Assessing sediment inputs to small reservoirs in Upper East Region, Ghana
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Date
2009-10
Journal Title
Journal ISSN
Volume Title
Publisher
Lakes & Reservoirs Research & Management
Abstract
Many small dams and dugouts have been constructed in the Upper East Region of Ghana to address the problem of
regional water scarcity. The reservoirs were constructed primarily as water supplies for agricultural irrigation and livestock
watering, aquaculture and domestic use. However, many of the reservoirs dry up during the dry season, affecting
the livelihoods of their basin inhabitants. A major cause for the dried reservoirs is siltation, which reduces the reservoir’s
storage capacities. The goal of this study is to quantify the annual siltation rate of four study reservoirs, using a bathymetric
survey and reservoir soil sampling. The sediment yield and its relation to catchment area also were assessed. The
results of this study indicate that the annual siltation rates are 1272, 3518, 2764 and 6135 t year)1 for Doba, Dua, Zebilla
and Kumpalgogo reservoirs, respectively. Analyses of the sediment yield and catchment areas illustrated that the sediment
yields decreased with increasing catchment area. All the study reservoirs have lost their dead storage capacity,
which was meant to store sediment until the end of their anticipated design lives. The decreasing storage capacity
because of siltation will affect the livelihoods of the local basin inhabitants, as the reservoirs will not be able to achieve
all their intended purposes. The results of this study indicate that, because siltation is not the only factor threatening the
benefits gained from the reservoirs, the integrated assessment of all relevant factors is required.
Description
This article is published in Lakes & Reservoirs Research & Management and also available at DOI: 10.1111/j.1440-1770.2009.00410.x
Keywords
bathymetric survey, Ghana, sediment yield, siltation, small reservoirs
Citation
Lakes & Reservoirs Research & Management, 14(4):279 - 287