MUNICIPAL FOCUS: NELSON MANDELA BAY
GROUNDWATER HAS THE MUSCLE TO PUSH BACK ‘DAY ZERO’ – BUT ARE WE PROTECTING IT? Groundwater is being used in the fight against the worst drought in Nelson Mandela Bay’s recorded history. To stop the taps from running dry, businesses, citizens and NGOs are drilling boreholes in Gqeberha. But, among the panic and desperation, is enough care being taken to protect this precious resource? By Kirsten Kelly Neville Paxton, chairman: Eastern Cape Branch, Ground Water Division (GWD)
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A successful water strike; groundwater rises to the surface under its own pressure (Photo credit: Stefanutti Stocks)
overing 1 959 km2, Nelson Mandela Bay (NMB) is major seaport and automotive manufacturing centre. With below-average rainfall being experienced in catchment areas, dam levels have continued to decline rapidly. The combined storage levels have not been above 25% since February 2020. As dam levels continue to decline, it is groundwater that is augmenting water supply in the region. “Depending on its quality, groundwater is generally more affordable than water reuse or desalination. It is a ‘sleeping giant’ and has huge potential in improving the region’s water security. Groundwater flows a lot
slower than surface water and can provide water when the surface water sources are stressed. Then, when rainfall levels improve, and the rivers start flowing again, the groundwater can be recharged, while the surface water sources again become the primary water source. Groundwater can buffer the impacts of drought,” says Neville Paxton, chairman: Eastern Cape Branch, Ground Water Division (GWD). NMB has a complex, favourable geology for good-quality groundwater with relatively high yield. It mostly comprises sedimentary rocks that have undergone tectonic stress, resulting in the mountainous landscapes and large faults that are subsequently overlain with
aeolian and alluvial material. There have been highly successful groundwater development projects in and around the city for the municipal, industrial and private sectors. When the big water users become completely, or partially, dependent on groundwater, that volume is freed up for other end-users.
Nelson Mandela Bay Municipality Nelson Mandela Bay Municipality (NMBM) conducted groundwater investigations during the 2010/11 Eastern Cape drought, and it was found that some properties owned by NMBM had a high groundwater potential. Subsequently, over 200 boreholes were drilled to locate suitable sites (Table 1).
TABLE 1 Sites identified with high groundwater potential
Location Coegakop St. George’s Park Glendinning Fort Nottingham Fairview Bushy Park Total Churchill (design phase)
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IMIESA July 2022
Anticipated completion month (2022) September September July July July September
Low yield (Mℓ/day) Medium yield (Mℓ/day) 6 10 1.4 2.1 1.6 2.3 0.8 1.0 0.9 1.5 7.0 10.2 17.7 27.1 1.7 3
High yield (Mℓ/day) 12.6 3.6 2.9 1.8 2.2 13.3 36.3 4.3
