse consequences of climate change. This study developed a new approach to investigate this issue by analyzing climate and water quality parameters in the Zayandeh-Rud River watershed over 14 years. Data were collected from relevant organizations in Iran. A correlation analysis was conducted to identify the impact of climate change on water quality. Moreover, ordinary kriging, and inverse distance weighting methods were employed for the spatial distribution of parameters. Furthermore, the spatial autocorrelation outcomes about water quality were validated. Hot spot analysis and Anselin Local Moran’s I indices were subsequently employed to effectively delineate clusters with high and low concentration of water quality parameters. The number of freezing days, annual average, minimum, and maximum temperatures, exhibited an upward trend. However, some water quality parameters (EC, TDS, HCO₃⁻, CO₃²⁻, SO₄²⁻, Cl⁻, Mg²⁺, and Na⁺) decreased during the study period. Furthermore, examination of clusters and anomalies revealed that this region is positioned within low–high outlier pattern. Most of the examined water quality parameters demonstrated a clustering of elevated values with a statistical confidence level of 99% within the eastern region of the research area. This study will facilitate the understanding of the impacts of climate change on water quality and the identification of appropriate adaptation measures for the ecosystem management of the Zayandeh-Rud river watershed in Iran.