UNREGULATED pumping and extraction of ground water for both domestic and industrial purposes is putting a strain of Zimbabwe’s underground water, with indications that the resource could deplete in the foreseeable future, water experts have warned.
By Michael Gwarisa
The warning comes in the wake of increased extraction of underground water due to unplanned urbanization which has resulted in the sprouting of new settlements where land developers and city authorities are settling people in areas where there are no basic amenities such as piped running water.
Renowned Hydrologist with the University of Zimbabwe, Dr Richard Own, told a Medicines Sans Frontiers (MSF) Environmental Seminar in Harare that the signs of a depleted underground water source are already showing.
The resilience of ground water is a mixture of the aquifer (a body of rock and/or sediment that holds groundwater) and how big is the aquifer,” said Dr Owen.
“This is where underground water is stored and when you have a huge store whether its money or what, you know you have resilience. Now Harare and most of Zimbabwe doesn’t have many aquifers. Botswana instead has big aquifers despite it being a dryer country and their resilience is much greater.”
He added that a study of the whole of SADC’s underground water drought risk indicated that Zimbabwe and Harare in particular is the most vulnerable community as a result of very high dependence on ground water
“You also find that Zimbabwe and Harare have shallow aquifers. In some places, the aquifer is high and low in some areas. In the future climate, we are in trouble, we are in trouble of running out of underground water. As people drill for water in Harare they are also drilling for water everywhere,” said Dr Owen.
Bulk water supply companies have in the past also been criticized for abusing the resource and invading wetlands where they sink boreholes to pump ground water.
A survey of 59,952 water points in Zimbabwe shows that only 30 percent of all recorded boreholes in the database were flagged as perennial while over 60 percent were flagged as seasonal and the remainder were unspecified.
Apart from the risk of running dry, underground water in Zimbabwe is also at greater risk of contamination as most boreholes and underground water sources were being sunk in shallow aquifers closer to compromised sewer infrastructure and anthropogenic activities that could expose residents to waterborne diseases.
“Shallow aquifers are contaminated and if drilling techniques are not adapted, we risk to contaminate the deep aquifers. The use of proper geophysical techniques can help increase the quality and quantity of water,” said Danish Malik, the Regional Environmental and Health Coordinator, MSF Southern Africa.
The MSF Environmental Health Project (2015-2022) has been strongly advocating and implementing catalytic and agile projects together with stakeholders to mitigate community resilience to address adverse effects of environmental degradation and climate change on the communities. MSF has conducted borehole diagnostics and rehabilitations where they targeted deteriorating boreholes, rehabilitations for the provision of safe water and conducted Hydrogeological investigations.
“We have installed Innovative borehole sealing techniques to seal contaminated shallow aquifers in accordance with the local geology of the ground. All shallow contaminated aquifers are sealed through proper cementation. An assessment on the effectiveness of the sanitary seal in protecting boreholes from contamination in Mbare Suburb, Harare revealed that boreholes are exposed to high risk of pollution due to high anthropogenic activities, against high sensitivity, due to shallow depth-to-water-table , soil media and aquifer media,” added Malik.
MSF through support from stakeholders and partners installed 72 water points at 11 suburbs in Harare. MSF together with UNICEF, WaterNet, University of Zimbabwe and partners has organized various capacity building programs to train both National and INGO’s partners on Borehole drilling supervision, Geophysical surveys and Diagnostics and rehabilitation of boreholes.
Meanwhile, City of Harare Mayor, Cllr Jacob Mafume said the lack of prioritization of surface water projects was exerting pressure on the ground water resource.
“The issue of water spread is a whole ecosystem. The last dam for Harare was built in 1976 that is Darwendale Dam. That was the last time a dam was built for the greater Harare. The last dam had been built in 1950 something that is Lake Chivero. It was meant to service a population of 500,000 people. We are now approaching the 5 million mark for the greater Harare only. There has not been any surface water source that was built after 1976,” said Cllr Mafume.