高山峡谷型河流形态特征识别与分析：以金沙江上游为例

Identification and analysis of morphological characteristics of alpine-gorge rivers: A case study of upper reaches of Jinsha River

摘要

【目的】针对高山峡谷型河流地形复杂、传统监测困难的问题，基于遥感技术明确河流形态特征，为无资料区径流估算提供理论依据。【方法】基于多源遥感数据采用改进的相对稳定性指数、比降以及蜿蜒度识别河流形态特征；基于汇流累计数结合地质类型分析径流通量稳定河段特征；基于河道比降变化，探讨河流的能量转换频率；基于多站水力几何法的原理，验证分析流量与水面宽度的水力几何关系。【结果】(1)金沙江上游平均比降1.71‰,河段稳定性受地质类型调控。直门达至生巴村(Ⅰ段)、温拖村至石鼓镇(Ⅲ段)为稳定河段；生巴村至温拖村(Ⅱ段)为不稳定河段。(2)河段能量耗散受地质类型和比降控制。花岗岩河段表现出侵蚀性，玄武岩及页岩河段则趋于堆积。(3)水文站点处径流通量稳定河段的比降显著低于其他地质类型的平均比降，稳定性较好。(4)奔子栏河段水力几何分析表明，以500 m为间距的河段平均水面宽度与流量具有幂律关系，且系数与指数呈现对数线性关系；宽度回归方程的指数与对数线性方程的斜率近似，有利于提高流量估算的精度。【结论】河段稳定性及形态特征受地质类型控制，与能量耗散特征密切相关，径流通量稳定河段识别可为高山峡谷型河流的径流估算及水文监测提供科学支撑。

Abstract

[Objective] To address the problems of complex terrain and difficulty in traditional monitoring in alpine-gorge rivers, river morphological characteristics are clarified using remote sensing technology, providing a theoretical basis for runoff estimation in data-scarce areas. [Methods] Based on multi-source remote sensing data, river morphological characteristics were identified using an improved relative stability index, gradient, and sinuosity. Characteristics of runoff flux-stable river segments were analyzed based on confluence accumulation combined with geological types. The energy conversion frequency of the river was explored based on variations in channel gradients. The hydraulic geometry relationship between discharge and water surface width was verified and analyzed based on the principle of multi-station hydraulic geometry method.[Results]1) The average gradient of the upper reaches of the Jinsha River was 1.71‰, and the stability of river segments was regulated by geological types. The segments from Zhimen Da to Shengba Village(segment I) and from Wentuo Village to Shigu Town(segment III) were identified as stable, while the segment from Shengba Village to Wentuo Village(segment II) was identified as unstable.(2) Energy dissipation in river segments was controlled by geological type and channel gradient. Granite segments were characterized by erosion, while basalt and shale segments showed depositional tendencies.(3) The gradient of runoff flux-stable river segments at hydrological stations was significantly lower than the average gradient of their corresponding geological types, indicating better stability.(4) Hydraulic geometry analysis of the Benzilan river segment showed that the average water surface width at 500 m intervals had a power-law relationship with discharge, and the coefficient and exponent showed a logarithmic linear relationship. The exponent of the width regression equation was approximately equal to the slope of the logarithmic linear equation, which was beneficial for improving the accuracy of discharge estimation. [Conclusion] The stability and morphological characteristics of river segments are controlled by geological types and are closely related to energy dissipation characteristics. The identification of runoff flux-stable river segments can provide scientific support for discharge estimation and hydrological monitoring of alpine-gorge rivers.

关键词

河流形态 / 河段稳定性 / 能量耗散 / 径流通量稳定河段 / 水力几何 / 遥感

Key words

river morphology / river segment stability / energy dissipation / runoff flux-stable river segment / hydraulic geometry / remote sensing

基金资助

国家自然科学基金项目长江水科学研究联合基金(U2240202)

国家自然科学基金项目(52394233)

国家重点研发计划(2018YFC0506904)