The water comes from perennial rivers, ephemeral rivers and aquifers. The Okavango River is a perennial river and forms the northern border of the basin. The main perennial tributaries are the Cubango and the Cuito in Angola. Other smaller sandy watercourses (known as omiramba), namely Nhoma and Kaudom, drain towards the Okavango Delta in Botswana. The Omatako dam is built on the Omuramba Omatako, also a tributary draining northwards. It serves as a water source for the Eastern National Water Carrier (ENWC). Several excavation/earth dams are found in the basin that collect seasonal surface water, which is primarily used for livestock water supply. Although the dams are expensive to build, the water 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 are not good for storing water because they lose most of the water through evaporation.
Good Groundwater resources are found all over the basin but in the Karstveld area one of the most productive aquifers in Namibia is found. Most groundwater is abstracted from boreholes.
• 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), subject 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 or supply their own water from boreholes for delivery to end users.
The supply of water from surface and groundwater resources to competing demands is prioritized 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 Karstveld area is the main maize-growing area in Namibia, hence large-scale commercial irrigation projects (including the Green Scheme along the Okavango River) are the biggest water users in the basin.
The major crops grown are mahangu, maize, cotton and wheat. Other water-use activities in the basin are:
• Domestic purposes: Towns in the basin include Grootfontein; Okakarara and Rundu. Surrounding settlements support approximately 17 500 people, while the rural population is estimated at 212 000.
• Subsistence and small-scale farming: This includes both livestock and crop farming, with mahangu, maize and sorghum as the main cereals, supplemented with vegetables.
• Large-scale commercial farming: The basin is a prime farming area, dominated by cattle and goats.
• Mining: In addition to using water for mining operations, water from Kombat mine is also used to supplement water in the ENWC canal which subsequently supplies Okakarara town and some parts of the Eiseb-Epukiro basin. Water can also be supplied from the Berg Aukas Mine or Kombat to places as far south as Windhoek.
• Fishing: There is an abundance of fish resources in the basin, mainly along the Okavango River and floodplains. The flood plains are reported to be rich in nutrients and rich communities of animals and plants survive there.
• Tourism and wildlife conservation: The Mangetti, Mahango, Khaudum, Popa and Caprivi Game parks are in the basin. The parks have open pans and surface water sources that are used by the wildlife. Tourist facilities are found along the Okavango River and on many commercial farms.
• Research: Government agricultural research activities take place at Kavango Cattle ranch, Mashare and Mile 46 cattle-breeding farm. Several horticultural projects (e.g. Salem vegetable garden) take place in the basin.
Water demand management (WDM) is a very important part of IWRM. WDM involves ways that 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 various ways such as 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: 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 that 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 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 and 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.
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 issues 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.
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 monitoring the water meters. This also gives an indication of the water bill (water tariff guides are available at the Municipality).
Some water quality concerns exist due to increasing chemical concentrations in the Okavango River due to increasing farming activities. In a few areas, contaminated water, mainly through animal waste (especially where cattle troughs are close to wells), has been declared as ‘unsafe’ for both human and livestock consumption.
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 and 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 the individuals to decide on the 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 Okavango 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 on 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.
In the future, the Eastern National Water Carrier (ENWC) is earmarked to transfer surface and groundwater to the central, eastern and western parts of Namibia. This is identified as the largest integrated water supply infrastructure project in the country. The system links different water sources: groundwater, ephemeral and international perennial surface water and reclaimed domestic sewage water. The development of the ENWC is postponed until 2020 based on water availability, artificial recharge and water demand management measures that are in place in central Namibia.
Development of irrigation projects along the Okavango River may result in pressure on the availability of water from the Okavango. Similarly, plans to build a hydroelectric power station at the Popa Falls are still under investigation, but there may be too many negative impacts to implement the project. The basin is home to the highest diversity of plants and animals in Namibia based on the presence of the Okavango River. As a result, the tourism industry is growing rapidly which may impact on water resource use in the basin in the future.