Submission by:
The Guardians of Pāuatahanui Inlet
November 2020

Porirua City Council Climate Change Strategy 2020

Summary

• The Guardians of Pāuatahanui Inlet support the Porirua City Climate Change Strategy and, in particular, the adaptation part of the strategy.
• We submit that adaptation is of immediate importance and work on this needs to start now.
• We note that the Strategy does not include any ecosystem or harbour components in the section on adaptation. This needs to be remedied.
• We consider that, although longer terms are mentioned in the Strategy, it is effectively only a short term action plan, and given the time frames over which climate change effects are likely to become more severe, this is not sufficient.

Submission

Strategy Time Frame

We note that the strategy is intended to encompass the three-year period to 2023/24 but it also says, on page 14 that “we will apply long term thinking” - 50 to 100 years is mentioned. But it is also stated that the approach adopted only “sets out the actions the Council intends to deliver over the next three to four years”. While this is understandable and we support tackling climate change issues immediately, if this is a Strategy, it must show the progressive pathway for responses well beyond the short term. Given this, it effectively indicates that the document is more operational in nature rather than strategic; A strategic document should be looking forward at least 10-15 years if not longer.

The document is thus more an Action Plan rather than a Strategy. We consider that the Council should develop a Strategy and that this should encompass the much longer horizon over which climate change issues will become more problematic. We suggest three horizons: the short term of up to five years which is in the document now; a medium term of 15 years, and a longer term of 50 years - and maybe extending to the end of the century. All actions should have evolving time frames that show how far they might extend and what issues are raised and will need to be resolved over the longer time frames. Monitoring mechanisms and measurement indicators should also be extended beyond the current short term.

Adaptation

We consider that adaptation is at least as important, if not more immediate than the other components of the Strategy. However, we note that, although the earlier parts of the document mention ecosystem issues (Item 6 says native species are under threat and coastal ecosystems are mentioned; Item 8 includes protecting natural defenses such as wetlands), the adaptation narrative ignores these. The Council’s priority focuses on infrastructure and property issues and does not mention ecosystem issues at all. Given the Council’s stated priority for Te Awarua-o-Porirua (A healthy and protected harbour and catchment), this is a notable and unacceptable omission. 

In terms of the Pauatahanui Inlet, the effects of sea level rise and storm surges will adversely affect a key component of the Inlet ecosystem - namely Juncus Maritimus (Sea Rush). This plant provides a large amount of the detritus that fuels the ecosystem of the Inlet. It is sensitive to changes in tidal levels and its extent is already reducing. If it reduces further ecosystem life will reduce, too. 

Juncus maritimus is most prolific in the Wildlife Reserve at the eastern edge of the Inlet. As the sea level changes, it will need to migrate inland if possible - but the reserve abuts the residential and commercial properties on the western side of Pauatahanui Village. These properties will eventually be inundated and, from an ecosystem perspective, it would be preferable if the buildings were eventually removed to allow the Wildlife Reserve some space to move inland. 

The sooner this issue is addressed the better. We consider discussions on the future of Pauatahanui Village, its extreme vulnerability to sea level rise and storm events, and its connection to the Wildlife Reserve need to start now, not wait until 2022/23 and beyond. 

Porirua City Council already has a report covering the relevant adaptation issues affecting areas like Pauatahanui Village and Grays Road - both of which face progressive inundation.

The PCC Draft Coastal Hazards Report of September 2019 says:

13.3 Management Options and Recommendations:
The coastal inundation analysis indicates that Pauatahanui Village, extensive lengths of
roading and adjacent low-lying rural areas will become extremely susceptible to coastal
inundation with projected sea level rise; complicated also by river flooding and ground water
levels, both of which hazards will also be severely aggravated by projected sea level rise.
Even a small amount of future sea level rise will greatly increase the severity and (most
significantly) the frequency of flooding.

These hazards (and tsunami) collectively raise significant issues. Accordingly, it is
recommended that no further expansion or intensification of development be considered on
low-lying flood risk areas unless a detailed adaptive management plan is developed which
indicates that these hazards can be sustainably managed.

Storm events such as the 2016 deluge show that the catchment of the Inlet is vulnerable to both water inundation and related release of large amounts of sediment. Management of the catchment - both its rural and urban components - is thus a vital part of the adaptation response. Stormwater management including limits to hard surfaces, water sensitive urban design for all new developments and for redevelopments, riparian planting, pest and weed control, and reintroducing more native vegetation are all issues that need to be part of the adaptation component of the Strategy.

In relation to actions designed to help the Inlet ecosystem, the Guardians wish to acknowledge the support from Porirua City in obtaining a grant from the Department of
Conservation's Community Fund to engage in planting of Sea Rush and other species (such as Oioi and Ribbonwood) around the Inlet. This will help the ecosystem, but more is needed and a wider programme reaching back into the catchment needs to be part of the Council’s Climate Change Adaptation Strategy.