THE IMPACT OF GROUNDWATER IN AFRICA
Kanini Evans Kariuki
May 14, 2009
Groundwater, the water that flows through soil and rock beneath our feet, is the primary source of water supply to half a billion people in Africa and over 80% of Uganda´s population, according to observations made a while back by leading water experts from Uganda and others from across the world.
In recognition of the urgent need to improve basic understanding of groundwater in Africa and the impacts of increased development and climate change on this vital resource, the Ministry of Water and Environment in Uganda in collaboration with the University College London (UK), UNESCO-IHP and IAEA-WRP organized the first international conference on groundwater and climate.
The conference took place at Speke Resort & Conference Centre (Munyonyo),Uganda, and brought together ministers in charge of water affairs in Africa, senior representatives of UN and donor agencies as well as international and regional scientists and policy makers in groundwater and climate.
The conference was attended by over 200 participants and featured 96 oral and poster presentations, primarily by African scientists and decision makers. Papers by a selection of researchers working in Africa from Europe, North America and Asia were also presented.
Reducing the risk of diarrhoeal diseases in Kampala associated with heavy rainfalls was among the issues debated at the symposium.
In Kampala and other cities in sub-Saharan Africa , cases of diarrhea disease often rise significantly during the rainy season. Recent research shows that heavy rains can flush disease-causing agents into water supplies where sanitation and community hygiene are inadequate. High-resolution climate models suggest that the frequency of heavy rainfall events will increase substantially over the 21st century in Uganda .
Together, these findings stress the importance of improved sanitation and community hygiene in reducing the increased risk of diarrhoeal diseases posed by climate change, according to a number of water experts at the seminar.
The sustainability of intensive groundwater pumping for town water supplies in Uganda in unclear. Detailed monitoring of groundwater levels in high-yielding wells supplying the towns of Wobulenzi and Rukungiri reveals interesting and very useful differences. In Rukungiri, groundwater levels have fallen steadily (-3m per year) since pumping commenced.
In contrast, the decline in groundwater levels in Wobulenzi is less than 10% that observed in Rukungiri under a similar pumping regime over same period. Further investigations show that wells in Wobulenzi draw groundwater from a much wider area than those in Rukungiri where groundwater is tightly constrained by local geology.
This vital knowledge not only permits pro-active, long-term planning to prevent water shortages in towns before they occur but also informs strategies for the development and management of groundwater-fed town water supplies in similar geological and hydrological conditions in Uganda, according to the experts.
In addition to more frequent heavy rainfall events, high-resolution climate models predict the total amount of rainfall over much of Uganda will increase over the next century.
Of concern is whether potential gains in the quantity of groundwater available from higher rainfall will be negated by greater evaporation under warmer air temperatures. Recent studies in the River Ssezibwa Basin of south-central Uganda indicate contributions from rainfall to groundwater resources, will increase.
In most places, ground water began its life as rainfall that soaked through soil and unused by plant roots, continued its downwards journey moving between grains of soil and cracks in rocks. Eventually, ground water resurfaces as seepage to a spring, river, lake or swamp. Pumping groundwater from shallow well or borehole interrupts this journey, the seminar heard.
Groundwater´s journey underground can vary from a few weeks or months to years, decades and even millennia. Groundwater underlying the Sahara desert is commonly between 5,000 and 25,000 years old! Preliminary research by the ministry of Water & Environmental and university college London indicates that most groundwater drawn from boreholes in Uganda has spent between 5 and 35 years underground.
In a warmer world, rainfall is expected to occur less frequently but with grater intensity. This shift will not only increase the risk of floods and droughts but also reduce crop productivity as dry periods became longer and more common, experts said at the seminar.
Groundwater, the natural store of freshwater, can therefore play a vital role in helping farmers overcome the impacts of more variable rainfall on food production.
Groundwater is at the heart of efforts to reach the Millennium Development goal of halving the number of people without access to safe water by 2015. Groundwater is widely distributed and generally of better quality than surface water sources like lakes, rivers and swamps.
These characteristics make it the principal target for the development of low-cost, safe water supplies to rapidly expanding towns throughout Uganda and Africa more widely. Groundwater is also the main source of water for many communities where surface water sources are seasonal or non-existent.
It is alarming that despite great dependence upon groundwater- set to increase in a warmer world of more variable rainfall, knowledge of this resource is severely limited. Indeed, a major impediment to improved knowledge and use of groundwater is the fact that current monitoring and assessments of water resources in many areas of Uganda Africa exclude ground-water.
It is from this vulnerable state of great dependence upon, but limited understanding of groundwater and its relation to climate change that the ground water & climate in Africa conference was born
In recognition of the urgent need to improve basic understanding of groundwater in Africa and the impacts of increased development and climate change on this vital resource, the Ministry of Water and Environment in Uganda in collaboration with the University College London (UK), UNESCO-IHP and IAEA-WRP organized the first international conference on groundwater and climate.
The conference took place at Speke Resort & Conference Centre (Munyonyo),Uganda, and brought together ministers in charge of water affairs in Africa, senior representatives of UN and donor agencies as well as international and regional scientists and policy makers in groundwater and climate.
The conference was attended by over 200 participants and featured 96 oral and poster presentations, primarily by African scientists and decision makers. Papers by a selection of researchers working in Africa from Europe, North America and Asia were also presented.
Reducing the risk of diarrhoeal diseases in Kampala associated with heavy rainfalls was among the issues debated at the symposium.
In Kampala and other cities in sub-Saharan Africa , cases of diarrhea disease often rise significantly during the rainy season. Recent research shows that heavy rains can flush disease-causing agents into water supplies where sanitation and community hygiene are inadequate. High-resolution climate models suggest that the frequency of heavy rainfall events will increase substantially over the 21st century in Uganda .
Together, these findings stress the importance of improved sanitation and community hygiene in reducing the increased risk of diarrhoeal diseases posed by climate change, according to a number of water experts at the seminar.
The sustainability of intensive groundwater pumping for town water supplies in Uganda in unclear. Detailed monitoring of groundwater levels in high-yielding wells supplying the towns of Wobulenzi and Rukungiri reveals interesting and very useful differences. In Rukungiri, groundwater levels have fallen steadily (-3m per year) since pumping commenced.
In contrast, the decline in groundwater levels in Wobulenzi is less than 10% that observed in Rukungiri under a similar pumping regime over same period. Further investigations show that wells in Wobulenzi draw groundwater from a much wider area than those in Rukungiri where groundwater is tightly constrained by local geology.
This vital knowledge not only permits pro-active, long-term planning to prevent water shortages in towns before they occur but also informs strategies for the development and management of groundwater-fed town water supplies in similar geological and hydrological conditions in Uganda, according to the experts.
In addition to more frequent heavy rainfall events, high-resolution climate models predict the total amount of rainfall over much of Uganda will increase over the next century.
Of concern is whether potential gains in the quantity of groundwater available from higher rainfall will be negated by greater evaporation under warmer air temperatures. Recent studies in the River Ssezibwa Basin of south-central Uganda indicate contributions from rainfall to groundwater resources, will increase.
In most places, ground water began its life as rainfall that soaked through soil and unused by plant roots, continued its downwards journey moving between grains of soil and cracks in rocks. Eventually, ground water resurfaces as seepage to a spring, river, lake or swamp. Pumping groundwater from shallow well or borehole interrupts this journey, the seminar heard.
Groundwater´s journey underground can vary from a few weeks or months to years, decades and even millennia. Groundwater underlying the Sahara desert is commonly between 5,000 and 25,000 years old! Preliminary research by the ministry of Water & Environmental and university college London indicates that most groundwater drawn from boreholes in Uganda has spent between 5 and 35 years underground.
In a warmer world, rainfall is expected to occur less frequently but with grater intensity. This shift will not only increase the risk of floods and droughts but also reduce crop productivity as dry periods became longer and more common, experts said at the seminar.
Groundwater, the natural store of freshwater, can therefore play a vital role in helping farmers overcome the impacts of more variable rainfall on food production.
Groundwater is at the heart of efforts to reach the Millennium Development goal of halving the number of people without access to safe water by 2015. Groundwater is widely distributed and generally of better quality than surface water sources like lakes, rivers and swamps.
These characteristics make it the principal target for the development of low-cost, safe water supplies to rapidly expanding towns throughout Uganda and Africa more widely. Groundwater is also the main source of water for many communities where surface water sources are seasonal or non-existent.
It is alarming that despite great dependence upon groundwater- set to increase in a warmer world of more variable rainfall, knowledge of this resource is severely limited. Indeed, a major impediment to improved knowledge and use of groundwater is the fact that current monitoring and assessments of water resources in many areas of Uganda Africa exclude ground-water.
It is from this vulnerable state of great dependence upon, but limited understanding of groundwater and its relation to climate change that the ground water & climate in Africa conference was born
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