Hydrological Responses to Climate and Land-Use Changes along the North American East Coast: A 110-Year Historical Reconstruction.

The North American east coast (NAEC) region experienced significant climate and land-use changes in the past century. To explore how these changes have affected land water cycling, the Dynamic Land Ecosystem Model (DLEM 2.0) was used to investigate the spatial and temporal variability of runoff and river discharge during 1901-2010 in the study area. Annual runoff over the NAEC was 420 ± 61 mm/yr (average ± standard deviation). Runoff increased in parts of the northern NAEC but decreased in some areas of the southern NAEC. Annual freshwater discharge from the study area was 378 ± 61 km³/yr (average ± standard deviation). Factorial simulation experiments suggested that climate change and variability explained 97.5% of the interannual variability of runoff and also resulted in the opposite changes in runoff in northern and southern regions of the NAEC. Land-use change reduced runoff by 5-22 mm/yr from 1931 to 2010, but the impacts were divergent over the Piedmont region and Coastal Plain areas of the southern NAEC. Land-use change impacts were more significant at local and watershed spatial scales rather than at regional scales. Different responses of runoff to changing climate and land-use should be noted in future water resource management. Hydrological impacts of afforestation and deforestation as well as urbanization should also be noted by land-use policy makers. [ABSTRACT FROM AUTHOR]