Thesis
Hydrogeochemical evolution of groundwater in Chikhwawa, Malawi
- Creator
- Rights statement
- Awarding institution
- University of Strathclyde
- Date of award
- 2012
- Thesis identifier
- T13172
- Qualification Level
- Qualification Name
- Department, School or Faculty
- Abstract
- Groundwater chemistry arising from natural hydrogeochemical processes is highly variable within the Chikhwawa district of southern Malawi, leading to problems of unsuitable water quality for domestic supply in some areas. This study was undertaken to investigate trends and processes controlling variation in groundwater chemistry across an area within the north east of the Chikhwawa district. Groundwater samples were collected and analysed for major cations and anions along with stable isotopes and the results have indicated three main groups of groundwater type based on dominant anion and cation composition. Group 1 (Ca/Mg-HCO3) represents fresh, relatively young groundwater along the edge of the shire valley with low overall cation, anion and total dissolved solid content resulting mainly from silicate weathering processes. Group 2 (Na-HCO3) represents groundwater chemistry with intermediate to high dissolved mineral load, where the groundwater chemistry is primarily altered by cation exchange of calcium and magnesium for sodium on the surface of clay minerals within the alluvium. Group 3 (Na-Cl), represents brackish groundwater of relatively poor quality and high dissolved mineral content, within the centre of the Shire Valley close to the western bank of the Shire River. Groundwater chemistry of this type is influenced largely by the dissolution of evaporite minerals originating from Karoo and Cretaceous sedimentary strata along with surface evaporation effects in areas of shallow groundwater. Results from this study help to understand the complex hydrogeochemical processes which can result in localised areas of poor groundwater quality. Improving understanding of natural groundwater chemistry evolution and variation is vital towards locating and sustaining usable water supplies in this region.
- Resource Type
- DOI
- Date Created
- 2012
- Former identifier
- 947482
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File | 2021-07-02 | University of Strathclyde |