PUBLISHED JOURNAL PAPERS
Characterization of groundwater discharge to rivers in the Shire River Basin, Malawi
Kelly, L., Bertram, D., Kalin, R.M., Ngongondo,C. Characterization of Groundwater Discharge to Rivers in the Shire River Basin, Malawi, American Journal of Water Science and Engineering. Vol. 5, No. 4, 2019, pp. 127-137
ABSTRACT: This study investigates groundwater discharge to rivers in the Shire River Basin, Malawi, using the base flow index (BFI) approach. The BFI represents the baseflow component of a river and is often used as a proxy indicator of groundwater discharge to a river. The smoothed minima method was applied to river flow data from 15 gauges in the Basin (ranging from 1948 to 2012) and the Mann-Kendall (MK) statistical test was used to identify trends in the BFI. The BFI results indicate that groundwater plays an important role in contributing to river flows in the SRB, especially in the dry season. Expressing the BFI as a percentage, these values indicate that annual groundwater discharge to the river’s ranges from 19% in the Rivirivi River to 97% in the Shire River. Seasonally, minimal difference was found between the annual and the wet season BFI. Generally, the dry season BFI was higher than those of the wet season with most rivers increasing to >75%. Groundwater data supported the seasonal fluctuations identified in the BFI data, however, there were no groundwater monitoring boreholes in close proximity to any of the river gauges for in-depth analysis. The results also showed long term trends in the BFI data indicating behavioural changes in the river baseflow and groundwater discharge. In some areas, the declines in BFI indicate that groundwater discharge has been reducing over time due to declines in groundwater levels. This is a concern for the sustainable management of water resources in the Basin. The findings of this study provide important new knowledge on the seasonal and long-term behaviour of groundwater discharge to rivers in the Basin which will be crucial for supporting sustainable water resources management practices. The results will be particularly useful to the new National Water Resources Authority within the Malawian Government, who will oversee catchment management plans.
Stranded Assets as a key concept to guide investment strategies for Sustainable Development Goal 6
Kalin, R.M., Mwanamveka, J., Coulson, A.B., Robertson, D.J.C., Clark, H., Rathjen, J., Rivett, M.O., 2019. Stranded Assets as a key concept to guide investment strategies for Sustainable Development Goal 6. Water 2019, 11, 702
ABSTRACT: The concept of Stranded Assets has been used for nearly 50 years across many sectors, most recently it has been a focus of investment portfolios in light of the possible impacts of climate change. However, to date there has been no in-depth determination of the impact of Stranded Assets for rural water supply, despite international development targets from Rio, through Millennium Development Goals (MDGs), and now the Sustainable Development Goals (SDGs). The limiting factor for carrying out such an assessment is the requirement of a full and detailed asset register recording all rural water supplies in a country. The Scottish Government Climate Justice Fund Water Futures Programme, in collaboration with the Government of Malawi, is undertaking a comprehensive asset audit across Malawi, and this paper introduces the concept of Stranded Assets for the rural water supply sector using Malawi as an exemplar. Here, we demonstrate how significant change in the implementation strategy for SDGs compared to the MDGs is needed to reduce the potential for Stranded Assets and meet its ultimate aim.
Understanding the functionality and burden on decentralised rural water supply: Influence of Millennium Development Goal 7c coverage targets
Truslove, J.P., Miller, A.V.M., Mannix, N., Nhlema, M., Rivett, M.O., Coulson, A.B., Mleta, P., Kalin, R.M., 2019. Understanding the functionality and burden on decentralised rural water supply: Influence of Millennium Development Goal 7c coverage targets. Water 2019, 11, 494.
ABSTRACT: The sustainability of rural groundwater supply infrastructure, primarily boreholes fitted with hand pumps, remains a challenge. This study evaluates whether coverage targets set out within the Millennium Development Goals (MDG) inadvertently increased the challenge to sustainably manage water supply infrastructure. Furthermore, the drive towards decentralised service delivery contributes to the financial burden of water supply assets. A sample size of 14,943 Afridev hand pump boreholes was extracted from a comprehensive live data set of 68,984 water points across Malawi to investigate the sustainability burden as emphasis shifts to the 2030 agenda. The results demonstrate that the push for coverage within the MDG era has impacted the sustainability of assets. A lack of proactive approaches towards major repairs and sub-standard borehole construction alongside aging infrastructure contributes to reduced functionality of decentralised supplies. Furthermore, costly rehabilitation is required to bring assets to operational standards, in which external support is commonly relied upon. Acceleration towards the coverage targets has contributed towards unsustainable infrastructure that has further implications moving forward. These findings support the need for Sustainable Development Goals (SDG) investment planning to move from a focus on coverage targets to a focus on quality infrastructure and proactive monitoring approaches to reduce the future burden placed on communities.
Arsenic occurence in Malawi groundwater
Rivett, M.O., Robinson, H.L., Wild, L.M., Melville, J., MCGrath, L., Phiri, P., Flink, J., Wanangwa, G.J., Mleta, P., MACLeod, S. Miller, A.V.M., Kalin, R.M. 2018. Arsenic occurrence in Malawi groundwater. Journal of Applied Sciences & Environmental Management, 22 (11), 1807-1816.
ABSTRACT: Despite an estimated 90,000 groundwater points, mostly hand-pumped boreholes, being used for drinking-water supply in Malawi, evaluation of groundwater arsenic has been limited. Here we review the literature and collate archive data on groundwater arsenic occurrence in Malawi; add to these data, by surveying occurrence in handpumped boreholes in susceptible aquifers; and, conclude on risks to water supply. Published literature is sparse with two of the three studies reporting arsenic data in passing, with concentrations below detection limits. The third study of 25 alluvial aquifer boreholes found arsenic mostly at 1-10 μg/l concentration, but with four sites above the World Health Organisation (WHO) 10 μg/l drinking-water guideline, up to 15 μg/l; the study also discerned hydrochemical controls. Archive data from non-governmental organisation (NGO) borehole testing (two datasets) exhibited below detection results. Our surveys in 2014-18 of hand-pumped supplies in alluvial and bedrock aquifers tested 310 groundwater sites (78% alluvial, 22% bedrock) and found below test-kit detection (<10 μg/l) arsenic throughout, except possible traces at two boreholes containing geothermal-groundwater contributions. Our subsequent survey of 15 geothermal groundwater boreholes/springs found four sites with arsenic detected at 4-12 μg/l concentration. These sites displayed the highest temperatures, supporting increased arsenic being related to a geothermal groundwater influence. Our 919 sample dataset overall indicates arsenic in Malawian groundwater appears low, and well within Malawi’s drinking-water standard of 50 μg/l (MS733:2005). Still, however, troublesome concentrations above the WHO drinking-water guideline occur. Continued research is needed to confirm that human-health risks are low; including, increased monitoring of the great many hand-pumped supplies, and assessing hydro-biogeochemical controls on the higher arsenic concentrations found.
Exploratory study of Polycyclic Aromatic Hydrocarbon (PAH) contributions to household air pollution arising from improved cookstove use in rural Malawi
Chidziwisano, K.R., Rivett, M.O., Tadsanaprasittipol, A., McGregor, L.A., Kalin, R.M. 2019. Exploratory study of Polycyclic Aromatic Hydrocarbon (PAH) contributions to household air pollution arising from improved cookstove use in rural Malawi. African Journal of Environmental and Science Technology, 13, 36-51.
ABSTRACT: Around three million premature deaths annually are ascribed to household air pollution (HAP) arising from inefficient burning of biomass and emissions of products of incomplete combustion. The developing-world response has been widespread adoption of improved cookstove (ICS) technologies. This exploratory study evaluates variation in polycyclic aromatic hydrocarbon (PAH) attached to inhalable particulate matter (PM) in rural Malawi households adopting ICS use. PM literature supports HAP exposure to inhalable PM is lowered, albeit variably, compared to traditional fires, but remains significant. Similar is expected for PAH; however, datasets lack discerning PAH chemical-specific contributions to risks. The study introduces the Malawian context, invokes a PAH reconnaissance approach sampling kitchen soot 'spots' and residential dusts, and relates PAH occurrence to the two sample types collected and ICS types surveyed. The total PAH for dusts was low (c. 2 μg/g mean), with volatile 2-ring naphthalene dominant. Soot total PAH was much higher (c. 200 μg/g mean to a maximum of 815 μg/g). Soot from PM emissions poses a major primary health concern. Despite PAH trends not being obvious with ICS type (limited sample size) and the wide range in soot total PAH, soot PAH-fingerprints were well constrained with low variation of diagnostic PAH ratios, exhibiting n-ring fingerprints close to the soot median (0.1% 2-ring, 20% 3-ring, 61% 4-ring, 14% 5-ring, 5% 6-ring PAH). These corroborate the expected wood-related combustions sources, but also point to the needs to understand factors that control wide variations in PM and (total) PAH emitted as these control variations in HAP and differing risks posed to individual households. Further household-based research is thus recommended discerning relationships between PM emissions and PAH contents, driving the chemical-composition health risks. These should establish influences on PAH exposure arising from ICS type/model selected, operational modes, building/ventilation conditions, variable fuel sources and non-optimal ICS use.
Responding to salinity in a rural African alluvial valley aquifer system: to boldly go beyond the world of hand-pumped groundwater supply?
Rivett, M.O., Budimir, L., Mannix, N., Miller, A.V.M., Addison, M.J., Moyo, P., Wanangwa, G.J., Phiri, O.L., Songola, C.E., Nhlema, M., Thomas, M.A.S., Polmanteer, R.T., Borge, A., Kalin, R.M., 2019. Responding to salinity in a rural African alluvial valley aquifer system: to boldly go beyond the world of hand-pumped groundwater supply? Science of the Total Environment, 653, 1005–1024.
ABSTRACT: for boreholes throughout rural Africa are exploited by a vast and increasing number of hand-pumped Groundwater resources. drinking-water supplies in the developing world may critically safeguard salinityEffective response to groundwater community supply. Our research in TA Ngabu (Shire Valley), Southern Malawi aims to: define groundwater-salinity problem occurrence within the semi-arid alluvial-valley aquifer, rural developing-world setting; critique current capacity to respond; and, to discuss future response options - in particular considering the need to explore alternative options that boldly go beyond the world of hand-pumped groundwater supply. Salinity problem definition was achieved through survey of 419 hand-pumped boreholes that revealed widespread brackish groundwater leading to non-potable (unpalatable) drinking-water supplies. Persistent non-functionality or abandonment of boreholes was typically ascribed to salinity. Whilst salinity is conceptualised to arise from shallow-groundwater evaporation, formation-evaporite dissolution and faulted-area upwelling, sparse data locally renders attribution of salinity sources to individual boreholes difficult. There is a significant need to better resolve the vertical distribution of salinity and local controlling processes. Problem response capacity was hampered by multiple factors, including, sector inertia, low drilling costs compromising water-point integrity, and lack of technical vision for alternatives. Various recommendations are made to improve response capacity continuing to work at the hand-pump supply scale. However, in areas where salinity is significant, exploring the feasibility of other options is advocated in conjunction with technical capacity development. Groundwater options may utilise high borehole yields possible from alluvial aquifers, grossly under-exploited by hand pumps. Groundwater at depth, albeit of unknown quality typically, or pipeline transfers of probable good-quality groundwater from valley-margin units, should be considered. Surface-water pipeline supplies may be viable for (growing) population centres. Canal-fed irrigation schemes (pending for the area), should be multiple-use, protective of groundwater and embrace pipeline drinking-water supply and managed-aquifer-recharge opportunities. Advancing desalination technologies, although presently unaffordable, should be kept under review.
A national approach to systematic trans-boundary aquifer assessment and conceptualisation at relevant scales: a Malawi case study
Fraser, C.M., Kalin, R.M., Rivett, M.O., Nkhata, M., Kanjaye, M., 2018. A national approach to systematic trans-boundary aquifer assessment and conceptualisation at relevant scales: a Malawi case study. Journal of Hydrology Regional Studies, 20, 35-48.
ABSTRACT: 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.
A conceptual model based framework for pragmatic groundwater-quality monitoring network design in the developing world: Application to the Chikwawa District, Malawi.
Rivett, M.O., Miller, A.V.M., MacAllister, D.J., Fallas, A., Wanangwa, G.J., Mleta, P., Phiri, P., Mannix, N., Monjerezi, M., Kalin, R.M., 2018. A conceptual model based framework for pragmatic groundwater-quality monitoring network design in the developing world: Application to the Chikwawa District, Malawi. Groundwater for Sustainable Development 6, 213-226.
ABSTRACT: Significant need exists in the developing world to transition from occasional groundwater-quality surveys to routinely sampled groundwater-quality network monitoring programmes that provide better safeguard of resources. Such networks contribute to the sustainable management of water resources, are integral to Water Safety Plans, and underpin delivery of Sustainable Development Goal 6. A framework for groundwater-quality monitoring network design is developed that is pragmatic for developing-world needs and its application is demonstrated using data from the Chikwawa District – Shire Valley aquifer system in Malawi. The step-wise framework is based upon a hydrogeological–hydrochemical process-based system conceptual model. The Chikwawa model developed is built upon our interpreted 2012 and archive 2008–9 major-ion survey data; major-ion data often constitute the most easily available datasets in many areas of the developing world. A versatile, semi-quantitative, approach is adopted which sets bespoke-system ‘Monitoring Objectives’, which are weighted on a scale of 1–5 and then rated against bespoke criteria using a scale of 0–10. This permits development of aggregate ‘Monitoring Potential’ scores at candidate network-point localities. Ideally the process is facilitated by the use of a GIS, although its use is not essential. Monitoring objectives are flexible and typically relate to various perceived risks to groundwater quality; including increasing salinity, anthropogenic activity, etc. The framework, as demonstrated for Chikwawa, allows an incremental build of a prioritised network of points, including a relative estimate of their potential to address the individual monitoring objectives set. The framework methodology is easy to use and adaptable to developing, and developed, world monitoring needs
alike. The proposed network for Chikwawa could help pilot transition to a higher resolution national groundwater quality network across Malawi than currently exists. However, attaining the spatial monitoring densities suggested remains challenging due to the investment required in current infrastructure-capacity alongside the need to develop mechanisms that allow network running costs to be met sustainably.
Local scale water-food nexus: Use of borehole-garden permaculture to realise the full potential of rural water supplies in Malawi.
Rivett, M.O., Halcrow, A.H., Schmalfuss, J., Stark, J.A., Truslove, J.P., Kumwenda, S., Harawa, K.A., Nhlema, M., Songola, C., Wanangwa, G.J., Miller, A.V.M., Kalin, R.M., 2018. Local scale water-food nexus: Use of borehole-garden permaculture to realise the full potential of rural water supplies in Malawi. Journal of Environmental Management, 209, 354-370.
ABSTRACT: Local-scale opportunities to address challenges of the water-food nexus in the developing world need to be embraced. Borehole-garden permaculture is advocated as one such opportunity that involves the sustainable use of groundwater spilt at hand-pump operated borehole supplies that is otherwise wasted. Spilt water may also pose health risks when accumulating as a stagnant pond. Rural village community use of this grey-water in permaculture projects to irrigate borehole gardens is proposed to primarily provide economic benefit whereby garden-produce revenue helps fund borehole water-point maintenance. Water-supply sustainability, increased food/nutrition security, health protection from malaria, and business opportunity benefits may also arise. Our goal has been to develop an, experience-based, framework for delivery of sustainable borehole-garden permaculture and associated benefits. This is based upon data collection and permaculture implementation across the rural Chikwawa District of Malawi during 2009-17. We use, stakeholder interviews to identify issues influencing uptake, gathering of stagnant pond occurrence data to estimate amelioration opportunity, quantification of permaculture profitability to validate economic potential, and critical assessment of recent permaculture uptake to identify continuing problems. Permaculture was implemented at 123 sites representing 6% of District water points, rising to 26% local area coverage. Most implementations were at, or near, newly drilled community-supply boreholes; hence, amelioration of prevalent stagnant ponds elsewhere remains a concern. The envisaged benefits of permaculture were manifest and early data affirm projected garden profitability and spin-off benefits of water-point banking and community micro-loan access. However, a diversity of technical, economic, social and governance issues were found to influence uptake and performance. Example issues include greater need for improved bespoke garden design input, on-going project performance assessment, and coordinated involvement of multi-sector governmental-development bodies to underpin the integrated natural-resource management required. The developed framework aims to manage the identified issues and requires the concerted action of all stakeholders. Based on the probable ubiquity of underlying issues, the framework is expected to be generalizable to the wider developing world. However, this particular application of permaculture represents a fraction of its greater potential opportunity for rural communities that should be explored.
Risk assessment to groundwater of pit latrine rural sanitation policy in developing country settings
Back, J.O., Rivett, M.O., Hinz, L.B., Mackay, N., Wanangwa, G.J., Phiri, O.L., Songolo, C.E., Thomas, M.A.S., Kumwenda, S., Nhlema, M., Miller, A.V.M., Kalin, R.M., 2018. Risk assessment to groundwater of pit latrine rural sanitation policy in developing country settings. Science of the Total Environment. 613-614, 592-610.
ABSTRACT: Parallel global rise in pit-latrine sanitation and groundwater-supply provision is of concern due to the frequent spatial proximity of these activities. Study of such an area in Malawi has allowed understanding of risks posed to groundwater from the recent implementation of a typical developing-country pit-latrine sanitation policy to be gained. This has assisted the development of a risk-assessment framework approach pragmatic to regulatory-practitioner management of this issue. The framework involves water-supply and pit-latrine mapping, monitoring of key groundwater contamination indicators and surveys of possible environmental site-condition factors and culminates in an integrated statistical evaluation of these datasets to identify the significant factors controlling risks posed. Our approach usefully establishes groundwater-quality baseline conditions of a potentially emergent issue for the study area. Such baselines are foundational to future trend discernment and contaminant natural attenuation verification critical to policies globally. Attribution of borehole contamination to pit-latrine loading should involve, as illustrated, the use of the range of contamination (chemical, microbiological) tracers available recognising none are ideal and several radial and capture-zone metrics that together may provide a weight of evidence. Elevated, albeit low-concentration, nitrate correlated with some radial metrics and was tentatively suggestive of emerging latrine influences. Longer term monitoring is, however, necessary to verify that the commonly observed latrine-borehole separation distances (29–58 m), alongside statutory guidelines, do not constitute significant risk. Borehole contamination was limited and correlation with various environmental-site condition factors also limited. This was potentially ascribed to effectiveness of attenuation to date, monitoring of an emergent problem yet to manifest, or else contamination from other sources. High borehole usage and protective wall absence correlated with observed microbiological contamination incidence, but could relate to increased human/animal activity close to these poorly protected boreholes. Additional to factors assessed, a groundwater-vulnerability factor is recommended that critically relies upon improved proactive securing of underpinning data during borehole/latrine installations. On-going concerns are wide ranging, including poorly constrained pit-latrine input, difficulties in assessing in-situ plume natural attenuation and possible disposal of used motor oils to latrines.