Urban Process With The Constraint Of Water Resource In Gansu Section Of Western Longhai-Lanxin Economic Zone

Western Longhai-Lanxin economic zone is a key area of "Two zones and one region" in implementing western development strategy; while Gansu section is an important segement of this econimic zone as well as the "Golden line" of Gansu province. To achieve economic revitalization in Gansu, the rapid urbanization in Gansu is an inevitable choice. Due to historical and practical reasons, future urbanization process will inevitably be faced with increasingly serious water shortage. Studying the urbanization process of Gansu section from the perspective of water resource constraint is not only necessary to the form an independent theoretical system between water resources and urbanization, but also have a great practical significance to establish resources conservation and environment-friendly cities in Gansu section as well as arid and semi-arid areas.In accordance with the "pattern-process-model" geographic research paradigm, the paper carries out the following studies:Systematically proposes the basic connotation of water resource constraint. Based on the basic theories about water-restrained urbanization, it discusses the influence of seven relations on water-restrained urbanization and explains the laws and mechanism of urbanization restrained by water resources.Based on multi-year sequence information and data, the paper systematically evaluates the temporal and spatial changes and water conditions of Gansu section water resources in terms of a series of water resource elements (rainfall, surface runoff, groundwater, total water resources, water quality), water resources endowment comparison in cities (production of water coefficient, modulus of producing water, agriculture water resources, per capita water resources), dynamic changes of water resource development (water structure, water-use efficiency) and conducted a comprehensive judgment of the richness of water resources can be used in 42 counties or towns.In the judgment of the integrated urbanization development in Gansu section, Jinchang ranks No.1, Dingxi is the last one and Lanzhou ranks No.3, which is resulted from different urbanization connotation of every city. In terms of the urbanization about population in Guansu section, among the 9 cities, only Jiayuguan, Lanzhou, Jiuquan, Jinchang enjoy a faster raising rate, reflecting the overall urban progress of Gansu section is slow with few outstanding areas; there is apparent urban polarization in 42 counties and towns, while there are quite a few with the growth rate higher than the average level, reflecting a good overall development trend and having a group with a certain of growth potential. Compared with the northwest region and the whole country, the urbanization in Gansu section has certain advantages; while compared with Western Longhai-Lanxin economic zone, its urbanization level and growth rate are lower, reflecting continuous depression of development in Gansu section.From history to a long period in future, water resource will influence the spatial and temporal order of urban development in Gansu section. Among more than 100 ancient cities in Gansu section, there are 26 cities decayed or abandoned directly due to water environment change; 64 cities located in both river sides or nearby, showing the rule of "living near the water"; and the moving of 8 cities was related to river change, showing the rule of "migration with the river". As for the modern cities in Gansu section, the economic development of most cities has a good relation with water utilization, such as the highly correlation of Jiayuguan, Lanzhou, Tianshui and Wuwei, and the significant correlation of Jinchang and Jiuquan, reflecting that the current water resources have a great restriction on urban economic scale expansion. The water pattern in Gaunsu section largely determines the spatial pattern of urbanization in the region. There are still 32 counties (built area) of the 42 counties (district) located directly across the straits or the side of the river, showing "strong hydrophilic nature". Most cities are also located near or along the river and the scales of nearby rivers largely determine city scale, so the two are highly related.Proceed from water-restraining rule and changing mechanism, the paper respectively make a quantitative measurement of water resources constraint intensity and its spatial difference and changes by dual indicator method and integrated index method in Gansu section.From temporal and spatial perspective, the paper quantitatively reveals the major influencing factors and coupling coordination level of two systems such as water and urbanization based on GRA (gray relational analysis) and the coupling models in Gansu section.