The Challenge of Solar Water Pumping: Ensuring Sustainable Groundwater Use in Africa

A World Bank study warns that uncontrolled photovoltaic water pumping in Sub-Saharan Africa risks overexploiting groundwater-dependent ecosystems, crucial for both biodiversity and vulnerable communities. Proper regulation and monitoring are essential to ensure sustainable groundwater use.

A recent policy research paper by Guillaume Zuffinetti and Simon Meunier from the University of Paris-Saclay, CentraleSupelec, and Sorbonne University explores the environmental risks posed to groundwater-dependent ecosystems (GDEs) in Sub-Saharan Africa by the uncontrolled expansion of photovoltaic (PV) water pumping systems. Published as part of the World Bank's efforts to understand development challenges, the research focuses on how the rapid adoption of solar-powered water extraction technologies, while beneficial for addressing water scarcity and agricultural productivity, can inadvertently lead to the overexploitation of groundwater resources. This situation presents significant risks to GDEs, which are essential not only for their ecological functions but also for the socioeconomic well-being of some of the most vulnerable populations in the region, such as farmers and pastoralists. These ecosystems, however, are highly sensitive to changes in groundwater levels, and unregulated access to water could cause irreversible damage, particularly in areas where these ecosystems are already fragile.

Risk Mapping Highlights the Vulnerable Areas in Sub-Saharan Africa

The study employs the analytic hierarchy process (AHP) to assess the risk posed to GDEs by the expansion of photovoltaic water pumping systems. It examines key factors such as solar irradiance, groundwater availability, population density, and specific data on GDEs to create a risk map across Sub-Saharan Africa. The results of the analysis are striking, revealing that 92 percent of the region’s GDEs are at risk of overexploitation if PV water pumping systems are deployed without proper regulatory oversight. The paper highlights that the most at-risk regions are in Southern and Eastern Africa, particularly South Africa and Namibia. In contrast, areas such as Gabon, the Republic of Congo, and southern Nigeria are less vulnerable to the risks associated with uncontrolled water extraction through PV pumping. This divergence is largely due to variations in solar irradiance and groundwater availability, with regions receiving higher solar irradiance and having less abundant renewable groundwater resources facing greater risks.

Groundwater-Dependent Ecosystems Are Critical for Communities

Groundwater-dependent ecosystems in Sub-Saharan Africa are crucial for supporting local communities and maintaining biodiversity. These ecosystems provide essential services, such as carbon storage, water filtration, and habitat for wildlife, and they play a vital role in supporting agricultural and pastoral activities. For example, perennial lakes, which are considered GDEs, help trap significant amounts of carbon dioxide, contributing to climate regulation. In addition, many rural communities in the region rely on these ecosystems for water supply, especially in arid and semi-arid areas. However, because of the delicate balance of groundwater levels needed to sustain these ecosystems, even minor changes in water extraction can lead to their degradation. Once disrupted, restoring GDEs is often difficult or impossible, especially in dryland areas. The study emphasizes that the protection of these ecosystems should be a priority in the planning of water infrastructure projects.

Balancing Photovoltaic Water Pumping Expansion and Groundwater Sustainability

One of the paper’s most critical findings is balancing the expansion of PV water pumping systems with sustainable groundwater management practices. While the adoption of PV technology offers a promising solution to water scarcity, particularly in areas with limited access to electricity and water infrastructure, these systems must be implemented with adequate safeguards in place. The researchers point out that regions such as southern Nigeria and South Sudan, where groundwater development needs are high but the risk to GDEs is lower, should be prioritized for investments in PV water pumping systems. These areas need improved water access, and deploying solar-powered pumps could significantly enhance water availability without posing an immediate threat to local ecosystems.

Targeted Investments and Monitoring Are Key in High-Risk Areas

Conversely, regions like Namibia and South Africa, where groundwater development needs are relatively low but the risks to GDEs are higher, should approach the implementation of PV water pumping systems with caution. In these areas, strict monitoring of groundwater levels and controlled access to water resources will be necessary to prevent overexploitation. The study advocates for targeted investments and regulatory frameworks that can balance the need for water infrastructure development with the protection of fragile ecosystems. Policymakers are encouraged to use the findings of this research to inform decisions about where to allocate resources and how to regulate the expansion of PV water pumping systems.

Improved Data and Monitoring Are Crucial for Long-Term Ecosystem Protection

Another key recommendation from the paper is the need for improved data on GDEs. Many of these ecosystems are poorly mapped, and their full value and benefits are not well understood. The authors suggest that better monitoring and mapping of GDEs would help policymakers and development agencies identify areas at risk of overexploitation and take preventive measures before significant damage occurs. This is particularly important in regions where GDEs play a crucial role in carbon storage and biodiversity conservation. Protecting these ecosystems is not only an environmental imperative but also a socioeconomic one, as many rural communities depend on them for their livelihoods.

The findings of this research highlight the potential unintended consequences of scaling up photovoltaic water pumping systems without proper safeguards. While the technology holds great promise for improving water access and boosting agricultural productivity in Sub-Saharan Africa, its deployment must be accompanied by measures to protect groundwater resources and the ecosystems that depend on them. By integrating sustainable groundwater management practices into water infrastructure development plans, policymakers can ensure that the benefits of PV water pumping systems are realized without compromising the long-term health of vital ecosystems.