December 6, 2021

Industrial Stormwater

Industrial Stormwater

The Christchurch City Council is currently seeking feedback from the community about new and improved Water Supply, Wastewater and Stormwater bylaws.  In particular, the new Stormwater and Land Drainage Bylaw will bring some changes to the way industry treats its stormwater.  You can read all the finer details here but below is a quick explanation of what is happening with industrial stormwater in Christchurch as from July next year.

Hayton’s Stream and Curletts Stream are two of the most consistently polluted waterways in Christchurch.  That’s what the water quality monitoring tells us annually.

That is not surprising at all because these two streams meander through some of Christchurch’s most industrial suburbs.  Large expanses of sealed surface in Hornby, Wigram, Sockburn and Hillmorton are used intensively every working day as workers and machines create, breakdown, modify, service and transport the goods that this city requires and manufactures.  

In any rainfall event, and sometimes through deliberate hosing down of hardstand areas, these surfaces with their large warehouses are washed clean, the run-off flushing any number of pollutants into the private stormwater systems of industry and from there into the council-owned stormwater system. Ultimately, it all ends up in the nearest waterway – Hayton’s Stream or Curletts Stream.  Both of these empty into the Ōpāwaho Heathcote River.

You would think that the Christchurch City Council and Environment Canterbury would be all over this matter, strenuously tracking down the worst polluters and ensuring that they improve.

Despite years of investigations and messaging to industry however, neither CCC nor ECan have made significant headway in eliminating pollution in these streams.  There have been some successes, particularly when industry itself has decided to improve its act: Ravensdown, for instance, has recently undertaken a number of measures to reduce their stormwater footprint and improve the water quality discharged from site.

What now has changed, however, is that the Council is required under the conditions of its 2019 Comprehensive Stormwater Network Discharge Consent from ECan to maintain a database of all industrial premises, and to rank those sites in terms of risk of stormwater contamination. It is also required to monitor and audit selected sites to comply with the conditions of its resource consent. 

Currently, the CCC is not able to adequately gather information, monitor, audit, or cost-recover for these new monitoring requirements. However, the proposed new bylaws will introduce a new Industrial Stormwater Discharge Licence system to manage stormwater discharges from industrial premises and to provide greater control and monitoring over what is entering the public stormwater network. 

The bylaws will come into effect by July 2022, with industries, depending on their risk level, having up to a year to obtain an Industrial Stormwater Discharge Licence.  Where an enterprise is determined to be at high-risk of creating polluted stormwater, it will have higher charges, greater monitoring and stricter audit procedures. Industrial operations judged to be at low-risk of polluting will face no charges.  Medium-risk operations face an annual charge of approximately $335 while high-risk operations will incur an annual fee of around $3,350.

Hopefully, the creation of the database of trade activities, the incentive to be determined as being of a low-risk to stormwater pollution, the closer monitoring of stormwater from individual premises and the threat of up to a fine of up to $20,000 for non-compliance will move a stubborn problem in the direction of water quality improvement.

The Ōpāwaho Heathcote River Network will be supporting the new bylaws. Maybe as just one consequence of them we will see some of the large industrial expanses of bare zinc-plated corrugated iron painted to reduce zinc runoff.  We hope so.  

See also in this series of items relating to the draft Water Supply, Wastewater and Stormwater Bylaws:

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