Waikato District Council (WDC) has been granted consents enabling it to continue urban stormwater discharges to land, waterways and the sea, provided it complies with a range of new conditions designed to minimise environmental damage caused by the discharges.
WDC told an Environment Waikato hearings committee that the council now recognized the "significant quality and quantity of issues created by stormwater" and that it intended to avoid or mitigate its adverse environmental effects.
The hearings committee said stormwater discharges from WDC’s individual urban areas identified as villages were unlikely to have more than a minor environmental effect.
But the committee’s decision said "cumulative adverse effects will occur on receiving water bodies from the town stormwater systems".
Greater definition of these effects would be provided for by a monitoring programme, which would help develop better techniques for addressing problems.
The conditions imposed by commissioners Basil Morrison and Craig Shearer included measures to identify and address the cumulative effects of discharges, and the preparation of formal stormwater management plans.
These conditions would allow WDC to "manage the stormwater on a day-to-day basis and approve developments and stormwater-related work in an integrated manner", the commissioners said.
They said they were "disappointed that WDC has not taken a truly comprehensive approach to stormwater management by firstly preparing catchment management plans, and then preparing stormwater management plans for the various towns and villages from which it discharges stormwater through municipal systems."
The committee felt the lack of a comprehensive stormwater management plan to support the consent applications had in fact "hampered" its work.
Meanwhile, the committee heard that polynuclear aromatic hydrocarbon (PAH) concentrations may be affecting biology near the Bow St outlet within Raglan Harbour, and investigations were suggested to determine the level of effect.
One submitter, Fred Litchwark from Whaingaroa Harbour Care, said heavy metals and PAH made shellfish inedible at times.
The committee said WDC had to complete a stormwater quality review at the Bow St outlet within six months to determine what impact it was having.