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|Monitoring and managing Africa's water resources
With water security being one of Africa’s biggest challenges, ESA’s TIGER initiative is using satellite observations to provide local authorities with the information they need to develop this vital resource.
Africa’s Lake Chad is the main source of fresh water for over 30 million people in Chad, Cameroon, Niger and Nigeria. It’s the main source for the region’s irrigation, drinking water for livestock, fishing and supports a rich biodiversity.
Despite seasonal fluctuations, the surface of the Lake Chad has changed enormously in the last decades, with high losses from the 1960s to 1980s, mainly due to climate change and increased human demand for water.
But recent assessments indicate a turning trend, with the water surface extent in 2011 nearly doubled when compared to the 1985 extent due to increasing rainfall in the Sahel, particularly from 2004 onwards. Part of this increase can also be attributed to flooding of the surrounding wetlands, which is a recurrent phenomenon in the flat costal area of the lake.
These and other results were presented in Tunisia last week at the TIGER workshop, which brought together over 100 scientists, national and transboundary authorities, water experts from 21 African countries and representatives from international development organisations.
Water security is of major significance to African countries that are subject to the effects of climate change and an increasing population, affecting the society in terms of access to drinking water, food and energy. The issue is also of political importance as many river basins on the continent cross national borders.
Satellite Earth observation provides an objective, transboundary solution to mapping and monitoring this precious resource on a large scale.
ESA’s TIGER initiative develops Earth observation applications in close collaboration with its African partners in order to respond to the urgent need for reliable water information in their countries. It also supports research, capacity building and training on the continent within both national and transboundary water authorities.
“If you look at the water resources sector in general, Africa is the continent that has the least developed water resources. This is where Earth observation technologies can help,” said Mohammed Bila from the Lake Chad Basin Commission (LCBC).
TIGER is now promoting a new Water Observation Information System (WOIS) for monitoring, assessing and taking inventory of water resources in a cost-effective manner.
The new system integrates satellite information such as flood monitoring and forecasting, water body mapping for irrigation and livestock, lake water quality, hydrological modelling for water management and urban sanitation planning. The WOIS is currently implemented in five African water authorities (LCBC, Nile Basin Initiative, Volta Basin Authority, Department of Water Affaires of Namibia and South Africa), which use it to support their decision-making.
“The WOIS will allow us to assess environmental variables by catchment over the whole basin for the first State of the Lake Chad Basin Report,” said Mr Bila.
While doing water assessment near the eastern edge of the Lake Chad Basin, land degradation and vegetation increase caused by the war in Sudan’s Darfur region was also spotted in the satellite data.
Since 2003, over 3300 villages have been destroyed, forcing millions of people to leave their homes and abandon agricultural activities. These areas have experienced an increase in vegetation, which is evident in satellite data acquired over the region.
Many of the displaced moved into refugee camps in neighbouring Chad. These areas are clearly visible in satellite data showing land degradation, where natural resources are being overused.
Over the next few years, the Sentinel satellites will be launched as part of Europe’s Copernicus programme. They will significantly improve availability of environmental information services and provide operational data to a variety of users such as water authorities in Africa.