Methodology to detect long-term trends in groundwater by monitoring changes in vegetation distribution

Abstract

Multidate remotely sensed images, covering a period of 34 years (1967–2001), have been used to detect long-term trends in groundwater resources around Lake Ngami in the distal reaches of Botswana's Okavango Delta. The detection methodology is based on monitoring changes in the vegetation distribution of the studied area. The changes consist of sustained shifts from perennial wetland to an intermittently flooded dryland and a significant increase in woody species adapted to low water table conditions (e.g. Acacia mellifera and Acacia erioloba).