Chinese Built-up Land in Floodplains Moving Closer to Freshwaters

Abstract

Human proximity to water and its dynamics are important to understanding the socio-hydrological dilemma between using floodplains and avoiding flood risk. However, previous studies have not distinguished between the water proximity of built-up land in floodplains (BLF) and the water proximity of built-up land outside floodplains (BLOF). This article provides a new and spatiotemporal perspective of the BLF water proximities for understanding the changing flood risk in China. The results show that China’s BLFs had an average water proximity of 5.41 km in 2014. Most of the BLFs (62%, 25.88×103 km2) were located within 3 km of waterbodies. From 1990 to 2014, China’s BLFs increased rapidly by 81% from 23.06×103 km2 to 41.74×103 km2, of which a large portion (57%) was concentrated in water surroundings (≤3 km), shortening the distance between BLFs and waterbodies by 169 m. The BLF growth concentrated in water surroundings even in areas where BLFs have an overall increasing distance from waterbodies. Both the increases in the BLFs and their proximity to waterbodies can increase flood exposure and exacerbate flood risk. The scientific community and policymakers should pay attention not only to the volume of BLF growth, but also its spatial relationship with waterbodies.

Attribution Analysis of Climate Change and Human Activities on Runoff and Vegetation Changes in the Min River Basin

“…This is due to the release of large amounts of meltwater from glacial melting caused by the increase in regional temperatures, which increased the volume of water in rivers and lakes and expanded the watershed area [57]. In addition, the large-scale reduction in arable land and grassland and the large increase in urban construction land are mainly due to accelerated urbanization and population growth, which require more supporting infrastructure as well as government policies and planning, resulting in the conversion of arable land and grassland in some rural areas to construction land [58]. In the S1 period, there was little association between precipitation and potential evapotranspiration with n; in the change period, there was a considerable correlation.…”