Archive for the 'Stormwater' Category

Support Auckland Water Quality $ Spend by 28 March.

March 17th, 2018

Further to Water Quality in Auckland Council 10 Year Plan STEPS has produced a draft submission supporting the Auckland Plan and 10 Year plan. Council has included approximately $2 billion for stormwater treatment and Central Interceptor. Water Quality spending over the next 10 years will focus on the Western Isthmus and bring some improvements to our communities, our Harbours and our streams. This draft is intended for groups or individuals who want to support stormwater plans. You can tailor 10 Year Plan Submission Draft to your own liking – have your say here

Auckland Council Applies for Discharge Consent by 20 March

March 11th, 2018

Auckland Stormwater Discharge Consent    Further to our blog of 1 Feb, we note this consent is for ongoing discharges for 35 years and the application contains very few conditions.  We are pleased to see Auckland Council is publicly notifying this consent in line with their commitment for more transparency with water investments. (By contrast the 35 year combined sewer network discharge consent obtained by Watercare Services in 2014 was not publicly notified). We also support the goal of aligning a range of stormwater consents into one framework.

Stormwater discharges frequently contain sewage because of inflow and infiltration caused e.g. by illegal connections, or lack of pipe maintenance. Therefore this consent relates both to human health and the environmental health of our harbours, as stormwater is the primary vehicle for heavy metals and oils off roads and other hard surfaces, which accumulate on the sea floor for the very long term. We note Meola Creek combined sewers and stormwater provide the worst deposits in Waitemata Harbour.*

We believe that the expenditure plans outlined in the 2018-28 Long Term Plan will go some way to reducing stormwater overflows and will submit on those plans before 28 March closing.  We propose therefore to briefly submit on this Stormwater Discharge consent application. We welcome members’ and public input on the following key points:

  • We ask Auckland Council to update this consent application to align with recent LTP proposals and current plans
  • Add a condition in the form of a roadmap agreed with the community showing dates by which improvements will be achieved.
  • Confirm public notification of each major project / step improvement – and a process for community involvement as improvements are prioritised
  • Review the BPO (Best Practicable Option) to ensure it is robust and less subjective in order to ensure optimal outcomes for community and environment.  The prioritising tool shown also needs updating to include water quality improvement.

Why is STEPS submitting on this? 

STEPS objective is to protect and enhance Meola Creek, our parks and the underlying aquifer;  the current state of Meola Creek* is unacceptable to the community. We cannot accept the status quo for another 35 years.

*Hauraki Gulf 2011 State of the Gulf report states:  Toxic metal and organic contaminants are causing localised effects in Auckland estuaries. A number of metal contaminants exceed sediment guideline values in the southern Firth of Thames as well. Threshold effects level (TEL) guideline values are exceeded at 21 of the 50 sites that are regularly monitored by Auckland Council. Probable effects level (PEL) guidelines are only exceeded at the lower tidal banks of Meola Creek and Motions Creek in the Waitematä Harbour. Management actions are not expected to remediate areas affected by urban and legacy contamination, but may slow accumulation and prevent the degradation of areas with clean sediments. Concentrations of zinc, copper and lead have been linked to adverse changes in benthic communities in Auckland, with contaminated sites tending to have fewer rare and large taxa. 

Update 17 March:  SASOC has made available to its members and to STEPS its Coalition stormwater Council Consent member submission. This SASOC draft opposes the Auckland Council  Healthy Waters’ Discharge Consent for 35 years. It is intended for groups or individuals  and people may tailor it to their own liking.  Submissions close on 20 March. Make a Submission here.

Meola Aquifer – how will it handle intensification?

December 27th, 2017

A study conducted for Auckland City’s integrated catchment study looked at two large aquifers on the isthmus, comparing current with “maximum probable 2050 land use” in Meola and Onehunga. This picture shows the  “paleo ridges” and “paleo valleys” of pre-volcanic Waitemata sandstone, along which the groundwater flows. It seems Meola Creek and its former tributaries closely follow the valleys of the old landscape.

The study concluded that although spare capacity existed in the aquifers to accommodate additional stormwater disposal there was a major unresolved issue is to find practical ways to capture and inject large volumes of stormwater generated by short, high intensity storms.  It noted that additional flooding would occur in high rainfall years.   See ICS Groundwater Behaviour and Assessment

This poses a few questions such as:

  • what is the significance of ‘spare capacity’ in the aquifer?  Does it mean that groundwater supplies have been reduced?
  • what methods would Auckland Council (AC) grant itself consents for, in order to reduce flooding and recharge the aquifer?
  • how would AC guarantee no reduction of groundwater quality as it tries to deal with further urban development and intensification?
  • what stormwater treatment methods can AC show us now as functional examples?

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