Aquatic Sciences Meeting, Albuquerque 2001

SS08 Processes at the Benthic Interface (Environmental Connections)

Date: Tuesday, February 13, 2001, Time: 10:45:00 AM

Location: Ruidoso/Pecos

McCullough, G, K, University of Manitoba, Winnipeg, Canada, gmccullo@cc.umanitoba.ca

Cooley, P, M, University of Manitoba, Winnipeg, Canada, pcooley@cc.umanitoba.ca

DISPERSION OF LINTHIPE RIVER SUSPENDED SEDIMENT LOAD IN LAKE MALAWI, S.E. AFRICA

Lake Malawi is affected by increasing influx of sediment due to catchment land use pressure. Specific effects depend on whether sediment is deposited locally, or dispersed in the mixed or anoxic layers of the lake. CTD water column surveys were used to quantify vertical distribution and horizontal dispersion of Linthipe River sediments in Lake Malawi. Rainy season river temperatures ranged from 32.1-22.0oC, higher and lower than maximum and minimum temperatures in the lake. River sediment discharge ranged up to >700,000 t/d. During low flow periods surface plumes accounted for up to 90% of sediment observed in the water column; in surveys after high discharge events, 80-98% was associated with density gradients (thermoclines). Suspended sediment concentration ranged up to >400 mg/l at 4 km offshore and to 29 mg/l at 8 km. Nonetheless, after large storm events, sediment observed in the water column accounted for as little as 5% of the influx. Most was deposited near the river mouth (>50%) or carried to deep water in density currents.

This Session Listing

Aquatic Sciences Meeting, Albuquerque 2001

Quicklinks