Pol. J. Environ. Stud. Vol. 30, No. 4 (2021), 3307-3316 DOI: 10.15244/pjoes/128537 ONLINE PUBLICATION DATE: 2021-04-08 Original Research Spatial Interaction of Urban-Rural System and Influence Pattern in the Arid Inland River Basin – a Case Study in Shiyang River Basin in Northwest China Wei Wei1, Xueyuan Zhang1*, Chunfang Liu2,3, Junju Zhou1, Binbin Xie4,Chuanhua Li1 1College of Geography and Environmental Science, Northwest Normal University, Lanzhou 730070, Gansu, China 2College of Social Development and Public Administration, Northwest Normal University, Lanzhou 730070, Gansu, China 3Gan Su Engineering Research Center of Land Utilization and Comprehension Consolidation, Lanzhou 730070, Gansu, China 4School of Urban Economics and Tourism Culture, Lanzhou City University, Lanzhou 730070, Gansu, China Received: 4 August 2020 Accepted: 15 October 2020 Abstract Different period remote sensing images of three years in 2000, 2010 and 2019 were selected as the data source, and the cost weighted distance model and urban-rural potential index were used to express the spatial connection. Besides, urban-rural expansion intensity index and urban-rural expansion speed index were also used to analyze urban and rural spatial structure of Shiyang River Basin. GIS technology combined with road grade and length was used to calculate the shortest time distance between urban and rural nods. Spatial association and interaction between urban and rural systems were analyzed through the time and distance, and the spatial structure changes and influential patterns of the Shiyang River Basin were discussed. The results showed that: (1) the urban-rural spatial expansion was dominated by central cities, the small towns had cluster distribution while the large towns were scattering. The urban-rural spatial structure system showed Jinchang, Wuwei city were the axis points, and Yongchang, GuLang, Minqin and Tianzhu are the axis line, which formed point- axis structure and the “F” layout. (2) The pattern of city-county-town showed network development patterns, which indicated the influence of administration privilege to the spatial structure of urban-rural system. The key connection between the urban and rural area was road network but the administrative association was the dominated factor, especially inside of the whole river basin. (3) The administrative contact was much more than economic contact, management contact and information exchanges. *e-mail: [email protected] 3308 Wei W., et al. The spatial structure and system formed a three-level management network pattern that was “city-county-small town” in Shiyang River Basin. Keywords: spatial interaction, urban-rural system, Influence pattern, Shiyang River Basin Introduction At present, studies on the spatial structure and inter-connection turn to the dynamic analysis from As the indicator in the state of regional development, the static description, and from qualitative speculation the urban-rural spatial structure is the function of of spatial connection theories to large application of the regional development, and the spatial clustering quantitative model. For the first time in 1942, G.K. Zipf scale and form made by the socio-economic objects’ [15] brought in the law of universal gravitation into the spatial interaction [1, 2], so it is of great significance city system to analyze the urban spatial interaction, to to study the spatial interaction of urban-rural system have founded the theoretical basis for the urban-rural for the urban-rural planning and the sustainable spatial interaction. From then on, the foundation of development. Urban-rural spatial structure pattern and growth pole, spatial interaction theory, spatial diffusion their interaction determines the efficient use of natural theory and spatial connection model provided abundant resources and the sustainable development of social theoretical basis for the study of spatial urban-rural economy [3, 4]. interaction. The present study on spatial structure of As a social, economic and physical entity, city has the urban-rural system and influence pattern mainly the attractive and radiological function to the small city includes the evolution of the urban-rural spatial and towns which are located in its surroundings. The structure, the formation of the spatial urban-rural influential range of the city, namely the attraction of system, the spatial organizing structure [16]. Since the the city, refers to a region in which the attractive and 1990s, some scholars have greatly achieved on the study radiological function of a city to its surrounding area and illustration of urban and rural system theory, and play a dominant role in social economic ties, with a some others analyze metropolitan circle through direct series of hierarchical nested, interlaced, excessive, surveys about many social and economic association competitive and varied characteristics [5-7]. The flow and the spatial reset of the related connecting influential range of the town is an important indicator strength as well as the economic spatial function of the to judge the intensity of competition and the regional city agglomerations with the model of measurement. function, and it is also an important field in the research The interrelationship of cities is indicated mainly by of urban spatial structure currently. At present, defining the urban flow model or the spatial urban interaction influential pattern of the city mainly has two kinds of strength model. method, including empirical and theoretical method However, the urban flow only reflects the outreach [8-10]. Empirical method often collects data about connection degree of the city itself, and the spatial personal, material, capital, information exchanges strength of urban only reflects spatial influence degree through actual investigation in different areas and cities, between cities, the single evaluation cannot explain all and then compare to associations and exchanges in all the different degree of cities’ connection [17]. Besides, aspects of the regions and cities. The connection among most models now available haven’t involved the different cities or towns are determined by connected influence of the natural condition of the inner city and frequency degree and exchange number [11, 12]. the spatial connection [18]. Finally, according to the connected frequency degree This paper tries to analyze the spatial connective between small region and urban, the influence area strength of urban-rural systems in Shiyang River is divided different sections, which is called the Basin in arid China base on spatial interaction cities’ influential and attractive range. However, using strength model and the urban-rural expansion index. empirical method to divide attraction scope of the The result can give making-decision support on the city needs to collect and select representative, high urban-rural sustainable development at the basin scale accuracy, easy to statistics and easily comparable and the scientific reference on urban-rural development indexes, which base on a large amount of statistical data planning and managements. The objectives of the [13]. At present, theoretical method is the main method study are: (1) understand the spatial connection between of the influence between cities and urban-rural system, the cities and small towns in arid inland at basin it is mainly based on the theory of spatial interaction, scale; (2) describe the spatial structure of urban-rural and the influence of the city on the surrounding systems in arid inland, and (3) explore the spatial area is proportional to the size of the city and inversely influence pattern among the cities, towns and rural proportional to the distance to the city [14]. For system. example, breaking point model, field strength model and voronoi graph model are the primary models in the field. Spatial Interaction of Urban-Rural System... 3309 Material and Methods Zi ik F = 2 Study Area Dik (1) The Shiyang River Basin (101°22´-104°16´E and In the formula (1), Fik is the field strength 36°29´-39°27´N) is one of the three inland river basins between city/town i and the city or town k, and Zi is in the Hexi corridor, lying in the east of the corridor, comprehensive scale value of the city i, Dik is the Gansu Province in northwestern China. The basin distance from city i to city k. occupies an area of 4.16 ×104 km2 and includes seven The model emphasizes the city’s influence and counties [19,20]. The basin is located in continental radiation to the surroundings according to the inverse temperate zone with arid climate and variable distance attenuation [23, 24]. In the model, the influence topography. The annual precipitation is 100-600 mm, from urban-rural area on each point in the area didn’t whereas the annual pan evaporation is 700-2,600 mm. simply reduce with the spatial straight-line distance, The Shiyang River originates from the Qilian Mountain but along the directions and routes of the minimum with eight tributaries, which are mainly fed by rainfall, resistance. The points may receive different radiation snowmelt and glacier melt in the Qilian Mountain. The because of the different resistance. In order to reflect total water resource is 16.61×108 m3,of which surface the different resistance, the cost weighted distance was runoff is about 15.61×108 m3 and groundwater is used to concept the factual distance and instead of the 8 3 1.00×10 m . The terrain of basin is high in south and Dik in the Formula (1) and improved the theory of field low in north, and tilt from the southwest to northeast. strength model [25]. To calculate the cost weighted Influenced by the climate, ecohydrology, landscape and distance, the resistance aspect of Shiyang River Basin other natural conditions, the soil and vegetation types needs to be determined. In this paper, the resistance of the basin form an obvious vertical spectrum of soil- was calculated by the following formula: vegetation [21]. Data Sources and Processing (2) Landsat TM/ETM/OLI images in May, 2000, July, In formula (2), Ck is the collected cost weighted 2010 and May, 2019 were obtained from http://www.