How do Walvis Bay and Swakopmund use water from the Namib Desert?

Because the Namib is an almost rainless region with a fragmentary drainage pattern, the towns of Walvis Bay and Swakopmund rely on water sourced from the desert's subsurface.1

While major rivers like the Kuiseb River typically die out in the desert sands, a portion of their water seeps through the streambeds. To secure a reliable water supply, this underflow of the Kuiseb River is tapped approximately 25 miles (40 km) inland, providing the necessary water for both Walvis Bay and Swakopmund.1