The water comes from ephemeral surface water flow and groundwater.
The Omaruru and Swakop Rivers are the major ephemeral rivers (they only flow after heavy rain) in the basin. The Okondeka and Khan Rivers are respectively their main tributaries (smaller river flowing into the larger river). Both rivers flow westward towards the Atlantic Ocean. The Omaruru River recharges several underground river channels that form the Omaruru Delta at the river mouth. Water from the Swakop River is stored in two major dams, the Von Bach and Swakoppoort Dam from where it is pumped to various large centers such as Windhoek, Okahandja, Karibib, the Otjihase Mine and the Windhoek Airport. The Von Bach Dam is part of the Eastern National Water Carrier (ENWC) system, which also gets water from the Swakoppoort Dam, the Omatako Dam and groundwater sources near Grootfontein in the north. The Omdel Dam was built on the lower Omaruru River about 40 kilometers east of Henties Bay, to artificially recharge the groundwater sources in the Omaruru Delta.
Other dams in the basin include the Avis and Goreangab, where most of Windhoek’s runoff is collected. The water supply schemes in this basin are interlinked and supply water to one of the economically most important parts of Namibia.
The basin has several groundwater sources (boreholes and wells) and springs that are recharged by floodwaters from the rivers. Important aquifers are located at the Omaruru Town, Okombahe, Neis-Neis and Henties Bay on the Omaruru River; at Karibib, Usakos and Otjimbingwe on the Swakop River and the Windhoek aquifer.
The institutions responsible for water resources are divided into the following categories for ensuring efficient and effective management there of:
• Overall water resource inventory, monitoring, control, regulation and management: Directorate of Resources Management within the Ministry of Agriculture, Water and Forestry (MAWF).
• Bulk water supply: Namibia Water Corporation (NamWater) abstracts water from primary sources (e.g. rivers, aquifers or dams) and supplies to some end-users directly.
• Self-providers: Commercial farmers, tour operators, mines and nature conservation (parks), subjected to appropriate agreements and licenses, supply their own water.
• Water supply to rural areas: Directorate of Water Supply and Sanitation Coordination in the MAWF.
• Water supply to urban areas: Local Authorities and Regional Councils buy water from NamWater for delivery to end users (with the exception of Omaruru town, which supplies its own water from the Omaruru River aquifer).
The supply of water from surface and groundwater resources to competing demands is prioritized in Namibia. The first is water for domestic purposes (including livestock water for both subsistence and commercial farming) and the second is water for economic activities such as mining, industries and irrigation.
Urban water demand is by the far biggest in this basin, with livestock, tourism, irrigation and mining the other main consumers. The City of Windhoek uses domestic sewage effluent from the Gammans Wastewater Treatment Plant to produce potable water at the New Goreangab Water Reclamation Works. Established in 1968, this is still the only direct potable reuse system in the world and provides approximately 25%+ of the potable water supply to Windhoek.
Specific water-use activities in the basin are:
• Domestic purposes: Towns in the basin include Swakopmund, Hentiesbaai, Omaruru, Usakos, Arandis, Windhoek; Okahandja and Karibib.
• Subsistence and small-scale farming: The stock found in this area is predominantly goats, but also includes a large number of cattle and a small number of sheep and donkeys.
• Large-scale commercial farming: Commercial farmers in the basin farm mostly with cattle and goats. Game farming is also practiced on a commercial basis.
• Mining: Navachab, Rossing and Langer Heinrich Mines use its water for gold (Navachab) and uranium production.
• Environment: The river system supports large trees, bushes and grasses which can be used by livestock and wildlife as fodder. In addition, the coastal wetland areas support a wide variety of birds and other wildlife.
Water demand management - how to use water more efficiently
Water demand management (WDM) is a very important part of IWRM. WDM aims to improve water use efficiency by reducing water losses or changing the wasteful way people use water. WDM is an approach to achieve „water use efficiency“. WDM is implemented through education and information; training; using economic and financial principles; water pricing and tariff policies (e.g. rising block tariffs) and technical measures. The price of water is determined by the cost to develop a water source; the distance the water has to be transported by pipeline to the consumer and the topography which determines the pumping cost to supply the water.
The consumer base and technology, i.e. household taps or pre-paid meters, that are affordable to various income groups also have an effect on the cost of water.
The ability of Local Authorities to enforce credit control measures also influences water consumption.
Municipal costs to provide a household with water and sanitation services include charges for water collection from a source; water production (treatment of raw water to drinking water standards); water delivery to the consumer and wastewater treatment and disposal. Wastewater collection and treatment contribute to hygienic environments and form part of the water chain to prevent pollution in order to ensure that good water quality and sanitation is achieved. Therefore it is essential that water consumers PAY for water services to ensure continued quality and efficient service delivery. Debt incurred by service providers (NamWater and local authorities) was estimated at N$400 million in 2009, due to non-payment of water bills. This will jeopardise provision of services in the future if consumers do not pay their bills.
In rural areas, the community based water management programme under the Directorate of Water Supply and Sanitation Coordination, established mechanisms for users to pay for water services. In addition, mechanisms for transparent and targeted subsidies for those who are unable to pay for water services are being considered. Local water point committees manage local aspects of water services, preventing actions such as illegal connections and vandalism to pipelines.
Different ways to save water in urban households:
1. Schedule garden watering for early or late in the day (before 10 am and after 4 pm)
2. Avoid the use of hosepipes for cleaning pavements, floors or cars; instead use buckets
3. Make use of retrofits (replacement with equipment specifically designed to reduce water use) such as:
3.1 Low flush and dual flush cisterns that are being used more and more.
3.2 Reducing the volume of existing toilet cisterns can be achieved by:
* Placing a 1 to 2 litre plastic bottle filled with water, or a brick wrapped in plastic, inside the cistern. This will decrease the volume of water held within it.
* Bending the swimmer arm inside the cistern downwards so that the inflow valve is shut off when the water reaches a lower level than previously.
4. Fix or report to the municipality any moisture or leak problems immediately. Most water leaks occur from toilet cisterns. A single leaking toilet cistern can lose up to 7 000 litres of water per day in a household.
5. Explore rain water harvesting (collection and storage of rain from run-off areas such as roofs) options. Remember - the first flush of new rain should be discarded before collection starts.
6. Keep track of water usage by regularly reading the water meters.
Most of the groundwater within the Omaruru River Basin is considered suitable for drinking. Naturally, water contains varying concentrations of dissolved oxygen and other gases, microscopic living organisms, tiny particles of dead decaying organic matter, inorganic salts and sediments. Water that contains high concentrations of naturally occurring salts is called ‘brackish’ water. It can taste salty and can appear cloudy.
The quality guidelines for drinking water have been set out by the Department of Water Affairs and Forestry, Water Environment Division.
Groundwater monitoring is considered very important, not only to understand and identify water quality trends and related indicators, but also to determine the availability of acceptable quality water sources. The Geohydrology division in the MAWF is responsible for groundwater investigation and monitoring.
Many people in the basin are exposed to "dirty“ unsafe water from open wells and watercourses which contain bacteria and organisms which can cause diseases, such as bilharzia, cholera, typhoid and dysentery. Dirty water can have a colour (yellow, brown or black) but it can also be clear and contain invisible bacteria or chemicals that are harmful to humans and animals. Therefore it is advisable to clean/cook water before drinking it.
Sanitation is vital for human health, generates economic benefits, contributes to dignity and social development, and protects the environment. Sanitation promotion focuses on stimulating demand for ownership and use of a physical good. Access to basic sanitation refers to access to facilities that hygienically separate human excreta from human, animal, and insect contact. Hygiene promotion focuses on changing personal behavior related to safe management of excreta, such as washing hands and disposing safely of household wastewater. Both are essential to maximize health benefits. Lack of sanitation facilities and poor hygiene cause water-borne diseases such as diarrhea, cholera, typhoid and several parasitic infections. Provision has been made for both urban and sanitation management objectives and principles in the Water and Sanitation Sector Policy of 2008, to contribute towards improved health and quality of life.
Considering that Namibia is a water-scarce country, in most (rural and urban) instances, the most affordable individual household or community sanitation options are ecological or dry sanitation facilities, however where possible it should be left to individuals to decide on the most appropriate technological and payment options as well as maintenance responsibility allocation.
The IWRM challenges in the basin are linked with climate variability and associated changes. In particular, the basin is highly prone to the following challenges:
• Land degradation and deforestation: The topsoil of land contains valuable nutrients for vegetation to grow. When vegetation cover or trees are destroyed (either through high population growth or overgrazing due to high livestock concentrations in an area) the land becomes vulnerable and results in topsoil being easily blown away by wind. The increased run-off (rainwater not infiltrating in the soil) therefore causes loss of agricultural productivity (soil fertility).
• Bush encroachment: Invader bushes are the highest single consumer of groundwater, with detrimental long-term consequences on the sustainability of groundwater resources and fodder availability.
Additional challenges in the basin are the timely development of the Windhoek aquifer recharge project which is currently lagging behind its programmed milestone dates as well as the development of the infrastructure capacity from Von Bach to Windhoek.
Due to the arid and highly variable climate in Namibia, water resource managers and users have to focus on improving efficiency of water resource use through improvement of water demand management practices.
In accordance with Namibia’s Vision 2030, the urban population is predicted to increase three-fold, which will cause a major strain on water resources if not properly addressed. With the increase in mining, tourist and livestock farming activities in the basin, high demand is placed on current water resources. Currently desalination (removing salt from sea water) of sea water is being considered as an option to meet the demand. This process is very costly and other options such as water banking and water demand management should be employed to reduce demand on conventional water resources.
Although Windhoek is relying on three major dams, Omatako, Swakoppoort and Von Bach dams for its water supply, future plans are to bank groundwater in the Windhoek aquifer. Water banking was identified as the best next supply option to the central area of Namibia. This involves storing excess treated water from surface dams, as well as reclaimed water, in the Windhoek Aquifer for abstraction during periods of drought. If completed in full (4 phases) it is estimated the stored water will be enough to supply Windhoek for approximately three years (about 60Mm3). No major concerns for water supply exist in the basin, provided that the planned Windhoek aquifer develops successfully and infrastructure of the Von Bach system is upgraded and well maintained to increase the rate of artificial recharge of the aquifer. The project is behind schedule and security of supply is a major concern with increased water demand.