Poster

In southern Africa, crystalline basement aquifers constitute approximately 55% of the land area and therefore it is important to understand these aquifers and the mechanisms that control them. These aquifers have been well documented in the northern parts of South Africa however the amount of research done on the central Namaqualand basement aquifers is severely lacking, especially in the area surrounding Kakamas in the Northern Cape (the study area).

The overexploitation of water resources has resulted in a global decline in groundwater levels. Managed aquifer recharge (MAR) is a globally acceptable practice to manage the depletion of water in overexploited aquifers in regions with limited water availability. The West Coast of South Africa experiences a semi-arid climate with predominantly dry summers. This study aims to identify potential areas suitable for MAR in the Saldanha Bay area to maximize the water available to these areas during the dry season.

The generation of acid mine drainage (AMD), as a result of mining activities, has led to the degradation of groundwater quality in many parts of the world. Coal mining, in particular, contributes to the production of AMD to a large extent in South Africa. Although a vast number of remediation methods exist to reduce the impacts of AMD on groundwater quality, the use of a coal fly ash monolith to act as a reactive and hydraulic barrier has not been extensively explored.

Historically Finsch Diamond Mine has experienced groundwater inflow in the underground workings of the mine. The inflow results in unsafe and undesirable working conditions. Sampling was conducted over a three month period in order to determine the source of the groundwater inflow. The sampling consisted of various underground samples, monitoring borehole samples as well as surficial water body samples. The samples were analysed for major and minor chemical constituents as well as O18 and H2 isotopes.

Groundwater in the West Coast has been utilised for many years as there are not many surface water resources in the area, and is therefore extremely important. Despite studies being conducted on the aquifer systems since 1976, they are still poorly understood especially with regards to their recharge and discharge processes. This means that the amount of water entering and leaving these systems are unknown, which may lead to over abstraction.

South Africa is generally a dry country, it receives an average rainfall of approximately 500 mm/a, which is below the global average rainfall of 860mm/a. The annual average temperature in the study area was 25?C from 1995 to 2016. South Africa has made an improvement since 1994 with supplying domestic water of suitable standards, communities in rural areas, mostly have groundwater as the best option for satisfying their water demands.

Groundwater forms an important part of the water resources of South Africa, especially in Karoo region, where groundwater is an important source of fresh water. Beaufort West is a town that uses groundwater as a major source of municipal and private water supply. Groundwater samples were collected from a network of 43 boreholes, between November 2015 to December 2018 within Beaufort West town and 10km radius surrounding. The water samples were analysed for inorganics, organics, stable isotopes and radioactive isotopes.

As part of supporting the National Development Plan (NDP) vision 2030, Council for Geoscience has been tasked by the Department of Mineral Resources to embark on an integrated and multidisciplinary geoscience mapping programme to systematically map South Africa in a more detail manner. With the idea of groundwater resource development and preservation purposes, a 1:100 000 geohydrological map, explanatory booklet, geohydrological data base for all data obtained from various sources and an ISO document was produced.

Millions of tons of coal ash are produced across the globe, during coal combustion for power generation. South Africa relies largely on coal for electricity generation. The current disposal methods of coal ash are not sustainable, due to landfill space limitations and operational costs. One way/means of disposing of coal ash that could provide environmental and financial benefits; is to backfill opencast mines with the ash. However, a limited number of studies have been conducted to assess the feasibility of this method in South Africa.

Hydrogeological mapping was first attempted in Kuruman River Catchment, Northern Cape Province, South Africa. The main geology underlying the area of study includes sediments of the Kalahari Group, limestone and dolomite of the Transvaal Supergroup, lavas of the Ventersdorp Supergroup, and Archaean granite and gneiss. The main objective of this study was to produce hydrogeological maps on a scale of 1/100 000. Demarcation of different aquifer types was done by analyzing factors that control groundwater occurrence.