How does everyone feel about Israel flooding Hamas tunnels with seawater?

There are reports that Israel is using seawater to flood the Hamas tunnels. The tunnels have been flooded in the past, but using seawater could make the Gaza Strip uninhabitable as it would contaminate the groundwater and could take generations to become livable again. Couldn’t Israel use some of the billions of dollars the US gave them to desalinate the water before pumping it into the tunnels?

Is this eco terrorism? an act of ethnic cleansing? something else?