Rocky Mouth Rehab – Media 8.10.07

“Conservation through sustainable use.  Making people part of the solution”
“The Voice of NSW Recreational Fishers”
Web site; www.ecofishers.com
                                                                   

Repetitive fish kills in the Richmond estuary have given rise to grave community concern. Rocky Mouth Creek, (near Woodburn,) and the Tuckean, have been identified as two of a number of “hot spots,” triggering disastrous fish kills.

In response, some environmentally aware land owners, along Rocky Mouth Creek, have invoked simple yet highly effective land and drainage management practices that will reduce the severity of the recurring problem.

“It’s happening and working a treat!”

750 ha of what was a highly productive wetland and fish nursery area, was drained and flood-gated for agriculture, during the last century.
The whole area is acid sulphate soil, which remains harmless while underwater, but releases devastating plumes of toxic sulphuric acid, after exposure to the air.
Introduced pasture species, (paspalum etc) replaced native grasses, which are much less tolerant of inundation and decompose rapidly when flooded, stripping vital oxygen from the water. And this is what creates the notorious toxic “black water.”

The drained acid sulphate soils created large “scalded areas,” devoid of all vegetation. The drained wetlands were now more susceptible to peat fires and severe winter frosts.

This situation was unsustainable.

Seeking a solution, farmers approached NSW Fisheries experts.
With funding from Northern Rivers Catchment Management Authority and support from ECOfishers, remedial and rehabilitation measures were implemented.
They involved four water control structures, (drop boards) located at strategic locations along the now shallowed agriculture drains. These initiatives now retain a controlled amount of fresh water (10 to 15 cm) across the former productive wetland and still maintains the flood mitigation capacity of the system.

Everyone is delighted. The farmers now have a new growth of highly nutritious native water couch as pasture. The previously drained country is once again a wetland, bursting with life. Brolgas are stalking the new shallow swamp. Fat cattle are grazing on the new luxuriant new growth. The dangerous acid sulphate soil is safely submerged. Black swans are honking and bonking on site.
The farmers are especially pleased. The new wetland provides a drought refuge with high quality feed for their cattle.

ECOfishers are also delighted. While 750 ha is only a small area of the broad picture, it is still a giant step in our “Richmond River Rescue.” It will mitigate against some future fish kills.