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Mean Annual Runoff 2013

This GIS layer represents the Strategic Water Source Areas (SWSAs) as “fuzzy blobs” for South Africa, Lesotho and Swaziland. Strategic Water Source Areas are those areas that supply a disproportionately high amount of the country’s mean annual runoff, in relation to their surface area, here defined as those areas that contribute >50% of the country’s mean annual runoff. These areas have been mapped for South Africa, originally derived from a 1 x 1 minute grid (MAR_SWSA) which is also on BGIS. They make up 8% of the land area across South Africa, Lesotho and Swaziland but provide 50% of the water in these countries. The intention of the SWSA_blobs layer is to denote fuzzy boundaries around general areas considered to be Strategic Water Source Areas, and to attach names to these “blobs”.

Simple

Date (Publication)
2013
Edition

1.0

Purpose

“Blobs” for the Strategic Water Source Areas were derived by roughly circling the general area where mean annual runoff for South Africa (mm/year for each 1 x 1 minute grid cell) = 135 mm/year. This was based on MAR_SWSA (also on BGIS) which represents mean annual runoff derived from disaggregating the Water Resources Assessment 2005 data (Middleton and Bailey 2009), which represents the most commonly-used national mean annual runoff data used by the Dept of Water Affairs for water resources planning and management. Blobs depict and name general areas of Strategic Water Source Areas for South Africa. Strategic Water Source Areas are those areas that supply a disproportionate amount of mean annual runoff to a geographical region of interest.

Status
On going
Custodian
  Principal Researcher - Dr Jeanne Nel ( The GIS Officer )
Stellenbosch , Western Cape , 0001 , South Africa
+ 27 (21) 888 2484
Maintenance and update frequency
As needed
Theme
  • Strategic Water Source Areas

Place
  • South Africa

Access constraints
Copyright
Use constraints
otherRestictions
Other constraints

-

Spatial representation type
Vector
Denominator
50000
Language
English
Character set
UTF8
Topic category
  • Environment
Begin date
2016-01-01
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Reference system identifier
WGS 1984

Distributor

Distributor
  SANBI
Name

ZIP

Version

1

OnLine resource
A list of services published are available at this URL. ( WWW:LINK-1.0-http--link )

BGIS Map Services

OnLine resource
A list of spatial data-sets are available at this URL. ( WWW:LINK-1.0-http--related )

BGIS Spatial Datasets

Hierarchy level
Dataset
Statement

Methodology:

On-screen digitizing of oval polygons roughly around Strategic Water Source Areas identified according to MAR_SWSA, SWSA_grid and SWSA_poly (GIS layers that are all on BGIS).


Available documentation:

Nel, J.L, Colvin, C., Le Maitre, D.C., Smith, J. and Haines, I. 2013. South Africa’s Strategic Water Source Areas. CSIR Report CSIR/NRE/ECOS/ER/2013/0031/A, CSIR, Stellenbosch, South Africa.

File identifier
b5cc8af3-d85d-4423-9096-fe8d2a65ae0a XML
Metadata language
English
Character set
UTF8
Date stamp
2022-08-18T15:16:48
Metadata standard name

SANS 1878

Metadata standard version

FGDC-STD-001-1998

Distributor
  SANBI - ( The Metadata Manager )
Kirstenbosch Research Centre , Cape Town , Claremont , 7735 , South Africa
+27 21 799 8738
 
 

Overviews

Spatial extent

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Keywords

Strategic Water Source Areas

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Associated resources

Not available


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