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08 April 2025 | Story Andre Damons | Photo Andre Damons
DrSophie-Biskop_ProfFrancois-Engelbrecht
Dr Sophie Biskop from the Department of Geography at the Schiller University Jena, Germany, and Prof Francois Engelbrecht, a Professor of Climatology at the Global Change Institute (GCI), University of the Witwatersrand, at the Southern African Mountain Conference (SAMC).

The severe El Niño drought of 2015/16, which culminated in the Vaal dam reaching an alarming low water level (~25%), prompted scientists to try and predict whether climate change could bring a drought so severe and long lasting that Gauteng could run out of water. 

Prof Francois Engelbrecht, a Professor of Climatology at the Global Change Institute (GCI), University of the Witwatersrand, is one of the scientists working on this project and says though they cannot predict a Day Zero drought with certainty, he thinks it is possible that Gauteng might run out of water in the 2030s or 2040s.

 “This is the biggest climate change risk South Africa faces”, he said.  

Prof Engelbrecht and Dr Sophie Biskop from the Institute of Geography at the Friedrich Schiller University Jena, Germany, together with other scientists are working on a project involving hydrological modelling to predict and prevent a Day Zero from happening. Dr Biskop presented their research paper titled ‘Projected hydrological futures of South Africa's mega-dam region’ at the second Southern African Mountain Conference (SAMC2025) in March, indicating there is a high risk that the water demand in Gauteng will exceed available water resources within the Integrated Vaal River System (IVRS) under future climate change.

 

Gauteng may be severely compromised

The IVRS, a large, complex water system comprising water resources of different river basins, and several mega-dams within, has been constructed to secure the water supply of the Gauteng province, the economic hub in South Africa. 

According to the researchers, Southern Africa is a water-stress hot spot and is projected to become significantly warmer and likely also drier under global climate change, increasing the risk of devastating hydrological droughts. The IVRS, Dr Biskop told the attendees, is vulnerable to the occurrence of multi-year droughts as experienced between 2012 and in 2016. The alarming low water level of the Vaal dam after a period of drought of 2015/16 provided early warning that water security of Gauteng may be directly and severely compromised in a changing climate. Potential evapotranspiration will increase as a consequence of strong regional warming.

 

Answering questions

“There is consequently a high risk that the water demand in the Gauteng province will exceed available water resources within the IVRS under future climate change. This raises the question if under ongoing climate change the natural hydrological system (without considering water transfers between dam catchments) can maintain dam levels in South Africa’s eastern mega-dam region, and particularly within the Lesotho Highlands,” explained Dr Biskop. 

 “To answer this question, the aim of our study is to quantify future water balance changes of several dams under changing climate conditions using the Jena Adaptable Modelling System (JAMS), a software framework for component-based development of environmental models. For this purpose, we build process-based hydrological models for several dam catchments.”

She said an ensemble of high-resolution regional climate change projections is subsequently used as forcing, to generate future hydrological projections. The analysis of projected changes in hydrological system components (precipitation, evapotranspiration, run-off) provides probabilistic estimates of the occurrence of a regional climate change tipping point - when the natural water supply can no longer achieve the full storage capacity of the mega-dams which supply the Gauteng region.

 

Working to prevent Day Zero 

According to Prof Engelbrecht, they are working with the City of Johannesburg, the National Department of Water and Sanitation and Rand Water on this project. Their hope for this research is to create awareness in order to try and prevent Day Zero from happening. They also hope to assist these role players in building resilience and help them prepare for Day Zero. Their work with the City of Johannesburg also includes helping the city to reduce water wastage and change water users’ behaviour as well as formulating a disaster management plan should Day Zero happen. 

The Southern African Mountain Conference (SAMC) series is unique as it seeks to integrate science, policy and practitioner sectors for sustainable interventions in southern African mountains. SAMC events are conceptualised by the Afromontane Research Unit (ARU) of the University of the Free State (UFS), the African Mountain Research Foundation (AMRF) and Global Mountain Safeguard Research (GLOMOS), a joint initiative between Eurac Research and the UNU Institute for Environment and Human Security. These three organisations form the Primary Partners, with the SAMC series being implemented by The Peaks Foundation (a non-profit company). SAMC2025 is being held under the patronage of UNESCO.

News Archive

Fight against Ebola virus requires more research
2014-10-22

 

Dr Abdon Atangana
Photo: Ifa Tshishonge
Dr Abdon Atangana, a postdoctoral researcher in the Institute for Groundwater Studies at the University of the Free State (UFS), wrote an article related to the Ebola virus: Modelling the Ebola haemorrhagic fever with the beta-derivative: Deathly infection disease in West African countries.

“The filoviruses belong to a virus family named filoviridae. This virus can cause unembellished haemorrhagic fever in humans and nonhuman monkeys. In literature, only two members of this virus family have been mentioned, namely the Marburg virus and the Ebola virus. However, so far only five species of the Ebola virus have been identified, including:  Ivory Coast, Sudan, Zaire, Reston and Bundibugyo.

“Among these families, the Ebola virus is the only member of the Zaire Ebola virus species and also the most dangerous, being responsible for the largest number of outbreaks.

“Ebola is an unusual, but fatal virus that causes bleeding inside and outside the body. As the virus spreads through the body, it damages the immune system and organs. Ultimately, it causes the blood-clotting levels in cells to drop. This leads to severe, uncontrollable bleeding.

Since all physical problems can be modelled via mathematical equation, Dr Atangana aimed in his research (the paper was published in BioMed Research International with impact factor 2.701) to analyse the spread of this deadly disease using mathematical equations. We shall propose a model underpinning the spread of this disease in a given Sub-Saharan African country,” he said.

The mathematical equations are used to predict the future behaviour of the disease, especially the spread of the disease among the targeted population. These mathematical equations are called differential equation and are only using the concept of rate of change over time.

However, there is several definitions for derivative, and the choice of the derivative used for such a model is very important, because the more accurate the model, the better results will be obtained.  The classical derivative describes the change of rate, but it is an approximation of the real velocity of the object under study. The beta derivative is the modification of the classical derivative that takes into account the time scale and also has a new parameter that can be considered as the fractional order.  

“I have used the beta derivative to model the spread of the fatal disease called Ebola, which has killed many people in the West African countries, including Nigeria, Sierra Leone, Guinea and Liberia, since December 2013,” he said.

The constructed mathematical equations were called Atangana’s Beta Ebola System of Equations (ABESE). “We did the investigation of the stable endemic points and presented the Eigen-Values using the Jacobian method. The homotopy decomposition method was used to solve the resulted system of equations. The convergence of the method was presented and some numerical simulations were done for different values of beta.

“The simulations showed that our model is more realistic for all betas less than 0.5.  The model revealed that, if there were no recovery precaution for a given population in a West African country, the entire population of that country would all die in a very short period of time, even if the total number of the infected population is very small.  In simple terms, the prediction revealed a fast spread of the virus among the targeted population. These results can be used to educate and inform people about the rapid spread of the deadly disease,” he said.

The spread of Ebola among people only occurs through direct contact with the blood or body fluids of a person after symptoms have developed. Body fluid that may contain the Ebola virus includes saliva, mucus, vomit, faeces, sweat, tears, breast milk, urine and semen. Entry points include the nose, mouth, eyes, open wounds, cuts and abrasions. Note should be taken that contact with objects contaminated by the virus, particularly needles and syringes, may also transmit the infection.

“Based on the predictions in this paper, we are calling on more research regarding this disease; in particular, we are calling on researchers to pay attention to finding an efficient cure or more effective prevention, to reduce the risk of contamination,” Dr Atangana said.


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