Submission to the Tasman District Council's Long Term Plan April 2018-28

Tim Neighbourly Lead from Mapua

Submitted by the Mapua & Districts Community Association

If there is one thing Council should address within the next 10 years, what would it be?

Reply: The woeful state of the storm-water infrastructure in the Ruby Bay region. This should be addressed with urgency – at least in the first half of the long term plan. The document below outlines some of the inadequacies and suggests action that should be taken urgently.

The Mapua and Districts Community Association acknowledges the considerable effort of Councilors and Staff to control costs over recent years. Unfortunately, recent storm events have brought renewed focus on whether delaying core storm water infrastructure is a sound policy.

The Mapua/Te Mamaku/Ruby Bay communities have suffered from a legacy of minimized and often delayed funding for reticulated water, sewage and storm water infrastructure.

Much of the original water and sewer infrastructure was poorly constructed and has long since exceeded its use by date. Both reticulated systems have regular breakages and overflows. This, no doubt, has been costing the districts residents dearly in avoidable maintenance. The breakages and sewerage discharges have been a regular complaint from residents at Association meeting for many years.

The Association has encouraged a rejuvenation of infrastructure and expansion of community facilities that is well coordinated and pragmatic such that it addresses current unmet needs and allows appropriate capacity for future expansion while minimizing community disruption.

The Association supports the urgently needed upgrades of the reticulated sewerage scheme as detailed in the LTP.

The Association supports the urgently needed upgrades of the reticulated water scheme as detailed in the LTP.

The Association supports the completion of the final phase of the Seaton Valley Stream widening but is disappointed that the timeline has again been pushed back. The Association seeks to remind the Council that the entire storm water drain down Seaton Valley to the sea is only as good as any remaining uncompleted part. Until the final phase is completed, the risk of damage from flooding remains high. And, in fact, recent increases of storm water from the Mapua Rise subdivision are assumed to worsen the potential for flooding in the catchment. Delaying completion, combined with increasing risks with more frequent and severe rain events are a recipe for more disaster.

The Association supports the completion of separable portion 3 of the Ruby Bay Storm water Improvements project (2012) as detailed in the LTP. It is understood that work needs to be completed in concert with the upgrade of the Stafford Tait Sewerage lift station upgrade. Unfortunately, the storm water has no place to go as this catchment has very limited capacity. The Broadsea Ave outfall downstream is severely constrained due to the lack of gradient, undersized pipe and tidal availability.

The Association supports a catchment wide “roof and road to sea” solution for the Stafford Drive to Broadsea Ave Outfall. A new or upgraded outfall is essential to providing resolution of flooding, seawater inundation and long-term resilience.

For years many Ruby Bay residents have felt a high degree of disenfranchisement. They had to self-fund sewerage and water reticulation schemes, watch while NZTA raised the carriageway above their sections and self manage drainage solutions where none existed. Cyclone Drina (12 January 1997) caused significant flooding and was a wakeup call. And now again the brunt of Cyclone Fehi’s wrath was suffered by the residents of Ruby Bay. In the ensuing 19 years little physical progress has been made towards building community resilience.

The Association asks that the Council review and action the following storm water improvements:

Complete Separable Portion 2 of the Ruby Bay Storm water Improvements Project from 2012. This is the pressurized storm water pipe from newer Crusader Drive subdivision into the Tait Street outfall.

There are two culverts on Pomona Road (labeled 1 and 2 that are not shown on council infrastructure maps). These culverts drain storm water from road reserve onto private property. Consider redirecting these flows into the adjacent Separable portion 2 of the Ruby Bay Storm water Improvements Project 2012. There should be considerable vertical head from these drains and the storm water is currently flooding multiple low land properties that have limited capacity to discharge.

Complete the curb and gutter on Stafford Drive between Pomona Road and Pinehill Rd. Replace sumps in the area (that drain to soakage pits) with storm water piping to sea. The current drainage is not sufficient; nor functional. There is an underutilized drain to sea at 119 Stafford Drive that would make this cost effective.

The Association asks that the Council upgrade the inadequate drainage system from Pinehill Road to the sea as we believe this drainage system has never been properly completed and this incomplete system has lead to serious issues for residents on the seaward side of this system.

The Association asks that the Council add an additional non-return valve on Broadsea Ave outfall pipe upstream of the sumps in the street. When rainfall, storm water and seawater enters the sumps at Broadsea Ave cul-de-sac, it can not get to sea through the outfall when the tide is up. Instead the storm water flows backwards through the storm water pipe and daylights on 32 Broadsea Ave where it exacerbates flooding and backs up through Stafford Drive. The additional head created by storm water ponding in the Broadsea sumps and outfall pipe are likely to help open the downstream non-return valve and assist the drainage to sea.

The Association asks that the Council correct the size and utility of the two scruffy dome inlets at Tait Street and Chaytor Reserve. Neither of these two scruffy dome inlets function properly, albeit for different reasons. During storm events they are generally clogged with debris and residents are often risk their limbs trying to clear the debris whilst waves and logs can be crashing nearby.

The Association asks that the stones and sand blocking the overland flow path to the concrete ramp in Chaytor Reserve be correctly re-contoured. The current pile of material on the approach blocks the overland flow path of seawater overtopping. The highest point in the flow path should be the top of the concrete ramp.

The Association asks that the Council re-establish the capacity of the Senior Drain which was inadvertently filled during the construction of Old Mill Walkway Coastal Protection Works. There is substantial evidence that this drain functioned as the overland flow path during Cyclone Drena and greatly reduced the severity and longevity of salt-water ponding inland.

The Association asks that the Council review overland flow paths in anticipation that future cyclone events will happen and with a focus on improving resilience.

There is ample evidence that Old Mill Walkway Coastal Protection Works preformed substantially better than the Broadsea Ave Seawall. The Association requests that Council identify why they preformed differently and correct the deficiencies. The sea and storms generally act with equal carnage along a section of coast; a consistent coastal protection work should be installed. The Association does not see this as solely the financial responsibility of the wider District but rather a combination of public and private partnership. The X, Y and Z river rating scheme could be a possible model of how coastal seawalls are funded. Regardless of how seawalls are funded, they need to be to similar standards, design, overland flow paths identified and exit strategies for seawater overtopping planned.

Recent storm events have brought into sharp focus the inadequacies of storm water infrastructure in Ruby Bay. And, while it is hard to envision that some flooding would not have happened, the extent and the severity of the storms events were clearly far worse then necessary. This wears heavily on the residents of Ruby Bay, particularly given that Council had prior knowledge that such an event was likely to cause extensive flooding and damage.

The Association does respect and accept that Council is trying to control costs. However, we are concerned when this has an adverse effect on citizens life and property as in the recent Cyclone Fehi flooding event.

For proper uniform action to be taken on these issues it is important Council carefully looks at the three driving policies for current action: the rate cap, the borrowing limit and the notion of targeted rates. Council needs to make a decision as to whether they fix a problem for the long term or do patch up jobs that are cheaper in the short term but are likely to be more expensive in the long term and certainly cause more stress for residents.

We respectfully request that Council redouble efforts to address deficiencies in the needed storm water infrastructure in Mapua/Ruby Bay.

On behalf of the members of the Mapua & Districts Community Association, thank you for your consideration.