Monday, February 05, 2018

Why Cape Town is Running Dry

Theewaterskloof dam provides half of Cape Town's water. It is about to run dry. According to the latest estimates Cape Town will run out of water on April 16th.

Day Zero: How Cape Town is running out of water is a Guardian article exploring the reasons behind Cape Town's current drought. The article includes an effective visualization of how the drought has effected the dam. A transition between two satellite images of the Theewaterskloof dam, shows the water levels when full and how it looks now. The article also includes mini cut out maps of Cape Town's four key reservoirs, showing how the water in them has shrunk since 2014. The satellite imagery in the article comes from Sentinel 2 & Landsat 8 (to trace the reservoir outlines).

Using a series of satellite images can be particularly effective in showing the scope of water loss in an area. For example in documenting the loss of the Aral Sea. The Aral Sea was once the fourth largest lake in the world. Due to Soviet irrigation projects the Aral Sea is now less than 10% of the size it once was. In fact the eastern basin of what used to be the Aral Sea is now called the Aralkum Desert

Lots of people have used satellite images to document how the Aral Sea has dwindled in size over time. This NASA Earth Observatory feature uses a series of images from the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite to document the water loss in the Aral Sea from 2000-2017.

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