干旱区生态环境知识资源中心

The paper selects slope, aspect, Relief Degree of Land Surface, land use, vegetation index, hydrology, transportation density and climate as evaluation indexes and sets up the Human Settlements Environmental Index (HEI) model to evaluate the environmental suitability for Human Settlements in Shiyang river basin. Through using spatial analysis technology of GIS such as spatial overlay analysis, buffer analysis and density analysis to establish the spatial situation of nature suitability and spatial pattern for human settlement. The Results showed that: the index of nature suitability for human settlement in Shiyang river basin was between 17.13 and 84.32. In general, nature suitability for human settlement decreased from southwest to northeast. Saw from area pattern, the suitable region mainly distributed in Minqin oasis, Wuwei oasis and Changning basin, which accounting for about 1080.01 km(2), 2.59% of the total area. Rather and comparatively suitable region mainly distributed around the county in Gulang, Yongchang and north of Tianzhu, which accounting for about 1100.30 km(2). The common suitable region mainly distributed outside of the county in Yongchang, Jinchuan and most area of Minqin county, which accounting for about 23328.04km(2), 56.08% of the total area. The unsuitable region mainly distributed upstream and north of river, which accounting for about 9937.60 km(2), 23.89% of the total area. Meanwhile, the least suitable region distributed around the Qilian Mountain which covered by snow and cold desert and the intersecting area between Tenger Desert and Badain Jaran Desert. The total area was about 6154.05 km(2), which accounting for 14.79% of the total area. Suitable regions for human inhabitance mainly distributed around rivers in the form of ribbons and batches, while others are scattered. Their distribution pattern was identical with the residential spatial pattern. In addition, the relationships between HEI and some factors were also analyzed. There was a clear logarithm correlation between situation of residential environment and population, that is, the correlation coefficient between evaluation value and population density reached 0.851. There was also positive correlation between situation of residential environment and economics, which reached 0.845 between evaluation value of residential environment and GDP. Results also showed the environment was out of bearing the existing population in Shiyang river basin. Spatial distribution of population was profoundly affected by severe environment such as the expanded deserts, the wavy terrains, and the changeful climate. Surface water shortage and slowly economic growth was the bottleneck of nature suitability for human settlement in Shiyang river basin. So according to these problems and various planning, some of residential parts need to relocate in order to improve situation of residential environment.