Evaluating Sustainable urban development indexes along with emphasis on infill urban development: Case study of eight regions of Ahvaz

One of the main plans for creating a sustainable urban form is the urban infill development plan. Infill development can be understood as the simplest interpretation of infill development, which attempts to extend development on the empty and abandoned land (Sharifian, 2010: 47; Mirkatoli & Hosaini, 2014: 71). According to Ahvaz municipality data (2017), from 1956 to 2016, 1,20098 persons and an area above to 2500 hectares had been reached to 130,2591 persons and an area of 22200 hectares. Arising problems caused by the large spatial- physical development of Ahvaz such as the low quality of life and indicators of human development, the lack of residential unit, the existence of worn-out urban texture in the central regions of the city with a severe need to organize and Re-development, locating a large percentage of the population (about 40%) in unsustainable urban regions, undesirable city life, lack of space and cultural facilities, and ... have led to a critical approach to horizontal distribution in this city which is one of control method against horizontal distribution of city and controlling its problems for achieving sustainable development is urban infill development that we can use this approach to identify urban development capacity in empty land and physical urban limits.Therefore, in this research, the aim is to investigate the distribution of selected indicators of research related to urban infill development in Ahvaz city and the impact of these indices on urban infill development on studied regions in order to strengthen and improve them to achieve sustainable urban development. In this regard, according to the above-mentioned problem, the present study seeks to answer the main research question "How will be the situation of the eight regions of Ahvaz based on infill development capacity indicators distribution in the form of sustainable urban development indicators”.

The purpose of the present study is to be considered as an applied research. The method of collecting information in this research is considering documents and library studies. In general, the process of doing research is as follows: first, the theoretical foundations related to the subject have been considered, then three main selected indicators and 13 sub-indicators have been used for evaluating and considering the situation of eight regions of Ahvaz in terms of infill development indicator and three main selected indicators and 20 sub-indicators have been used for evaluating and considering sustainable levels of eight regions of Ahvaz. In this study, using the statistics presented in the statistics of Ahvaz and according to the data available in the documents obtained from the municipality of Ahvaz (2016), the indicators have been selected for the purpose of considering the main objective. After identifying the indicators and collecting information, TOPSIS model is used to combine the selected indices and the ranking of the eight regions of Ahvaz in terms of the status of the affective indexes on the urban infill development. Also, Shannon's entropy coefficient was used to weigh the selected indices. After calculating the TOPSIS coefficient for the indicated indices, the levels of eight regions of Ahvaz related to the capacity of urban infill development and sustainable urban development using cluster analysis technique. Finally, using the GIS software, the results are presented as output of map.

The results showed that in terms of the capacity of urban infill development, using the selected indicators, regions 5,1 and 3 have the highest coefficient and the highest urban infill development. regions 2 and 7 have the least capacity in Ahvaz. Also, the results obtained from the TOPSIS model were ranked by cluster analysis, which was determined that region 5 in the first level and region 1 in the second level have the highest capacity for urban infill development and region 2 in fourth level has the lowest level of capacity in terms of urban infill development in Ahvaz city. Based on the results obtained from the TOPSIS model, it can be said that regions 4, 6 and 3 have the highest coefficient, and regions 5 and 2 have the lowest coefficient in terms of sustainable urban development respectively. Also, based on the results obtained from cluster analysis, region 4 is the most suitable region in terms of selected indicators of sustainable urban development and regions 5 and 2 is the least suitable region in terms of selected indicators of sustainable urban development in Ahvaz city.

According to the social index of the region 1, the urban services index of region 1 and the physical indicators of region 5, the eight regions of Ahvaz have the highest capacity for urban infill development. Also in accordance with the urban services index of region 5 and the physical indicators of region 2 have the lowest capacity for urban infill development. Also, the results of the survey on the status of the amount of access to indicators in eight regions of Ahvaz were different in terms of the selected indicators of sustainable urban development, so that in terms of access to the social index in region 4, the urban services index in region 1 and the physical index in region 4 has the highest rate of access to the indicators. It is necessary to say that the lowest rate of access to the indicators is belonged to regions 5,7 and 8 for the social index, the physical index and urban services index respectively. In general, it can be noted that due to the importance of infill development in the field of creating a sustainable urban form, it is necessary to pay attention to all important and effective indicators. In this regard, one of the necessities of reaching to urban development specially in Ahvaz is paying attention to type of development resources distribution, considering justice in utilization, and lack of attention and investment in a particular place. This point emphasizes that all these selected indicators can influence the sustainable development of Ahvaz city if it is properly paid attention to them.Keywords: Infill development, Sustainable urban development, TOPSIS, Shannon Entropy, Ahvaz Metropolis