Report to ENVIRONMENTAL PLANNING & REGULATIONS Committee for information

Transcription

1 Title: Section: Prepared by: Waikanae Stream Contaminated Site Investigations Environmental Services & Protection Kate Sykes (Environmental Risk Team Leader) Meeting Date: 28 November 2018 Legal Financial Significance = Medium Report to ENVIRONMENTAL PLANNING & REGULATIONS Committee for information SUMMARY The purpose of this report is to update the Committee on the outcomes of the Waikanae Stream Contaminated Land Investigation project and to outline the next steps to address the issues that have been identified. The project has painted a picture of poor ecological health of the stream and identified contaminants of concern in all the site investigations. By implementing on-site stormwater management plans (as required by the compliance date of May 2020 in the Regional Freshwater Plan) several of the sites will improve their current discharges to the stream. Of highest concern are two former landfill sites operated by the Gisborne City Council. Both sites will require remedial works to address the contaminants still leaching into the stream. The risk to the public of use of these two sites is low, provided no disruption of the landfill surface is undertaken and the areas are used for passive purposes only. A further application will be made to the Contaminated Site Remediation Fund operated by the Ministry for the Environment. This application will support further targeted sampling to establish the impacts and extent of landfill gas, and also to continue the investigation of sources and levels of contaminants in the lower stretch of the Stream from Grey Street to the mouth. The fund excludes remediation of contaminants on Crown land. The decisions or matters in this report are considered to be of Medium significance in accordance with the Council s Significance and Engagement Policy. RECOMMENDATION That the Environmental Planning & Regulations Committee: 1. Notes the contents of this report. Authorised by: Nick Zaman Director Environmental Services & Protection Keywords: Waikanae Stream, HAIL, Contaminated Site Remediation Fund Page 1 of 6

2 BACKGROUND 1. The Waikanae Stream is a small, modified tidal waterbody within a catchment of some 1,110 hectares. Its headwaters are west of Gisborne City and from there it flows eastward through the city to meet the Turanganui River near its exit into Turanganui a Kiwa (Poverty Bay). 2. Residential, rural, recreational, industrial and commercial activities take place on the banks of the Waikanae Stream and have resulted in it becoming one of Gisborne s most polluted waterbodies. Three hundred and two hectares of the catchment is covered by Council s Hazardous Activities and Industries List (HAIL) database. This lists land use activities which historically, or still, release contaminants. High Cultural and Recreational Value 3. The Waikanae Stream has a deep cultural significance for Ngai Tawhiri, a hapū of Rongowhakaata. Their marae (Te Kuri-a-Tuatai) sits adjacent to the stream. 4. Despite its degraded state, as an estuarine stream the Waikanae still has significant ecological values. It is a known inanga spawning ground, there are mullet and other estuarine fish species present and is an important area for estuarine birdlife. As well, locals still harvest kai moana, fish and swim in its waters. 5. Parts of the streams area are passive reserves (Department of Conservation and Council) and are well used by the public, including local schools. Land uses near the airport include pastoral farming. Our Obligations 6. As a unitary authority, Council has an obligation under the Resource Management Act 1991 (RMA) to investigate land for the purposes of identifying and monitoring contamination. As a territorial authority Council is also responsible for preventing and mitigating any adverse effects from the development, subdivision or use of contaminated land. DISCUSSION and OPTIONS 7. In 2017, Council submitted an application to the Ministry for the Environment s (MfE) Contaminated Sites Remediation Fund (CSRF). The CSRF provides financial assistance to support councils to fulfil their obligation to manage contaminated land. 8. Our CSRF application proposed that we complete an in-depth assessment of contamination affecting the health of Waikanae Stream from both the land use and ecological perspective, in alignment with the wider Waikanae Stream Restoration Project. 9. Following funding approval of our Waikanae Stream investigation project, a tender process to Tonkin & Taylor, with on-site investigations commenced in February of Detailed Site Investigation Results 10. Six sites were selected for detailed site investigation (DSI) from previous HAIL landuse activities. The DSI aimed to establish: a. sources of contaminated that had the potential to enter the Waikanae Stream environment from the site; b. pathways for contamination to enter the Waikanae Stream from the site; c. where the contamination is ending up if it is entering the stream; d. level of risk to human and environmental health from contaminants; and e. recommended further site investigations and/or remediation planning. Page 2 of 6

3 11. The sites chosen for investigation are identified on the map attached as Appendix 1. The sites were identified on the basis of a desktop assessment of previous HAIL land uses as follows: Site 1: Airport Municipal landfill from ; Site 2: Te Kuri-a-Tuatai marae municipal landfill from Site 3: 61 Innes Street/amenity reserve landfilling with refuse Site 4: Innes Street industrial/light commercial uses including the use and storage of chemicals from Site 5: Innes Street industrial/light commercial uses from Site 6: Innes Street industrial/light commercial uses from Site 7: Solander Street industrial uses from Site 8: Alfred Cox Walkway municipal landfill from 1957-sometime in 1960s. This site may also be influenced by Carter Holt Harvey copper-chrome-arsenic timber treatment plant , which is a registered contaminated land site under Council s Tairawhiti Resource Management Plan. Key Detailed Site Investigation Findings 12. On all sites, contaminants of concern were detected. In some instances, the discharge to the Waikanae Stream of some of these contaminants can be reduced by the occupant addressing the environmental site management practices on-site (Sites 4, 5 and 7). This will become part of the work undertaken to implement the requirements of the Freshwater Plan through stormwater management plans. 13. Of the eight sites, Council (and its precedent entities) is currently or has previously been the owner or occupier of sites 1, 3, 4, 6 and Of highest concern are sites 1 and 3. These are both former landfill sites operated by Gisborne City Council. While site 3 is now partially owned by both us and the Department of Conservation (DoC), we have a moral responsibility to take ownership of the issues caused by historical use of this site as a landfill. Both sites will require remedial works to address the contaminants still leaching into the stream. Ecological Survey Results 15. The ecological investigation undertaken concurrently with the DSI paints a poor picture of water quality, habitat and vegetation. a. Nutrient enrichment and elevated ammonia levels were found particularly in the upper levels of the catchment, with likely contributors being the upstream agricultural practices. b. The middle reach of the Waikanae Stream (from Aerodrome Road to Grey Street Bridge), has substantially degraded water and sediment quality, and the benthic fauna is likely to only comprise of pollution-tolerant species such as mud crabs and polychaete worms. Heavy metals are present in the sediment indicative of the HAIL activities that have occurred or are currently occurring along the reaches of the Stream. c. Positively, there are high value vegetation types along the banks of the stream such as indigenous reedlands, sedgelands, raupō wetlands. The indigenous salt meadow contains the at risk naturally uncommon native musk. d. The downstream reach (between Grey Street Bridge and the mouth of Waikanae Stream), has the highest habitat value and visibly better water quality and clarity. This is likely due to the strong tidal influence and regular flushing from tidal flows. Page 3 of 6

4 Next Steps 16. The Tonkin & Taylor investigation has provided a suite of recommended actions for improving the Waikanae stream s health. Some of these will be incorporated into project planning for the implementation of our Freshwater Plan requirements. 17. An application will be made to the next CSRF funding round for further investigation (water quality and sediment testing and repeat ground water sampling) in the downstream reach of the stream from Alfred Cox Park to the stream mouth. This will look more closely at the influence of the tidal flushing and also provide insight into the extent the former timber treatment plant site is contributing to contamination (if any). 18. Sites 1 and 3 are landfill sites of the previous Gisborne City Council and have been identified by the investigation as the sites of highest priority due to the nature of contaminants that continue to be discharged to the environment. 19. These landfill sites currently have no engineered solution (such as a landfill cap or leachate collection system) and Council is now required (by the RMA) to remediate contamination. Further investigation will identify what remedial system is most appropriate and quantify the cost associated with undertaking the remedial work. ASSESSMENT of SIGNIFICANCE Criteria This Report The Process Overall The effects on all or a large part of the Gisborne district Low Low The effects on individuals or specific communities Medium Medium The level or history of public interest in the matter or issue Low Medium Inconsistency with Council s current strategy and policy Low Low Impacts on Council s delivery of its Financial Strategy and Long Term Plan. Low High 20. This report is part of a process to arrive at a decision that will be of medium level in accordance with the Council s Significance and Engagement Policy. 21. Given the importance of Waikanae Stream to hapu and iwi, the number of invested stakeholders (both iwi, community, Crown and business) and the visible nature of any proposed remedial works, a reasonable amount of interest is likely to be generated. Remedial works are not budgeted for in the current Long Term Plan and further investigation is required to establish the nature and extent of works and associated costs. COMMUNITY ENGAGEMENT 22. Initial consultation occurred in the planning phase with MfE, Rongowhakaata Iwi Trust, Eastland Group Limited, Department of Conservation and Gisborne Holdings Limited. A supplementary brochure was developed for this, which outlined the project and provided stakeholders with a contact person within Council (see Appendix 2). 23. Once the on-site investigations were complete all landowners and occupiers were given a summary report of the contamination findings through face-to-face communication, with the offer of a full copy of the report if required. Gisborne Airport and DoC have taken advantage of this offer. 24. This project links with the work undertaken as part of the wider Waikanae Restoration Project. Page 4 of 6

5 CONSIDERATIONS Financial/Budget 25. This project to date has incurred costs of $197,781. Of this, $84,500 has been funded by the MfE CSRF. 26. The CSRF excludes capital expenditure items, and investigations or remediation work on contaminated land or identified sites of concern on Crown (Council) land where the Crown has accepted responsibility for the contamination. It is clear therefore that Council will need to fund the investigation into remediation options for Sites 1 and 3 and the operational work this will entail. 27. There is sufficient funding in the current Long Term Plan to cover the costs of the further investigation work, and the resource consents which will need to be lodged to undertake remediation and allow for a residual discharge. The extent of the remediation work is unknow at present and staff will need to reprioritise budgets to determine the nature and extent of works and associated costs. Legal 28. Council has a statutory obligation under the Resource Management Act to address the issues of land contamination in the district. 29. The National Environmental Standard for Assessing and Managing Contaminants in Soil to Protect Human Health (2012) is provided for under the RMA. It provides a nationally consistent set of soil contaminant values that protect human health. 30. Investigation has identified two landfill sites of concern, which require remedial action. The other sites in the investigation which are currently releasing contaminants can be addressed through a pathway of compliance by the implementation of the Freshwater Plan by POLICY and PLANNING IMPLICATIONS 31. The project will ensure that freshwater values associated with the Waikanae Stream are adequately provided for. The project aims to improve water quality, reduce priority contaminants, nutrient and bacteria levels so that they fall within acceptable levels for swimming and recreational activities. The Freshwater Plan requires that all water quality monitoring attributes are to sit within acceptable banding of the National Objectives Framework by RISKS 32. The risk to the public of use of the contaminated sites is low, provided no disruption of the landfill surface is undertaken and the areas are used for passive purposes only. 33. Recently a community group has been undertaking planting and fencing at the Site 1 landfill at the airport. Unfortunately, this activity needs to cease as it is penetrating the landfill and exposing rubbish. Once the site is remediated the planting activity can occur again, but for the next few years restoration work for the stream will have to focus on other locations. 34. This land is leased to Gisborne Airport. The Airport Manager and Gisborne Holdings Ltd s Property Manager have been advised of this impact on the planting/restoration of vegetation. Page 5 of 6

6 NEXT STEPS Date Action/Milestone Comments April 18 On-going June 2019 Application to CSRF for phase 3 submitted. Engagement with landowners and occupiers to improve stormwater management practices. Remediation options for Site 1 and 3 developed. For further investigation of lower reaches of Waikanae Steam. APPENDICES Appendix 1: Site Identification Map Appendix 2: Project Information Supplement Page 6 of 6