The Berg rises south of Franschhoek in the Drakenstein and Franschhoek Mountains, fed by winter rains that soak the rugged peaks. It flows northwestward, collecting tributaries as it goes: the Franschhoek River, the Wemmershoek, the Dwars. Past Paarl and Wellington, the valley broadens and agriculture intensifies -- about 65 percent of the Berg River catchment is farmland. Perennial streams drain from the Limietberg mountains to the east, while intermittent rivers like the Sand and the Doring flow only in winter, drying to sand in summer. By the time the Berg reaches Velddrif and empties into St Helena Bay on the Atlantic coast, it has passed through some of the most productive agricultural land in South Africa, its waters diverted and dammed at multiple points along the way.

When Abraham Gabbema arrived in 1657, sent by Dutch Governor Jan van Riebeeck to trade with the Khoikhoi for meat, he named it the Groot Berg Rivier. But settlement was slow. It took another two decades, until Governor Simon van der Stel's administration between 1679 and 1699, before Europeans moved beyond the Cape Peninsula in earnest. Van der Stel was reportedly so taken with the river's fertile banks that he established the first European settlements at Paarl and in the Drakenstein valley in 1687. Franschhoek, Wellington, and Tulbagh followed soon after, their founding tied directly to the agricultural promise that the Berg River's waters made possible.

A 2004 government report traced the grim arithmetic of the Berg River's hippopotamus population. In the late 1600s, hunters began killing hippos for meat and hides faster than the animals could reproduce. By the mid-1700s, Governor Tulbagh tried to save them with heavy fines, but habitat destruction accomplished what laws could not prevent. By the early 1800s, perhaps a dozen survived near Kersefontein and the estuary. In 1829, only six remained. Melck's shot in 1869 ended the story. The hippos' disappearance foreshadowed a broader pattern of ecological loss that continues to this day, as the river's native fish face similar pressures from an entirely different source.

The Berg River harbors species found nowhere else on Earth. The Cape galaxias and the Berg River redfin are endemic, their evolutionary histories bound to this single watershed. But introduced fish, especially the predatory smallmouth bass, have devastated native populations. The Cape whitefish, listed as Endangered by the IUCN, appears to have vanished entirely from the Berg River proper. The Berg River redfin holds one of its last major populations here, its decline slowed but not reversed. In 2022, the 1,163-hectare Berg Estuary earned designation as a Ramsar Wetland of International Importance, recognizing the 127 waterbird species that depend on its habitat -- including the threatened Cape cormorant. The designation offers some protection, but the tension between agricultural water use, invasive species, and conservation remains unresolved.