In Niger, the World Bank is supporting the Government reduce the vulnerability of populations at risk of flooding, while taking into account the requirements of community development and capacity building of national structures both at central and local level.
Understanding Niger’s Risks
Despite its semi-arid climate, Niger is regularly stricken by floods that destroy housing, infrastructure and croplands everywhere in the country. While flood damages usually occur in the vicinity of permanent water bodies such as the Niger and Komadougou rivers, more and more damages and casualties have been reported as linked to intense precipitations and runoff in urban areas. Despite the recurrent losses, little is known about the number of people who are living in flood-prone areas or the value of properties at risk. Furthermore, the vast majority of stations in the meteorological and hydrological collection network does not have the ability to transmit data in real-time and therefore cannot be fully exploited in emergency situations.
With the support of the World Bank, the PGRC-DU is supporting the Nigerien Ministry of water and sanitation to retrofit the hydrometric station network with new water level gauges with real-time data transmission capability. The new gauges will make hydrometric data collection more efficient and more reliable while allowing for a faster detection of flood risk. At the same time, the PGRC-DU is funding the collection of critical socio-economic information and building characteristics in all areas of Niamey (the capital of Niger) that are deemed vulnerable to floods. UAVs are being used to acquire high-resolution images of potentially flooded areas that would help better identify buildings characteristics and develop a Digital Terrain Model (DTM) with 10cm vertical resolution, which will help better predict water movement in the area.
The collected hydrometric data will be available to selected users in an online portal, along with various other data sets from regional and global sources. Part of the data collected in Niamey is expected to contribute to the OpenStreetMap project. The rest of the data will be analyzed and converted into vulnerability maps and reports available to the public.
It is expected that the network of real-time hydrometric stations will be used to feed a flood warning system that will provide authorities a better estimate of flood risk at any given time. The acquired DTM is being used to develop computer models that can simulate flood propagation in the city of Niamey and evaluate the effects of existing of planned flood protection infrastructures. Finally, the collected socio-economic data combined with flood simulations will provide decision-makers an accurate estimation of flood risk in terms of exposed populations and expected economic damages.