usaid/nambia environmental threats and opportunities assessment

Figure 11.
Surface and groundwater
sources in Namibia
(Source: Mendelsohn et t al 2002)
The rivers
in the interior are ephemeral, flowing only after good rains in the catchments. Most of these
are west-flowing and cross or enter into the Namib, serving as life-giving linear oases in
the desert. The
Fish River and its many tributaries flow southward into the Orange River, while relatively weak flows
occur in the southeast-flowing Nossob.
The main
surface water storage dams are situated
on some off these ephemeral rivers (Figure 12). The
largest is Hardap Dam
on the Fish River, which supplies the town of Mariental and irrigation farms in
the vicinity. The Swakoppoort and Von Bach Dams on the Swakop Riverr and the Omatako Dam supply
the Windhoek and Okahandja urban centres. Three other relatively smaller dams supply the towns of
Gobabis, Rehoboth, and Keetmanshoop. Approximately 20%
of the water used in Namibia is supplied
from the seven dams described.
Most of the water used
in Namibia comes from underground. Important aquifers are the Omaruru
Delta and
Kuiseb Delta Aquifers, which supply the Erongo coastal towns; ; the Karstveld aquifer
supplying
irrigation, mines and towns around the
centres of Tsumeb, Otavi and Grootfontein; the
Koichab pan which supplies Lüderitz; and the large Stampriet artesian aquifer, which irrigates fruit and
vegetable crops. All the ephemeral rivers also contain alluviall (riverbed) aquifers. There are
54 USAID/NAMIBIA ENVIRONMENTAL THREATS AND OPPORTUNITIES ASSESSMENT