Hate to tell you but waterfalls are very bad for chameleons. They collect bacteria, possible feces and who knows what else. Also a chameleon can drown very easy. please give in and get the mister.
Waterfalls aren't best. chameleons won't drink from them and they just get dirty and collect bacteria. I would say to get an automatic mister like from Mistking, if that's in your budget. Worth all the money, but for now I would say mist the cham and the enclosure with a spray bottle so the cham can drink the water from the leaves.