Immediate action is needed regarding a large shingle bank in the Waikanae River which threatens to spill into an environmentally important scientific reserve, Waikanae Estuary Whitebaiters Network member Chris Turver claims.
He said it was the largest shingle build-up "ever seen" and it threatened to inundate the lower Waikanae Estuary Scientific Reserve, especially with more frequent floods predicted.
"This huge shingle bank sits in the coastal marine area with its height almost level in places with the river banks which, in itself, raises the prospect of urban flooding issues when rain dumps try to force their way downstream.
"We've already seen a huge increase in mud smothering more than half the estuary and if the shingle breaks through as well that will be the end of Waikanae estuary as we know it."
He believed Greater Wellington Regional Council was prevented by lack of a resource consent from reducing the gravel build up especially as the Department of Conservation "which opposes activities which impact on the ecology of the waterway in its area of responsibility".
In the first of a two-part response by GWRC to an Official Information Act request by the Waikanae Estuary Whitebaiters Network, GWRC said the consent allowing it to extract gravel from the wet channel for river management purposes expired in September 2007.
Mr Turver said between 2001-2007 GWRC extracted 35,000 cubic metres of gravel from the river but was not allowed to go into the coastal marine area, including the scientific reserve.
"In May 2013, in the face of rising shingle levels, GWRC applied for a replacement wet gravel extraction consent bit it's still not been approved.
"GWRC says in the meantime the need for gravel extraction has been identified and it's planning the methodology and locations."
The regional council and DoC said, "Presence or removal of gravel in the river has knock on effects on other natural systems and helps shape our coasts.
"DoC are working with Greater Wellington around gravel removal in the Waikanae River for the best outcomes for the river, the estuary and the coast."