Implications of land use and land cover changes on hydrological regimes of the Malagarasi river, Tanzania

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Date

2013

Journal Title

Journal ISSN

Volume Title

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

Citation