Many things are out of our hands, but one can always keep rivers/streams clean. If you see trash along the bank, pick it up and throw it away. Many people are unaware that trash can eventually make its way to a river/stream, even if water isn’t nearby.
Knowledge is a great tool to preserve and protect aquatic ecosystems. Just being aware can show your beliefs in keeping streams/rivers clean. You can pass your knowledge on to others and spread your feelings of protecting aquatic ecosystems.