Editing Tagus (section)

=== Inverted delta ===
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The Tagus river is one of the few rivers in the world to have an [[Inverted river delta|inverted delta]]. Its delta is wider at the beginning and narrows down as it approaches the sea, contrary to a typical [[River delta|delta]]. This is because it flows into the sea through a small opening in a valley. Although due to sedimentation, this delta is now only very partially inverted, with the valley now mostly filled with sediment. The delta is about {{Convert|15|km|4=0|abbr=on}} wide and {{Convert|25|km|abbr=on}} long, but its exit into the sea is only {{Convert|2|km|abbr=on}} wide. It thus forms a large lagoon with large and very shallow sand banks which go uncovered during low tides. The delta used to be even bigger thousands of years ago.