Open access research article and cooperation map provide additional insights in transboundary aquifer cooperation


With in total 468 identified transboundary aquifers in the world, almost every nation-state shares groundwater resources with neighbouring states. Effective management of transboundary aquifers, therefore, essential for sustainable water resources. Despite the emphasis on this in SDG target 6.5, recent assessments show disparities in cooperation. In the open access paper "Transboundary water cooperation under SDG indicator 6.5.2: disaggregating data to provide additional insights at the aquifer level" former IGRAC Researchers Christina Fraser and Neno Kukuric, together with Tatiana Dmitrieva and Aurélien Dumont (both UNESCO-IHP), provide valuable insights into global aquifer cooperation, offering pathways for improvement. 

Because groundwater knows no boundaries

Around 60% of accessible water globally is transboundary and the majority of large aquifers that store groundwater are transboundary. Cooperation over these vital resources is therefore essential to ensure mutual benefits from sustainable development including poverty alleviation, food security, ecosystem protection and addressing the impacts of climate change alongside being a driver of peace and security in unstable regions.

Global Goals target 6.5.2 to measure transboundary cooperation

Acknowledging this importance, the UN 2030 Agenda for Sustainable Development dedicated target 6.5 to transboundary water cooperation. The target indicator 6.5.2 is dedicated to measuring this transboundary cooperation over water resources and calls for the percentage of a basin or aquifer under an operational arrangement to be calculated. Countries are asked to report on the state of cooperation over their transboundary river and lake basins and transboundary aquifers to indicate if an operational arrangement is in force.

However, a SDG progress report in 2021 revealed that only 24 countries have operational arrangements covering all their transboundary basins (rivers, lakes and aquifers) and that an additional 28 countries have operational arrangements for 90% or more of their transboundary basins. Regarding the aquifer component specifically, the numbers are even lower: 50 countries out of 145 that share groundwater resources reported that operational arrangements covered 30% or less of their aquifer areas.

Research outcomes: Much work to be done

The paper presents the results of a global analysis, illustrating the state of global transboundary aquifer cooperation, as reported under SDG indicator 6.5.2, per aquifer, to complement official national country reporting. Theoretically, the reported status of cooperation over a single transboundary aquifer should be matching for all riparian states. However, as shown on the figure below, this is often not the case. A lack of coordination between countries sharing aquifers is evident.


In addition, a total of 49 transboundary aquifers are reported by all riparian countries consistently and 64 are not reported by any riparian country. This leaves 229 aquifers that have data harmonization issues, with at least one country disagreeing with neighbours over the cooperation status of an aquifer, meaning that 67% of the SDG 6.5.2 indicator data on aquifers is inconsistent. The paper further zooms in on specific case studies in the Lake Chad Basin, Indus River Plain aquifer, and a set of transboundary aquifers shared by Mexico and the United States of America.

However, the paper also highlights to potential for achieving operational arrangements over a transboundary aquifer. Cameroon, for example, stated that two out of four criteria are met for the Aquifer Vallee de la Benoue. In general, targeting arrangements that are close to being operational should be a priority to improve coverage.

The way forward towards improved transboundary cooperation

Moving forward, it is suggested that the findings outlined in this paper could serve as a valuable resource for forthcoming reporting cycles, contributing to enhancing the comprehensiveness of SGD indicator 6.5.2 coverage. Additionally, the dataset created could serve as an awareness-raising tool for custodian agencies during workshops and for nations aiming to enhance their indicator performance through targeted interventions and enhanced collaboration with neighbouring countries.

Furthermore, it's essential not to underestimate the potential of data collected within the framework of the SDGs. This study exemplifies how such data can offer fresh perspectives and insights, complementing the formal reporting process. It's imperative for scholars and researchers to seize this opportunity to explore novel methodologies for interpreting and utilising SDG data to advance progress towards achieving SDG 6. Diverse approaches and perspectives will be instrumental in realising the goals outlined in SDG 6.

Research data in IGRAC's GGIS

All relevant data are available in the Global Groundwater Information System: