The temporal-spatial variation of water resources constraint on urbanization in the northwestern China: examples from the Gansu section of west Longhai-Lanxin economic zone.

Based on more than 2,000 data points reflecting various meaningful aspects of urban systems and water-resource systems, and using a quantitative measurement model and ArcGIS, this study discusses the temporal-spatial variations of water resources constraint on urbanization in the Gansu section of China. The conclusions were: (1) from 1989 to 2007 the water resources constraint intensities (WRCIs) of Gansu section and its 9 cities have been generally decreasing, albeit with much fluctuation, and the decrease has been more rapid since 2000, with Lanzhou and Jinchang as the most representative cities. There is, however, a great deal of variation of WRCI among the 9 cities: Lanzhou changed from intensive constraint to relatively strong constraint, with a significant decline in its WRCI; 5 cities changed from extreme constraint to intensive constraint, including Wuwei and Jiuquan with significant declines in their WRCI, Jiayuguan and Jinchang with no dramatic declines and Dingxi with a fluctuating decline; and 3 cities remained at the same level of water resources constraint, including Zhangye and Baiyin with extreme constraint, and Tianshui with intensive constraint. (2) Looking at the 20-year average of WRCI, there are three types of spatial variations among the 9 cities in the Gansu section: Lanzhou, the capital city of Gansu Province, belongs to the relatively strong constraint-high type; 4 cities-Jiuquan, Jiayuguan, Jinchang and Tianshui-belong to the intensive constraint-high type; and the remaining 4 cities-Zhangye, Wuwei, Baiyin and Dxingxi-belong to the extreme constraint-low type. These results show that the Gansu section will continue to be affected by water resources constraint on urbanization and local economic development for some time to come. [ABSTRACT FROM AUTHOR]