Emus are hilarious! My dad once had a ice cream stolen from him by an emu. He was holding it behind his back to stop an intrusive emu from getting it and another came up behind and nabbed it.
A few years ago I was in a 4WD somewhere past Wiluna in Western Australia (ie middle of bloody nowhere!) with a geologist looking for uranium (I found a little bit) and while driving through scrub drove through a flock of emus. For no particular reason they all started running alongside the car. I was sitting in the passenger eye to eye with a determined emu. This always seems to happen. Whether you're on a train or in a car they start running alongside until they get too tried to run any more.
That land under the bridge is the Gasgoyne river. Last time I was in Carnarvon it was a series of small puddles. In the wet season it can get busy though.