S |
| SADC | The 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 (www.sadc.int). |
| SADC common agenda | The set of fundamental principles and values, referred to in Article 5A of the SADC Treaty that will guide the integration agenda of the organisation. |
| SAfMA (Southern African Millenium Ecosystem Assessment) | 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. |
| Salinity | Concentration 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 water | Water where the salt concentration is relatively high (more than 10 000 mg per liter). |
| Salt water intrusion | The movement of saline water into freshwater aquifers. |
| Sanitation | The disposal of sewage and the use of measures to maintain hygiene and cleanliness. |
| SAPs (Subsidiary Action Programs) | A suite of investment projects administered by the NBI that confer mutual benefits at the sub-basin level, each involving two or more countries. |
| Saturated zone | Part of the water-bearing material in which all voids, large and small, are filled with water. |
| Savanna | A 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 1 | Water use authorizations in South Africa related to relatively small quantities of water, mainly for domestic and stock watering purposes. |
| Schistosoma | Flatworms that are parasitic to the blood vessels of mammals, including humans. |
| Schistosomiasis | A 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 aquifers | Aquifers where the water-bearing characteristics are dependant on openings occurring within the rock itself, which have occurred subsequent to deposition. |
| Secondary consumer | An animal that feeds on other animals. |
| Secondary production | The 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. |
| Secretariat | The Secretariat of SADC established by Article 9 of the Treaty. |
| Sector | A distinct subset of a market, society, industry, or economy, whose components share similar characteristics. |
| Sediment | Material 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 load | The total amount of suspended load, dissolved load, and bed load carried by a river. |
| Sedimentation | The deposition of sediment. Also known as siltation. |
| SEEA (System of Integrated Environmental and Economic Accounts) | A satellite system of the UN System of National Accounts. |
| Septic systems | Systems 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. |
| Sewage | Waste water or untreated water. |
| Sewerage | The system (pipes) that carry the sewage. |
| Shared watercourse | A watercourse passing through or forming the border between two or more States. |
| Shredders | Stream animals that feed on coarse organic particles, thereby reducing particle size. |
| Siltation | The deposition of sediment. Also known as sedimentation. |
| Sinuosity | Refers to the amount of curving in a river channel. |
| Social development | A process which results in the transformation of social structures in a manner which improves the capacity of the society to fulfill its aspirations. |
| Social equity | Generally 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 good | Water as a commodity to which social value is attached, arising from the fact that water is an essential building block for life. |
| Socio-economic / socioeconomic | The study of the relationship between economic activity and social life. |
| Socioeconomics | The 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. |
| Soil | Layer 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 grassveld | A 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. |
| Spatial planning | Spatial planning refers to the methods used by the public sector (governmental entities) to influence the distribution of people and activities in spaces of various scales. |
| Species | (1) 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). |
| Stakeholders | Any individual or group affected by and with an interest in a specific resource, project, program, or policy. |
| Standpipe | A tank or a pipe for holding water in an elevated position to create pressure in a water supply system. |
| Stock watering | Provision of water to quench the thirst of animals. Equipment or device to deliver water to quench the thirst of animals. |
| Storage reservoir | An 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 channelization | The process of re-structuring the natural course of a river for navigation or flood protection. |
| Stream order | Number expressing the degree of branching in a stream system. |
| Streamflow | General term for water flowing in a stream or river channel. |
| Sub-basin | A 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. |
| Subsistence | Subsistence agriculture is self-sufficient farming in which farmers grow only enough food to feed their family. |
| Subtractive consumption | Consumption of a resource that limits or prevents resource use by another because it is used up or degraded. |
| Subtropical high | Areas 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 vegetation | Group 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. |
| Supergroup | A term used to describe several associated lithostratigraphic groups or for associated groups and formations with significant lithologic properties in common. |
| Supervised classification | A 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 water | Water on the surface of the earth. |
| Suspended sediment | Eroded sediments held in suspension in water. |
| Sustainability | Refers 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 development | Defined 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 livelihoods | A 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 management | A 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 use | Use 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. |
