Swimming at Norak (Nurek) will be a cold experience, so it’s perfect for the height of summer when Dushanbe is baking. Norak reservoir is just over one hour away from the capital city. For accounts of swimming there, check out this 2009 blog post, and this 2015 blog post.
In addition to swimming, you should be able to do a variety of water sports. See our Norak page for more information.