池 and 沼: pond and swamp names versus observed water conditions
Read a garden pond and a swamp bordered by grass, separating the terms from size, depth, and observed cloudiness.
Naming a pond
池, read いけ, means pond. 庭の池に魚がいます。 says that there are fish in the garden pond.
池の水を抜きました。 says that someone drained water from the pond. Separate the named place from the water acted on inside it.
Naming a swamp or marshy water body
沼, read ぬま, can name a swamp or marshy body of water. 沼の周りに草が生えています。 says that grass grows around the swamp.
沼の水が濁っています。 says that the swamp’s water is cloudy. It reports an observed condition rather than a rule that every 沼 always has the same condition.
A place name and an observed property
大きな池や深い沼という説明もあります。 says that descriptions such as a large pond or a deep swamp also occur. Do not create a fixed size or depth threshold from the names alone.
池と沼の位置を地図で確認しました。 says that someone checked the pond and swamp locations on a map. It does not state a visit or an actual water measurement.
Does 沼の水が濁っています。 give the swamp’s depth?
Show the answer and why
No. It describes cloudy water without giving a depth measurement.