## 4 Results and Analysis
### Impact of River Channel Evolution on Ecological Water Diversion  
The Tarim River serves as the lifeline for agriculture and ecosystems in the arid regions of southern Xinjiang. River channel evolution is a fundamental aspect of natural fluvial processes, and its dynamic changes directly affect the feasibility and sustainability of ecological water diversion along both banks, thereby influencing agricultural production and ecological conditions in the surrounding The Xinqiman-Kelelik reach of the Tarim River traverses Shaya County and Kuche City. The water resources of the Tarim River are crucial for sustaining the agricultural systems and fragile ecological balance in these regions. Within this reach, there are five ecological diversion gates, namely the Paman Reservoir Diversion Sluice, Tuijianqu Ecological Diversion Sluice, Wenhuaqu Ecological Diversion Sluice, Jigedalaxi Diversion Sluice, and Tupitaxiti Diversion Sluice (Figure 9). These shuices are responsible for irrigating 22,100 hectares of farmland and 68,700 hectares of ecological land in the region. Therefore, it is crucial to investigate the impact of river evolution on these ecological diversion gates. As indicated by the analysis results from Section 3.2, the river channels at the Paman Reservoir Diversion Sluice (Cross-section CC), Wenhuaqu Ecological Diversion Sluice (Cross-section EE), Jigedalaxi Diversion Sluice (Cross-section FF), and Tupitaxiti Diversion Sluice (Cross-section MM) have undergone significant narrowing, while the river channel at the Tuijianqu Ecological Diversion Sluice (Cross-section DD) has remained stable. The primary cause of river channel contraction is the combined effect of natural flow and sediment variations (helicoidal flow in bends causing concave bank erosion and convex bank deposition) and human activities (reduced base flow due to dam/gate regulation and restricted lateral movement from bank protection). These have led to deepened concave bank scour threatening gate foundation stability and convex bank sedimentation narrowing the flow cross-section, resulting in a local rise in water levels near gates. However, the specific threats to human development activities (such as farmland, construction, and  
Figure 9: Distribution of farmland and locations of ecological water diversion sluices along the Xinqiman–Kelelik river reach. infrastructure) on both sides of the Strait need to distinguish between the relative effects of natural processes and human activities. The strong lateral erosion (concave bank erosion migration) observed during the study period is mainly the natural attribute of river dynamic evolution, especially in areas without engineering intervention or with weak lithological corrosion resistance. However, the intervention of human activities has significantly amplified the negative impact of natural changes. On the one hand, water conservancy projects (dam regulation) have weakened the base flow that maintains the stability of river morphology and accelerated the shrinking trend; on the other hand, early river management was improper or lagging behind, failing to set up effective protection in key areas in time, and not halting human encroachment on settlements and agricultural development in floodplains, exposing these areas to the potential risk of river swing or shrinkage. It is recommended that the concave bank be stabilized using pile-founded caissons combined with eco-friendly gabion structures to control erosion, and sediment-guiding groynes should be installed along the convex bank to optimize deposition patterns. These measures are essential to ensure the structural safety of the diversion sluices and improve water intake efficiency. Figure 10 illustrates the thalweg shifts near the eco-diversion gates of the Xinjaman-Kelelik reach. From 1993-2000, the thalweg in the vicinity of the Paman Reservoir Diversion Sluice shifted 557.3 m towards the gate at a rate of 79.6 m/a.