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Investigation of heuweltjie structure and soil chemistry in the Buffels River valley and implications for transfer of salts to groundwater

Thesis (MSc)--Stellenbosch University, 2019.

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Main Author: Vermooten, Marli
Other Authors: Miller, Jodie A.
Format: Thesis
Language:en_ZA
Published: Stellenbosch : Stellenbosch University 2019
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access_status_str Open Access
author Vermooten, Marli
author2 Miller, Jodie A.
author_browse Miller, Jodie A.
Vermooten, Marli
author_facet Miller, Jodie A.
Vermooten, Marli
author_sort Vermooten, Marli
collection Thesis
dc_rights_str_mv Stellenbosch University
description Thesis (MSc)--Stellenbosch University, 2019.
format Thesis
id oai:scholar.sun.ac.za:10019.1/107278
institution Stellenbosch University (South Africa)
language en_ZA
last_indexed 2026-06-10T12:42:07.859Z
license_str Other — see source repository
provenance_str_mv Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository
publishDate 2019
publishDateRange 2019
publishDateSort 2019
publisher Stellenbosch : Stellenbosch University
publisherStr Stellenbosch : Stellenbosch University
record_format dspace
source_str SUNScholar — Stellenbosch University Repository
spelling oai:scholar.sun.ac.za:10019.1/107278 Investigation of heuweltjie structure and soil chemistry in the Buffels River valley and implications for transfer of salts to groundwater Vermooten, Marli Miller, Jodie A. Clarke, Catherine E. Francis, Michele Louise Stellenbosch University. Faculty of Science. Dept. of Earth Sciences. Salinity -- South Africa -- Buffels River Soil salinization -- Analysis Soils, Salts in -- South Africa -- Buffels River Soil mineralogy Soils --Analysis Soil chemistry -- South Africa -- Buffels River Groundwater -- Quality UCTD Thesis (MSc)--Stellenbosch University, 2019. ENGLISH ABSTRACT: Globally, soil salinization is a major soil degradation problem. Saline soils damage the land by altering various Earth cycles and are especially a threat to farming. Saline soils can cause salts to leach into the groundwater, causing an increase in groundwater salinity. The Buffels River catchment, situated in the Northern Cape Province of South Africa, is affected by saline groundwater. Various locations along the coastal zone of southern Africa show similar mean annual precipitation profiles as the Buffels River catchment, yet do not suffer from the same salinization levels. Saline waters within this area are also not evenly distributed, suggesting that other factors may play a role in the groundwater salinization. Heuweltjies, circular earth mounds that can be up to 2 m in height and 32 m in width, are abundant in the Buffels River catchment, and have salinity levels an order of a magnitude higher than the surrounding soils, suggesting that heuweltjie salts may be contributing to this groundwater salinization. Detailed analyses were done on two heuweltjies, through excavation, to examine the salt profile of the heuweltjies, as well as other chemical and physical analyses of the sediments. This was done to see if heuweltjies could be contributing to groundwater salinity in this area. In order to gather this information, a range of analytical techniques were employed with the aim of determining whether the heuweltjies are leaching salts into the groundwater system. Amongst the analytical techniques available for this type of profiling, electrical conductivity, pH, mineralogy, particle size analysis, anion and cation profiling, and dissolved silica were analysed. Results showed that heuweltjies have different soil compositions compared to the interheuweltjie sediments. More clay was present on heuweltjie than off heuweltjie. Heuweltjies had elevated salt concentrations compared to the interheuweltjie sediments, and minerals such as gypsum, calcite, and calcium oxalate were only present in the heuweltjie soils. The source of salt is possibly from marine origin. This could be caused by evaporative concentration, transfer of marine blown salts, or termites bringing saline plant materials into the heuweltjies. Calcite was found in the top soils, and gypsum deeper down, indicating that the water is moving downwards. This was concluded since gypsum is a more soluble salt than calcite and moves further down the profile. Preferential flow pathways were observed through granular soils in one heuweltjie, and termite nests and tunnels within the second heuweltjie, aiding in the transfer of salts to the groundwater. Masters 2019-11-26T12:46:25Z 2019-12-11T06:56:28Z 2019-11-26T12:46:25Z 2019-12-11T06:56:28Z 2019-12 Thesis http://hdl.handle.net/10019.1/107278 en_ZA Stellenbosch University xii, 182 pages : illustrations, maps application/pdf Stellenbosch : Stellenbosch University
spellingShingle Salinity -- South Africa -- Buffels River
Soil salinization -- Analysis
Soils, Salts in -- South Africa -- Buffels River
Soil mineralogy
Soils --Analysis
Soil chemistry -- South Africa -- Buffels River
Groundwater -- Quality
UCTD
Vermooten, Marli
Investigation of heuweltjie structure and soil chemistry in the Buffels River valley and implications for transfer of salts to groundwater
title Investigation of heuweltjie structure and soil chemistry in the Buffels River valley and implications for transfer of salts to groundwater
title_full Investigation of heuweltjie structure and soil chemistry in the Buffels River valley and implications for transfer of salts to groundwater
title_fullStr Investigation of heuweltjie structure and soil chemistry in the Buffels River valley and implications for transfer of salts to groundwater
title_full_unstemmed Investigation of heuweltjie structure and soil chemistry in the Buffels River valley and implications for transfer of salts to groundwater
title_short Investigation of heuweltjie structure and soil chemistry in the Buffels River valley and implications for transfer of salts to groundwater
title_sort investigation of heuweltjie structure and soil chemistry in the buffels river valley and implications for transfer of salts to groundwater
topic Salinity -- South Africa -- Buffels River
Soil salinization -- Analysis
Soils, Salts in -- South Africa -- Buffels River
Soil mineralogy
Soils --Analysis
Soil chemistry -- South Africa -- Buffels River
Groundwater -- Quality
UCTD
url http://hdl.handle.net/10019.1/107278
work_keys_str_mv AT vermootenmarli investigationofheuweltjiestructureandsoilchemistryinthebuffelsrivervalleyandimplicationsfortransferofsaltstogroundwater