|Miga Magenika Julian||-Faculty of Earth Sciences and Technology, Institut Teknologi Bandung (ITB), Jl. Ganesha 10, Bandung 40132, Indonesia -Geographic Information Science, Friedrich-Schiller-Universität Jena (FSU-Jena),|
|Alexander Brenning||Geographic Information Science, Friedrich-Schiller-Universität Jena (FSU-Jena), Germany|
|Sven Kralisch||Geographic Information Science, Friedrich-Schiller-Universität Jena (FSU-Jena), Germany|
|Manfred Fink||Geographic Information Science, Friedrich-Schiller-Universität Jena (FSU-Jena), Germany|
In 2010, a spatial plan for West Java Province up to 2029 was published (Perda 22/2010). The purpose of the plan is to guide settlement area development. This study aims to assess the hydrological implications of the Spatial Plan 2029 within the Upper Citarum Basin (UCB) and with regard to climate change. A hydrological simulation based on land-use at the time of the plan (2010) and planned land use was performed using the JAMS/J2000 hydrological model. The settlement area from the spatial plan for 2029 was extracted and then superimposed onto the 2010 land use. Two different land-use scenarios (2010 and 2029) and a climate change scenario (1990-2030) were used for the hydrological simulation, with IPSL-CM4 and UKMO-HadCM3 being the products used for the latter. The simulation results were presented as river discharge and surface runoff. From the simulation results, the annual average of the simulated river discharge is expected to increase by 1.8% up to 2029 compared to the 2010 level. More substantial changes were noticed in the surface runoff, which is projected to increase on average by 8.9% annually due to the expansion of urban areas and agricultural land use. The seasonal analysis showed that river discharge and surface runoff both increased more markedly in the wet season. The study shows the potential of the JAMS/J2000 model to assess the impacts of land-use and climate change on hydrological dynamics.
Climate change; Hydrological modelling; Land-use change; Spatial planning
The combined effect of land cover and climate changes affects the hydrological regime (Giambelluca, 2015; Dwarakish & Ganasri, 2015). Climate change will have more influence on hydrological processes on a global scale, while on the regional scale (or smaller spatial scales), the impacts of land cover or land-use changes can be more critical (Giambelluca, 2015). The climate change factor is given more consideration in the projection of future hydrological dynamics (Kim et al., 2013).
In 2010, a spatial development plan for West Java Province up to 2029 was published (Peraturan Daerah Nomor 22 Tahun 2010). The primary purpose of the plan is guidance on settlement area development. Therefore, it is essential to identify the impacts of land-use changes on hydrological processes as a result of the implementation of the spatial plan, which can provide information for land-use planning.
Various researchers have studied the combined impacts of land-use change and climate change on hydrological responses (Julian et al., 2011; Marhaento et al., 2016). Based on Li et al. (2009), three major approaches can be implemented to assess these impacts, namely paired experimental catchments, statistical methods and hydrological modelling. In this study, in order to assess the hydrological effects of future land-use and climate changes, the JAMS/J2000 hydrological model (Krause, 2001; Kralisch et al. 2007) is applied. This model has been widely used for hydrological modelling studies, such as in the Kosi Basin, Himalayan Region (Nepal et al., 2014), the Vu Gia-Thu Bon Basin, Vietnam (Fink et al. 2013) and the Goksu Basin, Turkey (Donmez & Berberoglu, 2016). This study focuses on examining the impacts of the spatial development plan for West Java Province 2029 and future climate projections of hydrological dynamics in the Upper Citarum Basin (UCB) using the hydrological model. Julian et al. (2013) studied the initial set up of the J2000 model in a similar basin. The novelty of this study lies in the quantification of the combined impacts of the implementation of the spatial plan published by the local government and future climate projection, and their responses to several hydrological components.
We thank the Ministry of Research, Technology and Higher Education of the Republic of Indonesia (RISTEKDIKTI) and the German Academic Exchange Service (DAAD) for providing the IGSP scholarship.