Water conservation is the minimisation of water loss, the care and protection of water resources, and the efficient and effective use of water. The concept generally focuses on the efficiency of processes or actions associated with water resources.
In order for water conservation strategies to be effective, significant awareness raising is required in the form of campaigns through workshops, discussion forums, and newsletters to integrate the principles of water conservation into people's daily lives.
All of the countries in the basin have limited water supplies, and anticipate increasing demand for water as a result of climate variability and change, population growth, and industrial development. It is, therefore, very important that all water use sectors optimise the use of water to ensure that both basic human needs and the needs of the environment are met, now and in future. Implementation of water conservation principles is essential.
The goals of water conservation include:
Sustainability—To ensure availability for future generations, through the sustainable use of water
Energy conservation—Water pumping, delivery, and wastewater treatment facilities use significant amounts of energy
Habitat conservation—Minimising water use helps to preserve fresh water ecosystems, as well as reducing the need to build dams and other water diversion infrastructure
The SADC Protocol on Shared Watercourses requires all basin states to adopt Integrated Water Resource Management Plans (IWRMP) to address water resource usage and conservation. This is further discussed in the theme Goverance.
Re-using water is also a form of conservation, as the re-used water replaces water that would come from other sources. Virtually all the water coming out of a tap can be used at least twice. The discharge water from one process, say bathing, could be fit for further use, such as garden irrigation.
Water re-use not only provides an alternative source of water, it reduces pollution by minimising the discharge of wastewater. Additionally, water re-use in the largest sectors—agricultural and industrial—allows for a greater allocation to other sectors. Properly implemented, water re-use has the potential to bring about significant environmental, economic and financial benefits.
The concept of water re-use is applicable at both the household scale and at the large industrial and mining scale. At the household scale, grey water (un-treated household wastewater discharged from bathtubs, showers, wash basins and washing machines) can be re-used without pre-treatment for agricultural or landscape irrigation, with due care because certain plants are sensitive to detergents and other cleaning materials.
Effluent from wastewater treatment plants can also be re-used, for purposes ranging from irrigation to urban applications. Effluent re-use for agriculture should be practiced with good management to prevent adverse human health impacts. Water for many purposes does not have to be of the same quality as drinking water: treated domestic wastewater, though non-potable, may be suitable for toilet flushing in business or commercial buildings, car washing, garden irrigation, etc.
As the irrigated agriculture sector is the largest user of water within the Limpopo River basin, water conservation strategies should focus on this user group to obtain maximum savings. Significant savings can be obtained by reducing conveyance losses in canals, scheduling irrigation appropriately, metering and pricing irrigation water, and improving efficiencies in irrigation systems.
In southern Africa, Botswana and South Africa have developed partial water accounts, and there is a drive to incorporate wastewater into these accounts as a method of water re-use and conservation (Arntzen and Setlhogile 2007). In Botswana, re-using wastewater and defining it as an economic resource was emphasised in the 2003 National Master Plan for Wastewater and Sanitation. In the plan, wastewater can either be released to the environment or re-treated in wastewater treatment works. Re-treated wastewater could partially replace new withdrawals of fresh surface and groundwater flows.
Water recycling is currently being investigated as part of Botswana's strategy to address increasing demand for water. This subject is discussed in more detail in a SADC Waterwire article from August 2010.
Within Mozambique, water resources conservation is shared between the Southern Regional Water Administration (ARA-Sul) and the Ministry for the Coordination of Environmental Action (MICOA) (Barros 2009).
The National Water Act (1998) of South Africa includes fundamental reforms with respect to the sustainability of water use in the mostly semi-arid country. To satisfy this reform, all agricultural water user associations must submit a Water Management Plan detailing their current infrastructure management practices, measure the use and management of irrigation water, develop a water balance (inputs and outputs), and identify best management practices for water conservation and demand management (DWAF 2009a).
In southern Africa techniques of rainwater harvesting (RWH) have been in place for many years. Zimbabwe has since introduced the technique of fanya juu, infiltration pits and tied ridges in communal areas (Motsi et al. 2004). Infiltration pits improve water infiltration rates, water retention, evaporation is reduced, and surface storage and the time for infiltration to occur is increased. A study was done in the Mashonaland east and Masvingo provinces and it was found that improving tillage options would increase the retention capacity in the soil and it was recommended most farmers in low rainfall areas adopt these techniques (Motsi et al. 2004). A case study reported by the InterPress News Service is provided in the Agriculture sub-chapter.
Rainwater harvesting is a specific technique in water conservation and re-use.
Source: Kruchem 2008
( click to enlarge )