Achieving Sustainable Resource Use by Measuring What You Manage: Groundwater Monitoring in the Shared Tuli Karoo Aquifer
This post is written by Jonathan Lautze and Girma Ebrahim, IWMI.
The Tuli Karoo Aquifer, shared among Botswana, South Africa and Zimbabwe, is located in a very arid region. Surface water resources in Tuli Karoo Aquifer area are scarce and unreliable, so groundwater is used as the primary source of agriculture, domestic and industrial water in the mainly rural communities living there. The degree of reliance on groundwater in the Tuli Karoo, coupled with challenges of water scarcity, climate vulnerability, and poverty, amplifies the need to manage this resource optimally. Yet it is difficult to optimally manage this resource when essential inputs to management — such as trends in water levels — are unknown or separately housed by different countries.
In response to this challenge, a pilot groundwater-monitoring system is being developed for the Tuli Karoo. The near real-time system will be applied in a set of wells in the aquifer, to provide fast and reliable groundwater levels in a timely fashion. The pilot system consists of a data logger with a telemetry system (wireless telecommunication technology) and visualization platform. Users can access the groundwater level data via a web browser on a computer or smartphone. To reduce operating costs, groundwater levels are recorded every 30 minutes but transmitted to the server once per day. Where possible, the new system will build on existing manual recording of water levels.
The monitoring system will generate data can be acted on in a timely manner such as early detection of groundwater over-exploitation and drought warnings. The system will also generate data that allows for optimal management on a more routine basis, for example, by clarifying thresholds above which water levels should remain to achieve sustainable yields, and enabling understanding of how withdrawal in one country affects water availability in another. Coupled with data on surface water, the system will help depict surface-water interactions as well, which is key to unlocking benefits associated with conjunctive water management of different water sources.
The system will produce broader benefits beyond the immediate ones just outlined. Over time, it will work to build trust and cooperation among the three countries sharing the aquifer and should help inform selection of locations of future well constructions in the aquifer. Ultimately, the system can be expanded to promote more reliable and regular data sharing, help decision-makers to issue timely warnings and appropriate mitigation measures, and enable effective water management on a daily basis to foster sustainable use of the resource for food security and resilience.
Acknowledgment: This work is being undertaken in the context of a USAID-funded project entitled Conjunctive Management of Transboundary Waters in the SADC Region: Generating Principles through fit-for-purpose practice.