Adams S.,Water Research Commission |
Braune E.,University of the Western Cape |
Cobbing J.,Nelson Mandela Metropolitan University |
Fourie F.,Private Bag X |
Riemann K.,Umvoto Africa Pty Ltd
South African Journal of Geology | Year: 2015
The aim of this paper is to highlight the changes that have taken place in terms of groundwater resource development and management in South Africa in the 20 years since the political transformation of the country in 1994. Groundwater, the previously neglected resource, received a strategic role in the monumental programme to bring basic water infrastructure coverage to more than 95% of the population during this period. The post-1994 water policy reforms have also had a very positive impact on groundwater; its legal status changed from "private water" to a "significant resource" and it became an integral part of integrated water resource management in terms of the National Water Act, 1998. A systematic assessment of changes, undertaken within a framework of groundwater governance, indicates that significant advances have been made in the groundwater field at the enabling environment/policy level as well as at the strategic/national level in terms of institutional and management instrument development. Thus groundwater has become an integral part of water resource planning, with appropriate groundwater data and information systems to back this up. Groundwater management at the national level can still be significantly improved by way of appropriate regulations that address the unique requirements of groundwater resources in terms of protection, information management and human resources. The present challenge lies at the local level, where the management of thousands of groundwater schemes was transferred from national government and from community management structures to newly established municipal administrations. Urgent attention will need to be given to building the institutional capacity for groundwater resource management at this local level. It will require the coordinated effort of the entire groundwater sector, led by the national Department of Water and Sanitation (DWS) and founded in ongoing research and development through the Water Research Commission (WRC). © 2015 March Geological Society of South Africa.
Saria E.,University of Dar es Salaam |
Calais E.,CNRS ENS Geology Laboratory |
Stamps D.S.,Purdue University |
Stamps D.S.,Massachusetts Institute of Technology |
And 2 more authors.
Journal of Geophysical Research: Solid Earth | Year: 2014
The East African Rift (EAR) is a type locale for investigating the processes that drive continental rifting and breakup. The current kinematics of this ~5000 km long divergent plate boundary between the Nubia and Somalia plates is starting to be unraveled thanks to a recent augmentation of space geodetic data in Africa. Here we use a new data set combining episodic GPS measurements with continuous measurements on the Nubian, Somalian, and Antarctic plates, together with earthquake slip vector directions and geologic indicators along the Southwest Indian Ridge to update the present-day kinematics of the EAR. We use geological and seismological data to determine the main rift faults and solve for rigid block rotations while accounting for elastic strain accumulation on locked active faults. We find that the data are best fit with a model that includes three microplates embedded within the EAR, between Nubia and Somalia (Victoria, Rovuma, and Lwandle), consistent with previous findings but with slower extension rates. We find that earthquake slip vectors provide information that is consistent with the GPS velocities and helps to significantly reduce uncertainties of plate angular velocity estimates. We also find that 3.16 Myr MORVEL average spreading rates along the Southwest Indian Ridge are systematically faster than prediction from GPS data alone. This likely indicates that outward displacement along the SWIR is larger than the default value used in the MORVEL plate motion model. ©2014. American Geophysical Union. All Rights Reserved.
Hartnady C.J.H.,Umvoto Africa Pty Ltd
South African Journal of Science | Year: 2010
South Africa's coal reserves have been significantly reduced since 2003 and a re-assessment based on the complete statistical history of production from southern Africa has indicated that the present remaining reserve for the entire subcontinent comprises only about 15 billion tonnes or gigatonnes (Gt). South African coal geologists should therefore be mindful of experience in Britain, where reserves were grossly overestimated by conventional techniques and remained a large multiple of future production until very shortly before the effective collapse of the industry in the 1980s. The southern African historical analysis has shown that an impressive leap in coal production occurred between 1975 and 1985, from about 69 million tonnes per year (Mt/yr) to 179 Mt/yr. By 1989, the cumulative production had reached 4 Gt. Despite this doubling since to just over 8 Gt, the underlying pattern has been one of faltering growth. Hubbertarian analysis predicts a peak in production rate of about 284 Mt/yr in 2020, at which stage approximately half (12 Gt) of the total resource (23 Gt) will be exhausted. The Waterberg Coalfield (Ellisras Basin) in South Africa may be a remaining large resource, but structural complexity, finely interbedded coal-shale strata at large depths, low grades, high ash content and water scarcity are likely to inhibit its major development. Given South Africa's heavy dependence on coal for power generation and electricity supply, an anticipated peak production in 2020 will cause problems for future economic growth. © 2010. The Authors.
Hay E.R.,Umvoto Africa Pty Ltd |
Riemann K.,Umvoto Africa Pty Ltd |
van Zyl G.,Gerrit van Zyl Independent Consultant |
Thompson I.,Department of Water Affairs
Water SA | Year: 2012
The Department of Water Affairs (DWA) has embarked on a nationwide programme to develop water-reconciliation strategies for all towns across the country. Reconciliation strategies for the major metropolitan areas and systems (e.g. Johannesburg/Pretoria, East London, Cape Town and Durban) were developed next. The implementation of these strategies is monitored by strategy steering committees. The approach has now been extended to all other metropolitan areas as well as all towns and villages or clusters of villages. In order to prepare the actual strategies, regardless of the size of the town, thorough documentation, research and analysis of the available information was required, as well as evaluation of projected growth scenarios to assess water requirements over the next 25 years and identification of potential additional sources to meet this growing requirement. It has emerged that the poor operation and maintenance of water supply, treatment and reticulation infrastructure are resulting in significant losses, which, if corrected, can reverse the current water shortages being experienced. Similarly, the generally poor management of effluent remains a threat to surface water and groundwater quality downstream. It appears that many municipalities perceive groundwater as an unreliable resource; however, in general, the issue of staff and skills shortages to manage the resource effectively is the actual problem. This is an operational issue rather than a groundwater-resource-specific issue. This aspect requires special attention for existing groundwater schemes and proposed groundwater development. In most instances water conservation and water-demand management and the development of local surface and groundwater resources are the most feasible options to meet any current or projected future water-supply shortfalls. Any intervention must be combined with a skills-development programme at the operational level to ensure the sustainability of the proposed supply options. This paper is based on the experience gained in the development of reconciliation strategies for the towns and villages in the DWA Southern Planning Region (i.e. surface water drainage areas in the Eastern Cape and Western Cape Provinces), which was carried out by Umvoto Africa in association with engineering consulting practice Aurecon.
Blake D.,Umvoto Africa Pty Ltd |
Mlisa A.,Umvoto Africa Pty Ltd |
Hartnady C.,Umvoto Africa Pty Ltd
Water SA | Year: 2010
The Western Cape Province of South Africa is a relatively water-scarce area as a result of the Mediterranean climate experienced. Due to the increased usage of groundwater, and the requirement to know how much water is available for use, it is imperative as a 1st step to establish an initial estimate of groundwater in storage. The storage capacity, namely, the total available storage of the different aquifers, and the storage yield of the fractured quartzitic Peninsula and Skurweberg Formation aquifers of the Table Mountain Group (TMG), are calculated with a spreadsheet and Geographic Information System (GIS) model. This model is based on the aquifer geometry and estimated values (based on measured data) for porosity and specific storage (calculated using the classic Jacob relation). The aquifer geometry is calculated from 1:50 000 and 1:250 000 geological contacts, faults and major fractures, with dips and aquifer formation thickness calculated through structural geology 1st principles using a Digital Elevation Model (DEM). Balanced geological cross-sections constructed through the model areas provide an important check for the aquifer top and bottom surface depth values produced by the GIS model. The storage modelling undertaken here forms part of the City of Cape Town TMG Aquifer Feasibility Study and Pilot Project, with modelling focusing on the 3 main groundwater target areas at Theewaterskloof (Nuweberg), Wemmershoek and Kogelberg-Steenbras. In the storage models, the Peninsula and Skurweberg Formation aquifers have confined pore volumes ranging from approximately 29 bn. to 173 bn. m3 and 4 bn. to 26 bn. m3, respectively (based on using different porosity values ranging from 2.5% to 15%). Using an average head decline of 1 m across the confined aquifer areas across all 3 groundwater exploration areas, and confined pore volumes based on a porosity of 5%, 6.9 Mm3 and 1.1 Mm3 of groundwater, from the Peninsula and Skurweberg Formation aquifers, respectively, is available. The aquifer storage model intentionally makes use of low, geologically reasonable values for porosity and aquifer compressibility, so as to provide minimum large-scale 1st estimates of potential yields; however, when new data become available these initial porosity and compressibility assumptions will probably be revised upward. The storage yield approach is also very conservative, as it does not take into account the annual replenishment of the aquifer, and constitutes the yield potential during drought conditions (zero recharge) from the confined portion of the aquifer only. The yield model therefore provides a quantitative perspective on the common public and decision-maker perception that groundwater abstraction from the deep confined Peninsula Formation aquifer will significantly dewater the system, with (often unspecified) adverse ecological conse- quences. Even where the regionally-averaged decline in hydraulic head approaches 20 m, the volume released by aquifer compression generally remains in the order of 0.24% of the total volume in slow circulation within the deep groundwater flow system. A vastly greater volume of groundwater is essentially non-extractable by any practical and/or economical means.