Estimation of unplanned water use based on system dynamics model in arid areas

The rational utilization of water resources is crucial for the sustainable development of arid areas. However, the swift increase in agricultural water use has resulted in ecological challenges, potentially escalating into environmental crises in arid areas. Considering the sustainable utilization of water resources, a significant portion of agricultural water use is provided by the government through systematic planning, which is called planned water use. By contrast, unplanned water use is the unauthorized extraction of groundwater, river water, or lake water. Although unplanned water use may be a major contributor to ecological problems, estimating unplanned water use has been a challenge due to the lack of comprehensive data on unplanned water use in the relevant sectors. This study evaluated unplanned water use in the northern slope of the Tian Mountains in Xinjiang, considering the overall water use situation of various industries based on system dynamics. The results showed that unplanned water use has increased rapidly, mainly due to rapid expansion of cropland and limited growth in planned water use. The proportion of unplanned water use of all water use reached a maximum proportion of 35.2 % in 2020. This phenomenon should be attracted attention from various sectors of society. Finally, the study proposed recommendations for future improvements and deeper research, aiming to provide insights for water resources management and unplanned water use governance in arid areas. • System dynamics model used for estimating unplanned water use in arid areas. • Relatively stable growth in unplanned water use due to cropland expansion. • Unplanned water use reaching 35.2 % in the study area in 2020. • Unplanned water use should be paid more attention.