The Cimanuk River with a total watershed area of 4010.8 km² flowing from the Garut Regency to Indramayu Delta is the longest in West Java Province. However, the cumulative effects of climate change, increased population, and fish farming in the coastal area have continuously pressured the availability of water resources in its watershed. This study was, therefore, aimed to analyze the impact of land use and climate change on surface runoff and groundwater using a SWAT model. This is a physically based semi-distributed hydrological model with various applications, particularly to simulate water balance and watershed management. Daily discharge record for 2005–2008, land use data for 2002–2017, and the simulated climate (1979–2003) and projected climate data (2075–2099) retrieved from MRI-AGCM3.2 20-km by the Meteorological Research Institute of Japan Meteorological Agency were used in this research. The result showed that the calibration and validation of SWAT model have exhibited satisfactory criteria for hydrological simulations. The modeled period showed land use changes caused a general increase in runoff and decline in base flow contribution to annual streamflow. The changes between the current and projected climate exhibited increase in Q_max/Q_min ratio in certain years.

中文翻译：

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印度尼西亚奇马努克流域土地利用和气候变化对地表径流和地下水的影响

西曼努克河，总流域面积4010.8 km ²从Garut摄政区到Indramayu三角洲的流量是西爪哇省最长的。但是，气候变化，人口增加和沿海地区养鱼的累积影响不断给该流域的水资源压力施加压力。因此，本研究旨在使用SWAT模型分析土地利用和气候变化对地表径流和地下水的影响。这是一种基于物理的半分布式水文模型，具有各种应用，尤其是模拟水平衡和流域管理。2005-2008年的每日排放记录，2002-2017年的土地使用数据以及由美国气象研究所从MRI-AGCM3.2 20公里处获得的模拟气候（1979-2003年）和预计气候数据（2075-2099年）。日本气象厅被用于这项研究。结果表明，SWAT模型的校准和验证已经为水文模拟显示了令人满意的标准。建模期表明，土地利用变化导致径流量普遍增加，基础流量对年流量的贡献下降。当前和预计气候之间的变化显示出某些年份的Q _max / Q _min比率。