Don't presume people use shaving foam when they recommend shaving by ponds, creeks, and streams. I certainly don't - not even in my bathroom. Once skin is conditioned to water enough, the cream/foam is not necessary. When I was a Boy Scout, olive oil was the recommended green substitute for those with sensitive skin or who still want a shave conditioner, and can be used right at the water's edge with no imminent terror to the local wildlife.