Since then, the fate of this extremely dynamic system has been at the mercy of the rainfall in the Kwando River’s catchment area in central Angola where it is known as the Cuando. No two seasons are the same. Blockages caused by sedimentation and dense reed beds or floating vegetation divert water into channels that have been waterless for decades, while channels that flowed only recently become dry unexpectedly. Hippos play a role in the constantly changing waterways by keeping channels open, while a termite mound built in a channel during a dry cycle can force the water to find another course. Peat beds act as sponges, releasing the water gradually during the dry season, but during dry cycles they become part of the floodplain grassland and are prone to peat fires.

The Kwando River usually peaks at Kongola in May/June, but the water only reaches Nkasa Rupara several weeks later because of its meandering course and gentle gradient, while reeds, papyrus and floating vegetation also slows its flow. During very high levels, the water of the Kwando River flows along an intricate network of southeastward-flowing channels that dissect the grasslands and floodplains. Large areas are flooded when the channels overspill their banks.

During years of major flooding, such as the 2008/9 flood, up to 80% of the park is inundated, leaving only Nkasa and Rupara standing like islands amidst a vast expanse of water. Water flowing along the channels that dissect the floodplains transform the wetlands into a mosaic of lily-carpeted channels, vast reed beds, tranquil backwaters, pools and oxbow lakes. Large areas remained inundated until 2014 when the water began receding, but deep channels still prevented access to Nkasa Island many years later.

Wet cycles are periodically followed by dry cycles. Below- average flows of the Kwando River from 1991 to 2000 resulted in a dry cycle that lasted more than a decade. The floodplains were completely dry by 1994 and largely remained dry until the 2005 wet cycle started.