doi:10.16186/j.cnki.1673-9787.2020090078

Received:2020/09/18

Revised:2020/12/18

Published:2022/07/15

 Evolution of river network system in the mountain excavation and city construction in Yan’an New District

XU Xiaolu1, HAO Lina1,2, LIU Hanhu1, ZHAO Mailing1, MENG Tian1, JIANG Chuandong1

1.College of Earth Sciences，Chengdu University of Technology， Chengdu 610059 ， Sichuan， China;2.State Key Laboratory of Geohazard Prevention and Geoenvironment Protection，Chengdu University of Technology，Chengdu  610059,Sichuan, China

Abstract: In order to to study the influence of city construction on river network system, taking the mountain excavation and city construction project in Yan’an New District as an example,based on DEM data in 2009，2013 and 2017 ,the river net with different time series was extracted respectively. The river length , drainage density ,tributary development index and river bending index were selected to analyze the evolution process of river network system before and after the mountain excavation and city construction project for Yan’an New District. The results showed that:(1) From 2009 to 2017,the river length and the drainage density in the study area showed a downward trend, with the total river length decreasing by 16.88 km and the drainage density de creasing by 0.051 km/km². The Ⅲ river net reduced 13.38 km. (2) From the perspective of the structural of the river net system ,the river bend index of the Yanhe river droped from 1.67 to 1.64, and the natural characteristics of the river weaken. Both II and Ⅲ river net index decreased. The river development levels of the Ⅲ river net was far lower than the Ⅱ river network. (3) With the development of the mountain excavation and city construction project, many tiny river valleys have been buried or even disappeared, and tributaries have been attenuated ,river structure has been disturbed, resulting in the decline of the natural storage capacity to extreme rainfall events which might trigger floods and geological disasters has been increased.

Key words:mountain excavation and city construction;Yan’an New District;river network system;water system evolution

平山造城工程下的延安新区河网水系演变_许晓露.pdf