How Do I Keep My Hair From Going Wildly Frizzy In The Jungle ?

Okay so I'm Going to the Indonesian Jungle For 2 weeks For an Operation Wallacea expedition and I'm worried about my hair swelling up , frizzing out and eating me and everyone else in my expedition . I don't Have electronics I.E hair dryers + straighteners . I have pretty thick hair which is naturally curly and wavy ( But not in a nice neat way more of a Afro-tastic but without the 'tastic' ) I cant use any other type of shampoo becuase it has to be biodegradeable becuase im showering in waterfalls , rivers and streams :) PLEASE help I don't want to be a walking afro !!!! Thanks Jx