Abstract
Population growth, climate change, and a lack of infrastructure have contributed to an increase in water demand and groundwater exploitation in urban and rural Afghanistan, resulting in significant ground subsidence. Based on a 7‐year‐long Sentinel‐1 radar‐interferometric time‐series (2015–2022), we assess country‐wide subsidence rates. Of particular focus are urban Kabul and the growing agricultural sector of rural Ghazni. In Kabul, we compare spatiotemporal subsidence patterns to water table heights and precipitation amounts. In Ghazni, we monitored the transition from ancient to modern irrigation techniques by mapping solar‐panel arrays as a proxy for electrical water pumping and evaluating the vegetation index as a proxy for agricultural activity. Several cultural centers (Kabul, Ghazni, Helmand, Farah, Baghlan, and Kunduz) exhibit significant subsidence of more than ∼5 ± 0.1 cm/yr. In Kabul, ground subsidence is largest near the city center with a 6‐year total of 31.2 ± 0.5 cm, but the peripheral wells of the Kabul basin exhibit the highest water‐table drops. In Ghazni, with a 7‐year total of 77.8 ± 0.5 cm, subsidence rates are dramatically accelerating since 2018. Before 2018, barren land was transformed into farmland and traditional irrigation was replaced by electrical water pumps to tap groundwater. As a result, m‐wide and km‐long desiccation cracks appeared in the area with the highest irrigation volume and subsidence.
Political instability in Afghanistan limited access to freshwater resources for decades. At the same time, population growth, climate change, and more efficient electric water pumps lead to an increased demand for this vital resource. As a consequence, the lowering water table causes severe land subsidence in several Afghan cities and agricultural centers. Using space‐borne radar measurements from 2015 to 2022, we mapped Afghan land subsidence and found about 31 cm of subsidence over 6 years in Kabul city and about 78 cm over 7 years in the Ghazni agricultural province. In Kabul, we measured the fastest subsidence near the city center, but it is the wells in the marginal districts that are affected the most because here, the aquifers are thinnest and thus most vulnerable. In Ghazni, the land subsidence is caused by turning barren into fertile land and by excessive electrical pumping of groundwater since 2016 for farming. The subsidence problem was intensified by droughts in 2020 and 2021 that caused meter‐wide surface cracks over a length of a few kilometers in 2022.
Afghan‐wide subsidence data highlights several urban and agricultural centers with more than 7 mm/yr of subsidence between 2015 and 2022 Droughts and increased groundwater pumping caused subsidence of 31.2 cm in Kabul over ∼6 and 77.8 cm in Ghazni over ∼7 years In farmlands, mapped solar panels serve as a proxy for groundwater extraction and acceleration of subsidence using electrical pumps