The Ōpāwaho Heathcote River has always drained its catchment. Now, however, the CCC is required to stop treating it as an actual drain and to treat it as a taonga.  That involves us – those who live beside it – as well as our local government.

Even when it is not raining, the flow in the Ōpāwaho Heathcote River is substantial and that increases as the river gets closer to the estuary.  That is because this wonderful river is essentially fed by artesian springs. Springs bubble to the surface at the river’s headwaters in Hornby and Hillmorton.  Other springs in Halswell and Hoon Hay feed the Cashmere Stream which doubles the flow of the Ōpāwaho Heathcote River as it joins it at Shalimar Drive. Lesser visible springs, often trapped in pipes and built over, contribute to the river down its length.  Invisible springs add directly to the river from beneath. All of this flow is clear, almost pure artesian water from the highest of the aquifers beneath the Canterbury plains..

This is why, after a few days without rain, the Ōpāwaho Heathcote River runs largely clear until it starts to mix with saltwater moving upstream on the rising tide.

When it rains, however, runoff from the land and streets enters the river and that is when the picture changes. The river has always drained its catchment, but what has changed is the form of the catchment itself.  

The catchment used to be mostly densely forested hills and lowlands feeding into wetlands. The catchment now is hills significantly denuded of vegetation, buildings, roads and other large areas of impermeable surfaces.  Most wetlands have been drained and built over.

A drain no more   

For most of the European history of Christchurch, its citizens have treated the river as if it were an actual drain, with all the unpleasant connotations of that word. A change to the river’s status started in the 1970s and in December, 1999, the Environment Court issued a consent order for the Comprehensive Stormwater Network Discharge Consent (CSNDC) authorising the majority of stormwater discharges within the Christchurch City area and from the Council’s reticulated stormwater system. 

Put simply, terms of the consent require the CCC to make reasonable efforts to ensure that stormwater discharges meet minimum standards and to show that it is taking reasonable steps to continually improve the water quality of its waterways.  To help do that, the CCC monitors water quality along the river. It is trying to return the river from being just a drain to being treated as the taonga it is.

New Bylaw

That is why the CCC is interested in what is leaving your property in your stormwater and where your stormwater goes. The CCC is currently engaged in the process of adopting an improved, up-dated stormwater bylaw. Clause 15 of the new stormwater bylaw states:

No person may, without the Council’s written approval under this bylaw:

• • build or install, or allow to be built or installed, any structure in, on, over, or within three metres of any waterway;
  • lay or permit any utility service or private pipe across, within, or along the line of an existing waterway;
  • dig or undertake earthworks on, in, or within three metres of any waterway;
  • modify the bank or bed of any waterway; or
  • alter the course or flow of any waterway.

How you can help
Just recently, members of OHRN encountered people digging up a reserve beside the river to lay a stormwater pipe draining water from an industrial building.  No permission had been sought from the Council for this stormwater discharge; there was a likelihood that the stormwater discharge from this building would be polluted with zinc runoff.

The CCC doesn’t know what is happening if it is not brought to its attention: it just cannot have sufficient staff to patrol the city looking for issues.  As residents, we all have a duty of care to the river to help the CCC return the river from being just a drain to being treated as the taonga it is.  

If you see something happening along it which does not look right to you, be a good citizen and let the CCC know through Snap, Send, Solve or just telephone 941-8999 and log a Customer Service Request (CSR) regarding the issue.