Desalination & Reuse Handbook - Flipbook - Page 12
IDA
WATER SECURITY
HANDBOOK
WINDHOEK
Namibia has long been at the sharp end of global water scarcity: not only did 2016 witness the second declaration of a
state of emergency due to drought in three years, but population pressure and industrial development are set to push the
country’s water demand from around 900,000 m3/d in 2015 to 2.1 million m3/d in 2030.
Use of unconventional water resources is made necessary by inherent water scarcity: high evaporation rates mean only 1%
of annual rainfall goes to recharge groundwater aquifers, with 2% remaining as usable runoff in surface storage facilities,
whilst Namibia shares its perennial rivers with neighbouring countries preventing full exploitation.
Direct potable reuse (DPR) has provided a significant proportion of the water used by Namibia’s capital, Windhoek, for the
past half-century. Inaugurated in 1968, the Goreangab Water Reclamation plant was the world’s first use of DPR as a longterm solution to water scarcity. In 2002 the plant was replaced by the 21,000 m3/d New Goreangab Water Reclamation
Plant (NGWRP), which serves around a third of Windhoek’s potable water demand. A further 25,000 m3/d of DPR capacity
is planned at Gammams, with pilot studies set to start in 2018 with KfW funding.
As Namibia makes plans to increase its potable reuse capacity, the rest of the world remains hesitant to adopt it as a direct
source for drinking water. While indirect potable reuse (IPR) projects are in operation across the world, DPR projects
outside Namibia have been small-scale, short-lived, or use water blending and buffers in a way that, in practice, moves
towards IPR. Pipe-to-pipe potable reuse remains unique to Namibia.
In addition to increased wastewater reuse, desalination plays a prominent role in Namibia’s 5th National Development Plan
(NDP5). A planned 68,500 m3/d plant to supply the Erongo region would be the country’s first municipal desalination
facility, whilst pilots for brackish water desalination projects in Grünau and Bethanie are being carried out to investigate
the potential for small-scale, decentralised water supply to vulnerable communities.
The country’s water utility, NamWater, operates in a constant state of drought readiness. Water savings measures are
introduced as reserves fall. When reserves drop below 12 months’ supply, a state of crisis is declared with measures
targeted at achieving water savings of 50%. At this point variable tariffs will reach their most severe, all non-essential
construction will stop, and the most loss-prone water infrastructure will cease to operate. NDP5 also outlines plans
to expand and diversify the country’s water supply portfolio; manage existing resources more effectively, and increase
resource cooperation with its neighbours. Increased supply from DPR forms a significant part of these proposals.
As the climate becomes increasingly unpredictable, DPR is being considered as a solution for many arid communities,
particularly in the USA. Texas is perhaps the most likely location for the world’s second permanent direct potable reuse
programme to take root, with several smaller scale or temporary projects seeing success in the past (see chart, opposite).
At least in the short-term, however, Namibia will remain unique in its use of pipe-to-pipe DPR as a result of the extreme
conditions in which its population must secure water their water supplies.
4
