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

A comparative assessment of catchment runoff generation and forest productivity in a semi-arid environment

Understanding the dynamic interactions between forest ecosystems and water in the Mediterranean region is essential for increasing ecosystem services. Even if many studies were implemented to analyse the variations of water and net primary productivity (NPP) in the last decade, this is still an important research question especially for the Eastern Mediterranean, where the research attempts are limited. The main objective of this study was to carry out a comparative analysis of catchment runoff generation and forest NPP and to reveal their temporal dynamics at basin scale in a semi-arid Mediterranean environment. The methodology consisted three steps: (i) estimating catchment runoff generation by implementing process-based J2000 modelling suite, (ii) modelling NPP of the land cover/use types by adapting an ecosystem-process model (BIOME-Biogeochemical cycles) and (iii) assessing the spatio-temporal variability of NPP and runoff dynamics by incorporating the modelling results with multiple regression analysis. Model simulations showed that temperature highly contributed to NPP variations of needle-leaf forests and grasslands. The multiple regression analysis also indicated that runoff was influenced by elevation, precipitation and forest cover. This relationship showed that the inter-annual variability in forest NPP would relate to the variations in runoff distribution across a small Mediterranean subcatchment. © 2016 Informa UK Limited, trading as Taylor & Francis Group