FACTORS AFFECTING PRESENT AND FUTURE WATER AND RELATED RESOURCE USE IN THE OKAVANGO BASIN AND DELTA

摘要

This paper considers water and related resource use in the Okavango River Basin which traverses equatorial Angola, semi-arid Namibia and Botswana covering an area of ca. 120 000 km~2. Mostly previous work in the Okavango basin shows the availability of aquatic resources (relative to population densities) remains high throughout the length of the river which terminates in the Okavango Delta. In general, water and natural resource use throughout the basin is highly variable although at present mostly low in Angola, high in Namibia (Kavango) and low in Botswana (Okavango Delta). The data suggest that the total combined quantity of water currently abstracted by all three countries from the river system, and the proposed increases in these amounts, is still small in relation to the mean annual flow levels of the river. However the overall requirement for future natural resource use by local populations remains essential to ensure livelihood sustainability throughout the Okavango river basin and is threatened by riverine developments and landuse changes. Scenarios of change indicate that future dam development, general water abstraction and deforestation throughout the basin until 2025 appear to have less impact on river flow than climate change. Climate change scenarios predicting drier conditions appear (in conjunction with increased abstractions) to have serious impacts particularly on the southern reaches of the Delta. This may result not only in decreased natural resource useage but may also minimise groundwater recharge. This has the potential to adversely affect the 47000 people living in Maun and the surrounding areas along the downstream Boteti and Kunyere rivers.