Every wet season, Angola receives three times more rainfall than Botswana, discharging a higher than usual flow into the Okavango, turning swathes of outlying desert into a huge wetland.

The delta then swells to three times its permanent size, attracting animals from kilometres around and creating one of Africa's greatest concentrations of wildlife.

At its widest point in a big flood year, the seasonal swamp stretches to 150 km across from east to west; one of the factors that leads to the ever-changing nature of the delta is the flatness of the area.

The river carries annually 28,000 tonnes of suspended sediment and a similar amount of bedload to the terminal swamps.

There is low concentration of dissolved solids in the river water - around 40 mg/L, made up mostly of silica, calcium and magnesium bicarbonates - but these dissolved solids form the largest component of sediment carried into the delta because the annual water volume is so large.

Both Namibia and Botswana experience drought, and as a result, concerns have been expressed about possible conflict over use of the river's water.

Environmental activists have expressed concern that ReconAfrica’s plans for its test wells have not been properly vetted through Namibia’s environmental review process, however ReconAfrica and both the governments of Namibia and Botswana have stated that the company's activities have followed due process and that no fracking will occur.