A |
| Abiotic | Non-living thing. Usually refers to the physical and chemical components of an organism's environment. Also called inorganic. |
| Absorption | The act or process of absorbing or the condition of being absorbed. |
| Abstraction | The process of taking water from any source, either temporarily or permanently. Most water is used for irrigation or treatment to produce drinking water. Depending on the environmental legislation in the relevant country, controls may be placed on abstraction to limit the amount of water that can be removed. Over abstraction can lead to rivers drying up or the level of groundwater aquifers reducing. |
| Accelerated and Shared Growth Initiative (ASGISA) | A 2004 South African Government initiative to halve poverty and unemployment by 2014. |
| Accountability | A principle through which individuals, organisations and the community are responsible for their actions and may be required to explain them to others. |
| Acid | 1. Substance having a pH less than 7. (2) Substance that releases hydrogen ions (H+). |
| Acid mine drainage | Acidic run-off water from mine waste dumps and mill tailings ponds containing sulphide minerals, Also refers to ground water pumped to surface from mines. |
| Acidity | (1) Substance having a pH less than 7. (2) Substance that releases hydrogen ions (H+). |
| Act | A statute or law made by a legislative body. |
| Administrative unit | This term can be used to describe a division (town, municipality etc) with administrative powers. |
| Aesthetic | A term used to describe something of sensory or sensori-emotional value. |
| Afforestation | The process of planting trees and/or seeds in areas not previously forested. |
| Afrikaans | An Indo-European language, derived from Dutch, mainly spoken in South Africa and Namibia, with smaller numbers of speakers living in Botswana, Angola, Swaziland, Zimbabwe, Lesotho, and Zambia. |
| Agricultural drought | Occurs when there is insufficient water in the soil to grow a particular crop at a particular time. |
| Agricultural use | The use of water for irrigation purposes. |
| Agro-meteorology | The study of the relationship between conditions in the surface layers of the atmosphere and those in the surface of the Earth, as this affects agriculture. |
| Agroforestry | Combines agriculture and forestry technologies to create more integrated, diverse, productive, profitable, healthy and sustainable land use systems. |
| Agropastoralism | A livelihood that is based on land use that incorporates both settled crop agriculture and the tending of animals that are moved from place to place. |
| AIDS | Acquired Immuno-Deficiency Syndrome (AIDS) is a disease characterized by the destruction of the human immune system. Although there are treatments to hinder the progress of AIDS, there is no known cure or vaccine. UNAIDS and the World Health Organization (WHO) estimate that AIDS has killed more than 25 million people since it was first recognized on December 1, 1981, making it one of the most destructive pandemics in recorded history. In 2005 alone, AIDS claimed between an estimated 2.8 and 3.6 million people, of which more than 570,000 were children. |
| Algae | A simple, photosynthetic plant usually inhabiting moist or aquatic environments. |
| Algal blooms | A rapidly increasing community or presence of algae in an aquatic environment or ecosystem. |
| Alien species | A species not naturally occuring in a region. |
| Alkaline | (1) Having a pH greater than 7. (2) Substance that releases hydroxyl ions (OH-). |
| Alkalinity | (1) Having a pH greater than 7. (2) Substance that releases hydroxyl ions (OH-). |
| Allochthonous | Material introduced into rivers from terrestrial environments. Examples include leaves or branches from trees that fall into a river. |
| Alpine | High altitudes in mountainous environments. |
| Ambient environmental standards | Standards used to set limits to which levels of environmental resources may be permitted to fall. |
| Amoebas | Freshwater, marine or parasitic protozoa that form temporary pseudopods for feeding and locomotion. |
| Amphibians | A cold-blooded vertebrate animal in the class Amphibia. Some characteristics of amphibians include: 1) adults are land-dwelling but return to water to breed; 2) the skin and mouth lining can be used for oxygen exchange underwater; 3) skin is glandular and lacks hair, scales, or feathers; 4) eggs hatch into an aquatic larval stage. Examples of amphibians include animals such as frogs and salamanders. |
| Analog | A form of data display in which values are shown in graphic form, such as curves. Also a form of computing in which values are represented by directly measurable quantities, such as voltages or resistances. Analog computing methods contrast with digital methods in which values are treated numerically. |
| Anastomosed channel | A stream channel, consisting of sediments resistant to erosion, containing numerous smaller channels separated by stable islands. |
| Angiosperm | A flowering plant. |
| Annelid | Phylum of invertebrates that are typically elongated and segmented, including earthworms and leeches. |
| Annual renewable water resources | The average· annual flow of rivers and groundwater generated from endogenous precipitation. Annual averages disguise large seasonal, inter-annual and long-term variations. |
| Anomalous | Something that deviates from the normal or common order or form or rule. |
| Anoxic | Conditions lacking in oxygen. |
| Anthropogenic | Of or relating to the study of the origins and development of human beings. |
| Apartheid | Separateness in Africaans. A system of legal racial segregation enforced by the National Party government in South Africa between 1948 and 1994. |
| Aquaculture | All activities aimed at producing in restricted areas, processing and marketing aquatic plants and animals from fresh, brackish or salt waters. |
| Aquatic | With reference to water. |
| Aquifer | An underground area consisting of water-bearing unconsolidated material and permeable rock from which economically viable amounts of water can be extracted. |
| Arid (aridity) | An arid environment has a high precipitation deficit, receiving much less precipitation annually than would satisfy the climatological demand for evaporation and transpiration. This is mainly due to the high temperatures and few storms bringing rainfall. Regions are classified as arid if their aridity index falls between 0.05 and 0.20. |
| Artesian aquifer | Aquifer whose piezometric surface lies above the ground surface (sometimes used loosely as syn. for confined aquifer). |
| Artesian well | Well tapping a confined or artesian aquifer in which the static water level stands above the surface of the ground. |
| Artificial recharge | Augmentation of the natural replenishment of groundwater in aquifers or groundwater reservoirs by artificial supply of water through, e.g., wells. |
| Artisanal fisheries | Small-scale fisheries carried out by people who rely on fishing to support their families and other local people. This type of fishing is not fully commercial in nature. The fishing technology may be very sophisticated, but it is not highly dependent on outside sources of capital and materials. |
| ASGISA (Accelerated and Shared Growth Initiative) | A 2004 South African Government initiative to halve poverty and unemployment by 2014. |
| Attenuate | To reduce the force, volume or amount; to make small. |
| Autochthonous | Material produced within a river ecosystem, e.g. algae. |
| Autotroph | An organism that synthesizes organic matter from inorganic material, typically by the process of photosynthesis. |
| Average flow | Medium flow. |
