A Conceptual Flash Flood Early Warning System for Africa, Based on Terrestrial Microwave Links and Flash Flood Guidance

Abstract

A conceptual flash flood early warning system for developing countries is described. The system uses rainfall intensity data from terrestrial microwave communication links and the geostationary Meteosat Second Generation satellite, i.e., two systems that are already in place and operational. Flash flood early warnings are based on a combination of the Flash Flood Guidance method and a hydrological model. The system will be maintained and operated through a public-private partnership, which includes a mobile telephone operator, a national meteorological service and an emergency relief service. The mobile telephone operator acts as both the supplier of raw input data and the disseminator of early warnings. The early warning system could significantly reduce the number of fatalities due to flash floods, improve the efficiency of disaster risk reduction efforts and OPEN ACCESS ISPRS Int. J. Geo-Inf. 2014, 3 585 play an important role in strengthening the resilience to climate change of developing countries in Africa. This paper describes the system that is currently being developed for Kenya.

The Role of Kenya Meteorological Service in Weather Early Warning in Kenya

“…Nzoia River which runs through the catchment has a mean discharge rate of 118 m 3 /s, but with highly variable flow ranging from 20 m 3 /s to 1100 m 3 /s [21]. The origin of Nzoia River, in the highlands of Cherangani, occasionally receives higher rainfall that controls the swelling of the river downstream, resulting in rising river levels with increased incidences of flooding in lower areas of Budalangi.…”

“…Once the critical levels are reached, then either alerts or warnings are released [21]. Dissemination of the information is through the Budalangi community radio directly to local community members and local administrative officers [13].…”

Urban geology of African megacities

“…Thankfully, this is now being addressed in many strategic studies of geohazards in Africa (e.g., Douglas et al, 2008;Heath et al, 2012;Hoedjes et al, 2014).…”

“…Other authors, e.g., Hoedjes et al (2014), have described conceptual flash flood early warning systems for Africa, using a Meteosat Second Generation satellite; or have prescribed flood resilient, resistant or avoidant building design that can help buildings survive a flood event, reduce financial loss and improve the likelihood of survival of occupants (Jha et al, 2011(Jha et al, , 2012.…”

Using rainfall thresholds and ensemble precipitation forecasts to issue and improve urban inundation alerts

“…The European Flood Awareness System (EFAS) uses numerical weather predictions and the Enhanced Runoff Index based on Climatology, which is based on simulated climatology, an FFG-related concept, to provide flash flood warnings (Raynaud et al, 2015). In countries such as Kenya and Haiti that do not have enough well-trained operators and resources to set up an efficient flood warning system, the approach is a viable alternative that allows for the mitigation of flood damage (Georgakakos et al, 2013;Shamir et al, 2013;Hoedjes et al, 2014). The rainfall threshold approach has proven successful in identifying a number of flash floods across Europe (Alfieri et al, 2014).…”