Guardians of Pauatahanui Inlet object to the granting of Subdivsion and Landuse Consent (Porirua City Council) and Discharge permit and Landuse Consent (Greater Wellington Regional Council) applied for by Whitby Coastal Estates Limited on the former Duck Creek Golf Course.
Guardians of Pauatahanui Inlet
The Guardians of Pauatahanui Inlet is an incorporated society, with about 190 financial members.
The Guardians were set up in 1991 to promote the recognition of the ecological, historic, recreational and cultural values of the Pauatahanui Inlet (the Inlet). Guardians have conducted regular cockle surveys, made submissions on behalf of the Inlet in planning processes, have produced an education kit for use in schools, run a number of educational and promotional activities and have recently instigated a stream monitoring programme. Guardians were also instrumental in initiating, promoting and supporting the development of the Pauatahanui Inlet Action Plan. This plan is endorsed by the Guardians. We note the Action Plan’s endorsement also by the Porirua City Council and Greater Wellington Regional Council.
Pauatahanui Inlet is identified in the Regional Coastal plan as a significant coastal environment and is registered as a site of National Significance in the SSWI database (Sites of Special Wildlife Interest). Duck Creek is of concern to Guardians of Pauatahanui Inlet as it is an integral part of the catchment and coastal environment of the Inlet.
Summary of concerns in relation to subdivision in the Inlet catchment
The main areas of concern to Guardians of Pauatahanui Inlet with regard to any subdivision within the catchment of the Inlet are:
- Discharge of sediment and waterborne contaminants to Duck Creek and the Inlet
- Reserve Contributions, Riparian Protection and Public Access.
- Roading and Traffic
- Cumulative effects of subdivision of the former Duck Creek golf course.
There are also a number of lesser concerns which are noted later in this document.
Discharge of sediment and waterborne contaminants into Duck Creek and the Inlet
Earthworks and Erosion Protection
In a survey of the hydrology of the Inlet catchment. the Ministry of Works and Development advised that
“Where catchments undergoing urban development are discharging into embayments with low tidal flushing, particular care is necessary to ensure adequate erosion prevention measures are adopted” (Curry, 1981) .
The Healy Report (Healy, 1980, p 195) noted that
“large scale development around the inlet, particularly in the catchments of the larger streams (Duck Creek included) could result in widespread deposition of fine sediments which smother and kill intertidal animals, and therefore excessive earthworks with risk of silt runoff or erosion should not be undertaken. That is, developers should follow the alignment of least landscape impact in order to minimise silt and water runoff”
The proposal by the applicant to re-contour the land to achieve “uniform and gentle slopes”, and the associated volume of soil to be moved, does not fit with the recommendations of Healy.
Guardians of Pauatahanui Inlet has conducted regular three-yearly cockle surveys in the Inlet since 1991. Cockles were selected (on the advice of NIWA) as an indicator species that could be easily monitored by a community group, and yet would provide a useful indicator of the health of the Inlet. The number of cockles in the Inlet has more than halved since the 1976 survey quoted by Healy (1980.)
The 2001 results indicate that
“the cockle population appears to have stabilised over the past two surveys, providing an excellent base upon which future changes can be measured” (Grange and Toovey 2002).
The lowest densities of cockles occur at Camborne, Duck Creek and Motukaraka West. A causal relationship between increasing sedimentation and declining cockle numbers has not yet been established for the Inlet but the dramatic decline, coincident with the development of Whitby, cannot be ruled out as sedimentation is a known factor in the decline of filter feeding species elsewhere.
The proposal by the applicant for storage of earth a few metres from Duck Creek is unacceptable. Any earthwork storage should be required to be much further away from the Creek. Having soil stored so close to the stream means that there is little opportunity for control of sediment discharge in adverse conditions. Given the repeated failures of sediment control mechanisms during other recent developments in the Inlet catchment, high standards of control are essential. Also, given the availability of land to the applicant, the focus should be on avoidance rather than control.
Stormwater
The application does not address the long-term management of stormwater. This omission is of considerable concern to Guardians of Pauatahanui Inlet.
In this application all reticulated stormwater is to be discharged to Duck Creek directly through pipe outlets. This practice is of considerable concern to Guardians of Pauatahanui Inlet, especially if extended to the treatment of storm water from the planned subdivision of the entire golf course.
Subdivision, by its very nature, results in a greatly increased area of impermeable surfaces through roading, drives, paths, buildings and garden hard landscaping. The soils of the Duck Creek catchment are Korokoro Hill Soils (yellow-brown earths developed from greywacke drift on greywacke basement rock that are well drained). This means that rainwater readily enters ground water and the net amount of overland water reaching Duck Creek is smaller than total rainfall. However with the increased proportion of impermeable surfaces, the ability of the ground to drain naturally into groundwater is significantly diminished, resulting in increased volume of water directly entering Duck Creek. Thus there is an increase in the number and volume of peak flows entering the stream. The water enters the stream more quickly and in larger quantities resulting in
· increased frequency of peak flows with a faster mean water velocity exacerbating erosion, damage to the stream bed, and higher sediment outflow to the Inlet;
· increased concentration of heavy metal and PAH pollutants (inevitable in urban areas) in stormwater, and hence increased pollution of the Inlet.
Already there is evidence of detrimental effects from human activity in the Inlet. Hooper (2002) shows that pollution of Inlet sediments by heavy metals is increasing and is approaching (and on occasion exceeding) the Ministry for the Environment safe guidelines for species protection. The source of these pollutants mostly is vehicles and the most polluted site is
“located in an area of the inlet where it is apparent sediment from the nearby Duck Creek settles out and deposits on the bed of the Inlet” (Hooper, 2002, page 78).
These pollutants can only reach Duck Creek through storm water outlets, whose design is such that heavy metal ions swept from road surfaces cannot all adsorb onto suspended sediment particles before being discharged into the stream. Standard ‘end of pipe’ sediment traps alone are not sufficient treatment, especially at times of heavy rainfall. Hooper (pages 76-77) refers to the requirements of the Auckland Regional Council for more comprehensive storm water treatment, for example, by causing it to flow
“through grassed swales and batters, and the construction of ponds or wetlands above discharge points”
and gives a brief discussion of these and other advanced means of dealing with storm water. She further points out (page 76) that
“The regulatory framework is in place to enforce similar measures on any major roading developments in the Pauatahanui catchment”.
Since October 2001, Guardians of Pauatahanui Inlet has undertaken a stream-monitoring programme in the Inlet catchment. Two sites in Duck Creek are included in this programme. The early indications are that the quality of water and fauna is much superior upstream from housing development than it is in the lower reaches where development has taken place.
Guardians of Pauatahanui Inlet request that more significant treatment of stormwater be a requirement of any consent. At the very least direct discharge of stormwater into Duck Creek or the Inlet should be prohibited .
We note that Porirua City Council has set more stringent stormwater discharge standards for the development of the Aotea Block (and that for discharge into a stream that feeds into a harbour recognizably of lower environmental and wildlife values than the Pauatahanui Inlet). The Council decision (5 December 2002) relating to this application stated
“24. That Carrus Corporation shall design and construct a stormwater detention system… This detention system should be designed to handle a 1 in 5 year storm event and shall also take into account ecological and landscape values.
25. That the development of the Aotea Block shall follow the Comprehensive Development Proposal, particularly in respect to the following aspects;
……iii. Long-term treatment of stormwater.”
Reserve Contributions
We note that the applicant does not believe that a reserve contribution is necessary for this consent (Section 4.2.8), or that any esplanade or reserve contribution is required for this discretionary activity subdivision. But this is a special piece of land, being land adjacent to waterways in the catchment of the Inlet as well as being land that is part of a well established green belt providing access along the stream for the community.
The Environment Court has established the principle that not all residentially zoned land should necessarily be available for residential subdivision at usual urban densities. The most recent reinforcement of this principle was in a judgement relating to land adjacent to Waikanae Estuary, the closest important estuary to Pauatahanui Inlet. In his ‘Kotuku Parks Limited v Kapiti Coast District Council A73/2000’ judgement, Judge Sheppard declined a proposal for residential subdivision. Paragraph [141] states
“To the positive effects already identified, there is recent confirmation in the district plan of the Residential zoning of the site. However, that is a general zoning applying to large areas of the district. It does not imply that every part of every piece of land in the zone may be subdivided to the maximum permitted intensity, irrespective of the environmental effects. Nor does it imply that consent will be given to earthworks of the scale proposed here, where they damage the natural character of coastal dunes.”
We believe that a reserve contribution is required for this, as for any subdivision. This is especially so in this case where non-provision would set a dangerous precedent for the intended subdivision of the entire Duck Creek golf course. If it is not possible to take land for an esplanade reserve for riparian protection on this occasion, then the Council should take a financial reserves contribution in respect of this subdivision to enable it to buy land adjacent to Duck Creek for riparian protection in any future development of the golf course. If money is taken, it should be strictly earmarked for purchase of land along Duck Creek for riparian protection.
We respectfully ask the Hearing Commissioners to consider this issue carefully.
Cumulative effects of subdivision of the entire Duck Creek golf course.
It is the clear intention of Whitby Coastal Estates Ltd to develop the entirety of the former Duck Creek golf course (Appendix 18; public advertising). We are extremely concerned that the application under consideration only pertains to a small part of the golf course, and in an area which is possibly the least environmentally problematic part of the proposed entire development. It is difficult to consider the environmental impact of the entire development, or properly assess the effect of this smaller subdivision, until one can consider a comprehensive plan for the entire golf course. While we appreciate that the entire subdivision will be a staged process, there are certain environmental safeguards and standards that should be imposed on any development in this area, and their nature should be determined by considering the total environmental impact of a complete development.
One small development may not create significant effects, nor may the next application for a small subdivision. However, the total effect of all the intended developments will be significant and the end result is unlikely to be a linear extension of the effect of the initial small development.. Guardians of Pauatahanui Inlet submit that the Councils cannot ignore this probability of unacceptable cumulative effects when deciding on the present application.
Guardians of Pauatahanui Inlet believes that the applicant should be asked to present a detailed proposal of how the environmental effects we have identified would be managed for the entire development of the Duck Creek golf course.
Riparian Protection and Public Access
This application per se does not propose subdivisions immediately adjacent to Duck Creek, but we submit that riparian protection is an essential component for any development near it. This is regardless of whether Duck Creek is regarded as a ‘river’ and thus subject to the requirements Section 230 of the RMA.
We note that in the plan for the subdivision of the entire golf course (Appendix 18), sections appear to extend to the waters edge of Duck Creek with no provision for riparian protection or public access.
To promote sustainable management Porirua City Council should require an esplanade reserve along the length of both sides of Duck Creek This reserve is essential
· to protect the stream ecology,
· for flood protection, and
· to provide public access to a natural waterway that links the catchment to the Inlet .
Roading and Traffic
Guardians of Pauatahanui Inlet is concerned that the traffic analysis (Appendix 15) assumes that Transmission Gully highway will be built soon, and that it will be used as a main route for the additional commuter traffic generated by the development. However, the latest information is that it will not be built within the next decade at best. No consideration is given in the application of the effect of this delay - which presumably will cause more vehicles to use Discovery Drive, Postgate Drive, Spinnaker Drive and SH58 to Paremata or the Hutt Valley. Nor is any account taken of the effect of the increase in local vehicle movements between home and shops, schools, etc. caused by the subdivision. Both of these factors impact on assessment of the increased stormwater pollution that will result from this development. Chemicals derived from motor vehicle emissions and tyre wear are an important pollutant of storm water. (See also page 3 of this submission.)
Other Matters
Sewage Pipe
We note that a sewage pipe is proposed to cross Duck Creek. We request that the design of this pipe be such that the risk of a rupture and discharge directly into the Creek is very low.
Stream Monitoring
Guardians of Pauatahanui Inlet believe that should a consent be granted, a condition should be ongoing monitoring of water and biotic quality of Duck Creek by the relevant authorities
Since October 2001, Guardians of Pauatahanui Inlet has undertaken a stream monitoring programme in the Inlet catchment. Two sites in Duck Creek are included in this community based programme. Guardians of Pauatahanui Inlet believe that monitoring the environment in the Inlet catchment is in the public interest and thus that it would be beneficial to continue its programme; we therefore need to be assured that public access will be maintained. At every stage of the subdivision, care should be taken that opportunities for access to and along the stream are not precluded
Assessment of Environmental Effects.
Part B of the application forms refers to “reasonable distance downstream”. Duck Creek is a short and relatively steep waterway, and we submit that for the purposes of any application, any point in the creek should be considered to be within a reasonable distance of the Inlet. In other words, the Inlet is within a reasonable distance of the proposed sub division and therefore there is a need to protect the values of the Inlet when undertaking this development
Guardians of Pauatahanui Inlet wishes the consent authorities to decline the applications for consents because
1. Insufficent information has been provided on the cumulative effects of the planned subdivision of the entire Duck Creek golf course.
2. Insufficent treatment of stormwater prior to discharge into Duck Creek and Pauatahanui Inlet.
3. No Reserve Contributions.
4. Unacceptable siting of earthworks stockpile close to Duck Creek.
If the consent authorities decide to grant consents then they should impose the following conditions
1. Treatment of stormwater to a level that will protect the habitat, aquatic life and general health of Duck Creek and Pauatahanui Inlet.
2. Reserve Contributions.
3. Siting of earthworks stockpile a sufficent distance away from Duck Creek.
Guardians of Pauatahanui Inlet wish to be heard in support of our submission.
References
Curry, R.J. 1981. Hydrology of the catchments draining to Pauatahanui Inlet. Water and Soil Technical Publication 23. Ministry of Works and Development.
Grange, K, & Toovey, A. 2002. Cockles in Pauatahanui Inlet: results of the 2001 sampling programme. NIWA Client Report: NEL02401/2.
Healy, W.B. 1980. Pauatahanui Inlet: An environmental study. DSIR Information Series 141.
Hooper, K.L. 2002. The impact of stormwater discharges on freshwater, marine water and marine sediments and the implications for environmental management of the Pauatahanui Inlet, Porirua, New Zealand. Masters of Applied Sciencem Massey University, New Zealand.
