Gaathier Mahed

• PhD
• Senior Lecturer at Nelson Mandela University

A dual-purpose single mode optical fiber sensor was developed for simultaneous soil moisture and structural health monitoring. Unmodified G655 SMF with polarization coupled phase components was used to detect environmental changes due to ground movement and moisture content variations. Spectral distribution profiles of the baseband frequencies belo...

Communities living within Africa's river basins remain vulnerable to the negative impacts of climate change. This study aimed to explore the various local knowledge (LK)-based climate change adaptation strategies used by the vhaVenda and baTonga communities, residing in the Limpopo and Zambezi river basins (LRB and ZRB, respectively) in Southern Af...

We present and experimentally demonstrate a seismic ambient noise monitoring optical fibre sensor for early warning detection of sinkholes. The developed optical fibre sensor is designed for warning alert of subsidence and cover collapse sinkholes. The progressive process of sinkhole development causes structural change in the subterranean surface....

Air pollution is an environmental-health challenge that many developing and developed countries are struggling to deal with. The purpose of our study was to characterise the ambient air quality during the year 2019-2020 over two urban sites of DiepKloof and Vanderbijilpark which are located on the South African Highveld. The study characterised PM1...

Following the decommissioning of the Volve Field located in the North Sea, 200 kilometres offshore Norway, Equinor led joint venture released production and subsurface data for the 14 years of exploration and production on the Theta Vest structure. The four-way Theta Vest structure consists of sandstones from the Jurassic Hugin Formation as the mai...

Remote Sensing evapotranspiration models are critical in order to understand the cycling of water in the environment. Initially, an outline of the concepts related to evapotranspiration, as well as the shortcomings of land-based methods, is presented. The aim of the study was based on reviewing remote sensing evapotranspiration models which provide...

We present the measurement of fractures near the town of Beaufort West, South Africa. A field visit was conducted to examine the dip and azimuth of rock outcrops in and around the town. The locations of these various fractures were mapped and their orientation, which included the dip and strike of the rock surface, was measured using a geological c...

Evaluating anthropogenic changes to natural systems demand greater quantification through innovative transdisciplinary research focused on adaptation and mitigation across a wide range of thematic sciences. Southernmost Africa is a unique field laboratory to conduct such research linked to earth stewardship, with ‘earth’ as in our Commons. One main...

Temporary freshwater pools (pans) are known for their nature value and socio-economic importance especially in (semi-)arid regions, but it is still poor known how they develop in a natural setting. The ecologically valuable temporary freshwater pans of the Save Valley Conservancy, Zimbabwe, are studied in order to gain insights into their formation...

The purpose of this appendix is in order to highlight some of the possible FOSSTAR possibilities available for Hydro(geo)logical studies. This includes complimentary software, which is not necessarily strictly applied to scientific studies, but could aid in completing reports. The focus is Hydrogeology and its various branches. This includes but is...

A hydrogeochemical analysis of multiple samples stemming from two fractured rock aquifers in the Karoo geological formation of South Africa was undertaken. The samples were taken using various sampling methods in numerous locations over varying time frames. The ion error balance for the groundwater samples from the previously mentioned secondary aq...

An examination of an extreme weather event in the Western Karoo of South Africa in order to understand groundwater recharge within wellfields.

Sutherland is located in the Western Karoo, which is a semi arid to arid area. Furthermore the Geology is dominated by sandstones and mudstones with dolerite intrusions. The area is entirely dependant on groundwater for domestic and agricultural use. Thus the importance of understanding factors impacting groundwater are important for effective sust...

The soil and groundwater regime of the Rietvlei wetland near Cape Town, are characterised. Water stemming from 8 wells was sampled and analysed for Oxygen 18 and Deterium. Soil samples were taken for further analysis. Downhole salinity logs of the wells was also undertaken and rainfall and groundwater samples were analysed for the aforementioned st...

The current study aimed to determine the factors affecting groundwater recharge and its spatial distribution in the Rietvlei wetland located near Cape Town. To achieve this, the subsurface material was logged during the construction of eight shallow wells, complimented with field observations, and surveying the dug wells. The water stemming from th...

Gaathier almost failed science at high school and then went on to complete a BSc and MSc in Environmental Science and a PhD in Geology. He tells parts of this story and shares his views on the world around us through the lens of an Earth Scientist. He communicates the ideas related to geoscience in the form of short articles and highlights the obse...

Activity concentration and sensitivity of groundwater to radon contamination, and simple and sus- tainable radon mitigation possibilities have been studied and presented. Radon concentrations in groundwater at point of source (well site), point of use (homes), emission and exhalation rates from rock material (aquifer materials), as well as effects...

The Diep River estuary and associated Rietvlei wetlands are an urban conservation area in Cape Town, South Africa. Irrevocably altered in some respects by over 100 years of intensive urban and industrial development, it hosts a small urban estuary, among the last surviving seasonal salt pan ecosystems in western South Africa, abundant birdlife and...

The application of gravity to Geohydrology is reviewed. A short background and history related to the application of geophysics to Geohydrology is outlined. Multiple works related to ground based gravimetry applied to the hydrological sciences in general are examined. These include the possible errors which might occur when applying gravimetry to h...

An aquifer in the semi-arid environment of Sutherland, South Africa is examined. The characterization of the saturated geological unit was completed by mapping associated dolerite dykes and fractured outcrops of Beaufort Group sedimentary rocks. This was complimented by pumping tests in order to better understand the fracture connectivity that was...

A toolkit compiled for research students in the hydrological sciences in order to equip them with the necessary knowledge of data sources, software available as well as references.

This work outlines the methodology employed in order to develop a sampling protocol for radioactive elements in fractured rock aquifers. This has included the analysis of previously developed sampling protocols, historical data as well as the field application of a draft protocol to the area around Beaufort West in South Africa. The selected test s...

An analysis of current available sampling and monitoring protocols related to radioactivity has been undertaken. The international best practice is outlined in order to better understand the available sampling as well as monitoring protocols related to radioactivity. Thereafter, the most relevant South African groundwater sampling and monitoring pr...

Water demand in Beaufort West has been expanding. In addition to the 4 municipal wellfields, more wellfields are being developed to augment the current groundwater supply. The report summarises all the activities leading from a survey of the hydrology of the Beaufort West area to the radioactive protocols needed for proper evaluation of the threats...

Spatial and temporal variations in water storage can be attributed to the heterogeneous nature of the subsurface. In this paper, the properties of soil and fractured rock aquifers are examined for the example of the South African Gravimetric Observation Station (SAGOS) in Sutherland. Also, aspects of groundwater recharge and their implications for...

Charitable endowments (Waqf) are a community-based sustainable development initiative. The principle of charitable endowments has its roots entrenched in sustainability. The beauty of it is the fact that the donated asset is never lost but instead the returns stemming from the charitable endowments are utilized. Groundwater management has always po...

This technical note serves to inform of the Islamic charitable endowments. Historical aspects as well as modern ones are outlined. Awqaf South Africa is brought to the fore as an organisation managing charitable endowments. The administration and corporates structure are analysed in order to fully understand the corporate governance of the institut...