Remote Sensing of Wetland Dynamics as Indicators of Water Availability in Semi-arid Africa

Abstract

This chapter focuses on remote sensing techniques and applications for monitoring wetlands in sub-Saharan Africa, and provides three examples using different sensors. The role wetlands play in water availability, as well as their impact on people’s livelihoods, is described based on the example of Burkina Faso, a country in West Africa. The rationale for using earth observation for wetland detection, mapping, inventorying, classification, assessment, and monitoring is presented, and advantages, limitations, and gaps are discussed. Moreover, the parameters to be observed in wetlands are described based on pictures from a field study at Lac Bam, Burkina Faso. Three groups of remote sensing sensor types and the applicability of their data and methods for wetland mapping and monitoring are reviewed: optical high resolution imagery, optical medium-resolution time series, and synthetic aperture radar data. The Lac Bam case study is used to show applications of these three remote sensing sensors types. Conclusions and future perspectives for wetland remote sensing, as well as possibilities and limitations, are assessed. Remaining gaps and possible future solutions are discussed, with a focus on the European Space Agency’s new Sentinel missions. The role of wetland monitoring for both estimating water availability in semi-arid areas and indicating drought is also noted.