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Modeling the
fluxes of nitrogen, phosphate and sediments in Linthipe
catchment, Southern Lake Malawi Basin: Implications for
catchment management
Gomani McDonald Chikondi*, Valeta Joshua
and Samson J. K. S. Phiri
University of
Malawi, Bunda College, Malawi.
*Corresponding
author. E-mail:
gommc2000@yahoo.com. Tel: (+265) 9 384 402.
Accepted 11 February, 2010 |
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This study was carried out to
investigate the fluxes of nutrients and sediments in
Linthipe River catchment of Lake Malawi basin and the manner
in which it is affected by anthropogenic activities and
natural processes. Data on climate, nutrients, land use,
soil and hydrology were collected to model fluxes of
nutrients and sediments using the generalized watershed loading
function (GWLF) model. The correlation coefficient
(r2) derived from comparing the observed and
simulated river discharge was 0.92. For sediments, total
nitrogen and total phosphorus, comparison of predicted
values with observed data were not statistically
significant. The data was also used to model hypothetical
management scenarios. A hypothetical 10% deforestation of
the catchment may lead to an increase in annual sediment,
nitrogen and phosphorus loads by 27.1, 15.7 and 2.9%,
respectively. The GWLF approach overall appears to provide
reasonably good estimates of mean annual sediment and
nutrient loads. Results from this study suggest that
anthropogenic activities (agriculture and deforestation) may
be by far the largest source of sediment and nutrient
loading especially during the rainy season.
Key words:
Fluxes, nutrients, sediments, anthropogenic activities,
catchment management.
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