TAURANGA CITY STATE - STATE OF THEOF ENVIRONMENT ENVIRONMENT 2017 REPORTING

PREPARED FOR TAURANGA CITY COUNCIL | PREPARED BY BECA LTD | OCTOBER 2017 Tauranga City - State of Environment 2017

Revision History

Revision Nº Prepared By Description Date

0.1 Allanah Kidd Discussion document 20/06/17

1.0 Allanah Kidd Final document 29/06/17

2.0 Allanah Kidd & Dominic Final document revised following client 05/07/17 Adams comments 3.0 Gemma Wadworth & Dominic Revision of document following comments 20/10/17 Adams from BOPRC

Document Acceptance

Action Name Signed Date

Prepared by Allanah Kidd 05/07/17

Gemma Wadworth 19/10/17

Reviewed by Marc Dresser 19/10/17

Approved by Dominic Adams 20/10/17

on behalf of Beca Limited

Beca 2017 (unless Beca has expressly agreed otherwise with the Client in writing). This report has been prepared by Beca on the specific instructions of our Client. It is solely for our Client’s use for the purpose for which it is intended in accordance with the agreed scope of work. Any use or reliance by any person contrary to the above, to which Beca has not given its prior written consent, is at that person's own risk.

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Executive Summary

The purpose of this exercise for Tauranga City Council (TCC) specifically is to guide and inform the development of an Environmental Strategy by the Environmental Committee, including objectives, targets, priorities and actions; and to act as a baseline for assessing progress towards these targets etc within the Tauranga City limits . Meanwhile, Bay of Plenty Regional Council (BOPRC) also undertake State of Environment (SoE) assessments for specific areas within the Bay of Plenty Region. It is intended that this initial report will be reviewed on a regular basis as better and more robust data becomes available from both TCC and BOPRC monitoring activities where relevant, and for consistency with the regional approach.

In line with the pressure-state-impact approach as laid out in the 2015 Environmental Reporting Act, the research process examined available environmental data for Tauranga across five domains: atmosphere, air, land, water and marine. A minimum of three indicators of environmental state were identified for each domain and associated pressures and impacts were also examined in detail (Figure 1). The findings of this study are summarised below:

Atmosphere: When compared with other cities, Tauranga’s carbon emissions, while lower per capita than some other New Zealand cities can be said to be relatively high on an international scale with transport related GHG emissions making up a very high proportion of this.

Air: Tauranga City air is by global standards good and levels of SO2 are low, with 93% of samples in the ‘excellent’ band. Levels of particulate matter (PM10) are recorded with only 21% of samples in the excellent band and increases of PM10 levels in air anticipated with increasing population growth.

Land: Continued significant land use and land cover change has resulted in only 3% of land cover remaining in native vegetation. In the urban environment, TCC is working towards increased availability and accessibility to open space, and towards reducing the significant proportion of waste that is sent to landfill.

Water: Nutrient concentrations in rivers that run through Tauranga are fairly high due to upstream land uses, while turbidity and heavy metal contamination of this water is low. Analysis of both ecology and water quality for swimming indicated that watercourses passing through Tauranga range in scoring from ‘fair’ to ‘poor’.

Marine: Marine swimming water quality rated good or very good at all sites in Tauranga Harbour. Heavy metal contaminants in Tauranga Harbour are very low, with no exceedances and all sites received an overall grade of either good or very good. The estuarine environment exhibits good nutrient state but variable, and relatively poor overall macroinvertebrate index, as an indicator of ecological health.

The infographic provided in Figure 2 below depicts the key indicators in each of the five domains.

This study has identified, unsurprisingly, that as in other regions of New Zealand (MfE and StatsNZ, 2015) the activities of urban development and land use change are putting severe pressure on the environment. Tauranga’s population growth is causing urban development and urban sprawl leading to loss of natural habitats and biodiversity, and expected decreasing air, freshwater and marine environmental quality. On top of this, increasing resource use generates waste and contributes to climate changes, which in turn puts further pressure on the natural and human environment.

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It is evident that within Tauranga there are environmental issues to be addressed and that an integrated and adaptive management approach is essential in achieving this.

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Figure 1: Pressure-state-impact model used and key observations on indicators

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Figure 2: State of the Environment: Tauranga City Infographic

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Contents

1 Introduction ...... 1 1.1 Purpose ...... 1 1.2 Approach...... 1 1.3 Tauranga City Context ...... 2 1.4 Pressure-State-Impact Framework ...... 2 2 Atmosphere ...... 9 2.1 Pressures ...... 9 2.2 State ...... 9 2.3 Impact ...... 10 3 Air ...... 12 3.1 Pressures ...... 12 3.2 State ...... 13 3.3 Impact ...... 14 4 Land ...... 16 4.1 Pressures ...... 16 4.2 State ...... 18 4.3 Impact ...... 21 5 Water ...... 22 5.1 Pressures ...... 22 5.2 State ...... 23 5.3 Impact ...... 27 6 Marine ...... 28 6.1 Pressures ...... 28 6.2 State ...... 29 6.3 Impact ...... 30 7 Data Gaps, Limitations & Next Steps ...... 32 8 Summary ...... 35 9 References ...... 37

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1 Introduction

1.1 Purpose Tauranga City Council (TCC) has commissioned Beca Limited (Beca) to undertake a State of the Environment (SoE) assessment. The purpose of SoE reporting is “to inform the public and decision makers of the current and long term trends in the environment. It should identify and explain environmental issues, including their causes and location and contain conclusions about their significance” (MfE and StatsNZ, 2017b). The purpose of this exercise for TCC specifically is to guide and inform the development of an Environmental Strategy by the Environmental Committee, including objectives, targets, priorities and actions; and to act as a baseline for assessing progress for the city of Tauranga. Meanwhile, Bay of Plenty Regional Council (BOPRC) also undertake SoE assessments for specific areas within the Bay of Plenty. It is intended that this initial report will be reviewed on a regular basis as better and more robust data becomes available from both TCC and BOPRC monitoring activities where relevant, and for consistency with the regional approach.

1.2 Approach The approach comprised comprehensive research to identify existing current and historical environmental information relating to the city, and analysis of a) the state of the environment and b) the extent of knowledge in five key areas. This project is intended to encourage discussion and inform decision-making, but not to cover how environmental issues will be addressed, nor to define future monitoring regimes.

The Ministry for the Environment (MfE) has developed clear guidance on environmental reporting based on internationally accepted protocols. This study follows the pressure-state-impact (/response) approach as laid out in the 2015 Environmental Reporting Act and national environmental reports: thus, the framework divides the natural environment into five domains:

 Atmosphere  Air  Land  (Fresh) Water  Marine

Under each domain, we report on three main types of information:

 the state of the environment;  the pressures that have created that state; and  the ‘response’ - the way the state of the natural environment influences other spheres of the environment and aspects of people’s lives, such as public health, the economy, te ao Māori, culture and recreation.

It is important at this stage to note that while this environmental assessment is broken into five domains, they are inextricably linked and management of these within the Tauranga City limit (which is shown in Figure 3) must be undertaken in a holistic manner. It is also recognised that the city domains of fresh water and marine in particular, are influenced by the physical nature of the wider Tauranga Harbour catchment, with the steep slopes and vulnerable soils associated with the upland Kaimai-Mamaku Range and Mamaku Plateau, and the activities such as agriculture taking place within this wider area all of which can have an effect on water quality within the network of streams which can drain into the waterways passing through the city and the coastal environment outside the city administrative boundary.

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1.3 Tauranga City Context Tauranga, now New Zealand‘s fifth largest city, is a growing coastal city with a population of over 128,000, covering an area of approximately 13,380 hectares (TCC, pers.com.). The city landscape is dominated by a large harbour, the volcanic cone of Mauao (Mount Maunganui) and is bounded by the Kaimai ranges to the west and sandy beaches and the Pacific Ocean to the east (Figure 3).

Tauranga has a temperate climate with an average annual temperature of 14.9ºC and compared to the rest of New Zealand, a relatively high average of 2,200 to 2,400 hours of sunshine a year. Average rainfall is 1,195mm (Tauranga City Council, 2016c).

Figure 3: Tauranga City location and extent (depicted in green) (Source: Tauranga City Council)

1.4 Pressure-State-Impact Framework

1.4.1 Cross Domain Pressures The pressure-state-impact model for environmental reporting examines causes and outcomes, as well as assessing environmental quality at a point in time. As is typical for SoE reporting, a number of pressures have been found to be common across the five environmental domains. The key environmental pressures operating in Tauranga are summarised below:

Growth

Tauranga City’s population projections have been produced by the National Institute of Demographic and Economic Analysis (NIDEA) for SmartGrowth after the 2013 Census. The population of Tauranga City is projected to grow from 119,800 in 2013, 164,100 in 2033 (+37%) and to a further 198,400 in 2063 (+21%) based on the median projection scenario. In response to this, new residential suburbs have been developed in Pyes Pa, Bethlehem, Papamoa, and Wairakei. Pressure to keep up with projected growth and grow further outwards continues as plans are underway for the future urbanisation of Te Tumu, Tauriko

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West, and Keenan Road. The effect of this growth on the environment is rapid urban development which, if unchecked, results in urban sprawl and significant habitat loss and land use change, putting additional pressure on infrastructure, environmental health, ecology and threatened native species. It is estimated that between 2013 and 2063, up to nearly 50,000 new dwellings will need to be constructed (TCC, 2017). These are likely to be both on the periphery of the city and by infill/intensification of the pre-1990’s urban areas. There is uncertainty regarding the timing and rate of uptake of these proposed urban growth areas which are dependent on infrastructure upgrades, financial viability and topographical constraints.

Global Pressures

Global pressures also affect the Tauranga natural environment: in particular in the atmosphere domain, where increasing greenhouse gases cause climate changes leading to an increased risk of natural hazards and public health implications.

Resource Use

Finally, and again closely linked to the pressure imposed by population growth, resource use is an important pressure on the Tauranga natural environment and must be carefully managed. In particular, use of energy through the burning of fossil fuels (e.g. for transport) which has flow on effects, especially to air and atmosphere; use of water which must be carefully managed to meet competing demands for use and uphold natural surface and marine water quality; and consumption of other resources that leads to excessive waste generation.

1.4.2 Assessing State Using pre-existing data, we have assessed the current state of Tauranga’s natural environment across all five environmental domains. A range of potential indicators for use in SoE Reporting for Tauranga were identified based on indicators commonly used by other territorial local authorities in New Zealand, and those commonly used to assess environmental condition generally. The suitability of each potential indicator was then assessed against four factors: availability of data to calculate the indicator, value as an ‘indication’ of condition more generally, importance to Tauranga City (and level of influence by TCC), and level of uptake nationally. Based on these criteria, a minimum of three indicators of state were selected for each domain. These are summarised in Table 1.

MfE first published a guide to national environmental indicators for air, freshwater and land in 1998 (MfE, 1998). Since then, National Environmental Standards (NES) have been established for air, drinking water and soil contaminants (but not soil health). Standards for freshwater are under development. National indicators have been employed for this assessment where possible, because standardised indicators enable comparisons to be made across regions, and encourage collaboration between the monitoring programmes of councils and other resource management agencies. If common indicators are used, common protocols and techniques can be developed and research and planning can be better targeted and coordinated. However, in many cases a lack of available data pertaining to these guideline indicators lead to others being chosen.

Only data from the most recent year have been used to calculate indicators in each case, to prevent results from being skewed, and to assist with early detection of impacts of interventions on environmental condition. Efforts have also been made to develop metrics for each indicator in the form of both a numerical value and a grade. Using word descriptors for each grade provides a simple and easy to understand way of communicating scientific data, of attributing context to the results, and comparing against guideline values where available. Further justification of the indicators used can be found in the report.

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1.4.3 Impacts ‘Impact’ is also referred to as ‘response’ internationally, but MfE terminology has been adopted here and therefore impact is used. It describes what the indicators, and the observed ‘state’ means for society. It refers to impacts on biodiversity and ecosystem processes, on the economy, on public health and general wellbeing, and on cultural and Māori values.

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Table 1: Indicators of state for Tauranga City State of the Environment Reporting

Domain Indicator Unit / Data Used Source / Date Calculation Method Grading System

-e N/A Per capita CO2 (total annual) Aecom study / July 2017 Refer Aecom (2017) greenhouse gas

(GHG) emissions

-e N/A Per capita GHG CO2 (total annual) Aecom study / July 2017 Refer Aecom (2017) emissions from transport

Atmosphere -e N/A Per capita GHG CO2 (total annual) Aecom study / July 2017 Refer Aecom (2017) emissions from industry 3 Particulate matter PM Otumoetai BOPRC Natural Environment Annual median, Standard = 50 µg/m 10 Excellent = <10% of standard (PM10) monitoring site Regional Monitoring Network Good = 10-33% of standard (NERMN) programme / 2016 Acceptable = 33-66% of standard Alert = 66-100% of standard Action = >100% of standard Source = NES for Air Quality (MfE) Standard = 350 µg/m3

Sulphur dioxide SO Totara Street, BOPRC NERMN / 2016 Hourly mean 2 Excellent = <10% of standard

Air (SO2) bridge marina and Good = 10-33% of standard Whareroa/ Taiaho Acceptable = 33-66% of standard Alert = 66-100% of standard Place monitoring Action = >100% of standard sites Source = NES for Air Quality (MfE) Total suspended TSP Totara Street BOPRC NERMN /2016 Annual median % of total complaints to RC particles (TSP) monitoring site

Waste generation Kg/capita annual TCC waste assessment 2016 Total waste to landfill / urban population of TC and N/A

waste to landfill (data collected 2014/15) and WBOP Waste Management Services

Land Review, SLR Consulting, 2017

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Domain Indicator Unit / Data Used Source / Date Calculation Method Grading System

% recyclable, TCC waste assessment 2016 N/A N/A reusable or (data collected 2014/15) compostable waste sent to landfill

Availability of Households within TCC Annual report 2015/16 Total area / urban population of TC N/A urban green space 500 m of green space

Area of urban Green space per TCC Parks data; Statistics NZ Total area of public urban green space and N/A green space capita estimated resident population stormwater reserves owned & maintained by TCC / (ERP) / 2016 2016 ERP

Land cover Permeable/ NZ Land Cover Database TC land cover data summary BOPRC N/A impervious and indigenous/exotic (LCDB v.4.1) Landcare land cover area (ha) Research/ 2015 Water Quality E Coli, n/100 ml BOPRC NERMN / 2015 % exceedances over 540 cfu/100 ml and over 260 A = <5% samples over 540 cfu/100 ml; Sites: cfu/100 ml; median E.coli concentration for at least <20% over 260 ml  Wairoa d/s Ruahihi 60 samples within a maximum of 5 years. B= 5-10% samples over 540 cfu/100 ml; 20- Powerstn 30% over 260 cfu/100 ml  Waitao at 172 Waitao Rd C= 10-20% over 540 cfu/100 ml; 20-34%  Waimapu at Pukemapu over 260 cfu/100 ml Rd D= 20-30% over 540 cfu/100 ml; >34% over  Kopurererua at SH29 260 cfu/100 ml  Kopurererua at SH2 E = >30% over 540 cfu/100 ml; >50% over

 Wairoa at SH2 260 cfu/100 ml Median concentration ≤130 cfu/100 ml for all attribute states except ‘E’ which is >260 Water cfu/100 ml. (NPSFM, Amended 2017) Nutrient Total nitrogen g/m3 BOPRC NERMN / 2015. # Exceedance of ANZECC trigger value/year; % of samples over ANZECC trigger (614 concentration Sites as above. median µg/L or 0.614 g/m3)

Nutrient Total phosphorus BOPRC NERMN / 2015 # Exceedance of ANZECC trigger value/year % of samples over ANZECC trigger (33 µg/L concentration g/m3 Sites as above. or 0.033 g/m3)

Sediment Turbidity NTU BOPRC NERMN / 2015 # Exceedance of ANZECC trigger value/year % of samples over ANZECC trigger (5.6 Sites as above. NTU)

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Domain Indicator Unit / Data Used Source / Date Calculation Method Grading System

Stormwater Heavy metals: Sites 1-25, TCC stormwater # Exceedance of ANZECC trigger value/year. N/A arsenic (As), copper consent monitoring contaminant load (Cu), lead (Pb), zinc programme / 2016. Quarterly baseline monitoring values only; storm (Zn), nickel (Ni), events excluded. mercury (Hg), cadmium (Cd), chromium (Cr) μg/l Ecology Macroinvertebrate BOPRC NERMN / 2016. MCI actual Excellent >119 Community Index Sites used: Good = 100-119 (MCI) 75 Waitao Fair = 80-99 78 Waioraka Poor<80 79 Otumanga 80 Kaitemako 82 Kopurererua Water Quality Concentrations of BOPRC NERMN 2015/16 Assign grade based on the percentage of samples Very good: >95% samples <140 cfu/ 100 ml Enterococci bacteria sampling season. that have Enterococci concentrations <140 cfu/100 Good: >90–95% samples <140 cfu/100 ml in weekly samples Recreational water quality ml Fair: >75–90% samples <140 cfu/ 100 ml from popular monitoring sites used: Poor: <75% samples <140 cfu/ 100ml swimming sites in  Mt Maunganui Surf Club Regular weekly/ routine samples only; follow up the 2015/16  Pilot Bay Mid Beach (As adopted by Northland Regional Council

samples excluded sampling season  Te Puna Waitui Reserve and Horizons Regional Council; the grading  Maungatapu Bridge system has not yet been formally adopted by  Marine Tilby Point BOPRC)  Waimapu Bridge Marine ecology MCI TCC stormwater consent MCI actual Excellent >119 monitoring programme / 2016 Good = 100-119 Fair = 80-99 Poor<80 (Stark & Maxted, 2007)

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Domain Indicator Unit / Data Used Source / Date Calculation Method Grading System

Sediment Heavy metal NERMN Sediment Sites assigned a grade based on the Wriggle Very good: overall score <1.25 contamination monitoring Coastal Management condition ratings (Lawton, Good: overall score >1.25 to <2.25 contamination concentrations: 1 programme 2017) : Fair: overall score >2.25 to <3.25 arsenic (As), copper  Very good: <0.2 x ISQGLow Poor: overall score >3.25 (Cu), lead (Pb), zinc  Good: 0.2 x ISQGLow to 0.5 x ISQGLow Plates 1-24 / 2016  Fair: >0.5 x ISQGLow to ISQGLow (Zn), nickel (Ni),  Poor: >ISQGLow mercury (Hg), For each metal a number is assigned to each grade: cadmium (Cd),  Very good = 1  Good = 2 chromium (Cr) μg/l  Fair = 3  Poor = 4 Grades for each metal are averaged to provide an overall score ranging from 1 to 4. Nutrient state Percent TOC, total N NERMN Sediment Sites assigned a grade (Wriggle Coastal  Very good: overall score <1.25 Management condition rating) based on % TOC,  Good: overall score >1.25 to <2.25 and total P contamination monitoring total N and total P concentrations and macroalgal  Fair: overall score >2.25 to <3.25 concentrations in programme. cover in sediment samples which are averaged to  Poor: overall score >3.25 sediment samples, provide an overall score from 1-4. percent macroalgal Plates 1-24 / 2016 % TOC cover.  V good: <0.5%  Good: 0.5-1%  Fair: >1 to 2%  Poor: >2% Total N  Very good: <250 mg/kg  Good: 250 – 1000 mg/kg  Fair: >1000 – 2000 mg/kg  Poor: >2000 mg/kg Total P  Very good: <100 mg/kg  Good: 100 – 300 mg/kg  Fair: >300 – 500 mg/kg  Poor: >500 mg/kg Macroalgal % cover:  Very good: <5% cover  Good: >5% to 15% cover  Fair: >15% to 50% cover  Poor: >50%

1 The grading methods used are in the preliminary stages of development and the methods published in the final document may differ to what has been produced in this report.

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2 Atmosphere

6.3 tCO2 0.2 tCO2 4.0 tCO2 emissions per industrial emissions road capita. per capita. transport emissions per capita.

2.1 Pressures The single largest anthropogenic impact on the atmosphere is the release of greenhouse gases (GHGs) causing climate change. Under this particular domain, local and global activities have a significant impact on the New Zealand (and Tauranga) environment. The pressures on the state of the atmosphere (and climate change) are a result of:  Urban development (as a result of population growth)  Increased reliance on fossil fuels (e.g. for electricity and transportation)  Loss of natural habitats, green space and biodiversity  Excessive resource use and associated waste production

Climate change modelling has been undertaken for BOP based on the Intergovernmental Panel on Climate Change’s GHG emission scenarios as described in the Fourth Assessment Report (IPCC AR4) (Reisinger et al., 2014). Future projections are calculated from 10 global climate models (GCMs) that have been downscaled to a 5km x 5km grid across New Zealand. Projections in the Bay of Plenty Regional Council (BOPRC) assessment report focus on the A1B (mid-range emissions) and A2 (high emissions) scenarios, and two time periods: mid-century (2030-2050) and century-end (2080-2099), relative to present day (1980- 1999) (Griffiths et al., 2011).

Projected climate changes for the BOP region as a whole are:  Temperatures warm by about 1.2°C relative to 1990 by 2040 under the A1B scenario, with slightly more warming in winter  Hot days (recording 25°C or more) become the norm during the summer months by the end of the century  Reduced number of winter lows  Extreme winds generated by large-scale weather systems (such as fronts and lows) decrease in summer but increase in winter  Slightly decreased precipitation: less rain in winter, increased rainfall in summer  Sea level rise (Reisinger et al., 2010, 2014).

2.2 State Greenhouse gases in the atmosphere absorb heat radiating from the Earth’s surface causing warmer temperatures. They are predominantly carbon dioxide, methane, nitrous oxide, and carbon monoxide.

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Carbon dioxide has the greatest impact over the long term because it persists in the atmosphere longer than the other greenhouse gases. However, the others have a significant impact in the short term, because they absorb much more heat per kilogram than carbon dioxide. For this reason, greenhouse gases are measured -e with the unit ‘tonnes of carbon dioxide equivalent’ (tCO2 ). Aecom has been engaged by TCC to develop a carbon footprint for the City, to clearly show the most significant sources of GHGs and calculate tot al GHG emissions for Tauranga as a total of carbon dioxide equivalent. Only preliminary results were available at the time of writing, but the results converted into per capita figures are included as a key indicator of environmental state in the atmosphere domain (Aecom, 2017). To use this as an indicator of state, comparisons of gross emissions per capita (excluding forestry) have been made with three other cities nationally (Dunedin, Wellington and Auckland). Per capita, Tauranga -e produces 6.3 tCO2 annually which is lower than both Dunedin and Auckland but higher than Wellington (5.7 -e tCO2 ). Internationally, for emissions per capita based on stationary energy, electricity, transport and waste related emissions only, the AECOM report indicates thatTauranga emissions per capita are much lower than -e -e Sydney (5.8 compared with 19.6 tCO2 , respectively) , of a similar order to Toronto (5.9 tCO2 ) and higher -e than Stockholm and Copenhagen (2.3 and 3 tCO2 , respectively) (Aecom, 2017). It is pertinent to note that road transport is by far the largest source of Tauranga emissions, at 61% of total emissions. Electricity consumption is the second largest source of emissions associated with Tauranga. Although the emissions resulting from electricity production are produced outside of the city boundaries, it is noted that the demand for energy consumption within the city influences its production. While this does not directly influence the ‘state’ of the Tauranga enviornment, it is considered a contributer to global climate change which will ultimately have an impact on the local environment..

2.3 Impact Global climate change modelling shows wide ranging impacts as a result of pressure on the atmosphere and subsequent climate change. The following impacts will be the result of global emissions which Tauranga emissions will contribute to:

 Although extreme weather events have always occurred, these are expected to become more frequent due to climate change (NIWA, 2009). Extreme weather events (storms, flooding or wind damage, droughts) can cause millions of dollars of damage and lead to injury or the loss of life (Insurance Council of New Zealand (ICNZ), 2014);  With increasing sea level, more frequent flooding of coastal margins by extreme tides, surge and waves is possible, making lowland areas vulnerable to inundation (Dahm et al., 2005);  Climate influences the amount of water in our lakes, rivers, streams, and aquifers, and therefore how much water is available for our use. From current data, MfE was unable to determine the effect of climate change on surface or groundwater (MfE, 2015);  Many culturally significant sites are in low-lying or coastal areas and therefore vulnerable to sea-level rise or increased coastal-storm activity (Reisinger et al., 2014);  Patterns of erosion experienced along the open coast of the BOP are unlikely to change substantially (Bell et al., 2006);  Climate change, in combination with on-going pressures from urban expansion and land use change, will lead increasingly to loss of biodiversity and an increase in biosecurity problems. Kenny (2006) studied flow on issues of climate change for biodiversity specifically for the BOP. They included: – Warmer temperatures and sea-level rise will affect coastal vegetation, with the possibility of increased growth and spread of mangroves and favourable conditions for wetland ecosystems. – Pressure on bush margins from invasive weeds is likely to increase, especially when combined with ongoing subdivision and greater numbers of houses located immediately adjacent to (and even in) indigenous forest remnants. – On-going changes in agriculture and horticulture with an increasingly sub-tropical environment in coastal areas will exacerbate the significant changes over the last 30-40 years from an area that

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historically grew citrus and some apples to the growth of kiwifruit and the more recent development of the avocado industry. With warmer temperatures there will likely be further intensive land development further inland and at higher altitude (and closer to bush margins). – On-going changes in production ecosystems with the potential for subtropical grasses to increasingly prevail in coastal and semi-coastal areas will require significant changes in pasture management – A warmer, more favourable climate for established weeds such as woolly nightshade, encouraging increased spread. There could be increased pressure on coastal areas from weed pests such as lantana and Italian buckthorn and a very diverse range of pest plant species already present on coastal dunes.

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3 Air

PM10: SO2: TSP: 65% of readings in 91% - 97% of 'Good' category readings in associated with 57% 'Excellent' category annual complaints

3.1 Pressures

PM10 (airborne particulate matter with a diameter less than 10 micrometres) is a major air pollutant monitored in New Zealand, and one of the most obvious indicators of air quality. Significant sources of PM10, and therefore pressures on air quality in Tauranga are depicted in Figure 4. Home heating by domestic solid fuel burners and backyard burning, both significant sources of fine particulate matter and benzene, are problematic. Not only does open burning release harmful pollutants into the air, it causes adverse health effects and social problems. In an urban setting it is easy for smoke to cross property boundaries, in fact, backyard burning is the single highest source of public complaints to BOPRC (Ferguson, 2012).

Industrial and commercial operations are also responsible for fine particulate discharges. In Tauranga these are predominantly from port activities and associated industrial areas. The Port of Tauranga is the largest export (by volume) port in New Zealand. Discharges to air arise from shipping, cargo handling, and other export/import and servicing industries located next to the Port.

A growing population causes traffic congestion and local air pollution on a daily basis in Tauranga. Diesel use for transport results in emissions of contaminants including fine particulates (PM10). Forecast housing and commercial growth will exacerbate traffic congestion on key parts of the road network, potentially undermining efficient access to the nationally significant Port of Tauranga and other commercial centres. A consistently lower proportion of Tauranga residents use alternative modes of transport such as public transport, cycling and walking in comparison with similar cities: the proportion of Tauranga residents who drive to work is 2.2% and 6.6% higher than Hamilton and Christchurch respectively (Statistics NZ, 2013). According to the TCC 2016 annual report, 66% of people used their private car to commute to work. There was some increase in the proportion of bus usage in the same year, from 1% to 3%, and a decrease of 1% in the proportion working from home.

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Figure 4: Sources of PM10 (source: LAWA)

3.2 State The NES for Air Quality (NES-AQ) provides ambient air quality standards for five specific contaminants; carbon monoxide (CO), particulate matter less than 10 micrometres in diameter (PM10), nitrogen dioxide (NO2), sulphur dioxide (SO2) and ozone (O3). BOPRC have monitored the first four of these in Tauranga since 2012 under the NERMN programme. In Rotorua hydrogen sulphide (H2S) monitoring is deemed to be of value by BOPRC and has not been selected as an indicator for Tauranga.

Particulate Matter (TSP and PM10)

Particulate matter includes dust, smoke, aerosols, haze and fallout. Particles below 10 microns (PM10) affect visual air quality and can have respiratory effects because they are small enough to be inhaled. In Tauranga City, long term PM10 monitoring has been ongoing at Otumoetai for 13 years, and this data has been reviewed for this study as it provides a valuable baseline for trend detection. PM2.5 monitoring is not undertaken, however it is scheduled to be installed at Totara Street in late 2017.

Figure 5: Air quality state indicators and their meanings and threshold concentrations (BOPRC, 2012)

For the majority of time, PM10 values measure in the ‘Good’ air quality category (65% in 2016), a description of which is provided in Figure 5. However during the winter months, air quality can reduce and fall into the ‘Acceptable’ category. On a daily scale the winter time data shows the dominating effect of domestic heating sources, with a noticeable increase in the morning on top of the traffic contribution and then an increase being recorded during the evening as emissions from wood burners impact the Otumoetai site. Summer peaks are also observed due to the site’s proximity to the coast and exposure to sea salt. Daily averages at the Otumoetai site are well below the ambient standards (www.lawa.org, 2016).

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Analysis of BOPRC NERMN data for 2016 at the Otumoetai site found 21% of PM10 readings to be within the ‘Excellent’ category; 65% within the ‘Good’ category, 13% ‘Acceptable’ and 1% ‘Alert’. There were exceedances of the standard on nine days of the year. The median for TSP measured 22.87 µg/m3 for 2016. As there is no national grading scale for TSP, to give an indication of what this means in a social sense the complaint record for BOPRC was examined. This showed that current practices led to 57% of the 2,360 complaints to Council in the 2015/16 year falling within this category (BOPRC, 2016). While not an ideal indicator as a number of external factors will influence the reporting of an incident, registers do provide an indication of the frequency of complaints and the dominant issues (Environet, 2003).

Sulphur dioxide (SO2):

SO2 is mainly produced by the burning of fossil fuels. The primary sources are coal (<0.5 – 3.0 % sulphur), fuel oil (0.5 - 3.5 % sulphur) and diesel (0.3 % sulphur). A number of industrial processes also emit SO2. There is no significant sulphur in natural gas, petrol or wood. There is a history of SO2 exceedances in the Mount Maunganui industrial/port area the majority of exceedances of air quality standards at the Mount Maunganui industrial/port area in the earlier part of the record in 2010.

More recent analysis of BOPRC NERMN data for 2016 at the Mount Maunganui industrial/port area found 94% of readings to be within the ‘Excellent’ category; 5.7% ‘Good’ and 0.3% ‘Acceptable’ for SO2. Two further air quality monitoring sites, Bridge Marina and Whareroa /Taiaho Place have also been established reasonably recently.

th SO2 data have been collected at the Bridge Marina monitoring site from 16 April 2016. Data collected until the end of July 2017 from this site have been analysed for this report and the council has committed to SO2 monitoring at this site for at least the next 5 years. Since monitoring began at this site, 97% of the 1 hour mean readings were within the ‘Excellent’ category and 3% within the ‘Good’ category for SO2. The guideline value for the 1 hour mean for SO2 has not been exceeded.

SO2 monitoring has been conducted at Taiaho Place since September 2015. Data from 1 January 2016 up to the end of July 2017 indicates that 91% of 1 hour mean readings for SO2 were within the ‘Excellent’ Category, 7.8% ‘Good’, 1.2% ‘Acceptable’, 0.2% ‘Alert’, and 0.1% ‘Action’. Exceedances of the guideline for 3 1 hr mean SO2 concentration (350 µg/m the ‘Action’ category) occurred over limited periods during 10 days within the period January – May 2016 with the concentrations measured above the guideline ranging from 363.8 µg/m3 – 750.6 µg/m3.

3.3 Impact Air quality contributes significantly to urban quality of life. If air quality is degraded, effects on the environment can be apparent and the flow-on response to this is adverse health impacts, restrictions on recreation, damage to buildings or property, crop yield reductions, reduced natural biodiversity and impacts on the mauri of air. Polluted ‘airsheds’ (areas where air quality could reach levels higher than the national air quality standards) result in contaminant absorption to land or water, plants, animals, human health and amenity (Environment Bay of Plenty, 2003). In Tauranga, while compliance with the NES-AQ for SO2 is generally good (despite the limited exceedances noted above), PM10 levels - finely divided material such as smoke, fine powders, vehicle emissions, salt spray and the like that remains suspended in the air and can be breathed into the lungs - are consistently elevated.

The primary effect of SO2 is as a respiratory irritant, causing bronchitis, irritation of the nose, throat and lungs, for example while exercising, coughing, wheezing, phlegm and asthma attacks. On a global scale it is also of concern in the production of acid rain and acidification of soils.

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In New Zealand, it is PM10 that has been identified under the NES-AQ as being of particular concern to health and the environment, and Tauranga seems to be no exception. Particles emitted into the air from sources such as vehicles, industries and domestic fires, affect both amenity value of the environment in the form of unsightly smog and haze over cities, and human health effects such as bronchitis and aggravation of asthma. Larger particles (TSP) cause nuisance effects such as soiling of property and reduction of amenity (Environet Limited, 2003).

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4 Land

3% 630 kg 52.6% Native vegetation Waste to landfill Divertable waste land cover per capita p.a. sent to landfill p.a.

88.8% 120m2 43% Households Green space Impervious within 500m of per capita land cover green space

4.1 Pressures The area within Tauranga City limits (Figure 3, Figure 6a and Figure 6b) in its entirety encompasses 122,340 ha, 73% of which is privately owned. Land holdings within the city limits are generally small, being mainly urban residential, commercial and industrial with a few farming enterprises. The wider catchment (the Tauranga Harbour Catchment), which extends beyond the city limits, has a large and rapidly growing suburban landscape, lifestyle blocks and orchards in the upper catchment, and a number of dairy farms. Commercial production is primarily orchard-based, with kiwifruit and avocado the main fruit crops.

Tauranga has a long history of changing land use, including extensive forest clearance by Māori burning, followed by further clearance and modification for farming, logging, and mining (Wildlands, 2010). A landscape study undertaken in 2011 clearly shows historical and current land cover types and extent of urban growth (Figures 6a and b) (Boffa Miskell, 2011). Nowadays, there is growing pressure on land as a result of rapid growth of the city in commercial and industrial activity as well as residential leading to demand for development of greenfield sites. Land cover and land use change are therefore considered critical indicators of the environmental state of this domain, particularly in relation to city management and planning. Adequate greenbelt and reserve is necessary to protect the integrity of waterways and enhance biodiversity.

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Some analysis of the Tauranga Ecological District has been undertaken (Wildlands, 2003, 2010; Harfoot and Shaw, 2003) which indicates there are very few protected areas within the district with typically only small areas protected by DOC as well as QEII and other covenants, which legally protect an open space feature in perpetuity. Most indigenous remnants left in Tauranga Ecological District are recorded as degraded by weed invasion but are still considered to be of ecological significance, even those of small size (DOC, 2010). While the ecological district represents an area larger than the TCC administered area that this report relates to, it affects, and is affected by, flow on effects to biodiversity and water quality, among other issues, within the city.

Figure 6a: Tauranga City historical land cover (Source: Boffa Miskell, 2011).

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Figure 6b: Tauranga City current land cover (Source: Boffa Miskell, 2011).

4.2 State

4.2.1 Land Use Tauranga City has undergone a significant and dramatic change to the natural environment. Built form now dominates the coastal edge with high rise, port activities and suburban residential settlement. The high proportion of impervious areas in the urban environment causes stormwater flows to be more extreme and water and contaminants to directly enter streams and stormwater systems without filtration, rather than soaking into the ground. This is why permeable areas such as lawns, parks and gardens are important in the city. Robust information relating to the extent of impervious surfaces in Tauranga, or New Zealand for that matter, was not available at the time of writing, but it is recommended, as a potential indicator for land environment (MfE, 2017a).

TCC Parks and Reserves department monitors and has set performance measures relating to public access to green space. Indicators are currently slightly below target based on 2015/16 statistics, showing that 88.8% of households live within 500m of urban green space such as parks. This is up 1% from the previous year but still significantly down from the target of 95%. It is notable that this measure only relates to Council owned and maintained open space areas and stormwater reserves. Any additional open space owned and maintained privately is not included. Older areas of town tend not to meet this indicator as a result of past planning decisions and change in these zones is difficult. Open space is being acquired in other parts of the city in the form of neighbourhood reserves and stormwater reserves vested through subdivision. This is important as an indicator of quality of the environment in the city, not only for amenity and aesthetic values, but also for stormwater management and biodiversity. The total area of public urban green space, being that

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space owned and maintained by Council and including stormwater reserves is 1,549.42ha. Using the ERP from 2016 gives a total of 120.86m2 public urban ‘green space’/ park area per capita.

Boffa Miskell (2003) evaluated natural coastal character of Tauranga and the impact land use has had on coastal character. A common pattern was the lack of natural form and significant human modification to the natural environment. The evaluation is summarised in Table 2.

Table 2: Evaluation of natural coastal character of Tauranga (Boffa Miskell, 2003).

Sector Natural Comments Character

Tauranga City Low – Extensive reclamation and human modification, particularly around harbour. Small to Mauao Moderate pockets of remnant harbour edge are found within the upper reaches of the four estuaries.

Mauao to Moderate Mauao the dominant feature, with significantly modified vegetation patterns due to Maketu fires, historical grazing, settlement and infrastructure. Remnant pohutukawa remain. Coastal edge intact and vegetation patterns improving through replanting programs. Heavily modified dunelands at the Mount Main Beach, built upon for residential settlement. Small pockets of unmodified primary and secondary dune systems. Seawalls and retaining walls are present to manage erosion and water flow into the estuary at the river.

Tauranga City Very High Much of the harbour margins remain unchanged except for Tauranga City where industrial and commercial structures dominate the harbour margin. Dredging of the sea floor occurs for the Port of Tauranga shipping activities and sedimentation is apparent in the southern harbour estuaries where reclamation has contributed to the retention of sediment.

4.2.2 Land Cover The New Zealand Land Cover Database (LCDB) is a national classification of land cover and land use mapped using satellite imagery. The LCDB has four major versions (1–4), correlating to the four summer survey periods – 1996/97, 2001/02, 2008/09, and 2012/13. Version 4.1 was analysed for the Tauranga City area, finding a very small proportion of that area - roughly 3% - to be indigenous vegetation. 53% is exotic vegetation (predominantly pasture) and 43.14% is urban impervious.

4.2.3 Waste Waste generation is considered a key indicator for this assessment, as it is one which TCC has significant influence over. Most rubbish sent to landfill from Tauranga is collected together with that of Western Bay District and packed at one of the two transfer stations in Tauranga – Maleme Street or Te Maunga - for transport to landfills in the Waikato region.

The last waste assessment undertaken (TCC, 2016b) found that together Tauranga and the Western Bay sent close to 90,000 tonnes of waste to landfill in 2014/15, which translates to 630kg per capita per annum. The profile of Tauranga City waste in 2015 is shown in Figure 7.

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Waste increases with population but can be further influenced by changing patterns in consumption or product quality, or people’s awareness and behaviours, coupled with the relative ease and availability of alternatives. For this reason, the indicator is set per capita in order to assess relative change over time. The waste assessment found that a significant quantity of material – 52.6% of rubbish sent to Class 1 landfills - if separated, could be recycled, composted or otherwise put to beneficial use instead of being sent to landfill (Eve and Wilson, 2016). A waste management and minimisation plan is in place and there is significant ongoing research and investment into reducing this proportion through the reduction or redirection of waste intended for landfill (Eve and Wilson, 2016; SLR Consulting, 2017). Figure 7: Tauranga City Waste Profile in 2015 (Eve and Wilson, 2016) 4.2.4 Soil Contamination and Health Soil contamination due to past and present argicultural or horticultural activities can have an impact on biodiversity as well as the productivity of the land. Contamination of agricultural soils was assessed in a study undertaken by SEM New Zealand Limited (SEM NZ) on behalf of Environment Bay of Plenty (EBOP) in 2005. During this study, 21 soil samples were collected from within the city limits. Of these a total of five samples (25%) exceeded trigger values: three for copper (trigger Level 63 mg/kg for agricultural and 80 mg/kg for residential land use); two for total DDT (agricultural and residential limit of 0.7 mg/kg), and one for zinc (agricultural and residential limit of 200 mg/kg). The highest copper exceedance value (171 mg/kg), and the only zinc exceedance value (212 mg/kg) were recorded in samples collected from orchards. The random sampling method deliberately avoided any known hot spots, which achieved a better estimate of background agrichemical residue levels under different land uses, however it prevents the results of the research from being used to indicate the actual or maximum level of agrichemical residue either generally or at any one specific location and has not beeen repeated since 2005 (SEM NZ, 2005). Data on heavy metal contaminants in stormwater and in esturine sediments is collected and is considered a better indicator of contamination for this SoE report. Refer to Sections 5 and 6 for these results. No assessment of any soil contamination associated with existing or former industrial sites has been conducted for this report.

Soil health is determined by four indicators: acidity; organic reserves; fertility; and physical status. Although there are currently no national standards for soil health in New Zealand, there are concerns about the increasing levels of nutrients typically found in agricultural and horticultural soils. BOPRC monitors soil health as part of the NERMN programme, however it has not been selected as an indicator for the land domain of this urban SoE report because a) much of the land is covered by impervious surfaces, b) the monitoring programme has no sites within the city limits and c) assessment of soil health is typically conducted for areas of productive land as opposed to urban settings.

Nutrient levels in soils must be managed carefully to avoid increased nutrient leaching, which can cause enrichment of waterways (eutrophication) and accumulation in estuaries and harbours (MfE, 2014a). The waterways within the city limits are likely to be impacted from land use activities occurring outside of the city administrative boundary. It is considered that in an urban setting, consideration of the level, nature and distribution of contaminants within urban soils is of most relevance to environmental state.

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4.3 Impact

4.3.1 Land Use and Cover Providing access to areas for recreation, leisure and sport contributes to a healthy and happy city. Open spaces help to attract and hold community events. They contribute to having an attractive and liveable city, with preserved cultural landscapes and restored and enhanced ecosystems (TCC, 2016a). Areas of natural habitat are important for the above, and for biodiversity. The limited, and decreasing area of natural environment amplifies threats to native flora or fauna. The most pressing issues are the invasion of pest plants, destruction of natural areas by possum, predation of indigenous species by pest mammal species (mustelids, rats and mice), and disturbance of nesting and roosting areas (Harfoot and Shaw, 2003). Unfortunately, in the wider Tauranga Ecological District relatively little remains in the way of indigenous vegetation and habitats, and much of what remains is highly modified and fragmented. About 3% of land cover is indigenous vegetation; about 0.6% of land in the coastal bioclimatic zone is protected, and about 1.2% of the semi-coastal bioclimatic zone (Wildlands, 2003). Without protection, dune vegetation and coastal forests in the wider Tauranga Ecological District, considered extremely rare habitat (Harfoot and Shaw, 2003), are threatened by urban development as well as fires and mining. Likewise, freshwater wetland vegetation and habitat are highly threatened by draining of the wetlands for development. Coastal areas are also seeing increasing conflict between a recreational focussed human community and natural character and natural processes such as specialised nesting requirements of threatened bird species.

4.3.2 Waste The impact of excessive waste generation transfers to all other environmental domains: landfills produce leachate, greenhouse gases and toxins. Leachate is the liquid formed when waste breaks down in the landfill and water filters through that waste. The liquid is highly toxic and can pollute land, groundwater and waterways. Organic material breaks down anaerobically, releasing methane, a greenhouse gas with significant warming potential (21 times more than carbon dioxide), which adds to the problem of climate change. Landfills have not just environmental but economic and social impacts including public health impacts (e.g. vermin and odour) and financial costs. In Tauranga’s case, solid waste disposal costs the city and its residents in excess of $17 million annually for kerbside waste services alone (Eve and Wilson, 2016). While there are no landfills in Tauranga, the city produces a significant amount of waste that is sent to Waikato landfills unnecessarily, as a high proportion could be avoided, reduced or otherwise redirected with focus on awareness and incentives to change behaviour.

4.3.3 Soil Contamination and Health Impacts on the environment and to human health by residual agrichemicals and high nutrient levels in soils associated with horticultural and agricultural land uses can be significant as these nutrients and residues have the potential to leach to groundwater and accumulate in waterways, estuaries and harbours, affecting these ecosystems, and are covered in the following sections.

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5 Water

Turbidity: Nitrogen: Phosphorus: 88% of samples 55% of samples 60% of samples under trigger above trigger above trigger value value value

Water quality: Ecology 17% of samples Status = "Fair" Status = "Fair to above heavy to "Poor" poor" metal trigger values

5.1 Pressures Freshwater is a critical indicator of environmental health. It is also important for domestic, industrial, recreational and cultural purposes. In Tauranga, uses include horticulture and agriculture frost protection and irrigation, drinking water supply and recreation including swimming, boating, fishing or passive and scenic enjoyment. As alluded to earlier, the main pressures on the quality of freshwater result from land based activities. For example, it is expected that water quality at sites where the upstream land cover is urban and pastoral will be poorer than sites where native land cover is dominant (MfE and Stats NZ, 2017a).

The Kaimai ranges play an important role in maintaining the water quality in Tauranga city and harbour, as the indigenous forest cover helps to reduce peak flows and protect streambanks from flood events. Despite this, both the Tauranga Harbour catchment and Waihou catchment in Waikato Region have a history of storm-induced erosion and flooding, which has necessitated programmes of catchment protection measures (Wildlands, 2010). A study by NIWA identified that the greatest amount of sediment (64%) came from pastoral land surrounding Tauranga Harbour, the next closest being land used for bush, scrub and native forest (28%) (Green, 2009). Regional management to maintain and promote healthy forest cover is necessary to further reduce sedimentation and improve water quality, as well as leading to positive outcomes for biodiversity and recreation.

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While nutrients such as nitrogen and phosphorus are essential for plant growth and small amounts are a natural component of healthy rivers, agricultural and urban land use add excessive nitrogen and phosphorus to waterways leading to uncontrolled growth of algae and deteriorating river habitats. Nitrate-nitrogen and ammoniacal nitrogen are toxic to aquatic life at elevated concentrations. Nutrients enter urban streams through the stormwater system from spills, fertiliser used on lawns, and golf courses as well as upstream pastoral practices (Webster and Timperley, 2004).

Urbanisation causes vegetation to be removed and soil, which would absorb stormwater, to be covered by impervious surfaces such as roofing, asphalt and concrete. This leads to increased stormwater volumes and peak flows (Suren and Elliot, 2004). Tauranga’s urban streams are typical in that they have flashy flows (rapid increases and decreases in peak flows), elevated concentrations of nutrients and contaminants, highly modified channels, and reduced biodiversity. Only ‘tolerant’ species can thrive in streams with poor water quality (Walsh et al., 2005). These streams typically have increased bank erosion and sediment transport compared with native streams, which results in more sediments deposited in estuaries.

The degree of contamination of freshwater is linked to the amount of impervious area, as impervious surfaces and pipes direct stormwater run-off straight into urban streams, stormwater channels and the harbour (Lewis et al., 2015). This stormwater run-off can contain elevated concentrations of heavy metals from sources such as vehicle wear (copper from brake pads and zinc from tyres), metal roofing, and industrial yards (Kennedy and Sutherland, 2008).

5.2 State A number of rivers and streams flowing into Tauranga Harbour are monitored for various parameters by BOPRC as part of the NERMN programme and held on the Land, Air Water Aotearoa (LAWA) database. Of these, downstream monitoring locations have been selected to provide an assessment of surface water quality within the Tauranga city limits. The waterbodies used for water quality assessment comprise Wairoa, Kopurererua, Waimapu, and Waitao while Kopurererua, Kaitemako, Otumanga, Waioraka and Waitao were used for ecological health assessment. The most recent full year of data has been used in each case; in most cases this is from 2015.

The parameters that have been examined for the purposes of the state of the environment are E. coli bacteria count: considered a good indicator of water quality for swimming; total nitrogen and total phosphorus to assess nutrient concentration and turbidity to give an indication of sediment load. These four parameters are also important indicators in national freshwater management frameworks. In the absence of clear national limits or trigger levels for all of these parameters except E. coli, ANZECC guidelines for freshwater quality (2000) have been consulted to assess the current state against guideline values and to gauge what ‘good’ looks like. As a measure of freshwater ecological health, the macroinvertebrate community index (MCI) has been calculated for some of these monitoring sites as well. In addition to freshwater monitoring, TCC stormwater monitoring data has been used to analyse the effect of heavy metal contaminants entering the waterway.

5.2.1 E.coli Attribute states for E.coli are determined by using a minimum of 60 samples over a maximum of 5 years according to the National Policy Statement for Freshwater Management (NPSFM) 2014 (amended 2017) which took effect on 7 September 2017. The 2017 amended guidelines for human health for recreation (which are applicable to swimming) are compared to the original 2014 E.coli guidelines (which were developed for secondary contact) and this comparison is presented in Table 3.

Between 2010 and 2015, samples have been collected from each of six sites across four watercourses flowing through Tauranga (Waitao, Waimapu, Waiora, Kopurererua) Samples were collected at two sites in

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both the Kopurererua and Wairoa watercourses, and at one site in both the Waimapu and Waitao watercourses and analysis results provided on the LAWA site, however, the number of samples from Waimapu and from Wairoa near the Ruahihi power station were less than 60 and so have not been used for this analysis. It should also be noted that the 2017 amended guidelines only apply to streams of fourth order or greater and therefore Kopurererua will not be required to meet these new guidelines. Water quality requirements for Kopurererua and other similar streams are yet to be confirmed. Based on the 2010 – 2015 data a ‘C’ score is attributed to Wairoa and an ‘E’ score is attributed to Waitao. These results correspond with current river water quality scores for Tauranga rivers and streams as provided by MfE (http://www.mfe.govt.nz/fresh-water/about-freshwater/bay-of-plenty) which indicate the Wairoa River to have ‘fair’ quality for swimming, whereas the Waimapu Stream and Waitao Stream are recorded to be ‘poor’ quality for swimming. It is noted that the Waimapu Stream is scored as ‘intermittent quality’ to the south of SH29. Kopurererua stream is not scored.

Table 3: 2014 and 2017 amended E.coli guidelines for recreational use in lakes and rivers (MfE, 2014a; MfE, 2017)

Score 2014 guideline 2017 amendment to guideline

A (blue) <260 cfu/100ml annual median Exceeds 540 cfu/100ml <5% of the time; and exceeds 260 cfu/100 mL <20% of the time; and median concentration ≤130 cfu/100 mL

B (green) 260-540 cfu/100ml annual median Exceeds 540 cfu/100ml 5-10% of the time; and exceeds 260 cfu/100 mL 20-30% of the time; and median concentration ≤130 cfu/100 mL

C (yellow) 540-1000 cfu/100ml annual median Exceeds 540 cfu/100ml 10-20% of the time; and exceeds 260 cfu/100 mL 20-34% of the time; and median concentration ≤130 cfu/100 mL

D (orange) >1000 cfu/100ml annual median ; Exceeds 540 cfu/100ml 20-30% of the time; and exceeds 260 cfu/100 mL >34% of the time; and median concentration ≤130 cfu/100 mL

E (red) N/A: D = national bottom line Exceeds 540 cfu/100ml >30% of the time; and exceeds 260 cfu/100 mL >50% of the time; and median concentration >130 cfu/100 mL

5.2.2 Nutrients The annual medians in 2015 for total nitrogen and phosphorus were calculated for the same six sites within four waterbodies as referenced for the E.coli analysis above. To assess the acceptability of these medians, and in the absence of trigger values in the National Framework for Freshwater Management, they have been assessed against appropriate ANZECC (2000) guidelines (Table 4). The trigger values for 90% species protection were selected based on a conservative assessment that watercourses flowing through Tauranga would most closely resemble ‘highly disturbed systems’ defined by the guidelines as: ‘measurably degraded ecosystems of lower ecological value’ and ‘urban streams receiving road and stormwater runoff, or rural streams receiving runoff from intensive horticulture’.

From samples collected from the 6 sites, total nitrogen concentration exceeded the ANZECC trigger value for ‘90% species protection for slightly disturbed ecosystems’ in 55% of the samples. Median values for each stream indicate that these exceedances for nitrogen are typically from Kopurererua and Waimapu. This figure was similar for phosphorous, with 60% of samples collected exceeded the trigger value for ‘90%

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species protection’ with medians for each stream indicating Kopurererua and Wairoa samples typically exceed the trigger value. Elevated nutrient levels encourage the growth of nuisance aquatic plants and chokes up waterways.

Table 4: Nutrient concentrations compared to ANZECC (2000) trigger values for 90% species protection for NZ lowland rivers in disturbed ecosystems

TP (g/m3) TN (g/m3) Turbidity (NTU)

Trigger Value 0.033 0.614 5.6

Site Recorded Median Concentrations

Kopurererua at SH2 0.048 1.110 4.65

Kopurererua at SH29 0.046 1.077 4.35

Waimapu at Pukemapu Rd 0.030 0.744 2.00

Wairoa at SH2 0.042 0.565 1.25

Wairoa d/s of Ruahihi Powerstation 0.027 0.429 2.45

Waitao at 172 Waitao Rd 0.027 0.398 4.00

Bold values indicate exceedance of the trigger value

5.2.3 Turbidity Excessive turbidity can limit the ability of water to support plant growth. The per-stream medians for turbidity were all well below the ANZECC trigger of 5.6NTU. However, over the whole sampling year, 17% of samples taken exceeded this value. Samples collected in 2015 from Kopurerua at SH2 had the highest median NTU (4.65, from 11 samples), while samples collected in 2015 from Wairoa downstream of the Ruahihi Power station had the lowest median NTU (1.25, from 5 samples).

5.2.4 Ecology The macroinvertebrate community of a stream lives with the stresses and changes that occur in the freshwater environment, whatever their cause, human induced or natural. The MCI is a water quality indicator that evaluates four categories: excellent, good, fair, and poor (as summarised in Table 5) based on pollution-sensitivities, namely organic enrichment, of all macroinvertebrate taxa found at a site (Stark and Maxted, 2007).

Benthic macroinvertebrates are sampled for assessing stream health as they play a central role in stream ecosystems feeding on periphyton (algae), macrophytes, dead leaves and wood, or on each other. In turn, adult insects leave the water and become food for birds, bats, spiders, etc. They are extremely important for digesting terrestrial and aquatic organic matter and passing it on to higher levels in the food chain (Lawton, 2017).

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Table 5: Interpretation of MCI – type biotic indices (from Stark and Maxted 2007)

Of the streams in the sampling programme, those draining to the Tauranga City Harbour that are monitored in terms of ecology are: Kopurererua (pasture), Kaitemako (pasture), Otumanga (urban), Waioraka (urban) and Waitao (pasture just outside of the city limits). The MCI was calculated for each of these sampling sites to provide an indication of stream health (TCC 2016a). The average MCI across these sites has been used as a freshwater state indicator (Table 6). In accordance with Stark and Maxted’s (2007) quality classes (which are the same classes recommended as national guidelines by LAWA), this average represents ‘Fair’ quality (possible moderate pollution), though it is notable that there is a range across the five rivers from ‘poor’ (probable severe pollution) to ‘good’ (possible mild pollution) indicating that pollution issues are likely variable across the monitoring locations.

Table 6: MCI scores in Tauranga

Site ref River (sampling locations available on LAWA) MCI Class

75 Waitao 106.00 Good 78 Waioraka 99.61 Fair 79 Otumanga 93.66 Fair 80 Kaitemako 101.44 Good 82 Kopurererua 79.80 Poor Average 96.10 Fair

5.2.5 Stormwater Monitoring In urban areas, freshwater refers to the stormwater network as well as surface water such as urban streams. Stormwater (rainwater plus any contaminants it picks up on surfaces and carries through the system) has a negative effect on the receiving environment if land-based activities are not appropriately controlled. Therefore stormwater quality has been assessed as a significant indicator in the water domain in an urban environment and within TCC’s area of influence.

Stormwater discharges are monitored across Tauranga City. Baseline sampling is undertaken quarterly following at least three days of no rain, and storm sampling annually between February and April within 24 hours of a rainfall event greater than 10mm. For the purpose of this report, routine sampling data for 2016 across 27 sites over the city were analysed for exceedances of heavy metal ANZECC trigger concentrations at the 90% level of protection (Table 7). It was found that 17% of samples exceeded a trigger value. All exceedances reported were for zinc with one sample which also recorded a concentration of copper above the trigger value.

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Table 7: Tauranga stormwater parameters and trigger values (ANZECC, 2000)

Water quality parameter Trigger value for discharge Trigger value for discharge Unit to freshwater environment to marine environment

Arsenic 360 N/A µg/L Copper 2.5 8.0 µg/L Lead 9.4 12.0 µg/L Zinc 31 43 µg/L Nickel 17 560 µg/L Mercury 5.4 1.4 µg/L Cadmium 0.8 36 µg/L Chromium 40 85 µg/L

5.3 Impact When water quality declines, it influences the way people and communities use the water and the water’s ability to support both natural ecosystems and social, recreational and economic activities. River water quality and ecological condition are also particular concerns for local Iwi. The apparent high nitrogen and phosphorus levels in some streams will encourage excessive plant and algal growth which can reduce oxygen levels and change the composition of plant and animal communities.

Lower visual clarity (turbidity) and elevated E.coli concentrations negatively affect aesthetic values and use for drinking or recreation. Monitoring data available to date indicates that elevated turbidity is not a particular issue in watercourses passing through Tauranga. E.coli is an indicator of disease-causing organisms, which may affect human health and the recreational values of water bodies. An ‘E’ score under the National Policy Statement human health recreational guidelines, as indicated for Waimapu and Waitao, indicates poor water quality in those watercourses.

Urban streams and stormwater have unique water quality issues due to the presence of infrastructure and runoff from high levels of impervious surfaces. Heavy metals (mercury, arsenic, cadmium, lead, copper, zinc, chromium and nickel) are transported by stormwater into urban streams and harbours, either by pipes or run- off from surfaces directly into streams. They then accumulate in sediment and plant and animal tissue to concentrations that are toxic to freshwater and marine fish and invertebrates. They also accumulate in human food sources like fish and watercress making them unsafe to eat. In particular, zinc and copper accumulate in sediment and tissue to high concentrations that are toxic to aquatic life (MfE and Stats NZ, 2017b).

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6 Marine

Water Quality for Sediment Ecology Nutrient State Swimming Contamination Averaged MCI 87% of sites rated 93% samples 66% of sites indicates as below alert level = rated as 'Very 'Poor' water 'Good' 'Good quality' good' quality for marine organisms

6.1 Pressures Tauranga Harbour is a shallow tidal estuary of 224km2 (one of New Zealand’s largest), of which 93% is exposed at low tide (Boffa Miskell, 2003). The harbour area includes areas outside of the city limits. The pressures on the marine environment are not dissimilar to those already mentioned for other domains. Because the marine environment is essentially the ‘end of the chain’, contaminants from land and freshwater systems tend to be magnified in the marine environment. Urban development, particularly in locations in the vicinity of or draining to, Tauranga Harbour not only can alter the visual appearance of the harbour, it can contribute contaminants which accumulate in sheltered harbours over decades, eventually reaching levels which affect the life supporting capacity of the harbours and their natural character (Ryder and Clark, 2013).

There are a huge raft of pressures on the marine environment reported. Five major issues affecting New Zealand estuaries are identified by Wriggle Coastal Management. These are sedimentation, eutrophication, disease risk, toxins and habitat loss. (Stevens and Robertson, 2013a, 2013b). The Proposed Regional Coastal Plan for the Bay of Plenty (2015) lists 52 issues (pressures) on the coastal environment, most of which relate to upstream activities. They are grouped under eight themes:

1. Lack of integrated management 2. Lack of management integrating land activities 3. Loss of character due to land use change 4. Loss of biodiversity 5. Inappropriate restoration/mitigation 6. Water quality deterioration 7. Stormwater discharge contaminants or freshness 8. Shoreline and cliff erosion

A recent survey of over 600 Bay of Plenty residents to identify the key issues for Tauranga Harbour that worry them raised pollution, sewage discharge, sedimentation, port, mangroves, sea lettuce, water quality, reducing kaimoana stocks and ‘balancing economic growth and the environment’ as key issues (BOPRC, 2014). Outside of the urban area, pasture is the dominant land use along the Bay of Plenty coast, with horticulture a distant second. This large area of intensive land use upstream from Tauranga heavily influences the condition of the soils, waterways and estuaries downstream by increasing the supply of nutrients to rivers and streams that discharge to the coast. Changing land use (e.g. from forest to pasture, or pasture to developed) affects the quality of the coastal environment. Vegetation removal can increase erosion and the

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transport of sediment and contaminants into harbours and estuaries. Increased nutrient levels and associated leaching causes nutrient enrichment of waterways (eutrophication). Eventually nutrients often accumulate in coastal areas (estuaries and harbours) (BOPRC, 2014).

6.2 State

6.2.1 Water Quality for Swimming The concentration of Enterococci bacteria in marine waters is typically used as one of the indicators of coastal water quality and also an indicator for whether the water is safe for recreational use (swimming etc). Water in streams, rivers and the stormwater system is easily impacted by tertiary treated wastewater, sewer overflows, and run off from areas of intensive agriculture etc. which can all contribute to raising Enterococci concentrations which then discharge into coastal waters. BOPRC monitors coastal swimming water quality at popular recreational sites and shellfish beds which includes measuring Enterococci bacteria levels. In Tauranga, the monitoring sites are:

 Mt Maunganui;

 Pilot Bay;

 Tilby Point;

 Maungatapu Bridge; and

 Waimapu Bridge.

A single water sample is taken each week from each monitoring site (“routine” samples) from October to March each year (BOPRC, 2014).

The Ministry for the Environment and Ministry of Health guidelines (2003) provide a framework for managing bacteriological risk based on indicator values. An Enterococci concentration of a single sample collected from a monitored site that is greater than 140 cfu/ 100 mL triggers an alert mode for that site indicating elevated levels of Enterococci, while a concentration above 280 cfu/ 100 mL measured in two samples collected within 24 hrs requires that the public be notified that the beach is unsuitable for recreation.

The alert mode trigger value has been adopted by Northland Regional Council and Horizons Regional Council to develop a grading system as per Table 1, however the use of this grading system has been proposed for use, but has not been formally adopted by BOPRC or TCC. Data were obtained from the LAWA database for the 2015/2016 season and 112 of 120 samples (93%) measured Enterococci below the 140 cfu/100 ml MfE alert trigger level. As an indication of grade, this translates to a ‘good’ rating under the proposed grading system presented in Table 1.

6.2.2 Sediment Contamination BOPRC undertakes regular monitoring of contaminant concentrations in sediments across Tauranga Harbour as part of the NERMN Programme. Sediment samples are monitored to identify and trace contaminants and their sources to help identify measures that can prevent future contamination. Heavy metal contaminant concentrations from samples collected in in the Tauranga Harbour were found to be low, with all samples measuring contaminant concentrations well below the Interim Sediment Quality Guidelines (ISQG) low trigger values (ANZECC, 2000). Based on the grading bands outlined in Table 1, 66% of sites were graded as very good; and 33% ‘good’. It should be noted that these results are for the whole of Tauranga Harbour and so include monitoring sites outside of the city limits, which in view of the results will

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not seemingly change the outcome. The average overall score for this indicator across all sites was 1.13. Noting that this value can range from 1 to 4 with higher scores indicating poorer condition, this is an indication that the marine environment has a low level of contamination in the sediment. It may however, not be recommended as an indicator that will need ongoing monitoring.

6.2.3 Ecology As part of TCC’s stormwater monitoring programme for comprehensive stormwater catchment consents, State of the Receiving Environment monitoring was carried out to assess long-term trends in the marine receiving environment as a result of stormwater dischages. Parameters measured for its 2016 annual report (Tauranga City Council, 2016a) included marine habitat, sediment quality and benthic invertebrate communities. Sampling was undertaken for 14 TCC sites. The macroinvertebrate community data have been adopted as an indicator of marine ecological state. Results varied across the 14 sites with total number of individuals ranging from 18 (site M18-02 - Waimapu) to 535 (site M17-03 – CBD Waterfront) and taxanomic diversity from 2 (site M5-2 - Otumoetai) to 34 (site M17-03 – CBD Waterfront). However, the average score was calculated as 72.5, signifying ‘poor’ water quality and probable pollution based on the grading system outlined in Table 1.

6.2.4 Nutrient State Sediment organic content (measured as total organic carbon or TOC), sediment nutrient enrichment (measured as total N and total P concentrations in the sediment) and macroalgal cover are all key indicators of nutrient state for New Zealand estuaries (Robertson et al., 2016). Generally, an increase in any or all of these elements will lead to an increasing degree of eutrophication and therefore poorer state of the marine environment. These indicators have been combined using the proposed methodology adopted by Lawton (2017) whereby condition ratings specific to New Zealand estuaries developed by Wriggle Coastal Management (Robertson and Robertson, 2014) have been combined to produce an overall score for nutrient state across monitoring locations within the Tauranga marine environment (this methodology is in the preliminary stages of development at the time of writing this report and has not been formally adopted by the BOPRC). Data collected by BOPRC as part of the NERMN Programme at sites across Tauranga Harbour during the period from November 2016 and February 2017 were used and the data associated with the Tauranga administrative boundary, isolated. Of 24 sites (Plates 1-24), almost all (87.5%) rated ‘good’, with two ‘fair’ (8%) and one ‘very good’ (4%) in Waikareao. None were classed as ‘poor’.

6.3 Impact Tauranga Harbour is one of New Zealand’s largest estuaries. The accumulation of sediments, nutrients, pesticides, heavy metals and hydrocarbon residues in shallow estuaries have significant adverse effects on the species mix of benthic communities, availability of ecologically important habitats for survival of marine organisms, recreational use of beaches and harbours due to public health risks from recreation or shellfish gathering and on cultural values and mahinga kai. Of course, estuarine sites in urban areas can be expected to have high contamination levels due to the enclosed nature of estuaries and the influence of urban streams and rivers. While significant contamination has not been identified, a low MCI index indicates poor water quality for marine organisms. This as well as sedimentation (which is not addressed here) can lead to changes in the species mix of benthic communities and modification of habitats, especially those composed of habitat forming species such as seagrass beds, green-lipped and horse mussel beds, bryozoan and tubeworm mounds, kelp forests, sponge gardens and mangrove habitats as in Tauranga Harbour. The ecology and biological health of the harbour is also of concern to local Iwi.

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Excess nutrients in estuaries and harbours have impacts on marine water quality and mahinga kai through eutrophication, where excessive plant and algal growth degrades water quality and can cause loss of species, algal bloom or loss of habitat, which in turn can kill off plants that fish depend on for their habitat and alter habitat for invertebrate species. When algae increases in response to nutrients this reduces water clarity, visibility, and recreational suitability. It also reduces the ability of some fish to see prey or predators. While excess nutrients have not been identified in Tauranga Harbour waters by this report, it is recognised that the harbour waters are influenced by the watercourses which drain into it, some of which have been indicated to have high nutrient concentrations.

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7 Data Gaps, Limitations & Next Steps

The objective of this report, in addition to an assessment of the state of the Tauranga environment, was to assess the quality and quantity of data available and to identify whether the available data provide sufficient coverage to enable TCC to assess the issues impacting the state of the Tauranga environment which can be managed by TCC.

A summary of indicators selected and data sources used for this assessment is supplied in Table 1. Sufficient data were available to meet the objectives of the study, although it is recognised that any other ongoing studies will further inform subsequent revisions of the report. This study has been largely assisted by regional datasets collected by BOPRC under the NERMN programme monitoring: air quality; surface water quality and ecology; and the marine environment.

A 2014 review of the BOP NERMN programme concluded that, in general, the parameters monitored under the programme are appropriate and are needed to adequately manage natural resources. However, for some resources there was an identified requirement to increase monitoring frequency and/or geographical coverage to meet future needs. If achieved, this requirement would of course assist localised SoE reporting (Donald, 2014).

In the interest of enhancing temporal and spatial comparative analysis, common and well-accepted indicators have been used where possible but in several areas there is an obvious lack of robust and well- accepted national grades and indicators which leads to inconsistencies between monitoring frameworks and difficulties in interpretation of results. While intended as an assessment of the natural environment, it is important to consider that TCC’s jurisdiction is largely urban, and therefore all reasonable effort has been taken to select indicators that reflect activities occurring in the city, influence of city governance, and interactions between its inhabitants and the environment. Preference has been given to indicators that are of direct relevance to TCC, and that are reflective of the urban environment at the centre of the study.

It is important to recognise that while indicators provide some ‘indication’ of the state of the environment, they should be used alongside other relevant information, with expert guidance and with reference to the underlying data, before conclusions are drawn on overall environmental condition. Results must be interpreted with the understanding that indicator grading systems can easily mask or oversimplify underlying patterns or local effects. For example, large changes can occur within a grading band without resulting in a change in overall grade, and small changes near the edge of one grading band can shift the rating to the next grade.

Gaps Atmosphere: Only preliminary results were available at the time of writing, but even so, GHG emissions provide a good indication of impact on the atmosphere and environment more widely further. More detailed datasets and reporting, when available, may inform a revision of this report and TCC activities going forward.

Air: Limited parameters are measured, and limited monitoring sites are available due to cost, however the data record is solid and suggests no significant issues or significant changes over time. No monitoring of PM2.5 (particulate matter 2.5 micrometres or less in diameter) is undertaken in Tauranga. This is identified as a shortcoming of environmental monitoring data at national level:

“Some environmental monitoring networks are patchy, with some regions or sites well monitored but

others less so. An example of this is air quality monitoring – especially of PM2.5 – where we have a clear picture of the environment in some parts of New Zealand, but not a nationally representative view of the country” (MfE and Stats NZ, 2015; p.111).

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Therefore initiation of PM2.5 monitoring at Totara Street is now scheduled for late 2017, and may prove to be a suitable environmental indicator in the future.

Land: It is somewhat difficult to identify meaningful indicators in this area as soil health is not or cannot be measured within the city, nor is pest numbers, at risk species or any measure of biodiversity or terrestrial ecology. These would all be effective indicators if data were available. The need for an up to date soil contamination study has been raised in the 2014 Annual Report (TCC, 2016a) and again in annual stormwater monitoring report 2016 (TCC, 2017); the last having been done in 2005 (SEM NZ, 2005). Robust information relating to the extent of impervious surfaces in Tauranga, or New Zealand for that matter, is not available, and is recommended as a future indicator for land environment. The indicators that have been employed are suitable, but could be enhanced with collection of the same data from similar cities, either in New Zealand or internationally, for comparison and to identify what ‘good’ looks like and what best practices exist.

Water: A significant amount of data and multiple parameters are available for evaluation of freshwater quality, however indicators must be meaningful and contextual. Therefore wherever possible, efforts have been made to assess the results obtained for Tauranga against generally accepted trigger levels or grading scales available at the national level. As identified at the national level, there is commonly a bias for places with poor environmental health to be more carefully monitored, which may lead to an inaccurately negative picture of the state of the overall environment. For example, for public health reasons regional councils monitor swimming areas with a higher risk of exceeding recommended health guidelines. No investigation has been undertaken to assess whether this bias is inherent in the data used for this study, therefore caution should be taken when drawing comparisons with other regions, but, as long as monitoring locations remain the same, comparisons over time will be useful (MfE, 2014a).

It is also necessary to mention that there are alternative measures of state of the environment, particularly for stream and waterway health. One example is the Māori Cultural Health Index which provides indicators for recognising and expressing Māori value of water with attention to three aspects: site status, mahinga kai and stream health. There is now a tool available for nationwide use (Tipa and Teirney, 2006).

Marine: In some cases, no appropriate guidelines exist to assess the state of certain indicators (e.g. guidelines for assessing nutrients in marine water). In other cases, infrequent or incomplete monitoring records for some datasets mean that indicators were unable to be used. The only publically available dataset under this domain was for Enterococci bacteria – other data had to be sought from the regional council.

In addition to the use of ANZECC guidelines and Wriggle Coastal Management condition ratings, a measure of estuarine ‘health’ using benthic health models (BHM) as developed by Hewitt et al. (2015) could be used. This method requires multivariate analysis of macrobenthic community composition along with analysis of BHMmetal (benthic health model for metals contaminant content - total sediment copper, lead and zinc concentrations), BHMmud (benthic health model for mud content) and traits based index (TBI) values. These measures are combined to produce a single health score from ‘unhealthy’ to ‘extremely good’ (Hewitt et al., 2012).

In the marine environment pest species cause severe issues and impact heavily on community composition, cultural values and mahinga kai quality, particularly where there is a busy port such as Tauranga causing increased biosecurity risks. Pest plant species are commonly raised as a pressure on the marine environment. While this has not been considered for assessment as part of this report, BOPRC has a monitoring programme for marine pests in Tauranga Harbour which could be used to help inform future State of Environment reporting.

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Next Steps 1. State of the Environment reporting is intended to give a very high level overview of state and trends. Following further State of Environment reporting for Tauranga, over time, trends may be drawn for the various states. It is most beneficial if the underlying information is further interrogated to identify and assess local differences and key trends.

2. It would be hugely beneficial, where common indicators are available, to conduct a comparative assessment of Tauranga and the Bay of Plenty’s environmental state against other regions and national averages to see where BOP ‘sits’ relative to the rest of New Zealand. This may be a task most appropriately adopted by regional councils. However, in doing so, care must be taken as SoE reporting in New Zealand still lacks standardisation and different regions are likely to use different sampling methods and therefore data may not be consistent or comparable. It is noted that the BoPRC, under the Te Awanui Harbour Programme are in the process of developing a SoE Report for the Harbour Programme which will include marine, freshwater and land domain indicators. This work is due for completion at the end of 2017/early 2018 and it is anticipated that these indicators will be adopted in any future SoE reporting for Tauranga City and will provide a consistent basis for future analysis.

3. It is important to recognise that the results of this study represent a snapshot in time. It is the intention that regular ongoing analysis of these datasets as the body of data increases will identify trends and track the effectiveness of interventions. For this reason, where possible, sources of data that are part of an ongoing monitoring programme have been selected to enable easy and cost effective continuation of an environmental improvement programme.

4. The purpose of this report is to inform a forward strategy for TCC and to assist decision makers to identify objectives and areas of focus. These focus areas may relate to increased or additional monitoring where gaps have been identified, or actions focused on addressing the most influential pressures on the state of Tauranga’s natural environment. Commenting on how to address the pressures identified was outside the scope of this report, however, this report is considered to be an initial step to guide conversations of this nature.

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8 Summary

While making generalised comments on ‘state’ of the environment, even across a localised area is difficult considering the complex nature of processes occurring, the conclusions of this study may assist to direct resources, make decisions and prioritise certain locations for action, or certain issues for intervention. By repeating this assessment over time it will quickly be possible to identify increasing or decreasing trends, and therefore areas of focus for management and mitigation.

Results for each of the selected indicators are summarised in Figure 2. While further analysis is necessary, some observations and trends are apparent:

 Atmosphere: When compared with other cities, Tauranga’s carbon emissions, while lower per capita than some other New Zealand cities (namely Auckland and Dunedin) can be said to be relatively high on an international scale. Transport related GHG emissions make up a very high proportion of this. Public transport, walking cycling and flexible work options need to be encouraged or incentivised if this is to be reduced.  Air: Tauranga City air is by global standards good and levels of SO2 are low, with 93% of samples in the ‘excellent’ band. There is some concern about PM10 levels, with only 21% of samples in the excellent band and there are concerns that this will drop further with population growth pressures.  Land: in the ‘land’ domain, there has been and continues to be significant land use and land cover change reducing the overall area of the natural environment, with only 3% of land cover remaining in native vegetation, and only 0.7% of natural areas protected. In the urban environment, TCC is working towards increased availability and accessibility to open space, and towards reducing the significant proportion of waste that is sent to landfill. It is hoped that through waste management planning the current average of 630kg of waste per person per annum can be reduced through redirection of this waste and behavioural change.  Water: Nutrient concentrations in rivers that run through Tauranga are fairly high due to upstream land uses, while turbidity and heavy metal contamination of this water is low. Analysis of both ecology and water quality for swimming indicated that watercourses passing through Tauranga range in scoring from ‘fair’ to ‘poor’.  Marine: Marine swimming water quality rated good or very good at all sites in Tauranga Harbour. Heavy metal contaminants in Tauranga Harbour are very low, with no exceedances of ANZECC trigger values and all sites received an overall grade of either good or very good. The estuarine environment exhibits good nutrient state but variable, and relatively poor overall macroinvertebrate index, as an indicator of ecological health. The nutrient indicators for the freshwater and marine environments are not comparable as different sampling and analysis techniques have been used in each case.

This study has identified, unsurprisingly, that like in other regions of New Zealand (MfE and StatsNZ, 2015) the activities of urban development and land use change are putting severe pressure on the environment. Tauranga’s population growth is causing urban development and urban sprawl leading to loss of natural habitats and biodiversity, and decreasing air, freshwater and marine environmental quality. On top of this, increasing resource use generates waste and contributes to climate changes, which in turn puts further pressure on the natural and human environment. As stated by Kenny (2006), the wider Bay of Plenty environment is at medium to high risk from climate change, for example due to associated rapid establishment and spread of new pest plant species and adverse effects on small remnants of indigenous vegetation. Climate change is just one factor contributing to changes in the biota of the region, all resulting in “a very volatile biological melting pot that will have to be managed very carefully” (Kenny 2006 p38).

By evaluating the state of the environment across the five domains, it is evident that within Tauranga there are environmental issues to be addressed and that an integrated and adaptive management approach is

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essential in achieving this, to ensure that newer and more up to date data is consistently used to inform the approach and the root causes of issues leading to poor environmental state are addressed. This will require a cross-sectoral approach, but may also require a regional/partnership approach, given the significant impact of upstream land-based activities.

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9 References

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