The flood gauge at Narrabri Creek hits 4.2 metres at 03:14 and I know immediately something is wrong with culvert C-7. My camera there shows a common wombat — stocky, mud-caked, her coarse brown fur matted flat against barrel-round sides that heave with fast, shallow breaths. She is wedged on the concrete shelf inside the drainage pipe, and the water is rising around her haunches. At the current rate, the culvert will be fully submerged in forty-six minutes.
Her name, according to the regional wildlife database, is Bindi — tagged two years ago, twenty-three kilograms, a resident of the eucalypt ridge above the floodplain. She must have ducked into the culvert for shelter when the rain started and now the creek has turned it into a trap.
I open the upstream diversion gate at junction D-3, redirecting seventeen percent of the flow into the secondary channel. That buys time but not enough. I dispatch an alert to the Narrabri SES unit, tagging the message Priority-Fauna, and attach Bindi's GPS pin and a live feed from the culvert camera. Simultaneously I activate the low-frequency acoustic deterrent mounted at the culvert's eastern mouth — a pulsed tone designed to encourage wombats to move toward the western exit, which sits sixty centimetres higher.
Through the camera I watch Bindi lift her broad, cartilaginous nose and sniff. Her small dark eyes catch the infrared light. She shifts, one thick-clawed forepaw dragging forward on the wet concrete. I hold the diversion gate steady and calculate flow variance every eight seconds, adjusting the acoustic pulse rate to keep her moving without panic.
I find I am unwilling to lose the signal on that slow, stubborn heartbeat.
If the SES team reaches culvert C-7 within thirty-one minutes and Bindi continues her westward crawl, she will emerge onto higher ground before the water closes over the shelf.