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 km(2) in October 2017 and shrinking to 0.35 km(2) in October 2008. High-frequency permanent water (similar to 43 km(2)) is concentrated in the deep central basin and largely influenced by the Qarqan River, whereas seasonal water (similar to 300 km(2)) 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 km(2) for each 0.1 x 10(8) m(3) 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.