The Blue Heart

The Blue Heart sits at the very bottom of the coast's gradient, on the tidal Maroochy floodplain — the ground the whole reef-to-range slope ultimately drains into. For a century it was read as a problem to be solved by drainage: dig the channels, throw up the levees, drop the water table, and turn swamp into cane and pasture on the confident nineteenth-century assumption that a drained swamp was an improved one. The Blue Heart runs that logic backwards.

What is being done, and by whom. Across more than five thousand hectares — a substantial share of the floodplain — a partnership of Sunshine Coast Council, the Queensland Government, the water utility Unitywater and the Kabi Kabi Peoples Aboriginal Corporation is deliberately un-draining the country: opening levees, letting the tide creep back into old cane paddocks, and letting fresh water sit where the drains used to carry it away.

What reassembles, and why in that order. The wetland does not have to be planted; it re-sorts itself by the one variable that always ruled it — how far the salt water reaches (see estuarine-zonation and wetland-zonation). Where the tide runs in freely, grey mangrove and then saltmarsh return to the lowest, saltiest ground. Behind the tidal reach, where rain and groundwater pool but the sea seldom comes, freshwater reed, sedge and paperbark wetland reassembles. The gradient of salt writes the bands, exactly as it does in an undisturbed estuary; the restoration's job is mainly to restore the water regime and step back (see mend-the-conditions). The nearby Yandina Creek Wetland is the proof of concept in miniature — old cane paddocks that turned back into a bird-thick wetland on their own the moment failed tidal floodgates let the water return.

The unpaid work of a wetland. The case for spending money to put water back onto land earlier generations spent so much to drain rests on everything an intact wetland does for free, once you bother to price it: it soaks up floods that would otherwise reach houses; it filters run-off before it reaches the bay; it nurses the fish and prawns the estuary fishery depends on; and it banks carbon in its waterlogged, airless soils — the "blue carbon" of tidal wetlands. There is a second, quieter dividend particular to this floodplain: keeping the ground wet keeps the buried acid-sulfate sediment safely drowned, so it never wakes into the sulfuric-acid pulses that drained cane land can flush into the creeks.

An honest calibration. That a project on this scale is now paying to re-wet drained land is a real measure of how far the reading of this country has turned — but it is a deliberate, ongoing intervention, not a return to some untouched past. The floodplain is being managed back toward function, band by band, under the same principle as every other project here: restore the conditions the wetland needs, and let it do the rebuilding.