Sediment-bound nutrient export from five small reservoir catchments and its implications for the Sudan savanna zone of Ghana
Article first published online: 20 APR 2011
© 2011 The Authors. Journal compilation © 2011 Blackwell Publishing Asia Pty Ltd
Lakes & Reservoirs: Research & Management
Volume 16, Issue 1, pages 61–76, March 2011
How to Cite
Amegashie, B. K., Quansah, C., Agyare, W. A., Tamene, L. and Vlek, P. L. G. (2011), Sediment-bound nutrient export from five small reservoir catchments and its implications for the Sudan savanna zone of Ghana. Lakes & Reservoirs: Research & Management, 16: 61–76. doi: 10.1111/j.1440-1770.2011.00459.x
- Issue published online: 20 APR 2011
- Article first published online: 20 APR 2011
- Accepted for publication 12 September 2010.
- catchment soils;
- deposited sediment;
- nutrient export;
- small reservoirs;
- soil erosion
A study was carried out in the Sudan savanna zone in the Upper East Region of Ghana to assess the rate of sediment-bound nutrient export (NE) into five small reservoirs (Dua, Doba, Zebilla, Kumpalgogo and Bugri) and to analyse the implications of this export. The catchment soils and reservoir sediments from the various study sites were sampled and analysed for their bulk density, particle size distribution and nutrient content. Assessment of the nutrient concentrations indicated that the reservoir sediments were richer not only in nutrients and organic carbon, but also in clay and silt, than the catchment soils, having enrichment ratios >1. Nutrient export rates (NE; kg ha−1 year−1) from the reservoir catchments ranged from 0.755 (±0.264) for OC, 0.104 (±0.0245) for N, 0.0020 (±0.0003) for P, 0.016 (±0.0038) for K, 0.009 (±0.0024) for Na, 0.113 (±0.017) for Ca and 0.027 (±0.0093) for Mg. These rates were lower than those of other studies, likely due to the low nutrient content in the catchment soils. The relationships established between NE and specific sediment yield (SSY) indicated the NE was positively correlated with SSY (R2 = 0.66–0.98). The derived empirical equations can be satisfactorily used to predict the quantity of sediment-bound plant nutrients lost from similar catchments and subsequently stored in the reservoir sediments. The study results also suggest the need for sustainable land management practices to forestall erosion in the catchment areas and to reduce reservoir sedimentation, for enhancement of the livelihoods of the communities in the study area.