Revealing the effect of an industrial flash flood on vegetation area: A case study of Khusheh Mehr in Maragheh-Bonab Plain, Iran

Abstract

Floods are one of the most significant environmental hazards that can have harmful effects on agricultural activities and vegetation. The primary objective of this study is to analyze the destructive after-effects of an industrial flash flood on the vegetation of the Khusheh Mehr region. This flash flood occurred due to a break in the wastewater ponds of the Kaveh Soda factory on April 25, 2010. Using the Normalized Difference Water Index (NDWI) and the Normalized Difference Vegetation Index (NDVI) derived from time-series Landsat data over the period of 2000–2020, we analyzed the changes in wastewater ponds and regional vegetation before and after the wastewater flood occurred. We also investigate the quantitative and qualitative changes in vegetation during the past 20 years and detect the flood passage through this area. The results show that 538 ha out of the total 2123 ha of Khusheh Mehr were directly affected by the runoff resulting from the 2010 flood, and 1250000 m3 of industrial wastewater was discharged in the study area. The analysis of the vegetation in 2010 showed that during May and July, the efficiency and expansion of vegetation in these areas (NDVI >0.3) decreased by 90% and 55%, respectively, compared to the same periods in 2009 and 2006. The study is significant because it can help evaluate the effects of the flash flood not only on wastewater ponds and vegetation but also on the contamination of underground and surface waters as chemicals and industrial wastewater held in natural and artificial environments are discharged during a flood and directly affect vegetation. The findings can provide useful information for hazard and land use management and support policymakers, e.g., payment for financial loss of farmers.