SatFlood: Providing early-warning of flash flood events in Kenya

New cross-departmental collaboration receives internal GCRF (Global Challenges Research Fund) funding.

The effects of even small flash floods in developing countries can be disastrous. In Lodwar, the capital of the Kenya’s Turkana County – the country’s poorest region – flash floods frequently take lives and cause major disruption. Floodwaters can divide the city, isolating large swathes of the population from safe drinking water, food, medical aid, and access to places of work and study.

The unpredictability of flash floods, coupled with poor communication, and the lack of a financial means to build stocks of supplies, makes it near impossible for the people of Lodwar to be well prepared for flood disasters.

A new research collaboration, funded by University of Oxford’s internal Global Challenges Research (GCRF) money, with support from the Oxford-led water security programme REACH, aims to help tackle this challenge.

In Feb 2019, Dr Simon Proud of Oxford University’s Department of Atmospheric, Oceanic and Planetary Physics, and Dr Marina Korzenevica of the University’s School of Geography and the Environment, will launch SatFlood. The project will initiate a pilot study in Lodwar to assess the potential of a flash flood early-warning system based on satellite data coupled to a simple hydrological model to predict when floods may occur and provide warnings to those likely to be affected, enabling people to move to safety, return home from work and collect basic supplies, in advance of a flood.

The project aims to create a warning system appropriate to the social context of the heterogeneous local communities who have limited access to technology. A major part of this study will be to understand the social, not just technological, side of warning provision in order to explore and to discuss the optimum strategy to allow socially inclusive warnings that reach the most vulnerable people.

It is hoped that the project will provide the basis to develop and implement an operational flash flood early-warning system for East Africa in the long-term.

Fluorescence as a measure of microbial contamination risk in groundwater

Research from Oxford and the British Geological Survey advances a new water quality monitoring approach.

Globally, a quarter of people lack access to water that is free from microbial contamination. In some countries that proportion is much higher. Consuming water that contains pathogens has serious health consequences, especially for children. Groundwater, which accounts for a third of global water supply, usually has better microbial quality compared to surface water, but it can be vulnerable to pollution and must be monitored to confirm when it is safe to drink.

Sampling for individual pathogens is costly and slow, so microbial water quality monitoring is usually designed around risk indicators, with Escherichia coli being the preferred choice. The presence of an indicator like E. coli tells us whether pathogens of faecal origin are likely to be present in the water. Although E. coli sampling is less onerous than measuring pathogen presence directly, it can still be prohibitively costly and time consuming – especially in low resource settings. Furthermore, pathogens (viruses in particular) may still be present in groundwater systems when E. coli is absent.

Motivated by the limitations of relying exclusively on E. coli, a research team from the University of Oxford (Saskia Nowicki, Katrina Charles, and Patrick Thomson) and the British Geological Survey (Dan Lapworth and Jade Ward) examined the potential for improving microbial risk assessments by using a complementary parameter, tryptophan-like fluorescence (TLF). Faecally contaminated water has high TLF intensity, which can be measured immediately in-situ without laboratory processing or expensive consumables.

The research was conducted in rural Kwale County, Kenya. In brief, the team found that TLF cannot be used as a proxy for E. coli on an individual sample basis, but it can add value to groundwater risk assessments by improving prioritisation of sampling and by increasing understanding of spatiotemporal variability. In addition to the low cost of sampling, precision is a key benefit of including TLF in monitoring: unlike bacteriological methods, in-situ fluorimetry has negligible method-induced variability. Factors like turbidity, changing temperature, and humic organic content can interfere with TLF measurement, but such interference is minimal in typical groundwaters. Nevertheless, potential interferences should be considered before including TLF in sampling programmes.

Further details:
Nowicki, S., Lapworth, D.J., Ward, J.S.T., Thomson, P., Charles, K., 2019. Tryptophan-like fluorescence as a measure of microbial contamination risk in groundwater. Sci. Total Environ. 646.

Lead author, Saskia Nowicki is a DPhil scholar supported by the UK Commonwealth Scholarship Commission and the University of Oxford. This research was also supported with funding from the UK Natural Environment Research Council, the UK Economic and Social Research Council and the UK Department for International Development for the UPGro programme on ‘Groundwater Risk Management for Growth and Development’.