Analyzing Multisource Hydrological Variability for Precise Water Allocation in an Arid Terminal Lake: A Case Study of Taitema Lake, Northwest China

Terminal lakes in arid regions are highly vulnerable to climate variability and human water management, yet their long-term hydrological responses under multi-river regulation remain insufficiently quantified. Using Taitema Lake at the terminus of the Tarim Basin as a case study, this research integrates Landsat and Sentinel observations (2005–2025) with meteorological and river-inflow records to examine lake area dynamics and to identify river-specific hydrological controls. The results show pronounced intra- and interannual variability, with the lake expanding to a maximum of 461.52 km2 in October 2017 and shrinking to 0.35 km2 in October 2008. High-frequency permanent water (~43 km2) is concentrated in the deep central basin and largely influenced by the Qarqan River, whereas seasonal water (~300 km2) is broadly distributed and strongly affected by ecological releases from the Tarim River. Quantified inflow–area relationships indicate that the lake expands by 7–14 km2 for each 0.1 × 108 m3 of inflow. Based on frequency-based hydrological analysis, this study develops joint inflow strategies for wet, normal, and dry years, offering a practical hydrological basis for more precise and adaptive water allocation schemes in arid terminal lakes.