Not sure that April fool's works these days with so much instant communication.
The best one I remember was in the 90's - pre internet and mobile phones!. The local radio was reporting that a container ship had lost some containers going along the Solent and money and gold bars (that should have been the giveaway) had washed up on the beach in Portsmouth.
Caused gridlock on the septic isle for a good few hours!!
Swansea was supposed to be building a tidal lake to give power on demand.
Tides are always moving, either coming in or going out, so there is always tidal movement to be harnessed....