• Sustainable use of water could maintain a balance between its demand and supply.
• Rainwater harvesting is the most traditional and sustainable method
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Recent climate science reports have determined with high level of certainty that climate global is changing.
As the urgent need for climate change mitigation remains crucial, putting all the necessary resource and institutions in place for future adaptation is indispensable. The water sector must seek alternative resources and developed improved water management approaches that will reduce pressure on already stressed systems.
Water harvesting is a sustainable and effective solution for adapting to climate change in Africa. As climate change brings about prolonged periods of drought, water scarcity becomes more severe, especially in arid and semi-arid regions. Water harvesting involves capturing, storing and managing rainwater, making it a valuable source of water for agriculture, livestock, and households. There are various types of water harvesting techniques, including traditional and modern ones, that can be used to collect rainwater.
Rainwater harvesting is a system designed to collect run-off water from outlying areas or from areas where it is not used, store it, and make it available where and when there is a scarcity of water. It can be used for several applications in urban and rural areas to tackle environmental, agronomic and socio-economic issues, such as urban floods, crop irrigation and human consumption.
Methods such as dugout ponds and earth dams have proven effective in many regions of Africa. These methods involve creating a low-lying area or a dam and lining it with impervious materials to capture rainwater runoff. The collected water can then be used for irrigation, livestock watering, drinking purposes, and even for fishing.
Modern water harvesting techniques include rooftop rainwater harvesting, which simply captures rainwater from rooftops for domestic use. Other techniques include underground water storage tanks, recharge pits, and check dams. These methods are inexpensive and can easily be implemented on a small scale.
Investing in water harvesting as a way to adapt to climate change has significant benefits for African communities. It helps them become less reliant on more erratic sources of water and ensures food security, water supply and reduces their vulnerability to drought. Additionally, it is an effective way of conserving water resources, thereby promoting sustainable use of our natural resources. Sensitization on technology use helps individuals get information from important referents about the ease of use or the perceived usefulness of the technology introduced, which enables individuals to form stable perceptions of use or usefulness and influences adoption of the technology.
Water can be harvested at several stages in the water cycle, such as: Fog screens placed on hills, mountains and near the sea for domestic water. Gutters attached to roofs for domestic water. Garlands of stone gutters on rock outcrops for domestic water. Soil bunds and trenches on farmland for crops and animals. Harvesting rainwater allows the collection of large amounts of water and mitigates the effects of drought. Most rooftops provide the necessary platform for collecting water. Rainwater is mostly free from harmful chemicals, which makes it suitable for irrigation purposes.
Sustainable use of water could maintain a balance between its demand and supply. Rainwater harvesting is the most traditional and sustainable method, which could be easily used for potable and non-potable purposes both in residential and commercial buildings.
Principles of water harvesting and conservation is a way to go by to mitigate dangers of climate change. These measures can include: using rainwater effectively. In many climates, rainfall is distributed unevenly in intense downpours that cannot be readily used by a crop.
Storage techniques such as external catchments or roof top collection increase the availability of water in the drier seasons. They also harvest water from a wider area making more water available to the crop. Measures can also be taken to avoid the rainwater running off the surface during intense rainfall and making effective use of soil water reserves. Additionally, there is need to reduce water losses through drainage and also take measures to avoid run off.
There is need to however, address several challenges effectively to make rainwater harvesting efficient, particularly treatment of harvested rainwater in areas where pollution is rampant. For instance, it is now possible to use Nano filtration for the removal of hardness, natural organic material, micro pollutants such as pesticides, viruses and bacteria, salinity, nitrates and arsenic.
With an insightful policy, rainwater harvesting can be promoted as a core adaptation strategy for achieving the global security and sustainability of water resources in an era of anthropogenic climate change. Water harvesting reduces soil erosion, storm water runoff, flooding, and pollution of surface water with fertilizers, pesticides, metals and other sediments. It is an excellent source of water for landscape irrigation with no chemicals, dissolved salts and free from all minerals.
The rain harvesting system design uses gravity for water flow, reducing the electricity that would otherwise be needed for pumping. This water is then available for people to use and consume during the dry season when there is a shortage of clean water. Water is inextricably linked to energy and climate change. Energy is required for pumping and treating water that we get at home. Pumping and treating wastewater is energy intensive. Conservation of water indirectly conserves therefore, conserve energy and reduce greenhouse gas emissions.
Water harvesting is a viable, sustainable, and affordable method that can be utilized to mitigate the water crisis in Africa caused by climate change. It promotes food security, water supply, and reduces the vulnerability of African communities to drought, ultimately helping them thrive in a changing climate.
It helps in recharging the level of groundwater, gives life to the rivers and wells and also enhances the future availability of water. The role that the government play in improving awareness about rainwater harvesting to be able to mitigate climate change. Government can organize workshops, seminars and webinars, awards that encourage people to become active participants for water conservation and rainwater harvesting.
The government and other water related institutions should also consider factors that influence the amount of water to be collected and these include rainfall intensity, catchment size and demand size of conveyance and Storage system provided or that are in existence.
John Chumo is the CEO, MaMa Doing Good and an environmental expert