National Groundwater Archive - Glossary
DIRECTORATE: SURFACE AND GROUNDWATER INFORMATION
DEPARTMENT: WATER AND SANITATION

TERM DEFINITION
Abstraction An Abstraction refers to the volume of water that was obtained from of a Geosite, typically measured in cubic metres.
Assignor A person that works or has previously worked for a Reporting Institution that allocated an Other Number to a Geosite.
Audited and Reduced Water Level A water level recorded via HYDSTRA. Auditing was done on HYDSTRA. The reduced set was derived by pre-defined applying filter criteria.
Boulder Percentage Size > 256mm.
Bulk Meter A Bulk Meter is installed in a main pipeline that has water inflows from different Geosites, where water abstractions take place and the total water abstraction is measured.
Calibration Test A test performed to initialize/prepare the pump as well as to get an indication of the different discharge rates to be used for a Step Test.
Casing A piece of material inserted in a Geosite to stabilise the walls of the Geosite, i.e. a pipe.
Casing Collar Height A measure of how far a Casing sticks out above the surface level (ground or concrete surrounding it). It is measured relative to the surface level.
Chemical Suitability A recommendation about suitable uses regarding the groundwater chemistry.
Clay Percentage Size <3.9μm.
Cobble Percentage Size >64mm < 256mm.
Collective Measurement A Collective Measurement is taken from a Bulk Meter.
Colour Pattern Additional soil-specific description in terms of the colour.
Colour Qualifier Additional indicator for the primary colour.
Column A Column is derived from a physical description (i.e Log).
Composition Qualifier Additional indicator for the composition of the rocks.
Confidential Indicator The Confidential Indicator is used to restrict access to a Geosite and its data.
Consolidated Material Consolidated material is the hard surface of the land composed of solid rock.
Constant Yield Test A test that gives a long-term drawdown response in a Geosite for a given discharge rate. This procedure consists of pumping the Geosite at a constant Discharge Rate without any steps. The drawdown is then recorded at specific time periods.
Construction Company An Organisation responsible for drilling and/or construction of a Geosite with specialized equipment.
Construction Completion All the relevant administrative information regarding the creation of a Geosite.
Construction Contractor A person that works or has worked for a Construction Company.
Contact Information

A combination of contact types that a person can be reached at. These include any combination of the following:

- One or more Business Numbers

- One or more Home Numbers

- One or more Cellular Numbers

- One or more Switchboard Numbers

- One or more Fax Numbers

- One or more E-Mail Addresses

Coordinate Two values that represent the longitudinal and latitudinal offset of a Geosite. See Latitude and Longitude.
Coordinate GPS Accuracy / Estimated Position Error (EPE) An indication of the reliability of Coordinate readings.
Coordinate Method A way Coordinates are determined.
Data Owner An organisation that owns Geosite data.
Degree Of Fracturing Refer to Standard Descriptors for Geosites (SDG) on how to measure and describe the degree of 'Fracturing'.
Degree Of Weathering Refer to Standard Descriptors for Geosites (SDG) on how to measure and describe the degree of 'Weathering'.
Depth To Bottom Bottom of the layer being described.
Depth To Top Top of the layer being described.
Descriptor Designation Designate whether the person doing the logging is a scientist or lay person.
Descriptor Name Name of the person who made the description.
Development Actions performed on the Geosite after the physical Construction of the Geosite was completed.
Discharge Rate An amount of water that can be obtained from a Geosite in a specific time, typically measured in litres/second.
Downhole Geophysics A measurement logged (or recorded) by the lowering of different kinds of probes into a Geosite.
Drain A subsurface channel used primarily for intercepting, collecting and removing water from a shallow aquifer.
Drawdown Period A Drawdown Period indicates the amount of hours that a pump was pumping water out of a nearby Geosite, potentially reducing the Water Level of the Geosite in question.
Drilling Fluid A fluid used to make the drilling process faster and more efficient.
Duty Cycle A recommended maximum numbers of hours per day that water may be abstracted from a Geosite.
DWAF Geosite Purpose A reason why the Geosite has been identified for drilling, developing, monitoring etc.
Electronic Data Logger An Electronic Data Logger is an instrument that electronically takes measurements at pre-determined intervals and then stores the data.
Elevation The surface level of a Geosite above mean sea level.
Elevation GPS Accuracy An indication of the reliability of an Elevation reading.
Elevation Method A way Elevations are determined.
Elevation Reference A point from where an Elevation is measured.
Event Date Date the logging was done.
Fabric Attribute Attribute additional to the Fabric Qualifier.
Fabric Qualifier Additional indicator for the fabric of the rocks.
Farm Name A name registered at the Deeds Office and printed on the topo-cadastral maps.
Farm Number A number registered at the Deeds Office and printed on a topo-cadastral map. This number uniquely identifies a specific area.
Field Measurement A term used to describe pre-selected parameters that are observed in the field, as part of the Water Sampling process.
Fill Material A material used to fill the space between the wall of the Geosite and the Casing in order to stabilise the formation.
Fractured Column The construction of the 'Fractured Column' will be done automatically once the 'Lithological log' has been captured.
Geology Indicator A marker indicating the link to a specific Geosite Reference.
Geomorphological Classification A term used to describe the surrounding land surface of a Geosite.
Geosite A Feature that as is a naturally occurring, or artificially excavated, or constructed, or improved underground cavity which can be used for the purposes of water storing in an aquifer, extracting water from an aquifer, collecting data of water in an aquifer and recharging water in an aquifer.
Geosite Status An indication of the condition of a Geosite.
Granule Percentage Size >2mm < 4mm
Groundwater Occurrence A term used to describe the conditions of where water can be found.
Hardness Qualifier An attribute to qualify the degree of rock hardness
Hydrogeological Region A region that is defined on the basis of lithostratigraphy, physiography and climate. The regions were defined by J.R. Vegter.
HYDSTRA Time-Series Data Management System.
Identifier A number allocated to a Geosite by a Data Owner. This number is used along with the Data Owner to uniquely identify a Geosite.
Land Cover A term used to describe the surrounding vegetation of a Geosite.
Lateral/Radial Arm A pipe that is connected at an angle in a horizontal position to the Lateral/Radial Collector.
Lateral/Radial Collector A pipe with a very large Diameter placed vertically in an area with an Unconsolidated Formation/Strata.
Latitude A value to indicate the north to south position of a Geosite.
Lithological Log Description of the rock's visible physical characteristics with low magnification microscopy, such as colour, texture, grain size and composition.
Lithology Formation Type Differentiation between Lithology categories i.e. "Igneous", "Metarphic" and "Sedimentary".
Lithology Material Type Differentiation between Lithology categories i.e. "Consolidated" and "Unconsolidated" Lithology.
Lithology Name The composition of the sample, e.g. quartz, dolomite, etc.
Log A log is a physical description or geophysical measurement.
Logging Company An Organisation that specializes in the geophysical logging of Boreholes using scientific equipment.
Logging Contractor A person that works or has worked for a Logging Company.
Longitude A value to indicate the east to west position of a Geosite.
Loss Percentage The amount of the sample's material that was lost.
Loss Reason The reason for the sample material loss.
Map Number The number of a 1:50 000 scale topo-cadastral map.
Material Loss Sieve Analysis where previously done by mechanical shaking a set of sieves of progressively smaller seizes. (Sieve Analysis relates to Particle Size).
Mine An excavation in the earth from which substances such as ores and minerals are extracted.
Multi-rate Test A test that gives the drawdown response in a Geosite for different pumping rates. This procedure consists of pumping the Geosite at steps of different discharge. At each step the discharge rate is held constant for a specific time period and the drawdown is recorded. However, before another drawdown (step) is recorded, the water level has to recover back to the static or resting water level. This test can be used to determine the sustainability of the water in a Geosite. This can then be used as a recommendation for the discharge rate during the Constant Yield test in the aquifer.
Municipal District A feature that represents third tier Government with specific geographical boundaries.
Observed Casing A casing for which no information about the depths of the casing is available. Information that is available for these casings is based upon visual observation.
Observer A Person that goes to the field with regular intervals to collect measurement data for one/or more of the Monitoring Regions.
Opening A hole or slot that can be made in the Casing to allow water to access the Geosite.
Operational period A recommended period of time that an- Abstraction Yield can be maintained.
Other Loss Reason Another reason for the sample material loss (not part of the pre-defined loss reasons).
Other Number A number that identifies a Geosite according to another numbering system. The other numbering system can belong to another database, a group of individuals or an organization that has its own numbering system.
Particle Shape Vary from "Angular" to "Rounded".
Pebble Percentage Size >4mm <64mm.
Penetration Information The rate it took to penetrate the different geological formations. Can be measured in meters or hours.
Piezometer A small type of Casing inserted in a Geosite to measure various parameters at different depths.
Portion A part of a farm printed on a Topographical map.
Primary Colour Main colour of the rocks.
Protection Method A measure put in place to prevent objects from falling into a Spring, Dug Well or Well Point.
Province A Feature that represents an area of jurisdiction Government in South Africa.
Pump Power Rating The power capacity of the motor driving the Pump.
Quaternary Drainage Region A Feature that represents an area of land, from which rainwater or snowmelt drain towards a water body, defined for designated rivers by the Department of Water Affairs. This forms part of a tertiary drainage region, which in turn is part of a secondary drainage region. The secondary drainage region is part of a primary drainage region.
Recommended Abstraction Yield A recommended quantity of water that can be abstracted from a Geosite in accordance with the Duty Cycle.
Recovery Period for Observation Geosite The Recovery Period for an Observation Geosite is the elapsed time from the time that the pump was stopped on the Pumped Geosite to the time of the last Observation Geosite measurement captured.
Recovery Period for Operational Recommendations A recommended period of time between Duty Cycles.
Reference A source of Geosite data and/or information.
Reference Datum A point used as a Reference in the surveying or mapping of Coordinates.
Reference Details Combination of Library Report Number, Report Name, etc.
Reference Point A (Water Level) Reference Point is a set surface from where a measurement is taken.
Reference Type Refer to the main Glossary.
Registration District A Feature that represents an administrative area, defined and used by the Registrar of Deeds for registering a title to a property.
Reporting Institution An organisation that supplies data to the provincial office and/or Head Office of the Department of Water Affairs.
Reporting Institution Category A logical group into which different sectors of the economy is divided.
Riser A Riser is a type of pipe used for transporting the water from the pump inlet to the ground surface.
Sand Percentage Size >125μm <2mm (can be subdivided from very fine to very coarse sand).
Screen A pre-manufactured wire or plastic mesh, used to prevent fine particles of sand or gravel from entering the Geosite and damaging the pump equipment.
Secondary Colour Secondary colour of the rocks.
Seepage A small amount of water that infiltrates a Geosite.
Sieve Analysis Results Sieve Analysis where previously done by mechanical shaking a set of sieves of progressively smaller seizes. (Sieve Analysis relates to Particle Size).
Silt Percentage Size >31.25μm <62.5 μm.
Sinkhole A subsidence or collapsed feature formed at points of local instability within the dolomatic area.
Sinkhole Classification A group a Sinkhole is classified into based upon its size
Soil Lithology The usually thin upper surface layer of the earth's crust comprising living organisms, organic matter, decomposed rock or unconsolidated sediments.
Soil Origin Description of how the soil was formed.
Sorting Formal classification of the sand/ grain distribution.
Specific Yield A rate at which water is released from storage in an unconfined aquifer, per meter drawdown typically measured in either l/s or m**3/h.
Spring A Geosite that marks the position where groundwater emerges on the surface. It represents the natural leakage or overflow from an aquifer.
Spring Classification through Discharge Rate A group that a Spring is classified into, based upon its Discharge Rate.
Spring Geomorphological/Geological Type An indication of the Geomorphological and Geological controls that caused the Spring.
Spring Seasonality Regime An indication of whether the flow is controlled by the seasons.
Static Water Level A measurement indicating a resting water level.
Step A series of measurements taken during a Step, Multi-rate or Calibration Test.
Step Test A test that gives the drawdown response in a Geosite for increasing pumping rates. This procedure consists of pumping the Geosite at steps of increased discharge. At each step the discharge is held constant for a specific time period and the drawdown is recorded. Immediately after this, the following drawdown can be recorded (step). This test can be used to determine the sustainability of the water in a Geosite. This can then be used as a recommendation for the discharge rate during the Constant Yield test in the aquifer.
Storativity Storativity is a measure of the volume of water stored and released in an aquifer.
Supplying Company An Organisation that supplies specific equipment, but they are not necessarily the manufacturers thereof.
Supplying Contractor A person that works or has worked for a Supplying Company.
Surface Geology Description of the rock's visible physical characteristics at the surface of a Geosite.
Testing Company An Organisation that specializes in performing pumping tests.
Testing Contractor A person that works or has worked for a Testing Company.
Texture Qualifier An attribute to describe the 'Texture' of the rocks.
Total Blow Yield A quantity of water that was found while constructing the Geosite.
Transmissivity Transmissivity is a measure of the ease with which groundwater flows in the subsurface.
Tunnel A long, narrow, essentially linear excavated underground opening with a length of which greatly exceeds its width or height.
Unaudited Water Level A water level captured via the NGA.
Unconsolidated Material Material derived from the disintegration and erosion of consolidated rocks on the land's surface, as well as sediments deposited by coastal and glacial processes.
Village A small group of dwellings in a rural area.
Water Level A depth of the water beneath the ground surface.
Water Management Area An area established as a management unit in the national water resource strategy within which a catchment management agency will conduct the protection, use development, conservation and manage land control of water resources.
Water Strike A term used to describe the particulars where water was (first) encountered when a borehole was drilled.
Water Use A primary purpose for which water from a Geosite is used.
Water User Association A water management institution, but their primary purpose are to operate at a restricted localized level, and are in effect co-operative associations of individual water users who wish to undertake water-related activities for their mutual benefit.
Weathered Column The construction of the 'Weathered Column' will be done automatically once the 'Geological Log' has been captured.
Yield A quantity of water that can be obtained from a Geosite.