More about this website

GeoTerraImage has released a web-based application for monthly monitoring of South Africa’s surface water resources. Water is a critical and scarce resource in southern Africa, and is likely to become even more so as the regional impacts of global climate change become more evident. Being able to accurately and repeatedly monitor available water resources across the entire landscape is a key information requirement for successful water resource management.

Cloud-based satellite image data archives, combined with big data processing capabilities are used to generate spatially detailed information on the extent of all surface water features, from small farm dams to large impoundments, across the South African landscape, on a monthly basis.

Each month, information will be available that describes the current months total surface water, area as well as the previous months total. The total surface water area is generated from multiple Sentinel 2 satellite image observations (at 20m resolution), within each month. Should any area be obscured by cloud in all satellite over-passes then this is flagged and illustrated in the map. Water are statistics for catchments with very high cloud cover percentages should be used with caution.

By clicking on a quaternary catchment, the website will display the statistics of the current and previous month's total water surface area in that selected catchment, and indicate the trend.

The website will remain OPEN-ACCESS for all to use until 31 March 2018 after which a user subscription may be introduced.

Intepretation on Monthly Data:

  • Monthly water datasets will be updated and viewable between the 1st and the 5th of every month, and will be reflected in the side-menu monthly names.
  • The current cloud masking model may result in some permanent bright surface areas such as beaches, pans, tailings being identified as pseudo-cloud top areas. This will be corrected in subsequent versions, but doesn't affect the water identification output.
  • Areas of persistent hazy cloud cover (as opposed to bright white cloud tops) which occur over a water surface throughout the month may result in some data gaps. This will be corrected in subsequent versions.
  • Areas of floating aquatic vegetation that obscure the water surface will result in those water areas not being identified. This is very evident on Hartbeespoort Dam (North West) where changes in monthly surface water extent are a result of movements of the water hyacinth islands.

COMING SOON!

In the near future we will include:
  • Comparison to the preceding 6 months and long-term maximum water area extents.
  • Annual or Monthly Coastal and Estuarine high water delineations.
  • Generate downable reports on large area water statistics and trends.
  • Downloadable GIS compatible digital map data coverages (through user subscriptions).
  • Modelled water volume estimates for all individual large dams and quaternary level summaries.
  • Modelled wetland boundaries
  • Water classification (natural and man-made features)
  • Extending water coverage and monitoring across southern Africa (transfrontier catchments)

Please contact us if you are interested in the digital data access, and/or sample data.

Legend

  • Hydro Catchment
  • Roads
  • Places
  • Water Surface Area
  • Cloud Obscured
  • Bright Bare Surface