Actually earth, I'm being serious here now,I would get one of them choppers in with a big bucket under it, the one they use in the fires.OrYou could get a hose pipe or something and run it from the nearest beach, hope hat helps mate
I just wasn't 100% sure as when its really windy you can get spots on the windows.Learn to rinse so that the wind doesn't blow the water off course. Really windy weather can leave residues whether you wfp or trad