The first steps towards a Namibian Circular Bio Based Economy. Part 4

 

Water 

How to feed the world without degrading land and water resources, eroding biodiversity and contributing to climate change is among the greatest challenges of our times. FAO

With limited resources comes greater responsibility to look after those value resources. Putting proper management systems in place, ensuring quotas for output in relation to use. Offering people potable water at a affordable price where they live is probably the biggest issue in Namibia. Agriculture water use is a luxury in certain circumstances and is a problem that need to be looked at each step of the way.

It is estimated that a third of the world’s population use groundwater. Whether all if it are renewable is unknown, however it demonstrates where we are and what the future trends will be. 

Desalination technologies are available for small and large scale plants, using solar or conventional electricity, to serve small communities with ground water purification to large seawater desalination solutions. The only environmental negative about desalination is the waste water management issue, called brine that the process produces. There are solutions coming to the front that produces commercial salt and other extraction methods for minerals that should lead to zero brine. These solutions come at a high cost, however as with all technology will become more affordable and thereby offering financially viable water treatment at any scale. Replacing groundwater used should be a key driver when resources are utilised for agriculture and or human consumption.

The lack of detailed information about water usage and groundwater levels makes it difficult to develop a clear water management plan. It is foreseen that this situation will change as trusted data sources becoming available. While all data streams are being developed accurate extraction can be measured nationally with real time processes.

Water capturing from fog and rain holds promise for coastal and rural applications. Municipalities are behind on water treatment technologies and many are without drainage systems causing a significant loss due to run off. Natural storage basins and capture areas need to be determined. 

An example of using applicable technology in a financially viable way for water storage: The northern region of Namibia you find natural small dams called Oshana’s. These can be converted to a affordable water storage systems with some construction to stop leakage and evaporation.

Hydroponics address some of the water usage issues as the water can be re-used when filtered. Additionally precise water consumption can be monitored per plant. Generally hydroponics use 10% of soil water requirements. One kilogram tomatoes grown hydroponically will use 20 litres of water and in soil it will be at least 60 litres.

The data obtained from NASA shows that Namibia’s groundwater reservoirs are still not stressed when compared to the UAE and other Northern African countries. This offers Namibia an advantage that by managing this resource in conjunction with sea water desalination efforts, Namibia should never experience total draught devastation scenarios. The biggest risks for draught are animal based where the wrong farming methods are used due to culture and lack of knowledge. This causes losses in livestock and severe degradation of the soil.

The end result of water for agriculture and in particular Horticulture is that the cost of water after being pumped, filtered and delivered to the place of consumption needs to be in the N$3.00-N$9.00 per cube (1,000 litres) price range to make large scale hydroponic growing profitable. This is the challenge more so than any other variable including energy. If water costs are above N$12.00 per cubic than there is very little opportunity in growing profitability and is more suited for own consumption communities and families. These costs take into account everything needed including maintenance and filtering costs.

by Willem Baartman

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