Cambongo River/Negunza

The course of the Cambongo-Negunza River provides an insight into Angola's geological history. The river rises in mountainous areas, at altitudes of over 2,000 metres, crosses regions with very ancient rocks and flows through different types of terrain before reaching the coastal area. Near the sea, part of its water disappears underground, re-emerging at the surface shortly before reaching the small coastal plain.
In areas where limestone rocks are found, close to the ocean, the river displays a curious natural phenomenon: part of its water seeps into the ground and flows through extensive underground passages and caves, reappearing further downstream, near the coast.

The region also features natural depressions in the ground (holes) of various sizes, as well as rocky surfaces marked by grooves and small cavities. These formations have developed over thousands of years as a result of water erosion on limestone rocks.
This type of formation is not exclusive to the Cambongo-Negunza River. Other rivers in the region also follow courses influenced by ancient fractures and faults in the rocks, caused by movements in the Earth's crust over millions of years. In the case of this river, some sections follow almost straight lines, revealing the influence of these ancient changes in the landscape.

From its sources, located in the elevated areas of the so-called Marginal Mountain Range, the river descends through different levels of terrain until it reaches the sea. Inland, it crosses vast areas of very ancient rocks, some transformed by heat and pressure deep within the Earth, while others were formed through the cooling of rocky materials. Further towards the coast, it flows through a strip approximately 28 kilometres wide, made up of materials that accumulated over different periods of the Earth's geological history.

REGIONAL CLIMATE

The region has a relatively dry climate, with semi-arid characteristics. Annual rainfall is less than 700 millimetres, while water evaporation rates are high. Vegetation consists mainly of savannahs, grasslands and plants adapted to water scarcity, with scattered trees across the landscape or even no trees at all in some areas.
These climatic conditions directly influence the river's flow, causing water levels to vary considerably throughout the year, depending on the rainy and dry seasons.
The water of the Cambongo-Negunza River is extremely important to the communities living nearby. It is used for water supply, agriculture and small-scale livestock farming.
At certain points along the river, structures have been built to help regulate water levels and reduce the effects of prolonged periods of drought. These measures are becoming increasingly important due to climate change, which has contributed to worsening the challenges associated with water availability.