AbioticNon-living thing. Usually refers to the physical and chemical components of an organism's environment. Also called inorganic.
AbsorptionThe act or process of absorbing or the condition of being absorbed.
AbstractionThe 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.
AccountabilityA principle through which individuals, organisations and the community are responsible for their actions and may be required to explain them to others.
Acid1. Substance having a pH less than 7. (2) Substance that releases hydrogen ions (H+).
Acid mine drainageAcidic 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+).
ActA statute or law made by a legislative body
Administrative UnitThis term can be used to describe a division (town, municipality etc) with administrative powers.
AestheticA term used to describe something of sensory or sensori-emotional value.
AfforestationThe process of planting trees and/or seeds in areas not previously forested.
AfrikaansAn 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 droughtOccurs when there is insufficient water in the soil to grow a particular crop at a particular time.
Agricultural useThe use of water for irrigation purposes.
Agro-meteorologyThe 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.
AgroforestryCombines agriculture and forestry technologies to create more integrated, diverse, productive, profitable, healthy and sustainable land use systems.
AgropastoralismA 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.
AIDSAcquired 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.
AlgaeA simple, photosynthetic plant usually inhabiting moist or aquatic environments.
Algal bloomsA rapidlyi increasing community or presence of algae in an aquatic environment or ecosystem.
Alien speciesA 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-).
AllochthonousMaterial introduced into rivers from terrestrial environments. Examples include leaves or branches from trees that fall into a river.
AlpineHigh altitudes in mountainous environments.
Ambient environmental standardsStandards used to set limits to which levels of environmental resources may be permitted to fall.
AmoebasFreshwater or marine or parasitic protozoa that form temporary pseudopods for feeding and locomotion.
AmphibiansA 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.
AnalogA 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 channelA stream channel, consisting of sediments resistant to erosion, containing numerous smaller channels separated by stable islands.
AngiospermA flowering plant.
AnnelidPhylum of invertebrates that are typically elongated and segmented, including earthworms and leeches.
Annual renewable water resourcesThe average· annual flow of rivers and groundwater generated from endogenous precipitation. Annual averages disguise large seasonal, inter-annual and long-term variations.
AnomalousSomething that deviates from the normal or common order or form or rule.
AnoxicConditions lacking in oxygen.
AnthropogenicOf 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.
AquacultureAll activities aimed at producing in restricted areas, processing and marketing aquatic plants and animals from fresh, brackish or salt waters.
AquaticWith reference to water.
AquiferAn 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 aquiferAquifer whose piezometric surface lies above the ground surface (sometimes used loosely as syn. for confined aquifer).
Artesian wellWell tapping a confined or artesian aquifer in which the static water level stands above the surface of the ground.
Artificial rechargeAugmentation of the natural replenishment of ground- water in aquifers or groundwater reservoirs by supply of water through wells, through spreading or by changing natural conditions.
Artisanal fisheriesSmall-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.
AttenuateTo reduce the force, volume or amount; to make small.
AutochthonousMaterial produced within a river ecosystem, e.g. algae.
AutotrophAn organism that synthesizes organic matter from inorganic material, typically by the process of photosynthesis.


BackscatterBackscatter is the portion of the outgoing radar signal that the target redirects directly back towards the radar antenna.
BacteriaMicroscopic, single-celled prokaryotic organisms.
Bankfull dischargeThe level of flow occurring when water overflows the channel banks and begins to spread onto the floodplain.
BantuThe term Bantu is broadly associated with the cultural and language group originating in west Africa in about 3 000 BC, the descendants of whom migrated east and south throughout sub-Saharan Africa. However, it was also used by the former Apartheid government of South Africa from the 1920s onwards as a term to collectively describe African members of the population. Thus, it has become associated with this period and is generally seen as racially offensive and is generally not accepted in modern society.
BarrageAn artificial obstruction at the mouth of a tidal watercourse.
BasaltA dark colored fine grained igneous rock formed from mafic magma.
BasarwaRefer to hunter-gatherer peoples of southern Africa.
BaseflowPart of the discharge which enters a stream channel mainly from groundwater, but also from lakes and glaciers during long periods when no precipitation or snowmelt occurs.
BaselineConditions prior to change.
BasinA river basin includes the river channel and surrounding drainage area – that is, the land and tributaries that drain precipitation falling within this area to the river.
Basin statesStates that are part of a special river system.
BasothoThe Basotho people have lived in southern Africa since around the fifteenth century. The Basotho nation (modern Lesotho) emerged from the accomplished diplomacy of Moshoeshoe I who gathered together disparate clans of Sotho-Tswana origin that had dispersed across southern Africa in the early 19th century. Most Basotho today live in South Africa.
BedrockRock at or near (beneath soil and regolith) the Earth's surface that is solid and relatively unweathered.
Benefit sharingAn exchange between those who grant access to a particular resource and those who provide compensation or rewards for its use.
BenefitsSomething that aids or promotes well-being. Direct & indirect benefits are gained from ecosystem goods and services.
BenthicOrganisms living in or on aquatic sediments (river or lake bottoms).
BethulieBethulie is a small sheep and cattle farming town in the Free State province of South Africa. The town was also home to one of the largest concentration camps run by the British during the Boer War.
BilharziaA tropical disease spread by parasitic worms living in fresh water, hosted by snails, that can cause rash or itchy skin, fever, chills, muscle aches, and possible damage to the liver, intestines, lungs, and bladder. Also known as schistosomiasis.
BioaccumulationIncrease in concentration of toxic fat-soluble chemicals in organisms at successively higher trophic levels of a grazing food chain or food web because of the consumption of organisms at lower trophic levels.
BioavailabilityAble to be absorbed by a living organism.
BiodiversityRefers to the variety of life on earth. The most widely accepted definition of biodiversity is found in Article 2 of the Convention on Biological Diversity: “Biological diversity means the variability among living organisms from all sources including, inter alia, terrestrial, marine and other aquatic ecosystems and the ecological complexes of which they are part; this includes diversity within species, between species and of ecosystems.”
BiofilmA thin layer of biota—including algae, fungi, bacteria, and other invertebrates—that forms on river and lake substrate.
BiomagnificationA process in which concentrations of certain compounds found in tissues of organisms increase in successive levels of the food chain.
BiomassThe mass of all living and dead organic matter in an ecosystem. In certain contexts, the term ‘biomass’ may also refer only to the mass of living organisms in an environment.
BiomeLargest recognizable assemblage of animals and plants on the Earth. The distribution of the biomes is controlled mainly by climate.
BiophysicalThe biological and physical components of the environment .
BiotaAll plant and animal life in a particular region or area.
BivalveShellfish with two parts to their shell.
Blue waterThe water in rivers, lakes and shallow aquifers. (In the past this has received most of the attention from planners, engineers and policymakers because of its association with established forms of irrigation.)
Bm3Billion cubic metres.
BoerBoer is the Dutch word for farmer which came to denote the descendants of the proto Afrikaans-speaking pastoralists of the eastern Cape frontier in Southern Africa during the 18th century as well as those who left the Cape Colony during the 19th century to settle in the Orange Free State, Transvaal (together known as the Boer Republics) and to a lesser extent Natal. Their primary motivation for leaving the Cape was to escape British rule as well as the constant border wars between the British imperial government and the native tribes on the eastern frontier.
BoreholeGroundwater well drilled or dug into the ground for exploration for water or abstraction of water.
Brak RiverThe river in the Western Cape Province of South Africa.
BreadbasketA geographic region serving as a principle source of grain supply.
Bulk Transfer (of water)The removal and transfer of water out of its basin of origin by man-made diversions, tanker ships or trucks, and pipelines.
BuoyantFloats on water.
BushmenOne of the major tribal groups of the Orange-Senqu River basin.


Capacity developmentThe process whereby people, organisations and society as a whole unleash, strengthen, create, adapt and maintain capacity over time OECD (2006).
Cape of Good HopeA rocky headland on the Atlantic coast of South Africa. There is a very common misconception that the Cape of Good Hope is the southern tip of Africa and the dividing point between the Atlantic and Indian Oceans, but in fact the southernmost point is Cape Agulhas, about 150 kilometres (90 mi) to the southeast. However, when following the coastline from the equator, the Cape of Good Hope marks the psychologically important point where one begins to travel more eastward than southward. Thus the rounding of the cape in 1488 was a major milestone in the attempts by the Portuguese to establish direct trade relations with the Far East.
Carbon DioxideChemical formula: CO2. It is a gas at standard temperature and pressure and exists in Earth's atmosphere in this state. Carbon dioxide is used by plants during photosynthesis. It is produced during respiration by plants, and by all animals.
CarcinogenicA substance that can result in the development of a cancer.
CarnivoreOrganisms that feed on other animals.
Carrying capacityThe extent to which an ecosystem or resource can withstand pressure from external forces such as degradation, climate variability, development and internal use.
Cascade interactionOccurs when one group of organisms indirectly affects another group by feeding on the animals that would have eaten them.
Cash CropsIn agriculture, a cash crop is a crop which is grown for money. The term is used to differentiate from subsistence crops, which are those fed to the producer's own livestock or grown as food for the producer's family.
CatchmentA catchment includes the river channel and surrounding drainage area – that is, the land and tributaries that drain precipitation falling within this area to the river.
Catchment management agenciesAgencies responsible for implementing the best principles for integrated water management such as the integration of surface and groundwater management, public participation and community involvement and self-financing of water management groups by user groups (van Koppen et al 2005).
Child MortalityAlso known as "under-5 mortality" it refers to the probability that a child will die before the age of 5.
CholeraAn infectious gastroenteritis ailment caused by the ingestion of the bacterium Vibrio cholerae.
Chromic vertisolsA vertisol is a soil with a high content of expansive clay that forms deep cracks in drier seasons; chromic refers to a chroma (colour intensity) 1.5 or above as opposed to pellic.
Chronic PovertyChronic poverty is poverty that is experienced over an extended period of time.
ClayeyResembling or containing clay.
ClimateThe long - term average of weather in a particular region.
Climate Change Climate change as referred to in the observational record of climate occurs because of internal changes within the climate system or in the interaction between its components, or because of changes in external forcing either for natural reasons or because of human activities.
Climate classificationSee Köppen climate classification.
Climate variabilityChanges in climate around the globe over time. The term climate variability is often used to denote deviations of climate statistics over a given period of time (such as a specific month, season or year) from the long-term climate statistics relating to the corresponding calendar period.
Climatic patternsA reccuring characteristic of the climate.
ClimaxDescribes a state of balance that is reached through ecological succession (development and change in composition of vegetation communities in an area over time).
ClimeSynonym of Climate
Coefficient of VariationStatistical parameter describing the change of a stochastic variable in time or space, expressed as the ratio of the standard deviation to the mean. (Dimensionless)
CollectorsConsume fine to very fine organic particles suspended in the water (filtering collectors or filter-feeders) or deposited on the stream bed (collector-gatherers).
ColouredsIn the South African, Namibian, Zambian, Botswana and Zimbabwean context, the term "Coloured" (also known as Bruinmense, Kleurlinge or Bruin Afrikaners in Afrikaans) refers or referred to an ethnic group of mixed-race people who possess some sub-Saharan African ancestry.
CommercialNon-governmental, pertaining to a business.
Commodity pricesThe price of something for which there is demand, but which is supplied without qualitative differentiation across a market.
Common pool resourceA resource from which it is not feasible to exclude users, and for which consumption is subtractive. Incentives to improve individual welfare by overusing common pool resources can lead to depletion of the resource for all. An example of a common pool resource is a common grazing pasture or an unregulated lake fishery.
Common property resourcesRenewable natural resources with the characteristics of a common pool resource (i.e., subtractive consumption, difficult to exclude users) but to which access is controlled in some manner, typically by the group or unit that manages the resource.
Community Based Natural Resource ManagementBoth a conservation and rural development strategy, involving community mobilisation and organisation, institutional development, comprehensive training, enterprise development, and monitoring of the natural resource base by local communities.
CompactAn agreement, treaty, or contract. The term compact is most often applied to agreements among states or between nations on matters in which they have a common concern.
Comparative advantageA country has a comparative advantage over another if in producing a commodity it can do so at a relatively lower opportunity cost in terms of the forgone alternative commodities that could be produced.
Compulsory licensingCompulsory licensing is a mechanism created in the South Africa National Water Act to allow DWAF to review all the water use in an area to ensure that there is equal opportunity to apply to use water, water is shared fairly and used efficiently and water is kept clean and unpolluted.
Confined AquiferAquifer overlain and underlain by an impervious or almost impervious formation.
ConservationThe protection, maintenance, rehabilitation, restoration and enhancement of natural resources and includes the management of the use of natural resources to ensure the sustainability of such use.
ConsumersAn organism that feeds on other organisms or dead organic matter; see also heterotroph.
ContouringA system of planting row crops perpendicular to the natural slope to reduce soil erosion, protect soil fertility and use water more efficiently.
ConurbationWhen a number of cities, large towns and larger urban areas merge to form one continuous urban area through population growth and physical expansion.
Convective rainfallThe formation of precipitation due to surface heating of the air at the ground surface. With sufficient heating, the mass of air becomes warmer and lighter than the air in the surrounding environment, and begins to rise, expand and cool. Saturation occurs after sufficient cooling, and leads to precipitation.
Convention on Biological Diversity (CBD)An agreement signed by 150 world leaders at the 1992 Earth Summit in Rio de Janeiro. The goals of the CBD include the conservation of biodiversity, the sustainable use of its components, and the fair and equitable sharing of the benefits from genetic resources.
Conveyance lossesWater evaporation and seepage from surface water sources and man-made water transportation facilities, such as irrigation channels.
Cost recoveryThe extent to which users are charged for goods and/or services to generate revenue to cover the costs of provision.
Critically endangeredFacing an extremely high risk of extinction in the wild.
CultivatedTo prepare and use the land for growing crops.
CultivationPreparation and use of land for growing specifically agricultural crops in an organised system. Often requires irrigation, land management practices and the introduction of fertilisers.
Cultural diversityA result of cultural adaptations and livelihoods that are created through linkages between languages, social systems, customs knowledge systems, local histories and interaction with the environment.
CumulonimbusAn extremely dense, vertically developed cumulus with a relatively hazy outline and a glaciated top extending to great heights, usually producing heavy rains, thunderstorms, or hailstorms.
CumulusA dense, white, fluffy, flat-based cloud with a multiple rounded top and a well-defined outline, usually formed by the ascent of thermally unstable air masses.
CuneneThe Cunene River (Angolan spelling) or Kunene River (Namibian spelling) is a river in Southern Africa.
Customary lawTraditional common rule or practice that has become an intrinsic part of the accepted and expected conduct in a community, profession, or trade and is treated as a legal requirement.
CuvelaiA river in Southern Africa.
CyanobacteriaA large and diverse group of bacteria capable of photosynthesis. Also known as blue-green algae.


DamA barrier or structure across a stream, river, or waterway for the purpose of confining and controlling the flow of water.
DamaraOne of the major tribal groups of Namibia. They speak the Damara dialect of Nama.
DecadeA range of 10-years time-period.
DecentralisedThe process of dispersing decision-making governance closer to the people or citizen. It includes the dispersal of administration or governance in sectors or areas like engineering, management science, political science, political economy, sociology and economics.
DeforestationThe conversion of forested area to non-forested area through the removal of trees.
DegradationA process through which the natural environment is compromised in some way, reducing biological diversity and the general health of the environment.
DeltaLarge deposit of alluvial sediment located at the mouth of a stream where it enters a body of standing water.
DemocracyA form of government where the population of a society or country controls the government through a process where ministers and leaders are elected through free and fair elections.
DenitrificationThe reduction of nitrates to nitrites, nitric oxide, nitrous oxide and eventually dinitrogen by microorganisms.
Deposit-feedersAquatic animals that consume fine particles of organic matter found on and within the bottom sediments.
DesertificationThe increase of desert-like conditions caused by degradation on arid, semi-arid and subhumid lands.
DetritivoresOrganisms that consume dead organic matter.
DetritusDead organic matter; the particulate remains of dead plants and animals.
DevelopmentThe process of improving the quality of all human lives. Important aspects of development are raising people's living levels, creating conditions conducive to the growth of people's self-esteem and increasing people's freedom of choice.
DiarrhoeaA condition resulting in frequent, watery, or loose bowel movements.
DiatomA photosynthetic, single-celled organism enclosed in a shell of silica.
DifequaneOr difaqane. A time of immense upheaval relating to the military expansion of the Zulu kingdom in the early 19th century. Sotho-speakers know this period as the difaqane ("forced migration"); while Zulu-speakers call it the mfecane ("crushing").
Digital Elevation Model (DEM)Representation of elevation as a raster grid of regularly spaced elevation values. These grids can be directly computed (derived) from other elevation information such as contours, topographic maps, and irregularly spaced spot heights or from satellite images.
Direct use valueThe value obtained from raw materials and physical products yielded by ecosystems and their component species.
DischargeVolume of water flowing through a river (or channel) cross-section in unit time. (TR)
Discharge standardsStandards used to define the maximum acceptable quantity of pollutants that may be discharged into the area from emissions and effluents.
DiurnalExhibiting a daily cycle, e.g. over one day and one night.
DODissolved Oxygen
DoleriteA dark, fine-grained igneous rock
Domestic useMeans use of water for drinking, washing, cooking, bathing, sanitation and stock watering purposes.
DongasA gully in a veldt.
DownstreamAt a point further along the river in the direction of the flow or current.
DrainageThe removal of water from an area through natural or artificial processes.
Drakensberg MountainsThe highest mountain range in Southern Africa, rising to 3,482 metres in height.
DredgingThe removal of sediment and other material from the bottom of waterbodies by a machine equipped with a scoop or suction device. Dredging is often undertaken to maintain sufficient water depth for navigation.
Drivers (or Stressors)The physical, chemical and biological variables that influence response indicators and the overall health of the aquatic ecosystem.
DroughtProlonged absence or marked deficiency of precipitation.
Drought relief rationsRations (food and water) distributed to those affected by drought.
Dry land cultivationAgricultural techniques used to cultivate land that receives little rainfall.
Dublin PrinciplesDeveloped at the International Conference on Water and the Environment, held in Dublin Ireland in January 1992. The four guiding principles for managing freshwater resources contained within the Duplin Principles are (IRC 2006): (1) Freshwater is a finite and vulnerable resource, essential to sustain life, development and the environment; (2) Water development and management should be based on a participatory approach, involving users, planners and policy-makers at all levels; (3) Women play a central part in the provision, management, and safeguarding of water; (4) Water has an economic value in all its competing uses, and should be recognised as an economic good
DWADepartment of Water Affairs
DWAFDepartment of Water Affairs and Forestry (South Africa)
DWEADepartment of Water and Environmental Affairs - South Africa. Formerly known as the Department of Water Affairs and Forestry (DWAF). Part of the Ministry of Water and Environmental Affairs. The name of this Department change from DWAF to DWEA in 2009.
Dwell timeThe period during which a dynamic process remains halted in order that another process may occur.
DysenteryParasitic infection of the intestines, which left untreated can be fatal.


Earth Observation (EO)EO is the study of Earth and its changing environment by observing the atmosphere, oceans, and land through remote sensing technologies.
ECEuropean Commission
Eco-tourismDefined as tourism that is sustainable and environmentally and culturally sensitive, is a subset of nature-based tourism (Wood 2002; Scholes and Biggs 2004).
Ecological Flow Requirements (EFR)The water flow requirements needed to maintain the riverine ecology, recharge riverine aquifers and maintain the river channel.
Ecological integrityA condition that is determined to be characteristic of its natural region and likely to persist, including abiotic components and the composition and abundance of native species and biological communities, rates of change and supporting processes. (Canada National Parks Act 2000)
Ecological reserveRelates to the water reserved to protect and sustain the aquatic ecosystems in order to secure ecologically sustainable development and water use.
EcologyThe scientific study of: 1) the interactions or relationships between organisms and their environment, 2) the interactions that determine the distribution and abundance of organisms.
Economic cooperationTwo or more countries working together to promote their common economic interests through joint projects and programmes, physical or otherwise.
Economic efficiencyUsing of resources in such a way as to maximize the production of goods and services.
Economic goodA scarce resource that is limited in quantities in comparison to the demand for the resource. Treating water as an economic good recognises that water has an opportunity cost.
Economic growthThe steady process by which the productive capacity of the economy is increased over time to bring about rising levels of national output and income.
Economic integrationThe merging to varying degrees of the economies and economic policies of two or more countries in a given region.
Economic Water ScarcityA term used to describe lack of access to water, not from physical shortages, but the economic means to sustainably provide water in sufficient quantity and/or quality.
EcoregionA region characterized by distinctive regional ecological factors, including climate, physiography, vegetation, soil, water and fauna.
EcosystemGroups and communities of organisms (animals, plants, insects and micro-organisms) that form one functioning unit. It also includes all of the non-living physical and chemical factors of the environment that maintain its existence, linked together through nutrient cycling and energy flow.
Ecosystem diversityRefers to the variety of identifiable ecosystems in which organisms live.
Ecosystem goods & servicesBenefits derived from ecosystems. Goods provided by ecosystems are usually more tangible benefits such as food products, fuel wood, drinking water or timber. Ecosystem services are usually enabling benefits that people obtain from ecosystems and include provisioning services; regulating services; supporting services; and cultural services.
Ecosystem healthA concept that uses a systematic approach to the preventative, diagnostic, and prognostic aspects of ecosystem management, and to the understanding of relationships between ecosystem health and human health. It seeks to understand and optimize the intrinsic capacity of an ecosystem for self-renewal while meeting reasonable human goals. It encompasses the role of societal values, attitudes and goals in shaping our conception of health at human and ecosystem scales (University of Western Ontario’s Ecosystem Health group).
Ecosystem servicesThe goods (tangible resources) and services (functions) provided by an ecosystem.
EcotoneAn area of transition or overlap between two habitat types.
EcozoneLargest scale of biogeographical division. WWF use 8 primary ecozones: 1. Nearctic; 2. Palearctic; 3. Afrotropic; 4. Indo-Malaya; 5. Australasia; 6. Neotropic; 7. Oceania; 8.Antarctic
EffluentAn outflow of liquid waste released from a facility such as a sewage treatment plant or industrial operation.
EFREnvironmental Flow Requirement
El NinoName given to the occasional development of warm ocean surface waters along the coast of Ecuador and Peru. When this warming occurs the tropical Pacific trade winds weaken and the usual upwelling of cold, nutrient rich deep ocean water off the coast of Ecuador and Peru is reduced. The El Nino normally occurs around Christmas and lasts usually for a few weeks to a few months. Sometimes an extremely warm event can develop that lasts for much longer time periods.
Electrical Conductivity (EC)A physical characteristic of water used to indicate the level of Total Dissolved Solids in water; the level of electrical conductivity is proportional to the amount of dissolved solids found in the water.
EndangeredFacing a very high risk of extinction in the wild.
EndemicOccurring naturally in only one specific area.
EndemismAn organism being endemic - exclusively native to a particular location.
Endocrine disruptersSubstances that act like hormones in the endocrine system and disrupt the physiologic function of hormones.
Endorheic or MekgachaDraining into interior basins.
ENSOEl Nino Southern Oscillation (ENSO). Name given to the occasional development of warm ocean surface waters along the coast of Ecuador and Peru. When this warming occurs the tropical Pacific trade winds weaken and the usual upwelling of cold, nutrient rich deep ocean water off the coast of Ecuador and Peru is reduced. The El Nino normally occurs around Christmas and lasts usually for a few weeks to a few months. Sometimes an extremely warm event can develop that lasts for much longer time periods.
Environmental Education and Awareness (EE&A)A process designed to increase public awareness and understanding of the community of interest and the common ecospace that the Nile River creates.
Environmental Effects MonitoringThe repetitive and systematic measurement of environmental components to test specific hypotheses regarding the effects of human activity on the environment.
Environmental flow requirementThe water that is deliberately left in the river or released from a reservoir for maintaining the structure and function of aquatic ecosystems downstream.
Environmental Impact AssessmentA procedure that examines the possible environmental consequences of implementing a project, program, or policy.
Environmental managementThe management of human interaction with and impact on the natural environment. Environmental management is concerned with the links between the natural world and human social, cultural, and economic systems.
Environmental management planA plan outlining the means of achieving environmental objectives and goals.
Environmental Mitigation Compliance MonitoringMonitoring conducted to determine whether specified environmental mitigation measures are being implemented properly and are having the intended effect.
Environmental monitoringThe collection of systematic, geo-referenced observations of the environment to detect changes over time and space.
EphemeralStream which flows only in direct response to precipitation or to the flow of an intermittent spring.
EpililoBaskets woven from palm leaves in Namibia.
EpisodicTerm used to describe rainfall that occurs in single or multiple events, with no distinct pattern.
Equatorial Lakes PlateauAn elevated plateau bounded by two branches of the Rift Valley.
EquityThe equity dimension of governance seeks to ensure that development is inclusive, that all people benefit from well-functioning political and economic institutions and political, economic and social processes .
ErosionThe wearing away, detachment, and movement of surface materials by forces of wind, water, or ice.
EstuariesSomewhat enclosed coastal areas at the mouths of a river where nutrient rich fresh water meets with salty ocean water.
EstuarineSomewhat enclosed coastal area at the mouth of some rivers, where nutrient rich fresh water meets with salty ocean water.
EstuarySomewhat enclosed coastal area at the mouth of a river where nutrient rich fresh water meets with salty ocean water.
EtitiTraditional clay pot in Namibia.
EutrophicAn aquatic environment that has an excessive supply of nutrients, mostly in the form of nitrates and phosphates.
EutrophicationThe accumulation of nutrients in a waterbody that results in excessive growth of organisms and depletion of oxygen.
EvaporationThe conversion of a liquid substance to a gaseous state.
EvapotranspirationThe loss of water to the atmosphere via the combined effects of evaporation and transpiration.
ExcludabilityRefers to the possibility of controlling access to a natural resource or service.
ExoenzymesAn enzyme secreted by a cell that functions outside of the cell it originated from.
ExploitationThe improper or over use of a resource.
ExtinctNo longer in existence.


FanagoloFanagalo (or Fanakalo) is a pidgin (simplified language) based on the Zulu, English, and Afrikaans languages. It is used mainly in the gold, diamond, coal and copper mining industries in South Africa
FAOThe Food and Agriculture Organization of the United Nations (FAO) is a specialised agency of the United Nations that leads international efforts to defeat hunger.
FaultA fracture in rock caused by stress.
FaunaAnimal life. The fauna of an ecosystem is all of the animal life found in that ecosystem.
FDCFlow Duration Curve
FecundityThe number of offspring produced by an organism.
FeedlotsA plot of ground on which livestock are fattened for market.
FertilizerAn inorganic or organic substance that adds nutrients to soil for the purpose of increasing the growth of crops, trees, or other vegetation.
FillingAdding to and building up with material such as soil or gravel.
Fiscal policiesThe use of government spending and taxing powers to affect the behaviour of the economy.
Fitness for usea method of rating water as fit for different use cases.
FloodplainNearly level land along a stream flooded only when the streamflow exceeds the water carrying capacity of the channel.
FloraPlant life. The flora of an ecosystem is all of the plant life found in that ecosystem.
FlorisbadThe Florisbad archaeological and paleontological site is a provincial heritage site in Brandfort in the Free State province of South Africa.
Fodder cropsCrops grown primarily for animal feed.
Food chainA model describing the idea that organisms are dependent upon others for food and are linked to each other by this dependence.
Food securityWhen all people, at all times, have physical and economic access to sufficient, safe and nutritious food to meet their dietary needs and food preferences for an active and healthy life (FAO, 2004).
Food webA conceptual diagram that represents the feeding relationships of organisms within an ecosystem. It consists of a series of interconnected food chains.
FootprintFootprint is an abstract term used to present an area of influence or impact from a specific activity or phenomena.
Foreign policyA set of goals outlining how the country will interact with other countries economically, politically, socially and militarily, and to a lesser extent, how the country will interact with non-state actors.
FormationA geological formation is the fundamental unit of lithostratigraphy, used to describe rock strata that have a comparable lithology, facies or other similar properties.
Fossil RiverA river bed that no longer has water flowing in it.
FractureCrack or linear break in a rock formation.
FrameworkBasic conceptual structure used to solve or address complex issues
FreshwaterNaturally occurring water on the Earth's surface in bogs, ponds, lakes, rivers and streams, and groundwater in aquifers and underground streams. Freshwater is characterized by having low concentrations of dissolved salts and other total dissolved solids. The term specifically excludes seawater and brackish water.
Frontal rainfallPrecipitation resulting from the convergence of two air masses. Also known as convergence rainfall.
FungiA eukaryotic, multicellular organism that functions as a primary decomposer of dead plants and animals.


GastroenteritisAn infection or irrigation of the gastro-intestinal tract (stomach and small intestines). Usually caused by a virus, bacteria, toxins, parasites or allergy.
GastropodsUnivalve or class of mollusks typically having a one-piece coiled shell and flattened muscular foot with a head bearing stalked eyes.
GenderThe socially and culturally constructed roles, privileges, responsibilities, power and influence, social relations, expectations and value of men and women, girls and boys. There are significant differences in what women and men can or cannot do in one society when compared to another. In all cultures, the roles of women and men are distinct, as are their access to productive resources and their authority to make decisions. Typically, in most cases, men are held responsible for the productive activities outside the home, while the domain of women is the reproductive and productive activities within the home. In most societies, women have limited access to income, land, credit, education, limited ownership and control over these resources.
Gender mainstreamingDefined by the United Nations as the: process of assessing the implications for women and men of any planned action, including legislation, policies and programmes, in any area and at different levels. It is a strategy for making women's as well as men's concerns and experiences an integral dimension in the design, implementation, monitoring and evaluation of policies and programmes, in all political, economic and societal spheres so that women and men benefit equality, and inequality is not perpetuated. The ultimate goal is to achieve gender equality.
General Circulation Model (GCM)Models that simulate complex processes in the atmosphere, including the impacts of climate change from future increases in green house gas emissions. GCMs provide a global overview and need to be downscalled for use at regional or local levels.
Genetic diversityRefers to variety in genes or gene pools that exists within a species.
Genetic resource ownershipThe debated issue of the ownership of any plant, animal, or microbial material that contains functioning genes that could be of actual or potential value
Geographic Information System (GIS)Computer-based system for capturing, storing, checking, integrating, analysing and displaying geographic data.
GeographyThe study natural and human constructed phenomena relative to a spatial dimension.
GeohydrologyThat branch of hydrology which deals with groundwater, taking into account the geological conditions.
GeologyThe field of knowledge that studies the origin, structure, chemical composition, and history of the Earth and other planets.
GeomorphologyThe field of knowledge that investigates the origin of landforms on the Earth and other planets.
GHGGreenhouse Gas
GiardiaA genus of flagellated protozoan parasites of the phylum Metamonada that colonise and reproduce in the small intestines of vertebrates,
Gini coefficientA measure of inequality of income distribution measured in a ration with values between 0 and 1. A low Gini coefficient corresponds to a more equal distribution of wealth. The Gini Index is the Gini coefficient expressed as a percentage.
Global Information and Early Warning System (GIEWS)The Global Information and Early Warning System (GIEWS) of the United Nations Food and Agricultural Organization (FAO) was established in 1975. The System has been assigned the mandate of constantly monitoring the global food supply and demand situation and alerting the international community to countries or regions threatened by serious food shortages or which have exceptional localised or exportable surpluses of food available for donor purchases and distribution to deficit areas.
Global Land Cover Network (GLCN)The Food and Agriculture Organization of the United Nations (FAO) and United Nations Environment Programme (UNEP) have launched the Global Land Cover Network (GLCN) with the objective to improve the availability of global information on land cover and its dynamics, harmonizing land cover mapping and monitoring at national, regional and global levels.
GMOGenetically Modified Organism
Go thunyaA term used for both "bloom" and "explode" in the Setswana language
Gofethla pulaRainmaking Rites in Botswana.
GovernanceThe way that decisions are made in towns, cities, provinces, and countries. For those in government, it is the exercise of authority to manage the affairs of a constituency. While the government normally has the final say when it comes to public policies, programs, laws, and regulations, it is not the only player. Citizens, civil society organizations, and the private sector also have a role to play .
Governance IndicatorsA set of indicators used to measure the performance of a country or organization with respect to its adherence to the principles of good governance – Voice and Accountability; Political Stability and the Absence of Violence; Government Effectiveness; Regulatory Quality; Rule of Law; and Control of Corruption.
GovernmentThe system of governing (democratic, socialist, etc.) and the structure and arrangement of the government office. The government of a nation usually consists of three sets of power, namely the legislature, the executive, and the judiciary.
GrainCereal grasses.
GrasslandsEcosystem whose dominant species are various types of grass. Found in regions where average precipitation is not great enough to support the growth of shrublands or forest.
Grazer-scraperAnimals that graze the organic layer of algae, microorganisms and associated organic matter on stone and other substrates in streams; includes species which pierce plant cells and suck out the fluids.
Green waterWater in unsaturated soil; it is responsible for the production of biomass that accounts for 60% of the world food production.
Grey WaterAny household wastewater with the exception of wastewater from toilets, which is known as blackwater.
Gross Domestic Product (GDP)The total market value of all goods and services produced in a country in a given year. GDP is measured by: total consumer, investment and government spending, plus the value of exports minus the value of imports .
Gross Geographic Product (GGP)A particular area amounts to the total income or payment received by the production factors – (land, labour, capital, and entrepreneurship) – for their participation in the production within that area.
Gross productionTotal production of organic matter in a given area per unit time.
GroundwaterThe water that fills the pore spaces in soil, sand, gravel and in fractures and openings in the rocks (referred together as ‘formation’) below the surface. The portion of the formation that is filled with groundwater is known as the ‘Aquifer’.
Groundwater dischargeThe volumetric flow rate of groundwater through an aquifer.
Groundwater servicesSystems that include underground water reservoirs in order to provide groundwater for supply.
GroupTerm used to describe two or more continguous or associated geological formations.


Hadley cell circulationThe generalized circuit of air mass movement occurring between the equator and 30° latitude (north and south of the equator). The Hadley cell circulation is characterized by rising air masses at the equator and descending air masses at approximately 30º north and south latitude.
Hard waterWater in which relatively high amounts of minerals, mainly of calcium and magnesium salts, are dissolved.
HardnessWater in which relatively high amounts of minerals, mainly of calcium and magnesium salts, are dissolved.
HDIThe Human Development Index (HDI) measures human development by combining three dimensions of development: longevity (life expectancy at birth), knowledge (adult literacy and mean years of schooling), and income (UNDP HDR 2008).
Heavy MetalsIncludes cadmium, copper, nickel, zinc, chromium, arsenic, mercury, lead; are persistent in the environment and can bio-accumulated in aquatic organisms.
HepatitisInflammation of the liver caused by a viral infection.
HerbivoreAn animal that consumes living plants or their parts.
HereroOne of the major tribal groups of the Orange-Senqu River basin.
HeterotrophAn organism that requires organic molecules as a source of energy and nutrients because it is unable to manufacture their own food using the sun’s energy.
HibernateA period of biological rest that some animal species use to conserve energy during winter months.
HimbaOne of the major tribal groups of the Orange-Senqu River basin.
HIVHuman Immuno-deficiency Virus (HIV) is the retrovirus that attacks the human immune system resulting in AIDS. It is transmitted through direct contact of a mucous membrane with a bodily fluid containing HIV. This transmission can come in the form sexual contact; blood transfusion; contaminated needles; exchange between mother and infant during pregnancy, childbirth, or breastfeeding; or other exposure to one of the above bodily fluids.
Homo SapiensThe modern species of humans, the species to which all living humans belong. The Latin meaning, ‘wise man’ reflects the greater endowment of the brain power compared to his predecessors. The species is defined in terms of anatomy, and the first member of the species is recognized from about 150 000 years ago.
HorizonA layer of soil with physical and chemical properties distinct from layers above and below.
HotspotAn area of extraordinarily high biodiversity.
Human DevelopmentA complex concept of development, based on the priority of human well-being, and aimed at ensuring and enlarging human choices which lead to equality of opportunities for all people in society and empowerment of people so that they participate in - and benefit from - the development process.
Human Development IndexA composite index developed to measure progress in Human Development (above) through three basic components of human development: longevity, knowledge and standard of living.
HumidityA general term used to describe the amount of water vapor found in the atmosphere.
HusbandryThe agricultural practice of breeding or raising livestock.
Hydroelectric Power GenerationThe conversion of the flow of water into electricity.
HydrographGraph showing the variation in time of some hydrological data such as stage, discharge, velocity, sediment load, etc. (hydrograph is mostly used for stage or discharge) .
Hydrologic cycleRefers to the cycling of water from the ocean to the land and back again, including all the pathways and processes connected with the storage and movement of water in solid, liquid, and gaseous states.
Hydrological droughtOccurs when the surface and ground water resources are in a below average depleted state for a prolonged period, usually in response to below average rainfall.
Hydrological regimeThe long - term history of flow levels in a river.
Hydrology(1) Science that deals with the waters above and below the land surfaces of the Earth, their occurrence, circulation and distribution, both in time and space, their biological, chemical and physical properties, their reaction with their environment, including their relation to living beings. (2) Science that deals with the processes governing the depletion and replenishment of the water resources of the land areas of the Earth, and treats the various phases of the hydrological cycle.
HypertrophicAn acute concentration of nutrients.
HyphaeLong, thread-like branching filament found on fungus.
HyphomycetesA class of fungi.


ICPDRInternational Commission for the Protection of the Danube River
IgneousA rock which originates as molten magma from benearth the earth's surface.
ImageThe representation of an object produced by the reflection or refraction of light when focused by a lens or mirror. An image is the recorded representation (commonly as a photo-image) of an object produced by optical, electro-optical, optical mechanical, or electronic means. It is generally used when the electromagnetic radiation is emitted or reflected from a scene is not directly recorded on film. In remote sensing and GIS, image is a term that describes digital representations of earth features.
ImpermeableHaving a texture that does not permit water to move through it perceptibly under static pressure ordinarily found in subsurface water. (IGH)
ImperviousIncapable of being penetrated.
ImpoundmentThe process of restraining flow of a river to create a body of water using a dam or other physical barrier.
Improved Drinking Water SupplyA type of drinking water facility or water delivery point that by the nature of its design protects the drinking water source from external contamination, particularly of faecal origin.
IMSInformation Management System
Incised riverAn incised river channel is one that cuts deeply into the landscape.
IncomatiThe one of the several international river basins shared by southern African countries.
IndicatorA value or state used to determine and/or describe the condition of a system.
IndigenousNaturally occurring in or native to a specific place.
Indigenous knowledgeThe long-standing traditions, practices, wisdom, teachings and knowledge of local or indigenous communities (See traditional knowledge).
Indirect use valueValue arising from ecosystem functions that support and maintain human activity. The value obtained from the flood regulation services of a wetland is an example of indirect use value.
Industrial useUse of water for commercial, electrical power generation, industrial, manufacturing and mining purposes.
InfiltrationThe movement of surface water into soil or rock through cracks and pores.
Information systemA system consisting of the network of all communication channels used within an organization or group of people.
InfrastructureInfrastructure can be defined as the basic physical and organizational structures needed for the operation of a society or enterprise, or the services and facilities necessary for an economy to function. The term typically refers to the technical structures that support a society, such as roads, water supply, sewers, power grids, telecommunications, and so forth.
Infrastructure assetsInfrastructure assets are installations and services such as roads, water supply, sewage systems, power supply, flood management, leisure facilities, etc. Investment in these assets is made with the intention that dividends will accrue through increased productivity, improved living conditions and greater prosperity.
InsectAn invertebrate animal of the Class Insecta. Insects comprise the most diverse group of animals on earth.
Instream Flow Requirements (EFR)The water that is deliberately left in the river or released from a reservoir for maintaining the structure and function of aquatic ecosystems downstream.
Integrated Water Resources Management (IWRM)A process which promotes the coordinated development and management of water, land and related resources, in order to maximise the resultant economic and social welfare in an equitable manner without compromising the sustainability of vital ecosystems.
Intellectual property rightsLegal property rights over creations of the mind such as music, literature, ideas and symbols.
International Council for Science (ICSU)The International Council for Science (ICSU), formerly called the International Council of Scientific Unions, was founded in 1931 as an international non-governmental organization devoted to international co-operation in the advancement of science.
Intertropical Convergence Zone (ITCZ)Zone of rising air masses and low atmospheric pressure located at or near the equator. Rising air currents result from global wind convergence (trade winds) and convection from thermal heating.
InvasiveA species that heavily colonises a certain habitat.
InvertebrateAnimal that does not have a backbone. Also see vertebrate.
IonAn atom, molecule or compound that carries either a positive (cation) or negative (anion) electrical charge.
IRBMIntegrated River Basin Management
Irrigated AgricultureAgriculture that depends on irrigation to provide sufficient water for successful and often economic production of a crop.
IrrigationThe artificial application of water to the soil usually used to assist in growing crops in dry areas and during periods of inadequate rainfall.
ISO 14001ISO 14001 is a standard for environmental management systems to be implemented in any business, regardless of size, location or income. The aim of the standard is to reduce the environmental footprint of a business and to decrease the pollution and waste a business produces.
ITCZIntertropical Convergence Zone
IWRInstitute for Water Resources, South Africa
IWRMIntegrated Water Resource Management


Joint consumptionConsumption that is non-subtractable; that is, use of a natural resource or service that does not affect the amount or quality of the resource available for other users.


Kalanga(Or Bakalanga) is a tribe found in the entire Northeast District and the eastern third of Central District in Botswana. They are also found in Southwest of Bulawayo and along the Botswana border. Speak kalanga - one of the Bantu languages.
KarooidOf the Karoo - a word from Khoisan used to describe a semi-desert region of South Africa.
KgalagadiThe same as "Kalahari" Desert - a large, arid desert area in southwestern Sub-Saharan Africa extending 900,000 km², covering much of Botswana and parts of Namibia. "Kgalagadi Transfrontier Park" is a large wildlife preserve and conservation area in southern Africa. The park straddles the border between South Africa and Botswana. Also: The other main ethnic identity besides Tswana within southeastern Botswana.
Kgalagadi Transfrontier ParkThe Kalahari Gemsbok National Park in South Africa and the Gemsbok National Park in Botswana were combined to form this impressively large park of over 3,6 million hectares.
KhettaraSubsurface irrigation channels
KhoikhoiThe Khoikhoi ("people people" or "real people") or Khoi, (in standardised Khoekhoe/Nama orthography spelled Khoekhoe), are a historical division of the Khoisan ethnic group, the native people of southwestern Africa, closely related to the Bushmen
KhoisanLanguages indigenous to southern and eastern Africa.
Knowledge systemsThe organised assembly of knowledge.
Köppen Climate ClassificationSystem that uses monthly precipitation and temperature data and total annual precipitation data to classify a location's climate into one of five main categories: Tropical Moist Climates; Dry Climates; Moist Mid-latitude Climates with Mild Winters; Moist Mid-Latitude Climates with Cold Winters; and Polar Climates. These categories are further divided into number of subcategories. First developed in 1918 by German biologist W. Köppen, this system has undergone a number of modifications.


La NinaCondition opposite of an El Nino. In a La Nina, the tropical Pacific trade winds become very strong and an abnormal accumulation of cold water occurs in the central and eastern Pacific Ocean.
LakeInland body of water of considerable size.
Land TenureThe legal regime in which land is owned by an individual. The individual is said to 'hold' the land.
Landsat Satellite (Landsat)Oldest and most well known satellite of its kind, the first satellite in the Landsat series was launched in 1972. Subsequent satellites, with new and improved sensor technology (e.g., Thamatic Mapper) and an almost continuous data collection stream, have made Landsat the most successful civilian Earth observation program to-date.
LavaMolten magma released from a volcanic vent or fissure.
LegislationLaw that has been enacted by a governing body.
LenticelsA porous area on the surface of bark and certain fruits that allow for the exchange of gasses between inside and outside the plant.
LeveeA raised bank, natural or man-made, that contains the water within a river channel. Natural levees are formed by the deposition of sediments during floods.
LimpopoThe second largest river in southern Africa.
LithosolsA shallow soil showing minimal profile development and dominated by the presence of weathering rock and rock fragments. Lacking horizons other than an A1 (one layer only) (GSG Classification).
LithostratigraphicRelated to the geological discipline associated with the study of rock strata and formation.
LivelihoodCombination of the resources used and the activities undertaken in order to live. Resources consist of individual skills and abilities (human capital), land, savings and equipment (natural, financial and physical capital, respectively) and formal support groups or informal networks that assist in the activities being undertaken (social capital).
LivestockDomesticated animals, that may be kept or raised in pens, houses, pastures, or on farms as part of an agricultural or farming operation, whether for commerce or private use.
Low income countryGross national income per capita of USD $935 or less.
Lower basin statesCountries situated downstream or in the region of the mouth of a river.
Lower course of a riverThe lower course of a river corresponds to the region close to its mouth.
Lower KuneneThe lower portion of the Kunene catchment, the portion of the river closest to the mouth.
LüderitzA harbour town in southern Namibia.


MacrophyteA plant that can be seen with the unaided eye.
MalariaA disease causing parasitic infection of red blood cells and resulting in severe chills, fever, sweating, and sometimes coma or death. Malaria is caused by a protozoan parasite of the genus Plasmodium, and is transmitted to humans by an infected female Anopheles mosquito.
MammalA warm-blooded vertebrate animal characterized by hair on the skin and milk-producing mammary glands in females.
Management of a shared watercourse(i) Planning the sustainable development of a shared watercourse and providing for the implementation of any plans adopted; and (ii) Otherwise promoting the rational, equitable and optimal utilisation, protection and control of the watercourse.
Mean Annual Evaporation (MAE )The average amount of evaporation (measured in mm or cm) for a given area in a given year.
Mean Annual Precipitation (MAP)The average amount of precipitation (measured in mm or cm) for a given area in a given year.
MeanderOne curved portion of a sinuous or winding stream channel, consisting of two consecutive loops, one turning clockwise and the other anticlockwise
Medium Human DevelopmentThis group of countries has a Human Development Index between 0.5 and 0.8.
Mekgacha or EndorheicDraining into interior basins.
Member statesStates that joined a particular international treaty.
MetamorphicThe result of the transformation of an existing rock type, the protolith, in a process called metamorphism, which means 'change of form'.
Meteorological droughtOccurs when precipitation is below normal or average for a prolonged period of time.
MicrocreditA programme that extends small loans to very poor people for self-employment projects that generates income, allowing them to support themselves and their families.
MicrograntA financial grant aimed at funding the piloting of new and promising transboundary initiatives, on the development and dissemination of best practices, and on exchanges of lessons learned in environmental and natural resource management
MicroorganismThe collective term for organisms that cannot be seen by the unaided human eye. Examples of microorganisms include bacteria, yeasts, protozoa, blue-green algae, and some fungi.
MicroscopeScientific instrument used to magnify objects too small to be seen with the naked eye.
MicroscopicToo small to be seen with the naked eye.
Mid-latitude cyclonesAn area of low pressure located between 30 degrees and 60 degrees latitude. These cyclones can be responsible for storms that exist for about 3 to 10 days moving in a generally west to east direction.
Middle income countryGross national income per capita of USD $936- 3,705.
Middle Stone AgeThe Middle Stone Age (or MSA) was a period of African Prehistory between Early Stone Age and Late Stone Age. It began around 300,000 years ago and ended around 50,000 years ago.
Millennium Development Goals (MDGs)The eight goals (MDGs) – which range from halving extreme poverty to halting the spread of HIV/AIDS and providing universal primary education, all by the target date of 2015 –form a blueprint agreed to by all the world’s countries and all the world’s leading development institutions.
Mitigation measuresActions undertaken to reduce or eliminate potential negative effects or consequences.
Mm3Million cubic metres.
MolluscsInvertebrate animals with a soft body and, usually, a hard shell. Examples include snails, clams, mussels and related animals.
Monetary AccountsAn account in which the currency is the only unit of measure.
Monitoring (resource or environmental)Sampling various media at set intervals over time in order to determine the state of the environment and any temporal or spatial trends.
MonsoonA wind from the southwest or south that brings heavy rainfall to southern Asia in the summer and the rain that accompanies this wind.
MorphologyA term used to describe the shape of the land or a landscape. Also see Geomorphology
MultivalentRelating to the association of three or more homologous chromosomes during the first division of meiosis.
MutagenicCapable of causing a mutation in an organism.


National Poverty Alleviation PlansMany less developed countries have established strategic plans to coordinate public and private efforts to combat poverty. These plans normally aim to develop income-generating activities that broaden and strengthen self-employment, small enterprises, and/or community enterprises producing sustainable products and services.
National water lawA country´s legislation which regulates all the different aspects revolving around water resources.
Natural capitalThe stock of all natural resources, including water, soil, air, minerals, flora, and fauna.
Natural resourceAny matter or energy obtained from the environment that is used and valued by humans. Forests, water, soils, and air are examples of natural resources.
NematodeWorms with an unsegmented body; abundant in marine and freshwater habitats, soil, and as parasites of plants and animals.
Net productionThe rate of gross accumulation of organic matter minus the losses of organic matter to respiration and other processes.
NGONon-Government Agency
Nile Basin Initiative (NBI)Formally launched in 1999, the Nile Basin Initiative (NBI) provides an agreed basin-wide framework to fight poverty and promote socio-economic development in the region.
NitrateForm of nitrogen commonly found in the soil and used by plants for building amino acids, DNA and proteins. It is commonly produced by the chemical modification of nitrite by specialized bacteria. Chemical formula for nitrate is NO3-.
NutrientAny food, chemical element or compound an organism requires to live, grow, or reproduce.
Nutrient CyclingThe pathway by which a chemical element or molecule moves through both the biotic and abiotic compartments of the earth.


OmnivoreOrganisms that feed both on autotrophs and other heterotrophs.
Open access resourceA resource to which no control on access is applied; therefore, the resource can be accessed by any individual at any time.
Opportunity costs When economists refer to the “opportunity cost” of a resource, they mean the value of the next-highest-valued alternative use of that resource.
Option valueThe expected value of future information from or about natural resources. Conserving resources today maintains the option of resource value in the future.
OrbitThe path of a body or particle under the influence of a gravitational or other force. For instance, to go around the Earth or other body in an orbit.
Organic1. Relating to an organism. 2. Derived from an organism.
OrganismAny form of life.
Orographic rainfallOccurs when warm, moist air is forced to rise over elevated land. The air is cooled as it rises, leading to condensation, cloud formation, and rainfall.
Over-exploitationExploitation to the point of diminishing returns. Overexploitation of natural resources — through unsustainable hunting, fishing, or extracting raw material — has serious implications for biodiversity. The social costs of overexploitation are high, leaving communities with little alternatives for employment and possibly even food.
OvergrazingOccurs when plants are exposed to intensive grazing for extended periods of time, or without sufficient recovery periods.
Ownership (as defined in the Paris Declaration)The Paris Declaration of March 2005 on the effectiveness of development cooperation establishes ownership as one of the fundamental principles of cooperation. Ownership as a core principle means that the countries receiving development aid are primarily responsible for the initiatives implemented in the context of development cooperation.


PalaearcticOne of the eight ecozones into which the world is divided. This ecozone includes the terrestrial ecoregions of Europe, Asia north of the Himalaya foothills, northern Africa, and the northern and central parts of the Arabian Peninsula.
Panchromatic imageryImagery taken of all wavelengths within the visible spectrum (though not uniformly).
Parameciuma single-celled, microscopic aquatic organism with hairlike appendages (cilia) around its body used to move around and capture bacteria.
ParticipationA process that enables a wide range of stakeholders from the public and private spheres to participate in and influence decision-making processes, especially at the local level.
Participatory planningA planning approach in which all stakeholders, and in particular the envisaged beneficiaries are part of the decision process.
PastoralismA livelihood in which people living in the semi-arid areas support themselves by tending domesticated animals that feed on grass and other available plant foods and water sources, usually in areas characterized as semi-arid to semi-desert.
PathogenMicroscopic parasite organism that causes disease in a host. Disease causes the host to be less fit and may eventually cause premature death.
Per capitaUsually used in the field of statistics to indicate the average per person for any given concern, such as income, crime rate, etc.
PercolationFlow of a liquid through an unsaturated porous medium, e.g. of water in soil, under the action of gravity.
PerennialA plant in which the vegetative structures live year after year (some definitions say at least 3 years).
Perennial RiverA river that flows in at least parts all year round.
PeriphytonThe layer of algae, microorganisms and organic material coating the surface of stones, plants, and hard objects on the beds of streams, rivers, and reservoirs. See also biofilm.
Persistent Organic Pollutants (POPs)Organic compounds that are resistant to environmental degradation through chemical, biological, and photolytic processes.
PesticideChemical agent used to kill insects, usually associated with agriculture, but also associated with insect pest control in tourist areas, such as game parks.
pHScale used to measure the alkalinity or acidity of a substance through the determination of the concentration of hydrogen ions in solution. A pH of 7.0 is neutral. Values below 7.0, to a minimum of 0.0, indicate increasing acidity. Values above 7.0, to a maximum of 14.0, indicate increasing alkalinity.
PhotosynthesisThe process by which plants use energy from the sun to transform carbon dioxide (CO2) and water into carbohydrates and other compounds.
Physical Water ScarcityA physical lack of water available
PhysiochemicalA term used to denote something influenced by physical and chemical characteristics.
PhysiographicAdjective from "physiography" (or, Physical geography) – one of the three major subfields of geography. Physical geography focuses on understanding the processes and patterns in the natural environment, as opposed to the cultural or built environment, the domain of human geography.
PhytoplanktonMicroscopic plants suspended in the open water.
Pioneer speciesPlant species that dominate a community in the early stages of ecological succession.
Pixel"Picture element" is the ground area corresponding to a single element of a digital image data set. A two-dimensional ensemble of pixels forms the geometric grid on which an image is built.
PJTCPermanent Joint Technical Commission of the Kunene River.
PolicyA plan or course of action intended to influence and determine decisions, actions, and other matters.
Policy coordinationA voluntary and largely unenforceable alignments of national policies and measures in particular fields.
Policy harmonizationAn agreement on the manner in which each Member State will exercise or use a particular instrument over which it retains control.
Political insecurity (in terms of water transfers)The insecurity of a country when a water-scarce country depends on a water-abundant country for critical water supply and when the water-abundant country depends on the water-scarce country for its export revenue.
PollutantGenerally, any substance introduced into the environment that adversely affects the usefulness of a resource or the health of humans, animals, or ecosystems.
PopulationIn biology, a population is the collection of inter-breeding organisms of a particular species; in sociology, a collection of human beings.
PorosityRatio of the volume of the interstices in a given sample of a porous medium, e.g. soil, to the gross volume of the porous medium, inclusive of voids.
PotableWater of a quality that is fit for consumption by humans or animals.
Potential evaporationThe amount of evaporation that would occur if there was sufficient water available.
PovertyThe situation facing those in society whose material needs are least satisfied. Inability to afford an adequate standard of consumption because of low income is referred to as income poverty. If, apart from low income, a country is characterised by malnutrition, poor health, low survival rates, low literacy levels, inadequate housing and living conditions, etc., then there is human poverty.
Poverty alliviationReduction of poverty through public policies.
Poverty LineA measure of the money income required to attain a basic minimal standard of living – enough to purchase a nutritionally adequate food supply and to provide for other essential requirements
Poverty Reduction Strategy PapersThe anti-poverty strategy depends heavily on reducing poverty through the promotion of economic growth.
Precipitation(1) Liquid or solid products of the condensation of water vapour falling from clouds or deposited from air on the ground.(2) Amount of precipitation (as defined under (1) ) on a unit of horizontal surface per unit time.
PredatorAn animal that kills and eats other animals.
Prevalence of HIVThe AIDS / HIV prevalence rate in selected populations refers to the percentage of people tested in each group who were found to be infected with HIV.
Primary aquifersAquifers with intergranular porosities and permeabilities occur which produce the water-bearing characteristics.
Primary consumerAn animal that eats autotrophs.
Primary producerProduces the first form of organic carbon from inorganic compounds. See also autotroph.
Primary productionThe production of organic matter, such as new cells, mainly by photosynthetic plants.
Private resourcesResources for which consumption is subtractive and to which access can be controlled (access is exclusive).
PrivatisationThe sale of public assets to individuals or private business interests.
ProducerSee autotroph.
ProductionThe amount of organic matter produced by an organism over a period of time.
Protected areaAn area in which resource use and access is managed to protect valued environmental and natural resources.
ProtistsA collective term for eukaryotes that are not considered true animals, plants, or fungi; or, members of the kingdom Protista.
ProtocolAn instrument of implementation of the SADC Treaty, having the same legal force as the Treaty.
Protocol on Shared Watercourseshe protocol on Shared Watercourses in the Southern African Development Community (SADC) Region, was concluded as a legally binding document, in order to ensure equitable sharing of water and efficient conservation of the scarce resource. It established the River Basin Management Institutions and its financial and regulatory framework.
ProtozoaA large group of single-celled eukaryotic and often microscopic organisms.
Public goodA resource with non-subtractive consumption and unlimited access. Protection from UV radiation by the ozone layer is an example of a public good.
PulaThe currency of Botswana. Pula literally means "rain" in Setswana language, because rain is very scarce in Botswana and therefore valuable. Pula also means "blessing" as rain is considered a blessing.
Purification PlantA facility that treats raw water and removes its impurities, making the water safe.


QuartziteA hard metamorphic rock which was originally sandstone. Sandstone is converted into quartzite through heating and pressure usually related to tectonic compression within orogenic belts. Pure quartzite is usually white to grey.
Quaternary CatchmentBasin catchments developed of the second period of the Cenozoic Era, from the end of the Tertiary Period through the present, characterized by the appearance and development of humans and including the Pleistocene and Holocene epochs
Quinary catchment5th level sub-basins


Radio-nuclidesA radioactive isotope of an element.
RaindaysThe number of days with rainfall. In the water for future report the number of days with rainfall above a certain amount is expressed as a ration of the number of rain days.
Rainfed AgricultureAgricultural practices that rely solely on rainfall to provide the moisture necessary to grow crops.
RainshadowAn area of reduced precipitation commonly found on the leeward side of a mountain.
Rainwater HarvestingCollecting rainwater in buckets or specialized catchment areas.
RamsarRamsar is a town in Iran where the Convention on Wetlands was signed 1971 - an intergovernmental treaty which provides the framework for national action and international cooperation for the conservation and wise use of wetlands and their resources.
Ramsar SitesThe Ramsar Convention (The Convention on Wetlands of International Importance, especially as Waterfowl Habitat) is an international treaty for the conservation and sustainable utilization of wetlands. The convention was developed and adopted by participating nations at a meeting in Ramsar on February 2, 1971. The Ramsar List of Wetlands of International Importance now includes 1,847 sites (known as Ramsar Sites).
ReachA length of stream or river defined by characteristics – such as flow, chemical or biological factors, tributary confluence, human influence, or other factors – that differ from characteristics of adjacent sections of the stream or river.
RechargeProcess by which water is added from outside to the zone of saturation of an aquifer, either directly into a formation, or indirectly by way of another formation.
Recharge rateThe time required to replenish groundwater that it extracted from aquifers.
ReforestationThe process of restoring and replacing tree cover from areas where deforestation of forested areas has occurred.
RegionThe SADC region and not any geographic or jurisdictional area at country level.
Regional early warning systemThe main objective of Regional Early Warning System (REWS) is to provide SADC states and members of the international community with early warning on food insecurity in the region.
Regional Water Policy (RWP)The objective of the Regional Water Policy is to provide a framework in which various actors in the Water Sector will interact and carry out their business as a contribution to the overall SADC goal of regional integration and poverty eradication.
Regional Water Strategy (RWS)The role of the Regional Water Strategie (RWS) is to promote regional integration and poverty alleviation within the SADC region. To reach these gools, the overarching strategies are regional cooperation in water resources management, the use of water for development and poverty alleviation, to assure environmental sustainability and security for water-related disasters, stakeholder participation and capacity development. There were established a Water Resources Information and Management and a Water Resources Development Service, a Regional Water Resources Framework as well as a common framework for accessing funding and financial resources.
ReliefThe range of topographic elevation within a specific area.
Remote sensingThe science, technology and art of obtaining information about objects or phenomena from a distance (i.e., without being in physical contact with them).
Replacement rateThe period of time required to replace the entire volume of water in a lake or reservoir.
ReptileA cold-blooded vertebrate of the class Reptilia. Reptiles breathe using lungs and lay eggs on land. The group includes crocodiles, lizards, snakes and turtles.
Reserve determinationDetermining the amount of water available now and in the future.
ReservoirAn area where water is kept in reserve for later use.
Reset events
Residence timeThe length of time water remains in a reservoir or lake before evaporation or outflow.
ResilienceRefers to the ability of a community to return to its former state after some displacement.
ResistanceRefers to the ability of a community to avoid displacement after some disturbance.
ResolutionResolution is the ability of a sensor to distinguish two closely spaced objects or lines as two rather than one object or line. Alternately, it is the smallest object or narrowest line a sensor can detect.
Resource accountsAccounts that deal with stocks and stocks changes of natural assets, comprising biota, subsoil assets (proven reserves), water and land with their aquatic and terrestrial ecosystems. SEEA 2003.
Resource directed measuresTo provide a framework to ensure sustainable utilisation of water resources to meet ecological, social and economic objectives and to audit the state of South Africa’s water resources against these objectives (DWAF 2009)
RespirationA metabolic process that releases energy through the oxidation of molecules.
Response indicatorsOrganisms found in the aquatic environment that respond to the stressors of their environment.
Reticulated water supplyRefer to the piped-water network (as opposed to well water)
ReticulationTo create a network.
Revised Protocol on Shared Watercourses in SADCThe overall objective of this Protocol is to foster closer cooperation for judicious, sustainable and co-ordinated management, protection and utilisation of shared watercourses and advance the SADC agenda of regional integration and poverty alleviation.
RiffleAn area in a river characterized by faster flowing, shallow water.
Riparian countriesCountries sharing the same River basin.
Riparian zoneThe Riparian zone is the interface between the land and a stream or river.
RivalryCompetition for resource use resulting from the subtractability of resource consumption.
RiverLarge stream which serves as the natural drainage channel for a drainage basin.
River basinArea having a common outlet for its surface runoff
River basin action plan
River Basin Organisations (RBOs)River Basin Organisations (RBOs) are designed to help bring about Integrated Water Resources Management (IWRM) and improve water governance in Transboundary Water Basins. These organiations are becoming increasingly significant in all regions of the world. Historically, shared rivers were governed through treaties at the international level, or interagency compacts at local or state levels. The International Network of Basin Organizations currently has 133 member organizations in 50 countries (INBO 2003). These forums coordinate activities, share information, and develop integrated management approaches, are the most common expressions of transboundary environmental and water governance.
River bedThe area of ground over which a river flows.
River health River health is a term used to describe the ecological condition of a river. Health is more than just the plants and animals that live in a river or the quality of the water in it. It depends also on the diversity of the habitats, plant and animal species, the effectiveness of linkages and the maintenance of ecological processes.
River systemEvery river is part of a larger system of land drained by a river and its tributaries, flowing into larger bodies of water. Many river sources, called headwaters, form a system of tributaries flows, often located in mountains, the source may be fed by an under-ground spring, or by runoff from rain, snowmelt. The river mouth is the place where a river flows into a larger body of water, such as another river, a lake, or an ocean.
RivuletsA small brook or stream.
Run-off waterRun-off water is a term used to describe the water from rain, snowmelt or irrigation that flows over the land surface.
RunoffThat part of precipitation that appears as streamflow.
RuralDescribes that which is related to the countryside as opposed to the city.


SADCThe Southern African Development Community has been in existence since 1980, when it was formed as a loose alliance of nine majority-ruled States in Southern Africa known as the Southern African Development Coordination Conference (SADCC), with the main aim of coordinating development projects in order to lessen economic dependence on the then apartheid South Africa. The founding Member States are: Angola, Botswana, Lesotho, Malawi, Mozambique, Swaziland, United Republic of Tanzania, Zambia and Zimbabwe (
SADC Common AgendaThe set of fundamental principles and values, referred to in Article 5A of the SADC Treaty that will guide the integration agenda of the organisation.
SalinityConcentration of dissolved salts found in a sample of water. Measured as the total amount of dissolved salts in parts per thousand. Seawater has an average salinity of about 34 parts per thousand.
Salt WaterWater where the salt concentration is relatively high (more than 10 000 mg per liter).
Salt Water IntrusionThe movement of saline water into freshwater aquifers.
SanitationThe disposal of sewage and the use of measures to maintain hygiene and cleanliness.
Saturated ZonePart of the water-bearing material in which all voids, large and small, are filled with water. (IGH)
SavannaA tropical or sub-tropical plant community characterized by trees and shrubs scattered among a cover of grasses, herbs and forbs. The climate of a savanna is tropical with a dry season occurring in the low Sun period of the year.
Schedule 1Water use authorizations in South Africa related to relatively small quantities of water, mainly for domestic and stock watering purposes.
SchistosomaFlatworms that are parasitic to the blood vessels of mammals, including humans.
SchistosomiasisA tropical disease spread by parasitic worms living in fresh water, hosted by snails, that can cause rash or itchy skin, fever, chills, muscle aches, and possible damage to the liver, intestines, lungs, and bladder. Also known as bilharzia.
Secondary aquifersAquifers where the water-bearing characteristics are dependant on openings occurring within the rock itself, which have occurred subsequent to deposition.
Secondary consumerAn animal that feeds on other animals.
Secondary productionThe assimilation of organic material and building of tissue by heterotrophs. This may involve animals eating plants, animals eating other animals, or microorganisms decomposing dead organisms to obtain the resources (material, energy, nutrients) needed to produce biomass.
SecretariatThe Secretariat of SADC established by Article 9 of the Treaty.
SectorA distinct subset of a market, society, industry, or economy, whose components share similar characteristics.
SedimentMaterial transported by water from the place of origin to the place of deposition. In watercourses, sediment is the alluvial material carried in suspension or as bed load.
Sediment loadThe total amount of suspended load, dissolved load, and bed load carried by a river.
SedimentationThe deposition of sediment. Also known as siltation.
Septic systemsSystems that typically carry waste water away from a home.
Setswana(Also called Tswana or Sitswana), is a Bantu language spoken in Botswana, South Africa, and neighboring areas of Zimbabwe and Namibia
SewageWaste water or untreated water.
SewerageThe system (pipes) that carry the sewage.
Shared watercourseA watercourse passing through or forming the border between two or more States.
ShreddersStream animals that feed on coarse organic particles, thereby reducing particle size.
SiltationThe deposition of sediment. Also known as sedimentation.
SinuosityRefers to the amount of curving in a river channel.
Social DevelopmentA process which results in the transformation of social structures in a manner which improves the capacity of the society to fulfill its aspirations.
Social EquityGenerally implies fair access to livelihood, education, and resources; full participation in the political and cultural life of the Community; and self-determination in meeting Fundamental Needs.
Social goodWater as a commodity to which social value is attached, arising from the fact that water is an essential building block for life.
Socio-economic / socioeconomicThe study of the relationship between economic activity and social life.
SocioeconomicsThe study of the relationship between economic activity and social life. In many cases socioeconomics focus on the social impact of some sort of economic change.
SoilLayer of unconsolidated material found at the Earth's surface that has been influenced by the soil forming factors: climate, relief, parent material, time, and organisms. Soil normally consists of weathered mineral particles, dead and living organic matter, air space, and the soil solution.
Sour GrassveldA grassland landscape dominated by so-called sour grass, such as Themeda triandra. Usually occuring in areas of high rainfall, resulting in vigorous growth.
Southern African Millenium Ecosystem Assessment (SAfMA)Part of the Millennium Ecosystem Assessment (MA) – a research program that focused on ecosystem changes over the course of decades, and projecting those changes into the future. It was launched in 2001 with support from the United Nations and was conducted in a suite of sub-global assessments around the world.
Species1. The different kinds of organisms found on the Earth as defined by taxonomic and/or phylogenic classification. 2. A group of interbreeding organisms that do not ordinarily breed with members of other groups.
Species diversity (organism diversity)Refers to the variety of species that exists (or is thought to exist) within a region. Species diversity can refer to either the actual number of species (known as species richness) or to other indices of diversity that account for the relationships between species (e.g., relative abundance).
StakeholdersAny individual or group affected by and with an interest in a specific resource, project, program, or policy.
StandpipeA tank or a pipe for holding water in an elevated position to create pressure in a water supply system
Stock WateringProvision of water to quench the thirst of animals. Equipment or device to deliver water to quench the thirst of animals.
Storage reservoirAn artificial lake used to store water.
Stormwater (Storm runoff)That part of surface runoff which reaches the catchment outlet shortly after the rain starts. Its volume is equal to rainfall excess. Some procedures for its derivation include prompt subsurface runoff but all exclude base flow.
Stream channelizationThe process of re-structuring the natural course of a river for navigation or flood protection.
Stream OrderNumber expressing the degree of branching in a stream system.
StreamflowGeneral term for water flowing in a stream or river channel.
Sub-basinA smaller basin included within a larger basin.
Subsidiary Action Programs (SAPs)A suite of investment projects administered by the NBI that confer mutual benefits at the sub-basin level, each involving two or more countries.
SubsistenceSubsistence agriculture is self-sufficient farming in which farmers grow only enough food to feed their family.
Subtractive consumptionConsumption of a resource that limits or prevents resource use by another because it is used up or degraded.
Subtropical highAreas of high atmospheric pressure located at about 30º north and south latitude, produced by the descending air masses of the Hadley cell circulation pattern.
Succulent VegetationGroup of plants that have the ability to survive in deserts and other dry climates by having no leaves. Instead their branches and stems that are photosynthetic. This adaptation reduces the surface area for evaporation thus reducing the loss of scarce water.
SupergroupA term used to describe several associated lithostratigraphic groups or for associated groups and formations with significant lithologic properties in common.
Supervised ClassificationA procedure for identifying spectrally similar areas on an image by identifying “training” sites of known targets and then extrapolating those spectral signatures to other areas of unknown targets.
Surface waterWater on the surface of the earth.
Suspended SedimentEroded sediments held in suspension in water.
SustainabilityRefers to the ability to maintain a defined state over time. In terms of resource use and development, sustainability refers to the ability to meet the needs of the present without compromising the ability to meet the needs of the future.
Sustainable developmentDefined by the Brundtland Report as “Development that meets the needs of the present without compromising the ability of future generations to meet their own needs.”
Sustainable livelihoodsA livelihood comprises the capabilities, assets (including both material and social resources) and activities required for a means of living. A livelihood is sustainable when it can cope with and recover from stresses and shocks while maintaining or enhancing its capabilities and assets while not undermining the natural resource base.
Sustainable managementA process of leading or directing in a way that allows the needs of the present to be met without compromising the ability to meet the needs of the future.
Sustainable useUse in a way and at a rate that does not lead to the long-term decline of natural resources.
System of Integrated Environmental and Economic Accounts (SEEA)A satellite system of the UN System of National Accounts


TectonicRefers to structures and features resulting from changes in the earth’s crust.
TemperateA region in the mid-latitudes, typically subject to distinct seasonal weather patterns.
TemperatureTemperature is defined as the measure of the average speed of atoms and molecules. The higher the temperature the faster they move.
TemporalRelated to time.
TerracingThe creation of step-like, level surfaces along a slope in hilly agricultural areas.
ThunderstormAlso known as an electrical storm, a lightning storm, or a storm is a form of weather characterized by the presence of lightning and its effect: thunder.
TillageLoosening of the soil in preparation for planting of crops.
Toll resourceA resource that is non-subtractable, and can thus be consumed jointly without reducing the benefit of each single user, and from which users can be easily excluded. An example of a toll resource is a nature reserve where people pay an entrance fee to access the reserve. Also known as a club resource.
TopographyThe shape and configuration of the land surface as described by the position of physical features, elevation, slope, and orientation.
Total Dissolved Solids (TDS)The amount of dissolved substances, such as salts or minerals, in water remaining after evaporating the water and weighing the residue. Used as a measure of physical water quality.
Total Suspended Solid (TSS)A water quality parameter related to the amount of small solid particles which remain in suspension in the water.
TourismTravel for recreational, leisure or business purposes.
ToxicA substance that is harmful to health or lethal if consumed or otherwise entering into the body in sufficient quantities.
Trade windsSurface winds that generally dominate air flow in the tropics, blowing from about 30° north and south latitude to the equator.
Traditional agricultureFarming methods vary from one ethnic group or location to another, according to population density, climate, water supply, and soil.
Traditional knowledgeGenerally refer to the matured long-standing traditions and practices of certain regional, indigenous, or local communities.
Transboundary resourceA resource that is not confined within existing administrative boundaries.
Transboundary Water Resources ManagementTransboundary watercourses need to be managed to resolve issues before they develop into international conflicts, e. g. promotion of water demand management, conflict management, stakeholder-based decision-making to manage competing water demands, sanitation, institutional strengthening and capacity-building, training programs for monitoring, analysis, and planning of water resources management.
Transfer TunnelA tunnel used to transfer water from one area to another.
Transfrontier Conservation AreaAn area comprising two areas, which border each other across international boundaries and whose primary focus is wildlife conservation. Authorities responsible for the respective areas formally agree to manage the areas as one integrated unit according to a streamlined management plan. The authorities also undertake to remove all human barriers within the Transfrontier Park so that animals can roam freely (DEAT website 2009).
TranshumanceTranshumant pastoralism is a form of mobile pastoralism that involves more predictable patterns of cyclical seasonal movements of domestic animals and to varying degrees also people along specific routes. During the rainy season when water and grazing resources are relatively plentiful, animals usually remain at or close to the (semi-)permanent homesteads of the people. During the dry season, animals are moved to specific dry-season grazing areas where grazing resources tend to last throughout the dry season.
TransparencyAn expectation on organisations by society to be open and willing in the acceptance of public scrutiny, thus diminishing the capacity for an organisation to practice or harbour deception or deceit . Transparency ensures that the decision-making process, as well as the implementation and enforcement of decisions, is done in a manner that follows the rule of law.
TranspirationThe evaporation of water from plants through stomata, tiny pores on the surface of plant leaves.
Treatment facilityA facility where water undergoes physical and chemical processes for making water suitable for human consumption and other purposes.
TreatyA treaty is essentially a settlement or an agreement arrived at by treating or negotiation. In international law the word ‘treaty’ has been used to cover a variety of international agreements. The Vienna Convention on the Law of Treaties of 1969 is the codification of the practice of international treaty-making, which was previously regulated by the customary rules of international law. The Convention defines a treaty in the international context as an agreement whereby two or more nation states establish, or seek to establish, a relationship between themselves imposing binding obligations on themselves and governed by international law.
TrematodaParasitic flatworms.
TributaryA stream or other watercourse that flows into a larger stream or river.
Trophic levelArtificial classification of organisms according to feeding relationships and the transfer of food-energy. The first trophic level includes primary producers (green plants); the second trophic level includes herbivores; the third includes animals which feed on herbivores.
Tswana (Batswana)The name of a Southern African people (speak Tswana language, also called Setswana). Ethnic Batswana make up a majority of the population of Botswana.
TuberculosisTuberculosis, sometimes referred to as TB, is a disease caused by an organism called mycobacterium tuberculosis. These bacteria most commonly attack the lungs. People with weakened immune systems are most susceptible to TB.
TurbellariaFree-living flatworms.
TurbidCloudy water, usually due to increased sediment load.
TyphoidInfection usually associated with an intestinal inflammation and ulceration; caused by Salmonella typhosa ingested with food or water.


Unaccounted for waterUnaccounted for water (UFW) is water that has been produced and is “lost” before it reaches the customer. Losses can be real losses (through leaks, sometimes also referred to as physical losses) or apparent losses (for example through theft or metering inaccuracies). High levels of UFW are detrimental to the financial viability of water utilities, as well to the quality of water itself. UFW is typically measured as the volume of water "lost" as a share of net water produced.
Unconfined Aquifer Aquifer containing unconfined groundwater, that is having a water table and an unsaturated zone.
UnconsolidatedA term used to refer to sediments that are not cemented together.
Unsupervised ClassificationCategorization of digital image data by computer processing based solely on the image statistics without availability of training samples or prior knowledge of the area. The classification creates natural groupings in the image values, called spectral clusters or classes. In this fashion, values with similar grey levels are assumed to belong to the same cover type. The analyst must then determine the identity of these spectral clusters.
UnsustainableUnable to continue indefinitely.
Upper basin statesCountries located upstream of an international river basin.
Upper KuneneThe upper portion of the Kunene catchment, the portion of the river closest to the source.
Upper waters of a riverThe upper portion of the river, closest to the source.
UpstreamIn the direction towards the source of a stream.
Upstream TributaryRiver, brook or stream that flows into another stream, above the location to which you are referring to.
UrbanAn area with an increased density of human-created structures in comparison to the areas surrounding it
Urban heat islandRefers to the increased temperature in urban areas relative to surrounding rural areas.
UrbanizationThe expansion of a city or metropolitan area, often due to population growth caused by the movement of people from rural to urban areas.


VATValue Added Tax
Vector-borne diseasesWhen a pathogenic microorganism is transmitted from an infected individual to another individual through an 'agent' (ie. mosquito).
Vector-borne diseasesWhen a pathogenic microorganism is transmitted from an infected individual to another individual through an 'agent' (ie. mosquito)
VertebrateAnimal that does have a backbone. Also see invertebrate.
Virtual WaterThe amount of water embodied in the goods a country imports and exports.
VulnerabilityVulnerability is a state in which an individual or community’s proximity to hazards, health issue and/or food insecurity threatens their existence or ability to function.
Vulnerability contextIs a defined vulnerability scenario. They can be classified as shocks, trends and seasonal.
Vulnerability IndicatorsIndicators used to assess vulnerability.
VulnerableFacing a high risk of extinction in the wild.


WASAWater and Sewage Authority
WastewaterWater containing waste, i.e. liquid or solid matter discharged as useless from a manufacturing process.
WaterLiquid phase of a chemical compound consisting of approximately two parts by weight of hydrogen and 16 parts by weight of oxygen. In nature it contains small amounts of heavy water, gases and solids (mainly salts) in solution.
Water AccountsAccounts that treat water as any other product, valuing it by the price of its transaction
Water BowserA mobile water tank.
Water Conservation and Water Demand Management (WC/WDM)A strategy in South Africa to promote water use efficiency consistent with the National Water Act (Act 36 of 1998) that emphasizes effective management of water resources.
Water courseGeneral term for flowing water body. This can be a river, stream, creek, or brook, etc.
Water cycleSuccession of stages through which water passes from the atmosphere to the earth and returns to the atmosphere: evaporation from the land or sea or inland water, condensation to form clouds, precipitation, accumulation in the soil or in bodies of water, and re-evaporation.
Water deficitA water shortage that is either natural or man-made.
Water DemandThe demand of various user groups for water.
Water Demand Management (WDM)The adaptation and implementation of a strategy (policies and initiatives) by water management institutions to influence water demand and usage of water in order to meet any of the following objectives: economic efficiency, social development, social equity, environmental protection, sustainability of water supply and services, and political acceptability.” (DWAF 1999)
Water governanceThe political, economic and social processes and institutions by which governments, civil society, and the private sector make decisions about how best to use, develop, and manage water resources.
Water InfrastructureThe technical structures that support the transfer and storage of water.
Water LawWater law is the field of law dealing with the ownership, control, and use of water as a resource. It is closely related to property law and environmental law. Because water is vital to living things and to a variety of economic activities, laws attempting to govern it have far-reaching effects.
Water licenseA permit to abstract a given amount of water over a given period of time.
Water management Planned development, distribution and use of water resources.
Water Management Area (WMA)Any area defined for the purposes of water management, including a water resource plan area.
Water point agenciesAgencies responsible for managing point sources of water such as boreholes.
Water qualityPhysical, chemical, biological and organoleptic properties of water.
Water re-useThe recycling of already used water, such as bathroom and toilet water. A filtering system pipes the recycled water to the households.
Water resources assessment Determination of the sources, extent, dependability and quality of water resources for their utilization and control.
Water scarcityImbalances between availability and demand, the degradation of groundwater and surface water quality, intersectoral competition, interregional and international conflicts, all contributes to water scarcity. (FAO 2009)
Water securityThe capacity of a population to ensure that they continue to have access to potable water.
Water supplyThe process of self-provision or provision by third parties in the water industry, commonly a public utility, of water resource of various qualities to different users.
Water useUse of water or altering of its natural condition with the intention of increasing the production of goods and services.
Water utilityCompany that provides water and/or wastewater services.
Water vapourThe gaseous phase of water.
WatercourseA system of surface and ground waters consisting by virtue of their physical relationship a unitary whole normally flowing into a common terminus such as the sea, lake or aquifer.
WatershedSummit or boundary line separating adjacent drainage basins.
Watershed management Controlled use of drainage basins in accordance with predetermined objectives.
WeatherRefers to manifestations of atmospheric activity at a specific time and place.
WeatheringPhysical and chemical changes in soils or rock due to atmospheric processes and conditions. Physical weathering include changes in soils or rock due to temperature changes (e.g., expansion and contraction of rock) and abrasion by water, ice and wind. Chemical weathering includes the reaction of mineral particles with water or chemical substances in water, as well as the reaction of mineral particles with atmospheric gases or substances in the soil.
WeirA small overflow-type dam commonly used to raise the level of a river or stream
WellShaft or hole sunk, dug or drilled into the earth to extract water.
Well PointA perforated tube driven into the ground to collect water from the surrounding area.
Well-beingHas multiple constituents, including access to basic material needs, freedom and choice, health, good social relations, and security. Well-being is at the opposite end of a continuum from poverty, which has been defined as a “pronounced deprivation in well-being.” The constituents of well-being, as experienced and perceived by people, are situation-dependent, reflecting local geography, culture, and ecological circumstances.
WetlandAn area that is seasonally or permanently saturated with water, and is transitional between terrestrial and aquatic ecosystems. The Convention on Wetlands (Ramsar, Iran, 1971) defines wetlands as “Areas of marsh, fen, peatland or water, whether natural or artificial, permanent or temporary, with water that is static or flowing, fresh, brackish or salt, including areas of marine water the depth of which at low tide does not exceed 6 m.”
Wetland degradationThe impairment of wetland ecosystems as a result of human activity.
Wetland lossThe loss of wetland area due to the conversion of wetland to non-wetland areas, as a result of human activity.
World Environment Day (WED)Celebrated each year on 5 June, WED is one of the principal vehicles through which the United Nations stimulates worldwide awareness of the environment and enhances political attention and action.
World Water ForumThe World Water Council is an international think tank founded in 1996, with its headquarters in Marseilles, France. It has 323 members (March 2006) from the private sector (for example the french power company EDF and the manufacturing company Mitsubishi Heavy Industry), government ministries, academic institutions, international financial institutions (for example the World Bank), the UN and local government. Every third year the World Water Council organizes the World Water Forum in close collaboration with the authorities of the hosting country. The Forum is the largest international event in the field of water.
WormAn invertebrate animal with an elongated, soft, flexible, rounded or flattened body.


XerophyticA plant adapted to survive in an area with little available water or moisture.



ZooplanktonSmall, usually microscopic animals or non-photosynthetic protists that are suspended in water, float, or weakly swim.