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Botswana has one of Africa’s driest terrains |
Recent research conducted in Botswana, one of Africa's driest countries whose terrain is punctuated with both the Kalahari Desert and savannah woodland, has established that the use of water reservoirs, such as dams, in arid areas increases the risk of drought. The research also established that the use of water reservoirs in not-so-dry areas, called temperate or semi-arid regions, was comparatively less likely to cause drought. This information was released in Gaborone, Botswana yesterday, at a four-day International Conference on Water Resources of Arid and Semi-Arid Regions of Africa (WRASRA) that kicked off yesterday and ends on August 6, 2004.
Ninety delegates from 20 countries that include Africa, Europe, Asia and Australia are attending the four-day conference.
Researchers from the University of Witwatersrand, South Africa and from Mantswe Natural Resources Consultants of Botswana released the information that exposes the risks associated with establishing reservoirs in arid areas. Both groups had conducted research to determine the impact of a proposed dam construction on Botswana's Thune River in the Eastern part of that country.
The justification of constructing the dam lies in the fact that it would provide an alternative source of water for surrounding villages that are heavily dependent on depleting groundwater resources.
However, the central question that delegates who are attending the WRASRA Conference should answer is, should communities in Africa's arid regions stop using reservoirs such as dams, which are their major sources of water, when alternative sources of water such as underground sources cannot cater for both small and large populations who live in arid African cities and rural areas?
Depleting Water Resources Threatens Africa's Development
"Water plays a key role in the development of world societies and a sustainable use of this resource is of utmost importance," said a statement released by the organizers of the conference, the University of Botswana. "Africa's water resources are threatened by the increasing population trend with the resultant increase in water demand, the stresses of water use for various activities, desertification, global warming and climate change, and other interventions in the water cycle by man."
These effects are more pronounced in the arid and semi-arid regions of the world and especially in Africa. It is therefore vitally important that the water resources in these regions are developed and managed in a sustainable and integrated manner.
Integrated management of water resources in the arid and semi-arid regions of Africa requires a spectrum of efforts from local and community stakeholders to national and transboundary river basin management. This conference aims at sharing the best practices of water use and conservation around the globe.
The statement issued by the University of Botswana said there were no magic solutions in sustaining water supplies, as neither market forces, military might, mega-projects nor money alone were able to solve the world's water problems.
"On top of the technical problems, the social aspect of the problem should be integrated along with conservation and community initiatives to solve the root problems of water scarcity, which otherwise may incur immense human and governmental cost," the statement continued.
A Conference with Many Interests
The conference will discuss a wide range of water management issues in arid areas that include the following: groundwater recharge (natural and artificial), socioeconomic aspects of demand management, including wastewater re-use customs and developing communities, climate change and its impact on hydrology, water resources, carbon and environmental systems and vulnerability and risk assessment and development of water related risk-mitigating activities.
The UNESCO Water Affairs-funded International Conference on WRASRA is also expected to address water stress expected to result from limited water resources, population growth, increasing demand and pollution and other related risks resulting in insufficient water supply. The conference will also foster insights on issues of global sustainable development and set concrete targets to meet the need for drinking water and sanitation in arid and semi-arid countries.
Costly Impacts
But as the conference enters into its second day today (August 4, 2004), residents of eastern Botswana are anxious to know whether or not the dam construction project on Thune River will take off.
The research findings that seem not to be in favor of the dam construction on Thune River said of the proposed dam, "More water is going to be lost by evaporation than will be consumed."
The dam would also capture all the water, starving downstream communities of regular water flow and supply.
The researchers said, "Without releases from the dam, the river dries up for months a year and the time span between discharges increases considerably. There may only be one or even no flows down the river in any year."
They said this would result in communities based along the riverbanks being accustomed to a dry river and "can suffer when a flood, which is largely unexpected, occurs".
The researchers have already predicted that if built, the proposed dam will be nearly half full of sediment within 30 years and its reliable yield would be much less after 20 to 50 years.
The researchers said that the effects on downstream rivers would be noticeable, particularly regarding the low flow. The Motloutse River, into which the Thune River flows, and further down the Limpopo River, would receive less base flow from the Thune catchment.
"In fact, the entire base flow would be eliminated," said the researchers. "There is also a potential salinization problem."
Salinization is a major problem in irrigated land globally and has severe long-term and often permanent negative impacts on land, agricultural production and livelihoods, "if rehabilitation is not undertaken".
Cumulative Regional Impacts
The following negative cumulative regional impacts were predicted if the dam is constructed on Thune River:
- increased risks of flooding in downstream areas, e.g. Mozambique,
- long term deteriorating water quality and possible reduced species composition,
- increased erosion downstream because of reduced sediment load in the water (clean water has more energy),
- less water to downstream users not only in Botswana but also in South Africa, Zimbabwe and Mozambique,
- less water to sustain natural systems downstream
- and contribution to emission of greenhouse gases due to the rotting of vegetation and carbon inflows from the catchment.
The researchers said the lessons learnt from the research are that a dam constructed in an arid area had many pitfalls compared to one constructed in a temperate area.
Solving Water Sharing Problems
In view of the need to promote cooperation between member states within a particular basin on issues regarding a river, for example the Zambezi River, countries belonging to the Southern African Development Community (SADC) signed the SADC Protocol on Shared Water Course Systems on August 28, 1995.
Responding to a question on whether or not the Zambezi River was being managed satisfactorily, Professor David Stephenson of the University of Botswana's Department of Civil Engineering said, "The Zambezi River is badly managed." He referred to corruption, lack of will-power, poor communications and poor data as reasons for bad management of the river.
The Zambezi River is shared by eight SADC countries that include Botswana, Mozambique, Namibia, Zambia and Zimbabwe.
Stephenson said UNESCO would soon launch a giant research project to be based at the University of Botswana that will look at international water sharing problems in SADC.
The project, expected to last for a minimum of five years and to be funded with millions of US dollars, will focus on selecting the best managers and ensuring multi disciplinary integrated planning and capacity building, according to Stephenson.
At the international level, water management and use is governed by the Helsinki Rules on Uses of Water of International Rivers, adopted at the 52nd Conference of the International Law Association in Helsinki in 1966. An important principle of the Helsinki Rules is that each basin is entitled, within its own territory, to a "reasonable and equitable share" in the beneficial uses of water of an international drainage basin.
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