Hydrology and Earth System Sciences www.hydrol-earth-syst-sci.net 1027-5606 1607-7938 14 1 2010 10.5194/hess-14-1-2010 http://www.hydrol-earth-syst-sci.net/14/1/2010/ http://www.hydrol-earth-syst-sci.net/14/1/2010/hess-14-1-2010.html http://www.hydrol-earth-syst-sci.net/14/1/2010/hess-14-1-2010.pdf 1 24 2010-01-06 Reconstructing 20th century global hydrography: a contribution to the Global Terrestrial Network- Hydrology (GTN-H) D. Wisser dominik.wisser@unh.edu B. M. Fekete C. J. Vörösmarty A. H. Schumann Institute for the Study of Earth, Oceans, and Space, University of New Hampshire, Durham, New Hampshire, USA Civil Engineering Department, City College of New York, CUNY, New York, USA Institute of Hydrology, Water Resources Management and Environmental Engineering, Ruhr-Universität Bochum, Bochum, Germany This paper presents a new reconstruction of the 20th century global hydrography using fully coupled water balance and transport model in a flexible modeling framework. The modeling framework allows a high level of configurability both in terms of input forcings and model structure. Spatial and temporal trends in hydrological cycle components are assessed under "pre-industrial" conditions (without modern-day human activities) and contemporary conditions (incorporating the effects of irrigation and reservoir operations). The two sets of simulations allow the isolation of the trends arising from variations in the climate input driver alone and from human interventions. The sensitivity of the results to variations in input data was tested by using three global gridded datasets of precipitation.<br> <br> Our findings confirm that the expansion of irrigation and the construction of reservoirs has significantly and gradually impacted hydrological components in individual river basins. 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