Achieving a Sustainable Urban Form through Land Use Optimisation: Insights from Bekasi City's Land-Use Plan (2010–2030)

Rahmadya Handayanto, Nitin Tripathi, Sohee Kim, Sumanta Guha
2017 Sustainability  
Cities worldwide have been trying to achieve a sustainable urban form to handle their rapid urban growth. Many sustainable urban forms have been studied and two of them, the compact city and the eco city, were chosen in this study as urban form foundations. Based on these forms, four sustainable city criteria (compactness, compatibility, dependency, and suitability) were considered as necessary functions for land use optimisation. This study presents a land use optimisation as a method for
more » ... s a method for achieving a sustainable urban form. Three optimisation methods (particle swarm optimisation, genetic algorithms, and a local search method) were combined into a single hybrid optimisation method for land use in Bekasi city, Indonesia. It was also used for examining Bekasi city's land-use-plan (2010-2030) after optimising current (2015) and future land use (2030). After current land use optimisation, the score of sustainable city criteria increased significantly. Three important centres of land use (commercial, industrial, and residential) were also created through clustering the results. These centres were slightly different from centres of the city plan zones. Additional land uses in 2030 were predicted using a nonlinear autoregressive neural network with external input. Three scenarios were used for allocating these additional land uses including sustainable development, government policy, and business-as-usual. Future land use allocation in 2030 found that the sustainable development scenario showed better performance compared to government policy and business-as-usual scenarios. Many sustainable urban forms have been proposed. These include (i) the compact city; (ii) the eco city; (iii) neo-traditional development; and (iv) urban containment [2] . The compact city and eco city were chosen in this study as a foundation to achieve a sustainable urban form within the study area, Bekasi city, Indonesia. The eco city was also included as a base model in this study since the sustainability of the compact city is still being debated [8] . Based on the compact and eco city models, four criteria were chosen, compactness, compatibility, dependency and suitability, to determine the sustainability score for the city when optimising urban land use (LU). These criteria are similar to those of a previous study on current LU allocation [9] . Although difficult to change an existing city form with newly optimised form, some activities dealing with urban structure and land use pattern can be implemented to achieve sustainable urban form as in the current study. Some studies implemented sustainable urban development and urban intensification concepts for those activities [3, [10] [11] [12] [13] ]. In the current study, the optimisation process accounted also for future LU. Simple LU zoning has been implemented worldwide. These processes allocate each LU to appropriate locations based on their classes. In contrast, Alexander [14] criticised the LU zoning because of its tree formation instead of semi-lattice that makes the city unnatural and difficult to grow. Semi-lattice with inter-connections among LUs makes a city more natural, easy to grow and sustainable. Thus, Alexander suggested the planner calculating all LU relations instead of just proposing the LU zones based on the group of LUs. However, the semi-lattice concept of natural city is still under debate and difficult to manually calculate. The current study proposed a tool and method for calculating the sustainability score of all LU relationships while automatically generating a sustainable urban form using LU optimisation as an alternative to traditional methods. Additionally, the current study can be used for examining policy regarding sustainability since the study area has already implemented LU zoning in its city plan (2010-2030). A zoning system is affected by the street-block structure that sometimes creates problems. Since the city government has already established the street-block structure, the proposed model excluded it and only optimised other specific LUs. The current study optimised both current LU and future LU through a transformation and an allocation model respectively. Whereas the transformation model created a suggested LU zone, the allocation model allocated newly predicted LUs in the future. In allocation model three exploratory scenarios were used: (i) a sustainable development scenario (SD); (ii) a government policy scenario (GP); and (iii) a business-as-usual scenario (BAU). The main part of the current study is a LU optimisation model. Many techniques have been used and developed as candidates for LU optimisation methods such as fuzzy logic [15] , genetic algorithms (GA) [15] [16] [17] [18] [19] [20] , particle swam optimization (PSO) [9, [21] [22] [23] , and simulated annealing (SA) [24] . These heuristic methods have advantages in handling discontinuities, non-linear or stochastic problems [25] . Nowadays, there is a trend to use hybrid methods that combine several optimisation methods into a single and more powerful one [26] [27] [28] . In the current study, the PSO, GA and local search optimisation methods were combined into a hybrid method for LU optimisation. The specific objectives of the current study were: (1) to do an exploratory analysis of LU optimisation models and their use to achieve a sustainable urban form; (2) analysis of current LU optimisation with comparison to the Bekasi city plan (2010-2030); and (3) to develop future allocation of newly predicted LU through the devised modelling approach to examine different allocation scenarios in the study area. By achieving these objectives, the current study intended to fill the research gap about LU optimisation usage for achieving a sustainable urban form. Data and Methodology Study Area The study area, Bekasi city, is located to the east of Jakarta province, with Bekasi regency on the east and north, and Bogor regency on the south (Figure 1 ). This city is part of the Jakarta Metropolitan Region (JMR) with an area of 210.49 km 2 . More than 90 per cent of the land is residential and the
doi:10.3390/su9020221 fatcat:iqvb5deixvd3zh4dacccziq5ma