Groundwater monitoring is essential to sustainable water resource management and climate resilience strategies – a source of key data to support decision-making. However, in many regions of the world including in Malawi, a country that is heavily reliant on groundwater, the scarcity of groundwater monitoring data is a persistent challenge. The scarcity of data is compounded by the in-operation of existing groundwater monitoring networks. While operational challenges have often been framed as a technical or financial issue, this study applies a co-creation methodology to explore the wider institutional, procedural, and social factors contributing to persistent data scarcity. Drawing from sourced grey literature and a series of participatory workshops held in Malawi with stakeholders from across the water sector, including community representatives, several systemic and interconnected challenges were identified. Themes of challenges include institutional and governance fragmentation, procedural ambiguity, limited and uncertain financing, and a lack of formalised community engagement. Participants emphasised that these challenges are not independent and addressing them in isolation is unlikely to lead to long-term improvement in data availability. Instead, data scarcity is a symptom of deeper systemic issues, and any attempt to improve the monitoring network must consider the broader context in which it operates. The findings suggest that future efforts, in Malawi and in other global contexts, should prioritise adaptive and inclusive strategies, including strengthened institutional coordination, updated procedural guidance, and an expanded role for community participation in monitoring activities.

This study investigated how sporadic river datasets could be used to quantify temporal variations in the base flow index (BFI). The BFI represents the baseflow component of river flow which is often used as a proxy indicator for groundwater discharge to a river. The Bua catchment in Malawi was used as a case study, whereby the smoothed minima method was applied to river flow data from six gauges (ranging from 1953 to 2009) and the Mann-Kendall (MK) statistical test was used to identify trends in BFI. The results showed that baseflow plays an important role within the catchment. Average annual BFIs > 0.74 were found for gauges in the lower reaches of the catchment, in contrast to lower BFIs < 0.54 which were found for gauges in the higher reaches. Minimal difference between annual and wet season BFI was observed, however dry season BFI was >0.94 across all gauges indicating the importance of baseflow in maintaining any dry season flows. Long term trends were identified in the annual and wet season BFI, but no evidence of a trend was found in the dry season BFI. Sustainable management of the investigated catchment should, therefore, account for the temporal variations in baseflow, with special regard to water resources allocation within the region and consideration in future scheme appraisals aimed at developing water resources. Further, this demonstration of how to work with sporadic river data to investigate baseflow serves as an important example for other catchments faced with similar challenges.

In the published article [1], following correction. the authors realized two errors and wish to make the 1. Table 1 currently indicates that the SAAS separation tool does not meet the criteria for ‘can select seasonal periods’ (marked ‘N’). However, SAAS can indeed select seasonal periods. To correct this error, replace ‘N’ with ‘Y’ within Table 1 for the programme SAAS and criteria ‘can select seasonal periods’. The correct Table 1 is as below: 2. This change has no material impact on the conclusions of our paper; however, it reveals SAAS met all the criteria and is suitable for analysis. To explain this, the following sentence at the end of Paragraph 2 of Section 2.3 ‘As the BFI Programme [6] met all of the criteria it was selected for analysis.’ should be removed and replaced with ‘Although both the BFI Programme and SAAS met all of the criteria, the BFI Programme was selected for analysis in this study’. The authors would like to apologize for any inconvenience caused to the readers by these changes and also to the creators of SAAS for this error. Table is presented.

Developing countries such as Malawi require improved access to isotope tracer tools to better characterize and manage water resources threatened by land development, deforestation and climate change. This is the first published study to use an isotope facility developed in Malawi for this purpose, instead of relying upon sample analyses from abroad. Results from this new facility are used to evaluate an important Lake Malawi catchment in the Rift Valley. This work successfully established a stable-isotope baseline, hydrochemical signatures, and system conceptualization against which future policy change and management strategies may be measured. Precipitation isotopic composition was consistent with the Global Meteoric Water Line, but varied, confirming different precipitation systems nationally. Groundwater largely followed a Local Meteoric Water Line, with limited isotopic variation indicating predominant areal groundwater recharge, but with dry-season evaporative enrichment of groundwater near Lake Malawi. Surface-water isotopes widely varied with local precipitation, suggesting the latter accounted for wet-season river flows, but upstream dambo (complex wetlands occupying a shallow, seasonal waterlogged depression) helped sustain dry-season flows. Isotope capacity reinforced water-resource conceptualization and provenance in a hydrologically complex, but not atypical, Rift Valley system, exhibiting a noted complexity of groundwater–surface-water interactions. The latter, critical to integrated water resource management, requires more focused study, to which an expanded array of isotopes will contribute to tracking Sustainable Development Goal 6 targets. This study and future catchment studies should help underpin Malawian water-resource policy implementation on several identified fronts.

Study region: Malawi. Study focus: Integrated water resource management (IWRM) of transboundary aquifers (TBA’s) is becoming increasingly important. Without adequate and accurate scientific knowledge of their extent and characteristics, uninformed policy creation could lead to unsustainable management of these vital resources. This is particularly important within the Southern African Development Community (SADC) where up to 85% of domestic water is supplied by groundwater. In this paper, Malawi is used as a case study to critically evaluate the current transboundary aquifer assessment frameworks within the region and their value in promoting IWRM. A series of illustrative conceptual models of TBA interactions pertinent to the Malawian national border are presented and we consider how TBA assessments may be integrated to national IWRM and strategic policy development. New hydrological insights for the region: Current TBA assessments of Malawi and the wider SADC neglect multiple aspects needed for a national scale management plan. This includes full border TBA system identification alongside, given the geology of the region, consideration of the discontinuous nature of basement complex aquifers and localised alluvial deposits that both result in smaller scale aquifer units. Conceptualising such local scale complexity and encouraging countries to develop a strategy that systematically examines TBA systems along their national border at relevant scales will allow for more focused conjunctive policy creation and sustainable management of TBA’s.

Study region: Malawi. Study focus: Integrated water resource management (IWRM) of transboundary aquifers (TBA's) is becoming increasingly important. Without adequate and accurate scientific knowledge of their extent and characteristics, uninformed policy creation could lead to unsustainable management of these vital resources. This is particularly important within the Southern African Development Community (SADC) where up to 85% of domestic water is supplied by groundwater. In this paper, Malawi is used as a case study to critically evaluate the current transboundary aquifer assessment frameworks within the region and their value in promoting IWRM. A series of illustrative conceptual models of TBA interactions pertinent to the Malawian national border are presented and we consider how TBA assessments may be integrated to national IWRM and strategic policy development. New hydrological insights for the region: Current TBA assessments of Malawi and the wider SADC neglect multiple aspects needed for a national scale management plan. This includes full border TBA system identification alongside, given the geology of the region, consideration of the discontinuous nature of basement complex aquifers and localised alluvial deposits that both result in smaller scale aquifer units. Conceptualising such local scale complexity and encouraging countries to develop a strategy that systematically examines TBA systems along their national border at relevant scales will allow for more focused conjunctive policy creation and sustainable management of TBA's.