Port Waikato stormwater resilience project

Port Waikato’s stormwater network was affected when Cyclone Gabrielle hit, with damage to existing infrastructure and issues arising because of several landslips.

After completing initial repairs, Council successfully put forward a request for funding to central government and was allocated $2.35m to invest in stormwater resilience for Port Waikato.

Our specialist waters team has assessed the current stormwater network  and future demands for Port Waikato and has put together a list of projects that will improve its long-term effectiveness and resilience.

It is important that we prioritise the projects that will give greatest overall benefit. So, we have been working with the community to make sure we select the right areas to focus on.

Consultation

Feedback and discussions within the community to date have helped define a list of possible projects. We would now like further feedback to make sure we prioritise those projects to give the greatest possible benefit for Port Waikato.

If you would like to be involved, our next community feedback session will be on Thursday 23 May, 6pm at the Community Hub, Sunset Beach Surf Life Saving Club, 1 Ocean View Road, Port Waikato.

What we plan to do

We are currently undertaking modelling for those potential projects, looking at multiple combinations and scenarios to see the impacts and benefits they will have. The modelling will help us evaluate the options in terms of factors such as the impact of each project on property, reduction of future flood risk, long-term community benefit, environmental issues such as water quality, cultural considerations and, of course, costs. It is likely that the budget constraints will mean only 3 to 5 projects out of the below identified projects are able to be completed.

The current list looks like this. Please note this list is NOT yet in order of priority.

A: Landslide above Port Waikato Wharf Store & Post Centre
This blocked Tuakau Bridge Port Waikato Road and damaged buildings.  The proposed works are on farmland to reduce risk of future re-occurrences.  The works are predominately upper catchment planting but may also include reshaping of some gully sections. Subject to private landowner approvals.

B: Landslide above Pats Culvert
This blocked Tuakau Bridge Port Waikato Road. The proposed works are on farmland to reduce risk of future re-occurrences.  The works are predominately upper catchment planting but may also include reshaping of some gully sections. Subject to private landowner approvals.

C: Pumpstation option 1 - Power resilience updgrade
Control systems and backup power upgrade to ensure the pump station continues to operate during a flood/extreme weather events.

D: Pumpstation option 2 - Full upgrade 200-300 l/s
Upgrade all of the exiting pump station, including increasing pump capability from 60 litres/second to >100 litres/second.  New or revised pump station housing, sumps and an outlet that mitigates any increase in erosion from the increased flows.

E: Pumpstation option 3 - Full upgrade 200-300 l/s
Upgrade all of the exiting pump station, including increasing pump capability from 60 litres/second to >200 litres/second.  New or revised pump station housing, sumps and an outlet that mitigates any increase in erosion from the increased flows.

F: Main drain widening
Widening the main drain (from the pump station to Maunsell Rd sports field area) to increase flood storage.  This will likely consist of widening to the west and including some re-shaping of the existing drain/removing any existing sediment build-up.

G: Maunsell Road Bridge raising
Mitigation work to reduce flood levels in the upper urban area above the bridge by increasing the capacity under the Maunsell Road Bridge.  Proposed works would raise the existing bridge deck.  A new bridge is not being considered due to likely costs.  The nearby intersection will provide significant constraints which are being further considered. 

H: Reduced flood risk at Oraeroa Marae
Mitigation work to reduce flood levels around the Oraeroa Marae.  Likely to include daylighting of the existing culvert (removal and installing open channel(s).

I: Reduced urban flood risk at Port Waikato Holiday Park and surrounding Urban area.
Work to reduce flood levels in 2 flood zones without directing additional stormwater into the swamp. This is likely to include installing pipes to convey stormwater directly into the main channel.

J: Reduced urban flood risk around Westside Road and Phillips Reserve
Work to reduce flood levels in 2 flood zones. This is likely to include installing pipes to convey stormwater directly into the main channel/upgrading existing open channels.

K: Reduced urban flood risk around Maunsell Road
Reinstatement of roadside/verge swales to improve stormwater conveyance (and reducing flooding) along the section of Maunsell Road close to the Sunset Beach Carpark (southern side of road).