Water Quality and Sediment Behaviour of the Future: Predictions for the
21st Century (Proceedings of Symposium HS2005 at IUGG2007, Perugia, July
2007). IAHS Publ. 314, 2007, 231-238
Future
impacts of freshwater resource management: sensitivity of coastal deltas
CHARLES J. VÖRÖSMARTY1,2, JASON P. ERICSON3, S. LAWRENCE DINGMAN2, LARRY G. WARD2 & MICHEL MEYBECK4
1 Water Systems Analysis Group, Institute for the Study of Earth, Oceans and Space, University of New Hampshire, Durham, New Hampshire 03824, USA
charles.vorosmarty@unh.edu
2 Earth Sciences Department, University of New Hampshire, Durham, New Hampshire 03824, USA
3 Virginia Department of Conservation and Recreation, 101 N. 14th Street, Richmond, Virginia 23219, USA
4 UMR Sisphe, Université de Paris VI,
France Case 123, Tour 26, 4 Place Jussieu, F-75257 Paris Cedex 05, France
Abstract We present an assessment of contemporary and future effective sea-level rise (ESLR) using a sample of 40 deltas distributed worldwide. For any delta, ESLR is a net rate defined by eustatic sea-level rise, natural gross rates of fluvial sediment deposition and subsidence, and accelerated subsidence due to groundwater and hydrocarbon extraction. Present-day ESLR, estimated from geospatial data and a simple model of deltaic dynamics, ranges from 0.5 to 12.5 mm year-1. Reduced accretion of fluvial sediment from upstream siltation of reservoirs and freshwater consumptive irrigation losses are primary determinants of ESLR in nearly 70% of the deltas, while for only 12% eustatic sea-level rise predominates. Future scenarios indicate a much larger impact on deltas than previously estimated. Serious challenges to human occupancy of deltas worldwide are conveyed by upland watershed factors, which have been studied less comprehensively than the climate change and sea-level rise question.
Key
words deltas; sea-level rise; sediment flux; water
resource management; siltation; reservoirs