Spatial Drivers of the Electricity-to-Water Conversion Coefficient in an Inner Mongolia Plateau Irrigation District

Groundwater accounting in arid and semi-arid well-irrigated areas is often constrained by difficulties in water-meter installation and maintenance, as well as variability in well–pump operation, thereby limiting refined agricultural water-use management. The electricity-to-water conversion coefficient (Tc) can be used to estimate groundwater abstraction from electricity consumption; however, the applicability of empirical models developed for plain irrigation districts remains uncertain in plateau regions characterized by pronounced topographic relief and complex aquifer conditions. This study examined 56 typical irrigation wells in Chayouzhongqi on the Inner Mongolia Plateau. Based on pumping-test data and using correlation analysis, structural equation modeling, redundancy analysis, and random forest analysis, we investigated the spatial distribution of Tc and its associated mechanisms. Tc ranged from 0.08 to 3.88 m3 kWh−1, with a mean of 1.62 m3 kWh−1, and exhibited a pattern of higher values in the north, lower values in the south, and the lowest values in the western part of the study area. Electricity consumption, rated flow rate, and actual discharge were the principal associated variables, with relative importance values of 43.0%, 21.6%, and 15.7%, respectively. Topographic and aquifer conditions imposed regional constraints on spatial variation in Tc by influencing well–pump operating states. These findings indicate that Tc estimation in plateau well-irrigation districts should not directly adopt empirical relationships developed for plains, but should instead be calibrated according to regional hydrogeological and engineering operating conditions, thereby providing a basis for improved groundwater accounting and water-saving management in arid and semi-arid regions.