The original Kamehameha wave was used by Master Roshi in Dragon Ball manga volume 2 originally released in Japan in 1986 while Street Fighter only came out a year later in 1987. Since Capcom is a Japanese-based company, it's a safe bet that SF's Hadouken was a copy of the Kamehameha in Japan. More @Wikipedia
Hover over any link to get a description of the article. Please note that search keywords are sometimes hidden within the full article and don't appear in the description or title.