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.