Causes and consequences of environmental degradation along the Shatt Al–Arab River: a coupled human and natural systems (CHANS) perspective

Abstract:

The Shatt Al-Arab River region (SARR) in Iraq was an economically important area for food production. By the 1970s the environment of this region had begun to deteriorate, and since then the SARR has suffered from severe human- and natural-induced problems. In this study we use a coupled human and natural systems (CHANS) perspective to identify these problems, their interconnections, and the degree to which human or natural systems have contributed to environmental degradation. We used several measures of ecological, economic and social systems to quantify the problems and document changes over the past five decades. The SARR has experienced significant climatological changes from 1975 to 2017, including lower precipitation and humidity, and increases in temperature and sea level, which affected the salinity of groundwater and river water. Human systems in the SARR also experienced tremendous stresses, including war and economic sanctions. We calculated and analyzed changes in vegetation via NDVI classification of Landsat imagery for five dates between 1975 and 2017 to understand how the environment has been affected. Changes in climatological variables were associated with lower NDVI throughout the region. However, vegetation decreased on the Iraqi side of the river, while it increased slightly on the Iranian side. This drop appears related to higher salinity in both surface and groundwater in Iraq, while irrigation from less saline water has maintained more consistent vegetation in Iran, suggesting that hydrologic diversion may be driving distinct trajectories for land use and vegetation on either side of the Shatt Al-Arab River.