Potential water supply of a small reservoir and alluvial aquifer system in southern Zimbabwe

Hamer, W. de and Love, D and Owen, R and Booij, M J and Hoekstra, A Y (2008) Potential water supply of a small reservoir and alluvial aquifer system in southern Zimbabwe. Physics and Chemistry of the Earth, Parts A/B/C, 33 (8-13). pp. 633-639. ISSN 1474-7065

PDF - Published Version Restricted to ICRISAT users only Download (497kB) | Request a copy

Abstract

Groundwater use by accessing alluvial aquifers of non-perennial rivers can be an important additional water resource in the semi-arid region of southern Zimbabwe. The research objective of the study was to calculate the potential water supply for the upper-Mnyabezi catchment under current conditions and after implementation of two storage capacity measures. These measures are heightening the spillway of the ‘Mnyabezi 27’ dam and constructing a sand storage dam in the alluvial aquifer of the Mnyabezi River. The upper-Mnyabezi catchment covers approximately 22 km2 and is a tributary of the Thuli River in southern Zimbabwe. Three coupled models are used to simulate the hydrological processes in the Mnyabezi catchment. The first is a rainfall-runoff model, based on the SCS-method. The second is a spreadsheet-based model of the water balance of the reservoir. The third is the finite difference groundwater model MODFLOW used to simulate the water balance of the alluvial aquifer. The potential water supply in the Mnyabezi catchment under current conditions ranges from 2107 m3 (5.7 months) in a dry year to 3162 m3 (8.7 months) in a wet year. The maximum period of water supply after implementation of the storage capacity measures in a dry year is 2776 m3 (8.4 months) and in a wet year the amount is 3617 m3 (10.8 months). The sand storage dam can only be used as an additional water resource, because the storage capacity of the alluvial aquifer is small. However, when an ephemeral river is underlain by a larger alluvial aquifer, a sand storage dam is a promising way of water supply for smallholder farmers in southern Zimbabwe

Item Type:	Article
Divisions:	UNSPECIFIED
CRP:	UNSPECIFIED
Uncontrolled Keywords:	Alluvial aquifer; MODFLOW; Rainfall-runoff relation; Potential water supply
Subjects:	Others > Watershed Management
Depositing User:	Ms K Syamalamba
Date Deposited:	03 Jun 2014 07:55
Last Modified:	03 Jun 2014 07:55
URI:	http://oar.icrisat.org/id/eprint/8079
Official URL:	http://dx.doi.org/10.1016/j.pce.2008.06.056
Projects:	UNSPECIFIED
Funders:	UNSPECIFIED
Acknowledgement:	UNSPECIFIED
Links:	Google Scholar

View Statistics

Actions (login required)

View Item