498
A. Vushe
arid and semi-arid areas which usually depend on groundwater for water supply. An
example of the exploration of such methods is a pilot project using solar-powered
abstraction and desalination of saltwater that took place in the Cuvelai-Etosha Basin
in Namibia. Evaluation of sustainability of this approach is especially useful because
beneficiaries are low-income communities with few skills and little capacity to
manage novel technology. Additional research is necessary to build capacity, and to
invigorate Africa’s political framework to prioritize research in developing cuttingedge technologies and large-scale implementation of such technologies for solving
major African problems.
Exploitation and pollution in urban areas can exacerbate groundwater supply
challenges. According to CSE (2002b), making rainwater harvesting mandatory in
Delhi helped to mitigate depleting groundwater tables. Rainwater harvesting and
purification, gray water recycling, and ecological sanitation are potential solutions
for mitigating water scarcity in urban areas. Demand-side management, financial
and institutional support, groundwater contamination, and an integrated approach
to water literacy, economics, etc. need to be addressed before harvesting rainwater
for aquifer recharge in urban areas. Other relevant study themes are urban surface
runoff and sewage harvesting, catchment area treatment, watershed development,
artificial recharge, and water harvesting under special conditions such as groundwater
harvesting and snow harvesting. Formulation of methods for sourcing of funds for
subsidies and financial assistance as well as distribution and administration of funds
is also of serious concern for those who implement urban water harvesting projects.
2.3 Developing Cost-Effective Technologies for Floodwater
Harvesting, Treatment and Artificial Recharging
of Aquifers, Sediment Harvesting, and Irrigation
Flash floods that occur in semi-arid areas can be effectively harvested and utilized, for
example, use of the majaluba system devised in Tanzania (Hatibu and Mahoo 2000),
but there are serious constraints. River basin-scale challenges include the optimization of water harvesting, river channel storage, runoff diversion, and aquifer recharge
in a practical and economically sustainable way. During floods and high flow regimes,
rivers naturally desilt certain reaches and deposit the sediment in other reaches,
creating and filling up water pools simultaneously. This is why it is imperative to identify the best methods and technologies to control hydraulic deposition and desilting
of pools and dams, for low-cost river channel water storage and sediment management in semi-arid areas. Technology uptake and river basin-scale implementation
by communities are additional challenges for researchers, NGOs, and governments.
Studies are required to determine best practices for flood water harvesting, sand trapping, enhancing aquifer recharges by maximizing retention time of floodwater, and
trapping selected sediments (e.g., gravel, sand, and silt) while releasing the suspended
fine particulates downstream and protecting the integrity of estuary ecosystems. One
A. Vushe
arid and semi-arid areas which usually depend on groundwater for water supply. An
example of the exploration of such methods is a pilot project using solar-powered
abstraction and desalination of saltwater that took place in the Cuvelai-Etosha Basin
in Namibia. Evaluation of sustainability of this approach is especially useful because
beneficiaries are low-income communities with few skills and little capacity to
manage novel technology. Additional research is necessary to build capacity, and to
invigorate Africa’s political framework to prioritize research in developing cuttingedge technologies and large-scale implementation of such technologies for solving
major African problems.
Exploitation and pollution in urban areas can exacerbate groundwater supply
challenges. According to CSE (2002b), making rainwater harvesting mandatory in
Delhi helped to mitigate depleting groundwater tables. Rainwater harvesting and
purification, gray water recycling, and ecological sanitation are potential solutions
for mitigating water scarcity in urban areas. Demand-side management, financial
and institutional support, groundwater contamination, and an integrated approach
to water literacy, economics, etc. need to be addressed before harvesting rainwater
for aquifer recharge in urban areas. Other relevant study themes are urban surface
runoff and sewage harvesting, catchment area treatment, watershed development,
artificial recharge, and water harvesting under special conditions such as groundwater
harvesting and snow harvesting. Formulation of methods for sourcing of funds for
subsidies and financial assistance as well as distribution and administration of funds
is also of serious concern for those who implement urban water harvesting projects.
2.3 Developing Cost-Effective Technologies for Floodwater
Harvesting, Treatment and Artificial Recharging
of Aquifers, Sediment Harvesting, and Irrigation
Flash floods that occur in semi-arid areas can be effectively harvested and utilized, for
example, use of the majaluba system devised in Tanzania (Hatibu and Mahoo 2000),
but there are serious constraints. River basin-scale challenges include the optimization of water harvesting, river channel storage, runoff diversion, and aquifer recharge
in a practical and economically sustainable way. During floods and high flow regimes,
rivers naturally desilt certain reaches and deposit the sediment in other reaches,
creating and filling up water pools simultaneously. This is why it is imperative to identify the best methods and technologies to control hydraulic deposition and desilting
of pools and dams, for low-cost river channel water storage and sediment management in semi-arid areas. Technology uptake and river basin-scale implementation
by communities are additional challenges for researchers, NGOs, and governments.
Studies are required to determine best practices for flood water harvesting, sand trapping, enhancing aquifer recharges by maximizing retention time of floodwater, and
trapping selected sediments (e.g., gravel, sand, and silt) while releasing the suspended
fine particulates downstream and protecting the integrity of estuary ecosystems. One