The Grey District Council's Coal Creek water treatment plant supplies drinking water to the largest urban centre on the West Coast however it has complained it was not properly consulted by the West Coast Regional Council when the landfill was sited a short distance away. Photo: Greymouth Star/Brendon McMahon
A controversial landfill "facilitated" the discharge of contaminants, a new consent application to the West Coast Regional Council says.
The Taylorville Resource Park at Coal Creek, near Greymouth, is applying to design and build a new water treatment system following an abatement for leachate discharge into a roadside drain.
The accompanying assessment of environmental effects (AEE) says the current system has "facilitated the current discharge of contaminants".
As well, the water management system "may not have the capacity" to cope in significant weather events.
The site is less than 5km east of Greymouth township and sits immediately above the Grey District Council's town water supply treatment site, about 50m away.
However, the new application casts doubt on any possibility the Taylorville Resource Park site would affect Greymouth's drinking water supply.
"Other than via discharge from springs to surface water, it is highly unlikely groundwater present at the site is in connection with groundwater of the Grey River where a groundwater abstraction is located 380m south of the site," the AEE said.
Overall, the potential human health effects from landfill groundwater reaching the drinking water supply were considered "less than minor".
The Taylorville Resource Park workings now dominate the skyline in the rural neighbourhood of Coal Creek, a few kilometres east of Greymouth. Photo: Greymouth Star/ Brendon McMahon
While concentrations of arsenic, copper, chromium, nickel, zinc and toxic ammonia leachate from the site have been found to be "in excess of guideline criteria" for aquatic life, concentrations in the roadside drain below the site were "below or only slightly over" the guidelines and would be further diluted downstream.
Taylorville Resource Park is currently consented to take demolition waste, clean-fill, and contaminated material including asbestos and coal-tar.
But it has been plagued with problems including odour, dust, and water leaching issues during 2023.
Subsequent West Coast Regional Council abatement notices for dust and odour issues have been resolved. But the water abatement issue is driving a new water management system for the site.
The application outlines a large storage pond and a pre-pond leachate treatment scheme including a "post-pond final treatment/polishing system".
The site is also seeking a permit to discharge treated water via a creek immediately west of the site -- within land owned by affected party and regional council chairman Peter Haddock.
The Grey District Council and Te Rūnunga o Ngati Waewae are identified as affected parties in the application.
The AEE notes a positive effect of the new water treatment system is the site fulfills "a much needed repository" for demolition material in the Greymouth area.
The Greymouth water treatment plant sits below the landfill and the road and above the river, middle. The red shaded area, left, (Quadrello) is owned by West Coast Regional Council chairman Peter Haddock. Photo: LDR / supplied
Previous regional council abatements in 2023 for foul odour and dust have been resolved.
But an incident at the site in early August where two workers were overcome by gas compounded the issues for the operator.
WorkSafe has since cleared the landfill operator to resume although the site remains under investigation.
The new application notes surface water discharge and groundwater is monitored under current consent conditions.
The landfill site is on the edge of the fairly flat Coal Creek Plateau.
"To the south of the site the land drops steeply down to intermediate river terraces and then the Grey River 40-50 m below the site."
Hydrogeology evidence supporting the application notes groundwater from around 6 to about 11m below ground level at the site.
Groundwater flow direction within shallow gravel on the site was "expected to be" towards the southwest overall.
However, the underlying mudstone contours of the site was "likely to affect" localised ground waterflow direction, the AEE said.
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