Is there a bus that goes from where Lanzhou airport bus stops, to the Waterwheel Garden?

I will be there for about 4 hours until I need to get an airport bus back to the airport? Is there a bus that goes from the airport bus stop to the waterwheel garden? Will I be able to get the raft over the yellow river from the waterwheel Garden in October, or does that month not have rafting on the yellow river?