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.

Ensuring access to adequate and equitable sanitation and ending open defecation by 2030 is the focus of Sustainable Development Goal 6.2 (SDG6.2). We evaluated Malawi’s progress towards SDG 6.2 (specifically the goal to end open defecation), presenting the results of a national survey of over 200,000 sanitary facilities and evaluating their management. Based on non-linear population dynamics, we used a linear model to evaluate the reduction in open defecation between 1992–2018, and to project whether Malawi can meet the SDG target to end open defecation by 2030 under multiple scenarios of population growth. Whilst Malawi has made considerable progress in providing sanitary provision for the population, we estimate that, at the current rate of the provision of sanitary facilities, Malawi will not reach SDG 6.2 by 2030 under any of the modelled socioeconomic scenarios. Furthermore, we compare the estimates of the extent of sanitary provision classed as improved from multiple surveys, including the USAID Demographic and Health (DHS) Surveys and Government of Malawi Census data. We conclude that some of the surveys (particularly the 2015/16 DHS) may be overestimating the level of improved sanitary provision, and we hypothesize that this is due to how pit-latrines with earth/sand slabs are classed. Furthermore, we examine the long-term sustainability of pit-latrine use, investigating the challenge of pit-latrine abandonment and identifying pit-latrine filling as a cause of the abandonment in 30.2% of cases. We estimate that between 2020–2070, 31.8 (range 2.8 to 3320) million pit-latrines will be filled and abandoned, representing a major challenge for the safe management of abandoned latrines, a potential for long-term impacts on the groundwater quality, and a significant loss of investment in sanitary infrastructure. For Malawi to reach SDG 6.2, improvements are needed in both the quantity and quality of its sanitary facilities.

Consumption of groundwater containing fluoride exceeding World Health Organization (WHO) 1.5 mg/L standard leaves people vulnerable to fluorosis: a vulnerability not well characterised in Malawi. To evaluate geogenic fluoride source and concentration, groundwater fluoride and geology was documented in central Malawi where groundwater supplies are mainly sourced from the weathered basement aquifer. Lithological composition was shown as the main control on fluoride occurrence. Augen gneiss of granitic composition posed the greatest geological fluoride risk. The weathered basement aquifer profile was the main factor controlling fluoride distributions. These results and fluoride-lithology statistical analysis allowed the development of a graded map of geological fluoride risk. A direct link to human health risk (dental fluorosis) from geological fluoride was quantified to support science-led policy change for fluoride in rural drinking water in Malawi. Hazard quotient (HQ) values were calculated and assigned to specific water points, depending on user age group; in this case, 74% of children under six were shown to be vulnerable to dental fluorosis. Results are contrary to current standard for fluoride in Malawi groundwater of 6 mg/L, highlighting the need for policy change. Detailed policy recommendations are presented based on the results of this study.

Using wastewater accumulating around rural waterpoints to irrigate community gardens, borehole-garden permaculture (BGP) presents a method of sustainable water management. BGP also presents public health benefits through the removal of stagnant water around boreholes, key Malaria breeding grounds, and through providing year-round food to supplement diets. By analysing a dataset of over 100,000 cases, this research examines the awareness and adoption of BGP across Malawi. Generalised linear models identified significant variables influencing BGP awareness and uptake revealing that socioeconomic, biophysical and waterpoint-specific variables influenced both the awareness and adoption of BGP. BGP had low uptake in Malawi with only 2.4% of communities surveyed practising BGP while 43.0% of communities were aware of BGP. Communities in areas with unreliable rainfall and high malaria susceptibility had low BGP awareness despite BGP being particularly beneficial to these communities. This work suggests that future work in the promotion of BGP should focus their efforts within these areas. Furthermore, this work highlights the value of community networks in knowledge sharing and suggests that such social capital could be further used by NGOs and the Government of Malawi in the promotion of BGP and other sustainable practices.

1 Menstrual hygiene management (MHM) forms a critical component of ensuring access to adequate and equitable sanitation for all, as outlined in SDG 6.2. Despite its importance, little is known about MHM in Malawi, particularly at a household level. Through a household survey of MHM within 2 districts, we evaluated the type of menstrual absorbents used by people who menstruate. Reusable cloths/rags were the most used menstrual absorbent, used by 79.5% of respondents, whilst disposable absorbents, such as tampons and sanitary pads, were used by 18.6% of respondents. Appropriate MHM also incorporates adequate management of MHM materials, including the washing and drying of reusable menstrual absorbents. We evaluated the cleaning of reusable menstrual absorbents; most respondents (90.1%) reported appropriate washing of menstrual absorbents using soap and water, however only 20.3% reported that menstrual absorbents were dried outside in the sun (as is best practise) with most reporting that reusable menstrual absorbents were dried inside their homes. Our findings highlight the need for improved MHM within Malawi, not only in the access and affordability of appropriate menstrual absorbents but also the promotion of appropriate washing and drying of menstrual absorbents.

Despite widespread access to basic sanitation in Malawi, over 75% of the population lacks improved sanitation facilities. This national study investigates the resilience of pit-latrines across Malawi, focusing on the relationship between construction quality, facility lifespan, and collapse frequency. A survey of 268,000 pit-latrines revealed that high-quality latrines (lined and with a slab) collapse three times less frequently than low-quality latrines and last significantly longer. However, cost barriers remain substantial, with high-quality latrines costing five times more than low-quality facilities. Even when accounting for their extended lifespan, the annual cost of high-quality facilities is almost double that of low-quality options, highlighting a key financial challenge for widespread adoption. Pit-latrine emptying, while offering a potential solution to extend the lifespan of latrines, is rarely practiced due to its high costs and cultural resistance. Manual emptying, the most common method, raises health and environmental concerns, while emptying costs remain prohibitively high for many households. The study emphasises the need for significant investment in resilient sanitation infrastructure, promotion of affordable emptying services, and the development of faecal waste management systems. Addressing these challenges is essential to ensuring equitable access to safe and sustainable sanitation in Malawi, ensuring climate resilience and sanitation justice.