Water in the Kuiseb basin comes mainly from rainfall and runoff from the central highland. The Kuiseb River is a westward flowing ephemeral river, which flows for a short period following heavy rainfall. The Kuiseb river does not reach the sea very often, and ends in the sandy riverbed of a large delta. There are about 300 farm dams and one larger dam on the river, the Friedenau dam. This is the biggest in the upper basin.
The river has good groundwater flow and large aquifers in the lower basin area. The stored water is abstracted by means of boreholes or shallow wells. The large aquifers in the lower Kuiseb river are at Rooibank and Swartbank. They provide water to Walvis Bay and surrounding areas through a network of boreholes, reservoirs and pipelines operated by NamWater. The Directorate of Water Supply and Sanitation Coordination in the Ministry of Agriculture, Water and Forestry, provides water to the Topnaar communities living along the lower Kuiseb through communal water points.
The rest of the basin relies on boreholes and surface water in the farm dams when the rainfall is enough to generate runoff into the dams.
The institutions responsible for water resources are divided into the following categories for ensuring efficient and effective management thereof:
• Overall water resource inventory, monitoring, control, 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: These are 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 for delivery to end users.
The Kuiseb Basin Management Committee was the first BMC in Namibia and was formed in 2003. A Water Resources Management Plan for the Kuiseb was drafted by a mutli-disciplinary team in 2007. The plan serves as a road map for the KBMC and entails action plans focusing on:
• Agriculture and related issues
• Environmental issues
• Water planning and utilisation
• Socio-economic assessments
• Institutional development and capacity building
• Water education
The supply of water from surface and groundwater resources to competing demands is prioritised 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. Ninety-nine per cent of the population in the basin has access to safe drinking water. The main issue in the Basin is thus not so much providing access to potable water, but rather to ensure the supply of water is reliable, sustained and affordable.
The major water using activities/users in the basin include:
Upper and middle basin area:
• Commercial livestock farming. There are 109 farms (providing a livelihood for an estimated 1 700 people) in the freehold farming area. The estimated number of livestock is 30 000, of which 17% are small stock (mainly sheep).
• Game farming/trophy hunting. The estimated number of game is 17 000 and include kudu, zebra, oryx and other species.
• Communal livestock farming, mainly by the Topnaar community. The estimated number of residents is 200, keeping approximately 200 cattle, 2 500 goats, 120 donkeys and 50 sheep.
• Mining. Two active mines, produce minerals such as granite/marble and salt.
• Gobabeb Research and Training Centre. About 20-50 people reside at Gobabeb where fog is harvested for small-scale vegetable gardening.
Lower basin area:
• Urban area: Walvis Bay town (estimated population of 50 400) places the biggest single demand on water resources in the basin.
• Deep sea port and fishing industry, including mari-culture. Namibia has one of the most productive fishing grounds in the world, rich in populations of demersal and large and small pelagic fish. The fish is mainly processed in Walvis Bay.
• Walvis Bay Wetlands: This is a Ramsar site of International Importance and is considered the most important coastal wetland in Southern Africa, supporting more than 40 wetland bird found on the open ocean, bay, mudflats, salt pans and sewage ponds.
• Tourism: there are about 15 tourism establishments in the upper and middle basin areas and 28 in the Walvis Bay area.
Water demand management - how to use water more efficiently Water demand management (WDM) is a very important part of IWRM. WDM aims to improve 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. Walvis Bay Municipality reported 38 per cent reduction in water consumption in 2007. This is mostly because of the following reasons:
- reduced water consumption measures through appropriate pricing of water services;
- sale of recycled semi-purified water since 2003 for use in gardens;
- the fishing industry switching to seawater (as opposed to potable water) for some of their processes.
The price of water supply services is determined by the cost to develop a water source; the distance the water has to be transported by pipeline/canal; treatment costs; storage of treated water; pipelines 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 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.
The average water bill in Walvis Bay town was N$140 in 2009 (lower water tariff of N$7,33 for 19 m3) Noteworthy is that there are no pre-paid meters or communal taps in Walvis Bay town, thus all households are linked to water meters.
Different ways to save water in urban households:
1. Schedule watering of gardens 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 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.
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.
In urban areas: rapid urbanization – particularly unserviced informal settlements - is a major threat due to untreated/uncollected human sewage dumped directly into rivers and seepage of unprotected rubbish dumps into groundwater sources.
In rural areas: lack of serviced water and sanitation facilities is a challenge. Overgrazing and trampling result in excess removal of vegetation and lead, in turn, to excess run-off when rainfall is high. This causes the erosion of topsoil which causes sedimentation in rivers and dams in the upper basin area.
In terms of the Water Act, 54 of 1956, all water users engaged in any activity that produces waste water are required to apply to the DWAF for a permit to dispose of wastewater or effluent. The disposal of toxic mining effluent will become an increasingly important issue as more uranium and other mines come on stream.
There is no water available to dilute or flush pollutants from contaminated underground or surface water sources once such contamination has occurred. Pollution should therefore be totally prevented. 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 for improving efficiency of water resource use through improvement of water demand management practices.
In addition to water demand increasing drastically (by 2,15 per cent annually over the next 10 years), several potential threats to groundwater quality are predicted as follows:
• seepage from tailings dams of an increased number of uranium mines
• nitrate contamination from cattle feedlots and farming practices
• wastewater and effluent disposal of tourism operations
• possible seawater intrusion into the production area of the lower Kuiseb Aquifer
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.
It is expected that between 2009 and 2014, nine new uranium mines will come into operation in the Central Namib Area. These are predicted to provide 5 700 new jobs and would require 52 Mm3 water per annum.
In addition, a number of mineral deposits have been identified in the basin, leading to renewed prospecting at two old copper mines, Hope and Gorob, and initiation of a lead mine.
Apart from the known copper and uranium deposits, there are also substantial gypsum and marble deposits that are not yet fully mined. Accelerated economic development in the basin will not only increase demands for water, but introduce environmental risks due to lowering of the ground water table as a result of intensive groundwater abstraction in the lower Kuiseb valley.
The consequences of a lowering of the water table would lead to:
* the death of the dense acacia woodland which forms a linear oasis in the river water course across the desert
* the unhindered northward advance of dunes from the Namib Sand Sea
* the depletion of drought reserves for plains game and Topnaar domestic livestock through the loss of the acacia woodland and associated vegetation (fodder)
* saltwater intrusion into the lower aquifers To satisfy future water demand, desalination - the removal of salt from sea water/salty groundwater - is an alternative option currently being explored for both human consumption and new mining developments. A desalination plant at Woltzkasbaken was launched in October 2009 by Areva mine.
In response to these challenges, the development of environmental monitoring programs for mines (based on environmental impact assessments and resulting management plans) are prescribed and provided for in the Environmental Management Act, 2007. The Strategic Environmental Assessment (SEA) and the resultant Strategic Environmental Management Plan (SEMP) are both being applied by the Namibian Environmental Restoration and Monitoring Unit (NERMU) and various mines.