Slow progress on Ohangwena aquifer

ILENI NANDJATO The Kalahari Ohangwena Aquifer (KOH-2) steering committee has dispelled rumours that the aquifer has the capacity to supply water to northern Namibia for 400 years, but confirmed that it contains an estimated 20 billion cubic metres of water.However, the Ministry of Agriculture, Water and Forestry’s deputy permanent secretary for water affairs, Abraham Nehemia, expressed concern about the aquifer’s water quality.The committee held a meeting at Eenhana in the Ohangwena Region last week to share information on the status of the aquifer. During the two day meeting, it was revealed that the aquifer is currently supplying water to Eenhana, Okongo and Omundaungilo, but this water contains a high concentration of fluoride.The committee reported that water in the area between Oshikango and Eenhana is high in fluoride, while water between Eenhana and Okongo contains less fluoride.“The aquifer testing has demonstrated that the volume is very significant, but the quality of water is not as we expected. This water is high in fluoride and at the moment we mix it with pipeline water for the people of Eenhana to use.“As we are taking water from the aquifer, it is affecting both the quantity and quality. The more water we are taking, the more fluoride they are getting,” Nehemia explained.The Bundesanstalt für Geowissenschaften und Rohstoffe (BGR) project manager, Martin Quinger, said it must not be said that the aquifer has a capacity to supply water for the next 400 years. He said further studies were needed on how the aquifer reacts to the extraction of water.“We are not sure how the aquifer is reacting yet as the level has not subsided well yet. This aquifer is recharged by water sources coming from Angola and we do not want to dry it completely,” Quinger said.Quinger said they were studying the aquifer reaction by means of monitoring boreholes next to the production borehole. For the 2011/2012 year, the aquifer recharge volume was 635 000 cubic metres.“At the moment we only observed that recharge is very slow as the aquifer is still at the full capacity. We cannot really tell how it is reacting.”Namwater’s manager for geohydrology, Henry Mukendwa, said it was expensive and risky to set up these boreholes. He said the drilling of one borehole cost N$2.6 million, plus N$3 million worth of material.“We are talking about drilling up to 300 metres deep. The deeper you go the more expensive it gets and it also gets complicated. Sometime it gets difficult to pull out drilling equipment. There are some boreholes where we buried the equipment because we could not get them out,” Mukendwa said.He explained that the KOH-2 aquifer, which contains freshwater, lies below the KOH-1 aquifer, which contains salty water. When drilling they have to make sure that water from KOH-1 does not contaminate KOH-2. They also have to build a concrete shield after drilling.The meeting also reported that no independent body had tested the water quality. There is also no purification done: the groundwater goes straight to residents for consumption, except for Eenhana where it is mixed with pipeline water.Demand for speedy implementation The regional governor for Ohangwena, Usko Nghaamwa, urged the government to speed up the development of the aquifer because his region desperately needs water. He said the areas east of Eenhana have no pipeline supplying them with drinking water and people are suffering.The deputy permanent secretary could not indicate when the extraction of water from the aquifer would be fully operational.The cabinet has established a committee on water security. This committee reports to the president and it is monitoring the progress of the aquifer study.According to the Harambee Prosperity Plan the aquifer project will be implemented within five years. “All those areas east of Eenhana up to Oshivelo will be supplied with this water,” Nehemia said.The aquifer is part of the Cuvelai-Etosha Basin (CEB) - an extensive sedimentary basin which is part of the much larger Kalahari Basin covering parts of Angola, Namibia, Zambia, Botswana and South Africa.The CEB is divided into six groundwater regions, based on geological units (Damara Sequence) and the locally occurring Kalahari Sequence.Namibia and Angola have entered into an agreement on how to manage the aquifer. They have established the Kunene Bain Commission and Okavango Basin Commission.They have also established four management committees and a join groundwater task force is sharing research findings.Several abstraction scenarios have been calculated and their impact on the aquifer visualised.“The problem lies with the determination of the sustainable yield of the aquifer and the conceptualisation of water abstraction. The production well of Eenhana town does not prove that the aquifer is sustainable. More tests are still needed and this will take more time,” Nehemia said.Since 2009 up to 21 observation, production and monitoring boreholes have been drilled, but not all of them were successful. Namwater’s production borehole at Eenhana collapsed in 2014 and was replaced.NamWater and the ministry of agriculture are supervising the project with technical support from Germany, while the European Union has provided funding of approximately N$25 million.The meeting indicated that the study is expected to end by September next year.

Slow progress on Ohangwena aquifer

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Namibian Sun 2025-07-07

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Slow progress on Ohangwena aquifer

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Namibian Sun 2025-07-07

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