Plans are still in the beginning stages, so there are a lot of important unanswered questions at this point. For example: What affect will this have on the local flora & fauna? How will it be maintained? Is it secured to the riverbed...stable and safe for members of the community? The pool water is filtered river water, is the water that re-enters the river then contaminated by cleaning chemicals or the users of the pool? How could this object be used to better the environment it occupies, can exiting water be filtered in a way that helps to purify the river and reverse the effects of earlier pollution?
You can visit their website to find out more or get involved. It is an ambitious and innovative project. I'm excited to see how it develops and how it inspires the design community.