Here are two images of the windgap near Perth, Western Australia: a closeup of Walyunga NP, and a larger scale image of the Perth coast. They were obtained from Google Earth.
The first is a Google Earth screenshot, in which the purple represents a filled-in contour of 80m asl [above sea level], and the blue of 120m asl. The blue area delineates the westward flowing paleochannel which would appear to have been cross-cut and captured by the SE flowing Swan R., whose channel is purple.
This image is intriguing because it shows both the parallelism of the western Australia streams, and also a consistent jog in stream channels that appears as they approach the coastal plain.
The second image is from a Google Earth mapplet called Sea Level Rise, which allows the user to set 3 different sea levels in red, yellow and orange, in order to simulate sea level rises. The idea is that it simulates emergence from inundation. On this image, red is set at 80m asl, orange at 180m asl and yellow at 240m asl.”
Another feature on this second image is the flatness of the plateau east of the Darling escarpment. The Sheet flow stage of the retreating floodwaters explains the flatness of this plateau which has had kilometres of sediment removed in sheets from its surface.
Notice how far the valley of the Swan River (yellow) has cut westward (and then southward) into the plateau, for more than 100 km through Northam and York and as far as Brookton. This huge valley is more than 10 km wide in many places. It’s appearance is similar to the Grand Canyon in the USA but it is not as wide or as deep. Peter Scheele published a study on Grand Canyon in the Journal of Creation using a receding-Flood scenario for its origin.
Notice the fractal shape of the edges of the Swan River valley on the plateau. That is similar to the shape of Grand Canyon, USA. Sheele explains how a huge, deep body of water ponded on the plateau would carve that fractal shape as it drained off the plateau and across the escarpment.
Notice the faint ripple pattern on the surface of the plateau. It looks like the sorts of sand ripples often found on the beach after the tide has gone out. These sorts of features are noticeable in landscapes all over the world.
These images graphically reveal the signature of the Retreating stage of Noah’s Flood on the landscape. The ready availability of Google earth allows anyone to do these sorts of investigations.