HR: 12:05h
AN: GC32A-08    [Abstracts]
TI: Hydrological implications of glacial recession in the Rwenzori Mountains of Uganda
AU: * Taylor, R
EM: r.taylor@geog.ucl.ac.uk
AF: University College London, Department of Geography Gower Street, London, WC1E 6BT, United Kingdom
AU: Mileham, L
EM: ucfaljm@ucl.ac.uk
AF: University College London, Department of Geography Gower Street, London, WC1E 6BT, United Kingdom
AU: Tindimugaya, C
EM: ctindi.wrmd@dwd.co.ug
AF: Ministry Water & Environment, Water Res. Management Dir., Kampala, Box 20026, Uganda
AU: Leng, M
EM: mjl@nigl.nerc.ac.uk
AF: British Geological Survey, NERC Isotope Geosciences Lab. Keyworth, Nottingham, NG12 5GG, United Kingdom
AB: The areal extent of tropical icefields in the Rwenzori Mountains of East Africa has reduced steadily over the last century from 7.5 km² in 1906 to <1 km² in 2003. Considerable debate persists, however, regarding the impact of observed deglaciation on alpine riverflow and the precise climate signals indicated by glacial recession in the Rwenzori Mountains and other areas of the East African Highlands including Kilimanjaro and Mount Kenya. We present the first measurements of alpine riverflow in the Rwenzori Mountains to show that the contribution of meltwater flows from dwindling icefields to local freshwater resources is negligible, <1% of the mean annual river discharge recorded at the base of the mountains. Stable isotope ratios (¹⁸O:¹⁶O, ²H:¹H) in streamflow trace the contemporary origin of precipitation in the Rwenzori Mountains to the same source (Indian Ocean) as other alpine icefields in East Africa. Hydrometeorological trends, indicated by observational datasets (precipitation, lake levels) over the 20th century and palaeoenvironmental and anecdotal evidence over the 19th century, are inconsistent with an abrupt reduction in humidity that has been proposed to account for observed deglaciation in the East African Highlands.
UR: http://www.geog.ucl.ac.uk/~rtaylor/rwenzori.htm
DE: 1605 Abrupt/rapid climate change (4901, 8408)
DE: 1637 Regional climate change
DE: 1827 Glaciology (0736, 0776, 1863)
DE: 1860 Streamflow
DE: 9305 Africa
SC: Global Environmental Change [GC]
MN: 2007 Fall Meeting