Large River in Chinese / Japanese...

江 means large river in Chinese, Japanese Kanji, and old Korean Hanja. This generally refers to a river big enough that it's navigable by cargo boats, passenger boats, or small ships.

In Japanese, this can be a surname when pronounced as Minkou or just Kou.

漫瀾 is the Chinese, Japanese Kanji, and old Korean Hanja for “Having no boundaries or limitations.”

This literally talks of the vastness of an ocean or river.

Character breakdown:
漫 = free; unrestrained; to inundate; overflowing; boundless.
澜 = swelling water; large wave.