Davis Research Group

Photo: Sara Marks

Research Interests

Jenna Davis' research group (known as the Poop Group) focuses on the intersection of health, economic development and environmental protection, with particular emphasis on cost-effective and sustainable water supply and sanitation (W&S) service delivery in developing countries. Jenna is affiliated with:
  • Department of Civil & Environmental Engineering

Recent News of Interest

'Sense of ownership' and sustainability in rural water supply (Journal of Water, Sanitation and Hygiene for Development) -- Community sense of ownership for rural water infrastructure is widely cited as a key factor in ensuring sustainable service delivery, but no empirical investigation has evaluated the relationship between sense of ownership and sustainability outcomes. This study examines the association between system sustainability and sense of ownership among households and water committees, using primary data collected throughout 50 rural communities with piped water systems in Kenya. All else held constant, infrastructure condition is positively associated with water committee members' sense of ownership, whereas users' confidence and system management are positively associated with households' sense of ownership. These findings stand in contrast with much of the published literature on rural water planning, which assumes homogeneity of ownership feelings across all members of a community and which suggests a consistent and positive association between households' sense of ownership and sustainability. The full paper is available here.
Economic and environmental impacts of biodigesters in Tanzania (Energy for Sustainable Development paper)--Despite substantial programmatic investment in domestic bio-digesters across sub-Saharan Africa in recent years, little empirical evidence has been published regarding the existence or magnitude of socioeconomic or environmental benefits accruing from bio-digester implementation. A cross-sectional study of 40 households in Arusha, Tanzania, suggests that bio-digester adoption has the potential to reduce fuel-wood use, energy-related expenditures, and time-costs of energy procurement; to lower CO2e emissions; and to increase farm incomes. No significant differences in synthetic fertilizer use were observed between households with and without bio-digesters. Domestic bio-digester investments were found to have a positive net present value across a wide range of discount rates. Further, we estimate that domestic bio-digester implementation at the country wide level in Tanzania could potentially access $80–$115 million annually in carbon emissions reduction (CER) financing through the Clean Development Mechanism. The full paper is available here.
Hands and water as vectors of diarrheal pathogens in Bagamoyo, Tanzania (ES&T paper) -- Diarrheal disease is a leading cause of under-five childhood mortality worldwide, with at least half of these deaths occurring in sub-Saharan Africa. Transmission of diarrheal pathogens occurs through several exposure routes including drinking water and hands, but the relative importance of each route is not well understood. Using molecular methods, this study examines the relative importance of different exposure routes by measuring enteric bacteria (pathogenic Escherichia coli) and viruses (rotavirus, enterovirus, adenovirus) in hand rinses, stored water, and source waters in Bagamoyo, Tanzania. Viruses were most frequently found on hands, suggesting that hands are important vectors for viral illness. The occurrence of E. coli virulence genes (ECVG) was equivalent across all sample types, indicating that both water and hands are important for bacterial pathogen transmission. Fecal indicator bacteria and turbidity were good predictors of ECVG, whereas turbidity and human-specific Bacteroidales were good predictors of viruses. ECVG were more likely found in unimproved water sources, but both ECVG and viral genes were detected in improved water sources. ECVG were more likely found in stored water of households with unimproved sanitation facilities. The results provide insights into the distribution of pathogens in Tanzanian households and offer evidence that hand-washing and improved water management practices could alleviate viral and bacterial diarrhea. The paper is available here.
Sense of ownership for rural water systems (World Development paper) -- Despite broad acceptance of the idea that “sense of ownership” among users is critical to infrastructure sustainability in developing countries, little is known about what sense of ownership is, or its drivers. We present a novel measure of sense of ownership for piped water systems using empirical data collected from 1140 households in 50 rural Kenyan villages. This study establishes an empirical referent for households’ sense of ownership. We find that some, but not all, types of participation enhance community members’ sense of ownership for rural water projects. The paper is available here.
In sub-Saharan Africa, a shorter walk to water saves lives (ES&T paper) -- In the fight against child mortality in the developing world, simple things make a big difference. A new study by Amy Pickering and Jenna Davis published by the journal Environmental Science and Technology shows that decreasing the amount of time families must walk to obtain clean water can help save the lives of young children. More than a third of the world’s population does not have potable water piped into the home. In sub-Saharan Africa, that number jumps to 84 percent. The Stanford study analyzed data from 26 African countries, where it is estimated that some 40 billion hours of labor each year are spent hauling water, a responsibility often borne by women and children. The Stanford study is the first quantitative analysis of the relationship between the time devoted to fetching water and health outcomes.
See press release here
The world needs more toilets! (CNN op-ed) Palo Alto, CA (CNN) -- It does not make for pleasant dinner conversation. But we have a global sanitation crisis. More than 40% of the world's population does not have access to a toilet. These 2.6 billion people, most living in low- and middle-income countries in Asia and Africa, face the daily challenge of finding a bush, train track or empty lot where they can urinate and defecate in relative privacy.
Between 1990 and 2008, the share of the world's population that had access to basic sanitation increased only 7%, to 61% of the world's citizens. In many developing countries, mobile phone penetration is expanding at a faster rate than sanitation. In Tanzania, for example, half the country's citizens have mobile phones, but only 24% use an improved sanitation facility.
See the full article here.
Jenna's Blog: Jenna posts the latest news from her research group, as well as comments on developments in the field.