Implications of land use and land cover changes on hydrological regimes of the Malagarasi river, Tanzania
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Date
2013
Authors
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Journal ISSN
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Publisher
American V-King Scientific Publishing
Abstract
A study was conducted to investigate the impacts of
land use and land cover changes on hydrological regimes of the
Malagarasi River. Remote sensing techniques were used to
inventory land use and land cover changes in the watershed for
over 18 years. Hydrological data collected from 1975 to 2002 at
Mbelagule, a gauging station far downstream before Lake
Tanganyika were analyzed to reveal the alterations and trends
in flows for the pre-1980 and post-1980 periods after a large
influx of refugees in the catchment. Results revealed that
between 1984 and 2002, there was a in settlement and
cultivated area steadily increased from 42.91 km 2 to 51.01 km 2 ,
woodland area declined from 405.48km 2 to 398.91km 2 and
wetland area declined from 36.35km 2 to 19.91km 2 . River flows
were found to be highly variable within and between the years,
and sensitive to land use and land cover changes. There was a
shift in the peaking of the river post-1980 period, with high
flows attained earlier in April instead of May in the pre-1980
period. The dry season (June to October) flows for the post-
1980 period declined progressively when compared to the pre-
1980. A trend analysis on annual rainfall did not indicate a
significant change in amount of rainfall received in the area,
likewise for the annual discharges, but a downward trend was
detected in dry season flows. The flow duration curve analysis
indicated a progressive decline in flows for the post-1980
period unlike the former. The study concludes that the
modification of the land use and cover has resulted in changes
in temporal distribution of runoff. The study highlights the
need to consider the effects of land use and land cover changes
on ecosystems and water resources for an informed decision on
proper planning and management of the catchment.
Description
Journal of agricultural sciences and applications, 2013; 2(1): 45-50
Keywords
Flow regime, Hydrology, Land use change, Land cover change, Malagarasi river, Remote sensing, Wetland, Tanzania