JOURNAL OF NATURAL RESOURCES ›› 2019, Vol. 34 ›› Issue (7): 1429-1439.doi: 10.31497/zrzyxb.20190707

• Resource Evaluation • Previous Articles     Next Articles

The relationship between the change of water system and the urban land expansion in Changsha

JIANG Qi1,2, ZHENG Bo-Hong1   

  1. 1. School of Architecture and Art, Central South University, Changsha 410000, China;
    2. Changsha City Planning Survey and Design Institute, Changsha 410007, China
  • Received:2018-10-09 Online:2019-07-28 Published:2019-07-28

Abstract: In order to examine the connection between water system changes and the expansion of urban land use, and provide evidence and experience for the future coordinated development of water ecological restoration and urban and ecological environment, statistical methods were used to analyze the five-phase water system and urban land expansion in Changsha in the past 60 years. We selected river net density, water surface rate, mainstream river curvature indexes and river development coefficient to quantitatively describe changes in water system characteristics and used urban intensity expansion index to measure the strength and speed of expansion of urban construction land in the same period based on the topographic maps and urban construction land data of Changsha city in the 1950s, 1970s, 1990s, 2010s and 2016. After superimposing the water system change index and urban expansion intensity index in each basin, we analyzed the relationship between the water system changes in various stages of Changsha and the urban land expansion intensity. The results show that: (1) The expansion of urban construction land has a direct impact on the quantity and shape of urban water coefficients. In the past 60 years in Changsha, the main characteristic values of the water system experienced a large attenuation. In general, the amount and area of the water surface were greatly reduced, and both the river structure and the water system tended to be simple. Meanwhile, the river network density and water surface rate reflecting the characteristics of water coefficient decreased by 3.74% and 26.26%, respectively. (2) The intensity of urban expansion in each period was positively related to the decay rate of water quality index values. From the 1950s to the 1990s, the urban expansion of Changsha was concentrated in the Xiangjiang River system, the Liuyang River system and the Guitang River system east of the Xiangjiang River. During this period, the water surface rates in the three water systems decreased by 6.7%, 6.38%, and 6.75%, respectively. After 1990, Changsha entered the stage of rapid urbanization, but the urban expansion intensity in areas west of the Xiangjiang River was stronger than that in areas east of the Xiangjiang River. At the same time, the density of river network west of the Xiangjiang River was faster than that east of the Xiangjiang River, down by 1.13% and 6.19%, respectively. (3) Destruction of water system in urban expansion will increase the risk of ecological and natural disasters, and effective water ecological protection policies and protection measures can not only slow down the shrinking trend of the water system in the area, but also accelerate the expansion of surrounding land use.

Key words: land expansion, urban water system, Changsha city, water ecological environment, spatial pattern