In dry landscapes, water security is not only about finding new water resources. It is also about responsible groundwater management: protecting the resources that are already there and making better decisions about how water moves through the environment.
In arid and semi-arid regions, groundwater is often the quiet reserve beneath daily life. It supports farms, livestock, households, ecosystems and industry, particularly where surface water is limited or unreliable. However, once an aquifer is depleted or contaminated, recovery is slow, costly and uncertain.
For mining, infrastructure and industrial projects operating in water-stressed regions, this creates a practical challenge: how to manage operational water needs while protecting the aquifers that communities, ecosystems and other land users may depend on.
A project in western Botswana provides a useful example of how hydrogeology can turn a water management challenge into an opportunity for longer-term resilience.
Water security in dry landscapes
The project area lies in a dry part of Botswana where annual rainfall is low, evaporation is high and groundwater plays an important role in supporting surrounding land users. The landscape is underlain by Kalahari sediments, calcrete and fractured sedimentary rocks. In places, groundwater occurs at shallow depths, making the aquifer important but also requiring careful management.
As part of a proposed mining development, groundwater would need to be abstracted to allow safe mining below the water table. This created a familiar challenge for water-stressed regions: what should be done with excess mine water when water itself is such a valuable resource?
Rather than treating the water only as a surplus that needed to be discharged or stored on surface, the project considered managed aquifer recharge. This involves returning suitable water to the aquifer under controlled conditions, allowing the subsurface to act as a natural storage system.
In a drought-prone setting, this matters. Water stored underground is less exposed to evaporation than water stored in open dams. if managed properly, it can also help maintain local groundwater levels and can support longer-term water security for nearby communities and land users.
The groundwater management challenge
Artificially recharging an aquifer is not as simple as putting water back into the ground. The receiving environment must be understood. The aquifer must be able to accept the water without causing waterlogging, surface expression or unintended changes in groundwater flow. Water quality must also be protected. The risk of spills, contamination and changes in groundwater chemistry must be managed.
The local setting added complexity. The area includes shallow soils, calcrete layers and fractured aquifer systems. These features influence how water infiltrates, where it moves and how quickly groundwater levels respond.
Monitoring data showed that some groundwater levels can respond quickly after large rainfall events, meaning that recharge cannot be managed in isolation from climate and seasonal conditions.
A regional groundwater vulnerability map suggested that the area had a low to moderate vulnerability to pollution. However, a more detailed site-specific assessment showed that vulnerability varied across the project area, with some locations having higher relative risk due to factors such as shallow groundwater and the nature of the overlying sediments.
This is an important lesson for drought and desertification resilience: regional data is useful, but local decisions need local evidence.
Using hydrogeology to assess recharge potential
The assessment brought together groundwater quality, aquifer vulnerability mapping, infiltration testing, groundwater modelling and environmental management planning.
A managed aquifer recharge trial was proposed before any full-scale scheme. The trial was designed to test whether surplus water could be returned to the aquifer safely and effectively. The design included two recharge areas, each using a network of infiltration trenches. These trenches were intended to distribute water across the landscape and allow it to infiltrate through the shallow subsurface into the underlying aquifer.
The technical work considered both the benefits and the risks of recharge. Groundwater mounding was expected, meaning that water levels beneath the recharge areas would rise. Modelling suggested that this rise would be localised, but it still needed to be managed carefully to avoid surface expression. Water quality impacts were expected to be low if mitigation measures were implemented, but monitoring was essential to confirm this during the trial.
A site-specific aquifer vulnerability assessment was also completed using the DRASTIC method. This method considers depth to groundwater, recharge, aquifer media, soil type, topography, vadose zone characteristics and hydraulic conductivity. By combining these factors, the assessment helped identify where the aquifer may be more vulnerable to pollution and where additional controls may be needed.
The outcome was not a simple “yes” or “no”. It was a management framework based on evidence, monitoring and adaptive response.
Managed aquifer recharge: evidence, monitoring and controls
The assessments showed that managed aquifer recharge could provide a practical way to reduce water losses and return suitable water to the groundwater system, provided the trial was carefully managed.
Several important management measures were identified:
- Water should be transferred through a closed system from the source to the recharge area to reduce contamination risk.
- Access around the infiltration areas should be controlled to reduce the likelihood of vehicle-related hydrocarbon spills.
- Groundwater levels should be monitored using dedicated monitoring boreholes and automatic water level loggers.
- Recharge should be reduced or stopped if groundwater levels rise too close to surface.
- Groundwater chemistry should be monitored regularly, with trigger values set for electrical conductivity and total dissolved solids.
- Monitoring should continue after the trial until groundwater levels and chemistry stabilise.
These measures reflect an adaptive approach. Instead of assuming that the system will behave exactly as predicted, the project uses monitoring to test assumptions, detect change early and adjust operations before impacts become significant.
What this means for drought resilience
Drought resilience is often discussed in terms of emergency response. But long-term resilience is built through planning, evidence and stewardship before the crisis is fully felt.
Managed aquifer recharge is not appropriate for every site. Its value depends on the local hydrological setting, water quality, operational controls and the ability to monitor and respond to change. In the right conditions, it can help reduce evaporation losses, support groundwater systems and improve how water is managed across competing needs.
The broader message is that every water decision in a dry landscape should be guided by a clear understanding of the system.
- Where is the water coming from?
- Where will it go?
- How will it affect the aquifer?
- Who depends on that groundwater?
- How will change be detected early enough to respond?
These are the questions that turn environmental data into responsible action.
Protecting groundwater for long-term resilience
In dry and climate-vulnerable landscapes, responsible water management depends on understanding the system before decisions are made.
Hydrogeology helps projects test assumptions, manage risk and protect shared groundwater resources, not only for today’s operations, but for the people, ecosystems and landscapes that will depend on groundwater long after the project is complete.
About the Author
Megan Taylor is a Senior Hydrogeologist at Digby Wells Environmental, specialising in water geosciences. With over 15 years of experience across Africa and the Middle East, Megan has led hydrogeological assessments for major mining and infrastructure projects, including water supply and dewatering assessments, aquifer vulnerability studies, and environmental authorisations. She holds an Honours degree in Hydrogeology from the University of the Free State and is a registered Professional Scientist with SACNASP.
Digby Wells supports projects with water assessments, groundwater management, monitoring and practical environmental planning in water-stressed and climate-vulnerable landscapes.