Ephemeral Rivers - linear oasis
Updated: Jan 18
Among Namibia’s many assets are its dramatic landforms that both delight and enchant, giving a new dimension of wonder for the processes that formed these ancient landscapes.
Ephemeral rivers as landforms are a feature of all our riding safaris. Image above - riding down the Swakop River.
The Kuiseb - which we cross, along with the Gaub, on our Namib Desert Safari - has been know to reach a flood level of 3 metres and to flow for as long as 103 days, giving it enough power to form that dramatic end to the over 400 km dune sea that has its origins in the distant south near Luderitz. The high canyon walls of the Kuiseb means there is almost always some water throughout the year, sustaining surprisingly large herds of Zebra, Oryx and birds.
Image above, our horses taking full advantage of water in the Gaub Ephemeral river
While many of Namibia’s westward flowing rivers might appear inactive and in fact some are almost invisible (image below of what remains of the Koichab river basin, Wild Horses Safari), the rivers have played a role in forming the desert landscapes we ride across.
Ephemeral river systems are linear oasis - lifelines of riparian woodland made up of enormous Camelthorn and Anna trees - the pods of which are a rich source of protein almost all year around (image below). Large shrubs such as the Salvadora and extensive reed beds give shelter and food to smaller animals. Occasional springs occur in many of the seemingly dry rivers, sometimes supplying enough water for large herds of Elephant to venture far into the western deserts.
These westward flowing ephemeral rivers have their origin in the interior highlands of Namibia - some having catchment areas of over 21 000 square km. they flow westward across the Namib Desert, occasionally reaching the sea. Image shows the Swakop River in flood reaching the Atlantic.
Some rivers, like the Tsauchab (right) end in terminal pans as their passage is blocked by the massive dunes at Sossusvlei.
By the time the rain arrive in summer, the sun-baked soil has low permeability so the rushing head-waters often surprise unwary campers and have been known to carry vehicles and whole campsites downstream. Don’t think that because it has not rained in the immediate area there is no risk! Fed by distant catchment areas, a dry river bed can become a raging torrent in about 20 minutes - an incredible site to behold!
In contemplating rivers, we are perhaps reminded that a ‘river’ flows through all of us too - a river seeking the great ocean. A profound passage from a most unlikely source - Winnie the Pooh - hopefully we too will give up running and jumping and come to know there is no hurry:
“By the time it came to the edge of the Forest, the stream had grown up, so that it was almost a river and, being grown up, it did not run and jump and sparkle a
long as it used to do when it was younger, but moved more slowly. For it know now where it was going, and it said ot itself: “There is no hurry. We shall get there some day”. But all the little streams higher up in the Forest went this way and that, quickly, eagerly, having so much to find out before it was too late.” A.A. Milne