This project is generating new remote sensing methods for DOI use and across the globe. Recently published research introduced the Augmented Normalized Difference Water Index (ANDWI), which employs an expanded set of spectral bands—red, green, blue (RGB), near-infrared (NIR), and short-wave infrared (SWIR) 1&2—to maximize the contrast between water and non-water pixels. Using the Otsu algorithm, which is a dynamic thresholding method, researchers enhanced ANDWI and found improvements over other water remote sensing indices such as the normalized difference water index (NDWI), modification of normalized difference water index (MNDWI), automated water extraction index (AWEI), and water ration index (WRI). These methods are now being used in a study of endorheic inland lakes, which face increasing climatic and anthropogenic stress that at times causes them to recede and desiccate. Determining the relative influence of drivers is problematic even in data-rich environments; it is exceedingly difficult in less developed regions of the world and in data-poor environments. The terminal Hamun Lakes, on the border of Iran and Afghanistan, embody the amplified challenges facing inland waters. Although drought triggered the lakes’ recession, they would not have desiccated without increasing anthropogenic pressures. Upstream Afghanistan has experienced rapid growth in irrigated agricultural lands in the recent decade; annual growth reached 7,822 km2 from 2015–-2019, which is four times that from 1984–1988. Compounding this pressure, in 2009 Iran began storing flood water that fed the Hamun Lakes for urban and agricultural consumption. Researchers estimate that the lakes’ surface area in the recent decade would have been 2.5 times larger without increasing anthropogenic stress across the basin. This data integration effort is an unprecedented analysis of the basin hydrology and land use change of the region..
Hamun Lakes desiccated in the recent decade. (a) The Hamun Lakes’ monthly surface area from 1984–2019. (b) Map of the Helmand River Basin, HRB, and considered sub-basins. (c) Monthly water storage in the 4th artificial reservoir (Chah-nimeh 4). (d) Monthly water storage in the Kajaki Dam. (e) Monthly water storage in sub-basin 4 including the Arghandab Dam and three lakes. In (b), the Hamun Lakes in sub-basin 1 are marked with a dark red ellipse, the Kajaki dam in sub-basin 3 is marked with a light red circle, and the Arghandab Dam and three lakes in sub-basin 4 are marked with pink circles. Blue dashed lines represent statistically significant trends based on the Mann-Kendall test and red dots show statistically significant change points based on the Pettitt test.