Selectors will meet at the conclusion of the British Gas Diving Championships to formulate their squad, with two individual slots open in the women's platform event.
Powell, eighth at the recent European Championships, won gold with a total score of 376.05 points, well clear of Tonia Couch and third placed Monique Gladding, who will both hope they've done just enough to fill the remaining place.
"I've been focusing a lot more since the Europeans and sharpening things up in training, so all I had to do was dive like I do in training," said Powell.
"I've proved I can do my dives as well as anyone else - I'm still around."
Couch, who is guaranteed to compete with Sarah Barrow in the 10m synchro event at London 2012, after winning gold at the Europeans, underlined her form by posting a personal best in the individual discipline.
"I've been trying to get my PB for a while,” she said. “It was a really tough competition - I knew I had to put something special in."
It means an anxious wait for Gladding, who finished fifth and top Brit in Eindhoven last month.
Twelve months ago the 30-year old didn't know whether she would dive again after hitting her head on the platform while competing in Russia - a horrific accident which her coach and husband, watching from the pool deck, initially feared had claimed her life.
"Obviously I wanted to be in the top spot but I couldn't have done any better than I did," said Gladding, who qualified seventh but was leading the final after three dives.
"After qualifying, I was really angry with myself but I thought that if I was going to go out, I wanted to go out with a fight.
"Every step I've taken has been about getting my confidence back; I've had to dig deeper than ever this year."
Elsewhere, Jack Laugher booked his Olympic slot with a gold in a 3m springboard final that he led from start to finish.
"Some of my dives weren't as good as I could do them, so there is still more improvement to be made," he said.
"I made a couple of mistakes which shouldn't really happen. But I was only ten points off my personal best in the final.
"There have been good points and bad points, so now I just have to work on my bad points for the Olympics."