Water  |  13 Sep 2019

Christchurch City Council is concerned proposed new changes to freshwater planning rules won’t protect the district’s drinking water supply from increasing nitrate levels.

The Council today submitted formal feedback to Environment Canterbury on its proposed Plan Change 7 to the Canterbury Land & Water Regional Plan and Plan Change 2 to the Waimakariri River Regional Plan.

Public submissions on the proposed plan changes close today at 5pm.

“While the Council supports the intent for reductions in nitrate concentrations in groundwater as a result of this plan change, it is considered it does not go far enough to ensure that nitrate levels in the Council drinking water aquifer do not raise dramatically from where they currently are,” the Council’s submission says.

“The Council considers that the timeframes proposed for nitrate reductions are far too long, and that Christchurch aquifers will have increasing nitrate levels, with associated negative health effects, as a result.”

In its feedback to Environment Canterbury, the Council has recommended a number of changes with regard to nitrate levels. These include extra protection for the Waimakiriri River through a nitrate water-quality target, and a limit on nitrate for the deep aquifer bores that supply the district’s drinking water.

The Council’s submission says maintaining water quality within the district’s catchment is part of a multi-barrier approach to managing drinking-water supply and surface water quality.

“The primary ‘treatment’ barrier is the raw water source itself. Some of the deep groundwater is over 175 years old and once it is in the aquifer system, it is too late to do anything about it other than treat it at abstraction.”

“Maintaining a supply of high-quality groundwater without treatment is of paramount importance to Christchurch and the Council, and the Council seeks through Plan Change 7 further critical dialogue on appropriate management regimes to achieve this.”

Public hearings on the proposed plan changes are expected to be held in the first half of next year.

The Independent Hearings Panel will then prepare a set of recommendations for Environment Canterbury to consider and potentially adopt as its decision.