The words damming sound the same but have different meanings and spellings. Why do damming sound the same even though they are completely different words?
The answer is simple: damming are homophones of the English language.
Present participle of <xref>dam</xref>.
Definitions from Wiktionary, Creative Commons Attribution/Share-Alike License. and Wordnik.
Homophones (literally "same sound") are usually defined as words that share the same pronunciation, regardless of how they are spelled.