Marine Parade Stormwater Upgrade

Location Plan
In 2006, the Auckland Regional Council sought public feedback on a proposed new storm water pipe on Sloanes Beach. The results were very clear:

Support Proposal: 1 submission

Oppose Proposal: 89 submissions

Forms have been sent out by the City Council seeking feedback on new options, some of which avoid building this large structure on the beach.

There is an existing storm water/sewage outfall at 39/41 Marine Pde. By making better use of this, the proposed new pipe on Sloanes Beach is not needed.

Option 2: Existing Outfall + Overflow

1/ Refurbish existing pipes at 39/41 Marine Pde, & use this existing outfall as main discharge point. (The pipes need to be re-lined, & some upgrades may be required around the pipe junctions.)

2/ Add a smaller ‘overflow’ pipe that exits onto Sloanes Beach or in Short St Reserve. This pipe would flow only in extreme rainstorms.

Large overland flows on grass/sand could cause erosion. A new modified Option 2 addresses this:

Option 2 discharging behind existing Boat Ramp

1/ Extend the overflow pipe to follow the existing seawall along the front of 33 Marine Parade (to the north of the beach), and exit behind the existing concrete boat ramp.

2/ Design the pipe to blend in by either matching the existing natural papa rock or by looking like a concrete seawall, whichever is most appropriate for each section of the pipe.

3/ Prevent the current scouring of the beach by redirecting the existing storm water outlet at the northern corner of the beach into the new pipe.

(This was proposed by the author & owners of 33 Marine Parade, and is preferred by them over Option 4. It is not listed explicitly by the Council as a separate option.)

Option 3 sends all the storm water to the existing outfall at 39/41 Marine Pde, and so requires no new structures on the beach or reserve. It needs a new pipe at 39/41 Marine Parade. This could potentially affect buildings at these locations, and so is a potential risk for the Council & property owners.

These 3 options avoid a large new outfall structure on Sloanes Beach while delivering benefits similar to the original proposal, at a similar cost. They all:

1/ address the flooding in Marine Parade

2/ discharge storm water (i.e. road runoff), not sewage, on the beach

3/ allow for future storm water/sewage separation

4/ give similar reductions in the frequency of raw sewage discharges into the harbour.

Options 1 and 5 are significantly more expensive. Option 1 may not fix the flooding in Marine Parade.

Options 2 & 3: Low cost options with minimal impact on Sloanes Beach

Registering your continued opposition to the large pipe (Option 4) will help protect Sloanes Beach:

Complete the City Council feedback form, or see www.aucklandcity.govt.nz/MarineParade to give your feedback online

Select options other than 4, eg “Option 3 (if property owners agree) or Option 2”

Add a note opposing the original Option 4

Council Report

This document uses information and drawings from the council report: Auckland City Council Report for Marine Parade Stormwater Project, Design Option Review, GHD, July 2008

Plans of Options

Option 2 refurbishes the existing two pipes under 39/41 Marine Pde; these carry most of the storm water flows and continue to act as a sewage overflow. A new 0.525m underground storm water (not sewage) overflow pipe either exits in the reserve, or extends around the front of 33 Marine Pde to exit in an existing concrete boat ramp. This extended pipe would be disguised as papa rock or seawall.

Option 3 installs a new pipe under 39/41 Marine Pde running down to the existing outfall. These carry storm water and continue to act as a sewage overflow. There are no new structures on Sloanes Beach.

Option 4, the original option, brings a 1.05m diameter underground pipe down to a new outfall structure on Sloanes Beach. This pipe carries storm water only, not sewage. The existing outfall at 39/41 Marine Pde remains, and continues to act as a sewage overflow.

Source: Auckland City Council Report for Marine Parade Stormwater Project, Design Option Review, GHD, July 2008

Notes:

1/ New pipes in the reserve or at 39/41 Marine Pde would be thrust underground giving minimal surface disturbance.

2/ This unofficial document attempts to summarise the key options and their impact on Sloanes Beach. More detailed official documents are available from Andrew.Stewart Ltd, info@andrewstewart.co.nz, ph 303 0311.

3/ The author, Andrew Mason, would like to acknowledge the valuable contributions made by the Auckland City Council’s consultants and engineers in acknowledging the issues and working to develop these alternative options.

You can view our earlier information from August 2007.

Document prepared by Andrew Mason, 33 Marine Parade, pipe@hbcc.net.nz, 021 884 673, 12 Nov 2008