Remotely sensed flow patterns can reveal the location of the subaqueous distal tip of a distributary channel on a prograding river delta. Morphodynamic feedbacks produce distributary channel tips that become shallower over their final reaches before becoming deeper over the unchannelized foreset. The flow direction field over this morphology tends to diverge and then converge providing a diagnostic signature that can be captured in flow or remote sensing data. Twenty-one measurements from the Wax Lake Delta (WLD) in coastal Louisiana, and 317 measurements from numerically simulated deltas show that the transition from divergence to convergence occurs in a distribution that is centered just downstream of the channel tip, on average 132 m in the case of the WLD. With these data we validate the Flow Direction to Channel tips (FD2C) inverse model for remotely estimating subaqueous channel tip location. We apply this model to 33 remotely sensed images of the WLD between its initiation in 1974 and 2016. We find that the distributaries grew unevenly, 6 of the primary channels grew at rates of 60–80 m/yr while one grew at 116 m/yr. We also estimate the growth rate of the total area enclosed by the subaqueous delta platform to be 1.83 km 2 /yr with no obvious rate changes over time.