|Sourcebook of Alternative Technologies for Freshwater Augmentation in Africa (International Environmental Technology Centre - United Nations Environment Programme, 1998, 182 p.)|
|Part B - Technology profiles|
|1. Agricultural technologies|
|1.4 Water conservation|
Most ornamental gardens (domestic and institutional) use a lot of water to maintain green plants and flowers in the midst of a dry environment. High water consumption then results. Water conservation gardening involves the use of indigenous plants for different climatic regions. In order to conserve water, plants with similar water requirements are grouped together. The introduction of plants indigenous to a region ensures that not much watering is required (Holland and Holland, 1994).
Extent of Use
The full extent of use of this technology is difficult to quantify as it is subtly practised at household level. Therefore, little information available is available. This technology is being used for landscaping in some office parks in South Africa.
Operation and Maintenance
Drought-resistant plants need to be watered until they are established. Often drought-resistant plants are already present in gardens, but have not been separated from those which are water-thirsty.
Level of Involvement
The level of involvement is user-dependent, but householders are thought to be the major user group. Local authorities, private companies, and other organisations can promote the technology by example through using and refining it. Water agencies can assist by disseminating information about the technology, together with lists of plants suitable for various regions within their service areas. Preparation and distribution centres, often garden supply outlets, are required to provide initial stocks. Gardeners need to be informed so that they can identify hardy plants and transplant them in groups which are determined by their water requirements. There is a need also to continually raise the awareness of householders with respect to the continued economical use of water.
The costs are negligible in the long run as these are incurred mainly at the start of the project during procurement of suitable plant varieties. In general, these costs are no more than the start-up cost of landscaping with non-native plant species. On a national basis the major costs involve the identification of the plant species and the suitable agro-ecological regions.
Effectiveness of the Technology
The technology is potentially very effective in conserving water, given that approximately 30% of the total quantity of water drawn by urban households from municipal connections is used for garden watering. Hence, even if a small percentage of urban dwellers start using the technology, the impact could be significant and lasting. In Israel, the use of more efficient garden watering practises resulted in individual savings of over 50%. These savings were achieved by supplying only enough water to maintain adequate plant and soil moisture levels.
This technology is suitable in all urban situations as a water conservation strategy.
These are positive as the technology conserves water and promotes use of indigenous plants.
It is a simple technology to implement. The technology can effectively extend the design life of the water sources supplying a municipal area. The resultant water savings also have labour and financial savings.
The initial plant identification and grouping phase can be time consuming and costly. The use of local/regional and indigenous plants might become a national requirement, in which case the classification could be done on a provincial basis. However, groupings made in one region may not be transferable. Further, recent research in the United States suggests that care must be exercised so as not to contaminate the gene pool by moving native plant materials between ecological genomes, even if the plants are visually identical. Likewise, care must be taken to avoid introducing nuisance species.
The technology is culturally acceptable. However, acceptance of some native plant over non-native species may be limited since water conserving flora rarely exhibit the diversity of flowers that are found amongst plants from more water-rich regions.
Further Development of the Technology
Further development of this concept is required to identify locally appropriate plants for each region.
D.M.C. Fourie, Department of Agriculture and Water Supply, Post Office Box X388, Pretoria, South Africa, tel +27 12 3197165, fax: +27 12 3262817.
Eiovson, S., 1955. South African Flowers for the Garden, Department of Agriculture and Water Supply, Pretoria.
Fourie, D.M.C. s.d. A Preliminary List of Plants for Water Conservation Gardening in South Africa. Department of Agriculture and Water Supply, Pretoria.
Holland, J.R. and S.M. Holland 1994. Urban Water Supplies Conservation Study for MLGRUD. Emergency Drought Recovery and Mitigation Programme, Department of Agriculture and Water Supply, Pretoria.
Van Der Spuy, U. 1971. Wild Flowers of South Africa for the Garden, Department of Agriculture and Water Supply, Pretoria.