The grass (hydrilla) will be back, They spray to control it more than kill it (I think). They have been doing it for several years now. "Back in the day" there was almost to much at times.
Good thing is they do not kill the Primrose off nearly as bad as the hydrilla.
This is from 6 years ago when there was a mat like this almost all the way around the lake. This was late summer 2012. It will not be back like this but it will be back.
fwiw...She made it out no problems... but I was worried I was going to have to go get her.