Two photographs of Karori reservoir from 1988 and 2012, merged to show changes in the area covered by the lake.  The blue/grey area shows the original lake level, an area now reclaimed by natural regrowth of the forest.  Wellington, New Zealand.  The two images were manually aligned and scaled using CombineZP, then merged to form one image using Gimp (layers merged by colour saturation difference gave the clearest result.
Tony Wills
CC BY-SA 3.0
<a href="//commons.wikimedia.org/wiki/File:Karori_reservoir_1988.jpg" title="File:Karori reservoir 1988.jpg">File:Karori reservoir 1988.jpg</a>, <a href="//commons.wikimedia.org/wiki/File:Karori_reservoir_2012.jpg" title="File:Karori reservoir 2012.jpg">File:Karori reservoir 2012.jpg</a>