First time hearing of this, but I think it's a bad idea that will probably or eventually lead to drought, the evaporation goes to the cloud and then becomes rain and the cycle continues.

The need of floating solar panel isn't actually needed as hydroelectricity exist already, each has their advantages and disadvantages in my own opinion a hybrid or tribrid way should be found to boost clean power not making a method breach the other.

In the case of having more land space for more productive activity I guess the creation of high towers that goes up then houses the solar is way more effective than encroaching the space for hydroelectricity and disrupt the weather system.