Africa can save billions with water harvesting

Posted on March 23, 2017 12:00 am

According to data available, only a third of African population has access to water and more than half of those don’t access clean water. Water is the most precious natural resource and something that most people take for granted. Africa is now increasingly becoming aware of the importance of water to its survival and its limited supply, especially in such a dry continent as it is. Thats why water harvesting during the rain season has become critical. The harvesting of rainwater simply involves the collection of water from surfaces on which rain falls, and subsequently storing this water for later use. Normally water is collected from the roofs of buildings and stored in rainwater tanks. This is very common in rural Africa. Water can also be collected in dams from rain falling on the ground and producing runoff. Either way, the water collected can be considered to be precious. Implementing water efficiency measures in planning policy could help save Africa billions of dollars, improve water resilience and help reduce the emissions of housing stock, but most African governments are dragging the chain.Applying water efficient measures, such as rainwater harvesting systems, into new buildings in African cities could reduce the net present costs of water cycle management to 2060 by $300 billion, and save $500 billion between now and 2060 as research about the water situation in Africa shows.One of the researchers your blogger spoke to said: “When you turn the tap on in Africa, it comes from a dam or another water source through big pumps and pipes and storage reservoirs until it gets to your house. The water you don’t use is then discharged by another set of pipes and infrastructure to the wastewater system for those in urban areas and in rural areas is poured on surface.“However, putting rainwater harvesting tank on that house, using rainwater rather than getting it from the water supply system. That means a certain proportion of water is no longer travelling through all the centralised water infrastructure, which will defer that cost, and that saves money,” he added.

For example, water prices in Dar Es Salaam and Nairobi are currently around $5 – $10 for 1000 litres, but the cost of supplying water to different parts of the two largest cities in East Africa, including storage, pumping, treatment and testing, means the real cost of delivering water could be over $20 a kilolitre. If the cost of delivery was taken out of account, it could save $10 per kilolitres. While listening to him, it became clear that if the marginal cost of rainwater harvesting paid by the homeowner is $10/kL there is a significant community benefit. The small benefit at a household scale becomes considerable at the neighbourhood scale, significant at Nairobi and Dar Es Salaam scale and massive at a regional scale measured over 35 – 40 years.As well as cost savings in delivery, rainwater harvesting could also reduce stormwater infrastructure costs and flood damage by billions of dollars.Rainwater tanks storing water rather than it being runoff into the system, which also helped to protect waterways and wetlands means there’s double benefit of changing behaviour.Another expert argued that the financial and environmental savings that can be had from rainwater harvesting could be realised if African countries implement water and energy saving targets to all new buildings and significant renovations.However, only Botswana, South Africa and Egypt to date has implemented such a policy which sets sustainability targets for water and energy as well as minimum performance levels for the thermal comfort of new developments.To date, that has resulted in rainwater harvesting being implemented in more than 50 per cent of all new dwellings and delivered a 30 per cent water and energy saving in building performance.

I wonder why have other African countries been dragging their heels on implementing such policies. Me thinks that countries are aware of the findings, but are not motivated to implement such a scheme. No one analyses the whole system together, it’s partial accounting in my view. African countries are more interested in the revenue earned from water monopolies than counting for the full cost of what they’re doing. Water companies don’t have to worry about how much things cost because someone else picks up the tab.Customers just get a price increase from the regulator and folks pay for it. However I’ve been to Dar Es Salaam and feels that rainwater harvesting ideas will reduce the water demand by a fair bit, thereby reducing the revenue earned by the water monopolies. It could reduce the cost by twice as much. Most African countries know about that, but they needs to be higher profile because it’s something they need to do as a continent. To do that, African countries need to take a whole society perspective rather than revenue. It takes a pretty strong public-based conversation to get to a better answer for society.Interestingly, Africa will need to build about 60 million new households by 2050, a 100 per cent increase from 2015.My suggestion is that those houses should be considerably better than the houses Africans build now and that there is an existing low risk policy to achieve this. Given the public savings are measured in the billions of dollars I believe African have a public responsibility to promote this policy. From my conversation with the experts, I fully agree with the need to have an African conversation about this. It’s more than just about the revenue and single infrastructure agenda of a small group of organisations. Africa need a water policy discussion in place that represents more of society.

Contador Harrison