Bananas disappearing from hills
EROSION of slopes left bare because of changes to agricultural practice was unfortunate, but was bound to occur, Coffs Harbour district horticulturist Peter Newley said.
The disappearance of bananas from hillsides behind Coffs Harbour has been pinpointed as one of the contributing causes for this year’s disastrous flash flooding.
Middle Boambee and Woolgoolga residents have also pointed to the erosion and siltation caused by the changeover from banana cultivation to blueberry growing, with bulldozed bare slopes exposed to heavy rain.
Middle Boambee resident Michael Johnson identified the differing treatment of erosion potential on construction sites and agricultural sites, saying construction sites had requirements to place silt fencing and hay bales to minimise erosion when sites were disturbed, but the same rules did not apply to agriculture.
Industry and Investment NSW horticulturalist Peter Newley said the best way to avoid problems was to reduce the area which was changed over at any one time to minimise the amount of loose soil.
He said they recommended reducing the time between operations as much as possible and diverting water from the disturbed site and it was in farmers’ interest to retain as much soil as possible.
He said Industry and Investment NSW did not restrict the type of agricultural use like changes to crops or the steepness of farmland slopes, although there were restrictions on clearing native vegetation.
“You can’t say (a farmer) can only grow one crop,” Mr Newley said.
“There has been significant erosion all over the place this year, even on established farms.”
Mr Newley said guidelines on blueberry growing published several years ago recommended diverting water running down the slopes by breaking up the length of rows and putting in spoon drains across the slope to catch run-off water before it gains volume and velocity and diverting the water to a gentler slope.
A spokeswoman for the Northern Rivers Catchment Management Authority said as a non-regulatory body the CMA could not force people to do anything, but could do site inspections and offer help and advice.
Coffs Harbour Mayor Keith Rhoades said in his 38 years as a local resident he had seen creeks narrow and lose a lot in depth.
He said at the Fred Hansen Bridge on Boambee Creek, it used to be eight metres from the road to the top of the water but now someone hanging a foot over the side of the bridge could touch the water.
“There used to be banana-clad hills at Korora, Red Hill and Boambee and Middle Boambee – have a look now,” Cr Rhoades said.
“Each stool held 5-7 litres of rainwater and tens of thousands of those have been removed – it is nobody’s fault but I wonder how much of a role that has played?”