nontidal
adjective
non·tid·al ˌnän-ˈtī-dᵊl 
: not relating to, caused by, or having tides : not tidal
a nontidal body of water
a nontidal current
nontidally adverb
Example Sentences
Recent Examples on the Web The property’s unique ecosystems could also provide a living classroom for visitors to learn about tidal and nontidal wetlands. 
Aegis Staff, baltimoresun.com, 24 Sep. 2020 Outdoors Record muskie caughtin upper Potomac River The Maryland Department of Natural Resources confirmed that a Washington County woman has set a muskellunge (muskie) nontidal state fishing record. baltimoresun.com, 11 May 2017
Aegis Staff, baltimoresun.com, 24 Sep. 2020 Outdoors Record muskie caughtin upper Potomac River The Maryland Department of Natural Resources confirmed that a Washington County woman has set a muskellunge (muskie) nontidal state fishing record. baltimoresun.com, 11 May 2017 Word History
First Known Use
1843, in the meaning defined above