The water comes from dams in the ephemeral rivers and groundwater.
The Nossob-Auob Basin is comprised of two main rivers, the Auob and Nossob (Black and White), which join the Molopo River in Botswana. There are several tributaries (smaller rivers) of these rivers, which include the Olifants, Seeis and Skaap. The Oanob Dam was built in the Oanob river to supply water to Rehoboth town. The Oanob River flows eastwards from the central highland and is considered part of the Nossob-Auob Basin, but the river dissipates into the sand to the south of Rehoboth. Two dams (Daan and Tilda Viljoen) were built on the Black Nossob river, while the Otjivero Dam was built on the White Nossob river all supplying water to Gobabis. Groundwater comes from the Stampriet Artesian Aquifers and the upper Kalahari aquifer. The groundwater from these aquifers is supplied to towns and settlements in the basin. Pans (shallow, seasonal, unvegetated depressions in the landscape) are very common in the basin (for example the Aminius pan), but only fill with water after good rains or when ephemeral rivers flow into them.
Several excavation/earth dams are found in the basin and collect seasonal surface water, which is primarily used for livestock water supply. Although a dam is expensive to build, the water from dams in the communal areas is free for people and livestock to use. The major disadvantages of earth dams are that they can only recharge water in one place and they are not good for storing water because they loose most of their water through evaporation.
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, contol, regulation and management: Directorate of Resources Management within the Ministry of Agriculture, Water and Forestry (MAWF).
• Bulkwater 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), subject to appropriate agreements and licences, 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 or supply water from their own boreholes for delivery to end users.
The Constitution of the Republic of Namibia is the primary law for sustainable resource management and equal distribution of water to people. Specific documents dealing with water management include the: Water and Sanitation Policy of 1993; Namibia Water Corporation (NamWater) Act of 1997; National Water Policy White Paper of 2000; Water Act 54 of 1956 and Regulations, soon to be replaced by the Water Resources Management Act (2004) [which has not yet entered into force and is currently under revision] and the Water Supply and Sanitation Sector Policy of 2008.
The Water Resources Management Act makes provision for the establishment of basin management committees (BMCs) to make sure that integrated management takes place at the basin level. The role of a BMC is to provide scope for addressing various challenges affecting water resources in the basin, ranging from efficient water use to monitoring the health of the basin.
The aim of such a committee is to equip basin communities (ensuring gender equality wherever possible) to take full ownership of their own development (through establishing a strategic basin management plan) with strong support from the relevant service providers. The committee is ideal for knowledge and experience sharing to realize a common vision for the basin based on principles such as stakeholder participation, transparency and information sharing.
The process of establishing basin management committees is currently being implemented in phases and thus the Nossob-Auob basin committee is still pending based on demand and priority assessments. However, there is at present a Stampriet Artesian Aquifer Management Committee in place which is responsible for assisting the Department of Water Affairs and Forestry with the management of groundwater sources in the Artesian Aquifers.
The supply of water from surface and groundwater resources to competing demands is prioritised in Namibia. The first priority 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.
The people in the basin are mostly confined to the main town areas of Rehoboth (estimated 21 300 people) and settlement areas such as Witvlei, Leonardville, Aminius, Aranos and Stampriet as well as the commercial farming area with an estimated rural population of 40 600. Gobabis (population estimated at 19 200) is on the border between the Nossob-Auob and Eiseb-Epukiro Basins. Gobabis obtains surface water and groundwater from the Nossob-Auob basin.
Water in the Nossob-Auob Basin is mostly used for domestic and livestock farming.
The basin is characterized by large-scale commercial farming activities (mainly with cattle, sheep and goats).
Water from the Stampriet Aquifer is used by nearby farmers for irrigation, producing vegetables, melon, grapes and maize. Vegetation (mainly camelthorn forests) downstream of the Oanob Dam is provided with periodic water releases from the dam as an alternative to natural floods that are captured since the dam was built.
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 supply services is determined by: the cost to develop a water source; distance the water has to be transported by pipeline/canal; treatment costs; storage of treated water; pipelines to the consumer; and 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.
The quality of water is determined by its aesthetic (colour, smell, turbidity), chemical and bacteriological quality. There is a direct link between water quality and health and therefore it is important to be able to differentiate between safe and unsafe water sources. Water quality is determined by both natural and human-induced contaminants (pollutants) that may have found their way into the water supply. 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. The water is described to be highly saline, when the concentration of salts dissolved in the water is high. This includes nitrates, fluorides, sulphates as well as sodium chloride and carbonates. Water with high salinity tastes salty and is usually called ‘brackish’ water. In some areas (Aminius), saline water overlies the freshwater and has the potential to contaminate the freshwater. It is reported that water in the basin becomes more salty towards the Botswana border. 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.
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. Where possible it should be left to individuals to decide on their most appropriate technological and payment options as well as maintenance responsibility allocation.
The institutions responsible for water sanitation and hygiene are divided into the following categories:
• Public health issues and awareness: Ministry of Health and Social Services; Directorate of Water Supply and Sanitation Coordination within the MAWF; Regional Councils and Local Authorities
• Health policies and legislation: Ministry of Health and Social Services
• Advice and research on alternative sanitation options and development: Habitat Research and Development Centre
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. Increased run-off (rainwater not infiltrating into the soil) causes loss of agricultural productivity (soil fertility).
• Bush encroachment: Invader bushes are the highest single consumer of groundwater, with detrimental long-term consequences to the sustainability of groundwater resources and fodder availability.
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.
The basin is predominantly rural in nature (covered by Kalahari sand) and relies heavily on groundwater sources. Major challenges include the location of sustainable boreholes and ensuring water demand management in the basin.