Constructing Comprehensive Datasets for Understanding Human and Climate Change Impacts on Hydrologic Cycle

Climate change and human activities altered the hydrologic systems and exerted global scale impacts on our environment with significant implications for water resources [1]. To secure a complete picture of future water resources, it will be necessary to consider climate change and variability, hydrology, water engineering, and human systems in an integrated framework [2]. Climate change can be characterized by the change of precipitation and temperature, and both precipitation pattern change and global warming are associated with the increase in frequency of flooding or drought and the decrease of low flows. With increasing water demand from domestic, agricultural, commercial, and industrial sectors, humans are increasingly becoming a significant component of the hydrologic cycle. Human activities have transformed hydrologic processes at spatial scales ranging from local to global as shown in figure 1. Human activities affecting watershed hydrology include land use change, dam construction and reservoir operation, groundwater pumping, surface water withdrawal, irrigation, return flow, and others e.g., Wang and Cai [3], Vogel [4]. The land use change impacts have been studied in many watersheds around the world. However, the fundamental role of human water use in the hydrologic cycle is not yet well understood [5].