Creek Diversion & Reinstatement

A pit footprint moved north and put a creek through the middle of it — so the creek had to be diverted for the life of the mine and put back at closure, in a form that returns flow to the downstream floodplain in the proportions it had before mining.

The assessment ran three conditions rather than two: the pre-mining baseline, the staged operational diversion, and the reinstated landform at closure. A diversion that works for fifteen years and then leaves the floodplain drier than it found it has not solved the problem, only deferred it.

Reinstatement is where creek diversions are actually judged. Getting the operational channel to carry the flow is the straightforward half; getting the closure landform to redistribute flow across the floodplain the way the original creek did is the half that has to be designed for from the start.