پیامدهای امنیت زیست‌محیطی کاهش دبی رودخانه هریرود در ایران: مطالعه موردی شهرستان سرخس

The persistent reduction in the discharge of the Harirud River entering Sarakhs County, located in the Khorasan Razavi Province of northeastern Iran primarily a consequence of the commencement of the Salma Dam project in Afghanistan in 2016, further exacerbated by regional climatic variations constitutes a measurable and escalating threat to Iran's environmental security at the sub-national level. Utilizing a quantitative descriptive–analytical approach grounded exclusively in secondary data from the years 2000 to 2023, this study employs Mann–Kendall trend analysis, Sen's slope estimation, Pettitt change-point detection, and bivariate correlation analysis within an integrated Pressure–State–Response (PSR) framework alongside the environmental security paradigm established by the Copenhagen School. An analysis of hydrometric, remote sensing (NDVI), piezometric, agricultural census, meteorological, and demographic data reveals statistically significant, multidimensional deterioration across all assessed security indicators following the alteration of the structural discharge regime in 2016. The annual discharge has decreased at a rate of 12.3 million m³ per year, resulting in the inflow to the Doosti Dam being reduced to approximately 70% of its pre-2016 baseline, while downstream impacts include an estimated 41% decline in NDVI, a 72% increase in annual dust storm occurrences, a 7.4-meter drop in groundwater levels, a 34% reduction in irrigated land, a 33% decrease in irrigated wheat production, and a reversal in rural demographic growth from +1.2% to −2.8% annually. Correlation analysis further demonstrates that annual discharge accounts for between 37% and 71% of the variability in key environmental security indicators. Collectively, these results corroborate the causal link between unilateral upstream water-infrastructure developments and multidimensional downstream environmental insecurity, thereby establishing a robust empirical basis for advocating a binding trilateral water-sharing agreement for the Harirud/Tejen Basin among Afghanistan, Iran, and Turkmenistan.