I saw your post and decided to tell you what I found/know about "Zaslavskoe Vodohranilische". Is that what you're looking for?
If so, than here it is:
We call it Minsk sea actually, which is situated about 10K NW from Minsk. It was formed in 1956, after they built a dam and other hydrotech buildings. There are something like 11 small islands in this lake. The biggest one is called the Love Island. There are lots of villages on its shores and beaches too cause that's where most of the Minsk population goes to swim/tan in the summer. As far as I know the islands themselves are covered in trees & bushes and are not inhabitable.
Hope this helps,