Photographs taken at Meridian's West Wind project above the Makara coastline show how sediment has been overflowing from the construction site.

The photos were taken by marine environmentalist Jim Mikoz, who wrote an article in the NZ Fishing Coast to Coast magazine with the headline: The dirt behind wind turbines.. your fishing is at serious risk. In response to the article, Meridian wrote a letter to the editor stating that there would be no mud runoff into the sea from its construction site. The letter, by Adam Muldoon, NZ Wind Development Manager Meridian Energy, said:

"Meridian can unequivocally state there will be no significant damage to the coastal intertidal or estuarine environment from any wind development it carries out in the south coast Wellington area, either during construction or long term operation."

Three of the comments received by Wellington.Scoop in response to Monday's article on the Makara windfarm have expressed concern about environmental damage, with a diver describing a layer of silt on rocks, plants and the seabed. Jim Mikoz's photos focus on problems with sediment traps at the one of the Meridian turbines.

Jim Mikoz says the Wellington Regional Council shares responsibility for the problems because of the design failure of sediment traps and inadequate management of the resource consent conditions of compliance.

"Not only is the mud being directed down the hill, there is no requirement to require operators to clear a sediment trap once it becomes full or to remove the mud into sediment boxes - which is a requirement made of industrial sites where mud may flow into a stream."

Alongside this wind turbine, the concrete pipe with the hole in it catches the mud which is then directed down the bank, bypassing any other sediment trap.

The pipe is poking out of the bank under the nose of the turbine.

The sediment trap with two ponds has clearly overflowed, with the mud going down into the stream around the coast from Makara Beach. However, says Jim Mikoz, there is no evidence that provision has been made to clear it, and a dam made of dirt will always fail when the rain is heavy.

"The history of heavy rainfall at Makara has not been researched to even consider building a sediment trap dam of loose dirt," says Jim Mikoz. "This one will fail in the first big rain fall, just as other dirt dams in the Wellington region have done made of dirt dams."

Photos taken at the Aotea subdivision in Porirua are proof of the damage that is caused by an inadequately-designed sediment trap.

A sediment trap overflows after heavy rain.

As a consequence, mud flows into Porirua Harbour. In the last ten years, mud has decreased the harbour water depth by over one metre.

Jim Mikoz writes: Another impact of sediment traps is the practice of flocking them with chemicals to trap the mud into the sediment so that the public can think they look clean. Unfortunately when it rains the sediment flows down the streams into the Porirua harbour where those who use the water for their sport receive skin infections for some days after, because the fresh water, now full of chemicals, lies on the sea surface for a number of days without wind to break it down into the seawater. The impact on marine life from mud and chemicals is massive and those that can swim have to move out while the marine life they feed on is smothered and killed.

Editor's note: photos of the runoff can be seen by clicking on the link below.