昆明盘龙江流域数字水系提取及水文特征分析

Digital Drainage Network Extraction and Hydrological Characterization in the Panlong River Basin, Kunming

摘要: 本研究以昆明市盘龙江流域为对象，基于30米分辨率的ASTGTM DEM数据，运用ArcGIS水文分析模块，构建了该流域的数字水文网络。研究重点探讨了集水面积阈值对河网提取精度的影响，通过基于流域面积与像元分辨率的比值关系确定了合理阈值。在此基础上，系统完成了流域边界提取、河网生成、水系分级及子流域划分，并利用河流链接与分级方法实现了水系拓扑结构的完整表达，同时计算了地形湿度指数，定量刻画了流域内径流汇集区与水分富集潜力的空间分异格局。结果表明，所提取的盘龙江流域结构与实际水系分布具有较高吻合度，主干河道形态呈“S”型特征，支流网络符合地形驱动规律，TWI高值区主要分布于主干河道两侧、河谷平原及子流域出水口，低值区集中于流域边界附近的山脊、陡坡地带，其空间分布与双支流交汇格局、主干河道形态形成良好耦合，验证了地形对径流汇集的显著驱动作用。本研究形成了一套适用于高原城市小流域的数字水文分析方法体系，成果可为盘龙江流域的水资源管理、洪水模拟及生态保护提供可靠的空间数据基础与决策支持。

Abstract: This study focuses on the Panlong River Basin in Kunming. Using 30 m resolution ASTGTM DEM data and the ArcGIS hydrology analysis module, a digital hydrological network of the basin was constructed. The research specifically investigates the influence of the catchment area threshold on the accuracy of river network extraction, determining an appropriate threshold based on the ratio between the actual basin area and pixel resolution. On this basis, a systematic process was undertaken to extract the watershed boundary, generate the river network, classify the stream order, and delineate sub-basins. The topological structure of the drainage system was fully represented through stream link and ordering methods. In addition, the Topographic Wetness Index (TWI) was calculated to quantitatively characterize the spatial heterogeneity of runoff convergence areas and soil moisture potential within the basin. The results indicate that the extracted basin structure of the Panlong River aligns well with the actual hydrographic distribution. The main channel exhibits an “S”-shaped morphology, and the tributary network conforms to topographically driven patterns. TWI high-value zones are mainly distributed along the main channel, valley plains, and sub-basin outlets, while low-value zones are concentrated along watershed ridges and steep slopes. This spatial distribution shows strong coupling with the dual-tributary confluence pattern and main channel morphology, validating the significant role of topography in driving runoff convergence. This study establishes a methodological framework for digital hydrological analysis applicable to small plateau urban basins. The outcomes provide a reliable spatial data foundation and decision support for water resource management, flood simulation, and ecological conservation in the Panlong River Basin.