This paper investigates the hydro-climatic reasons behind the desiccation of the Hamun Lakes in the Iran-Afghanistan border. We analyzed changes in the flow of the Hirmand River (90 percent of the total inflow to the lakes) at the international border, and precipitation over this river’s sub-basin during 1960–2016 by calculating standardized indices for precipitation (SPI) and discharge (SDI). We applied Normalized Difference Spectral Indices using satellite images from 1987 to 2021 to observe monthly areal change of the lakes. The results show that the major cause of desiccation is upstream water regulation which severely reduced the Hirmand River inflow delivery to the lakes. Constructed reservoirs near the lakes by Iran in 2008, compounded the effect of Afghanistan water regulation to aggravate the situation. There is a discernible shift in the relation between the Hirmand River flow at the border and upstream precipitation before and after 2004. In 1960–2003, high Hirmand River inflows were expected due to high precipitation, while the flow declined after 2004 despite large amounts of upstream precipitation. Although a long period of drought from 1998 to 2004 decreased the lakes’ area, the lake system is primarily falling victim to anthropogenic flow reduction recently. Increased regulation of flows and use of water for irrigation in Afghanistan and Iran underscores the necessity of bilateral dialogues between the two countries to consider environmental flow for the lakes. The lakes’ shrinkage places socio-economic stress on an already-vulnerable region with public health implications as the exposed lake beds turn into major sources of dust storms.

本文调查了伊朗-阿富汗边境哈蒙湖干涸背后的水文气候原因。我们通过计算降水量 (SPI) 和流量的标准化指数，分析了 1960-2016 年期间国际边界的赫尔曼德河流量（占湖泊总流入量的 90%）和该河流次流域的降水量变化。 SDI)。我们使用 1987 年至 2021 年的卫星图像应用归一化差异光谱指数来观察湖泊的月面积变化。结果表明，干旱的主要原因是上游水量调节严重减少了赫尔曼德河流入湖泊的流量。2008 年，伊朗在湖泊附近修建了水库，加剧了阿富汗水资源管制的影响，加剧了局势。2004 年之前和之后，边界的赫尔曼德河流量与上游降水之间的关系发生了明显变化。在 1960-2003 年，由于降水量大，预计赫尔曼德河的流入量很高，而 2004 年之后流量下降，尽管有大量的上游降水。尽管 1998 年至 2004 年的长期干旱减少了湖泊面积，但最近湖泊系统主要成为人为流量减少的牺牲品。在阿富汗和伊朗加强对流量和灌溉用水的监管，强调了两国之间进行双边对话以考虑湖泊环境流量的必要性。随着裸露的湖床变成沙尘暴的主要来源，湖泊的萎缩给本已脆弱的地区带来了社会经济压力，并对公共卫生产生了影响。