Evaluation of hydrological responses to climate change for a data-scarce mountainous watershed in Taiwan

Despite the mountainous watersheds being important for the ecosystem, water resources, and hydropower, little hydrological data has been collected. This data scarcity makes it difficult to evaluate their hydrologic response to climate change. This study integrated short-term hydrological data with physics-based meteorological and hydrological models to measure the impact of climate change on future water scarcity in the Wuling Mountain Watershed, Taiwan. Twenty-eight-month hydrological datasets from 2013 to 2015 were used for the hydrological characterization. Scenarios from CMIP5 were selected for the climate projection for the period 2021–2040 based on the inferred 1986– 2005 baseline data. The results showed that precipitation, water percolation, and streamflow will decrease by about 10% and increase by about 20–25% in the dry and wet seasons, respectively. The evapotranspiration is lower than that of the baseline in January, March, and December, whereas it can be as high as 4% during the other months. The increase in the annual amount and change in the water distribution for all studied water components indicate the possible acceleration of the water cycle. Spectrum analysis showed that surface water tends toward becoming more irregular. Groundwater remains mildly persistent and thus may serve as a buffer for the impact of climate change on water resources.