water feature
US /ˈwɑː.tər ˌfiː.tʃər/
UK /ˈwɑː.tər ˌfiː.tʃər/

1.
a decorative element in a garden or landscape that involves water, such as a fountain, pond, or waterfall
:
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The garden was enhanced by a beautiful water feature.
•
They installed a small pond as a new water feature.