Modelling Of Hydrological Responses In The Upper Citarum Basin Based On The Spatial Plan Of West Java Province 2029 And Climate Change

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.