Climate Effects
Consolidated Report
for River Scheme Sustainability
Project
May 2015
Bay of Plenty Regional Council
5 Quay Street
PO Box 364
Whakatane 3158
NEW ZEALAND
Prepared by Ingrid Pak, Environmental Engineer
Document control
Document information
Document name:
Climate Effects Consolidated Report for River Scheme Sustainability
Project
Contact person:
Ingrid Pak
Status:
For presentation to Council workshop
Document review
Review timeframe:
n/a
Reviewers:
n/a
Document history
Author
Description of change
Date
Version
Ingrid Pak
First draft report
April 2015
V1
Ingrid Pak
Comments from RSS project team and
steering group
May 2015
V1.1
Distribution control
Person
Role
Date of issue
Version
Mark Townsend
Engineering Manager
November 2015
V1.1
Authorised by:
Mark Townsend
Reviewed by:
Ken Tarboton
Date: 3 November 2015
Date: 3 November 2015
Climate Effects Consolidated Report – River Scheme Sustainability Project
i
Acknowledgements
Katalin Maltai and Mark James for their support and guidance. Ken Tarboton, David
Boothway, Roger Waugh, Sandra Barnes, Justine McLeary, Martin Butler and Michelle Lee
for their valued reviews. Rachael Musgrave and Gail McKee for formatting and the colourful
schematic. Trig Yates for producing the rainfall projections maps.
Climate Effects Consolidated Report – River Scheme Sustainability Project
iii
Executive summary
This report summarises what we know about climate change and climate cycles in the
Bay of Plenty. It consolidates findings from a range of reports on an international, national
and regional level, and provides guidance as to how Council could or should use this
information in its policy, guidelines and projects. It forms the deliverable part of the Climate
Effects Workstream of Bay of Plenty Regional Council’s (BOPRC) River Scheme
Sustainability Project.
Generally, the climate in the Bay of Plenty is likely to be warmer and drier in the future. We
can expect:

Warmer winters, reduced frequency of frost inland and at higher elevations and a
longer growing season.

Drier average conditions will lead to increased drought risk.

More frequent and intense rainfall events, with an associated increase in risk of
flooding and erosion.
Climate change will likely impact on the coastal margins of the Bay of Plenty, by altering
coastal processes such as erosion and sediment supply.
Current advice for future sea level for New Zealand is a base rise of 0.5 m and potential rise
of at least 0.8 m by 2090, based on Ministry for the Environment Guidelines (MfE, 2008). It is
expected that these forecast rises will increase with the new MfE guide due out next year.
Bay of Plenty Regional Council already incorporates the effects of climate change in natural
hazard risk assessments through the Operative Regional Policy Statement. It uses a
projection of a base sea-level rise of at least 0.6 m (above the 1980–1999 average) for
infrastructure and developments that are relocatable, a projection of a base sea-level rise of
0.9 m (above 1980–1999 average) for structures where future adaptation options are limited,
such as regionally significant infrastructure and developments which cannot be relocated,
and an additional sea-level rise of 10 mm per annum for infrastructure with a life span
beyond 2112.
In addition to climate change, there are four large-scale climate cycles that affect the climate
in New Zealand and the Bay of Plenty. These are the Interdecadal Pacific Oscillation (IPO),
the El Nino Southern Oscillation (ENSO), the Southern Annular Mode (SAM), and the Indian
Ocean Dipole (IOD).
Analysis of river flows and extreme rainfall records show some evidence that the IPO and
ENSO phases influence the observed temporal clustering of floods in some Bay of Plenty
rivers, but the relationship is not always clear. Therefore, designers of permanent structures
such as bridges and stopbanks need to use records extending beyond the phases of the
IPO, if possible. There is not enough evidence to delay infrastructure spending based on the
timing and effects of climate cycles.
Bay of Plenty Regional Council aims to future-proof the region against climate change by
providing advice and developing policy to help the region adapt and become more resilient to
the effects of climate change. Some examples of what Council is doing to manage/address
climate change are outlined in this report.
Climate Effects Consolidated Report – River Scheme Sustainability Project
v
Contents
Acknowledgements
iii
Executive summary
v
Part 1: Purpose
1
Part 2: Introduction
3
2.1
What is climate change?
3
2.2
Climate change at international, national and regional levels
3
2.3
Report structure
5
Part 3: Research summary
7
3.1
International
7
3.2
National
7
3.3
Regional
7
Part 4: Climate Change for Bay of Plenty
9
4.1
Climate change science
9
4.2
Climate change projections for the Bay of Plenty
12
Part 5: Sea level rise for Bay of Plenty
15
5.1
Impacts on coastal margins
15
5.2
Sea level rise
15
5.3
Council Policy – Operative Regional Policy Statement
15
Part 6: Climate cycles in the Bay of Plenty
17
6.1
Rainfall regime and trends
17
6.2
Impacts of climate oscillations
18
6.3
Climate change and other variables
20
Climate Effects Consolidated Report – River Scheme Sustainability Project
vii
6.4
Conclusion
20
Part 7: Regional application of climate change and sea level rise in
policy and guidelines and projects
21
7.1
Local Government role
21
7.2
Council policy and guidelines
21
7.3
Council projects
24
Part 8: Application of climate change
27
8.1
Effects of climate change on river schemes
27
8.2
Recommendations for future work
27
Part 9: Conclusion
29
Part 10: References
31
Appendix 1 – Glossary
35
Appendix 2 – Rainfall projection maps
37
viii
Climate Effects Consolidated Report – River Scheme Sustainability Project
Part 1: Purpose
This report summarises what we know about climate change and climate cycles in the
Bay of Plenty, based on several commissioned reports and international and national
documents. It forms the deliverable part of the Climate Effects Workstream of BOPRC’s
River Scheme Sustainability Project (RSS). It consolidates findings and summarises the
implications of these findings on the river schemes.
As we expect the climate to change over the next 100 years, this will affect the management
of the river schemes. This report will help us better understand the impact of weather cycles
and climate change on the river schemes.
Climate Effects Consolidated Report – River Scheme Sustainability Project
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Part 2: Introduction
2.1
What is climate change?
Climate change has taken place over thousands of years but there is now an
influence on climate from a rapidly increasing world population and its use of
resources. In the past few generations humankind has been exhausting fossil fuel
reserves that were generated over several hundred million years. More greenhouse
gases such as carbon dioxide in the atmosphere are enhancing the natural
greenhouse effect. The result of the enhanced greenhouse effect is called
“anthropogenic climate change”, or climate change that is a result of human activity.
The long term effects of climate change are additional to the short and medium term
variability in climate, caused by large-scale climate cycles, such as the Interdecadal
Pacific Oscillation (IPO) and El Nino Southern Oscillation (ENSO).
2.2
Climate change at international, national and regional levels
Climate change research is carried out at an international level by the
Intergovernmental Panel on Climate Change (IPCC). The findings of the
international research then feed into national guidance documents published by the
Ministry for the Environment (MfE), which in turn feed into regional investigations
and assessments, most of which are carried out by the National Institute of Water
and Atmospheric Research Limited (NIWA). Figure 1 shows schematically the
climate and climate change information available to Council (top section of Figure
1). Findings of these regional reports then feed into regional policy and guidelines
and are applied in regional council projects (bottom section of Figure 1).
The role of Local Government is defined in a draft report on “Climate Change and
Local Government” (Dickie, et al, 2015) to the Society of Local Government
Managers (SOLGM) through consideration of various acts, namely the
Local Government Act (LGA), the Civil Defence and Emergency Management Act
(CDEMA), the Building Act (BA) and the Resource Management Act (RMA)
(SOLGM, 2015).
This report focuses on the available information that relates to the river schemes.
Other climate change work exists within Council, such as implications on pest
management, water quality, and working with the industry, which is not included
herein.
Climate Effects Consolidated Report – River Scheme Sustainability Project
Figure 1
Schematic of available climate and climate change information and its use within Council.
Climate Effects Consolidated Report – River Scheme Sustainability Project
4
2.3
Report structure
The report structure generally follows the schematic in Figure 1 and is outlined
below:
Part 3 outlines the available climate and climate change information at an
international, national and regional level. It lists the research reports Council has
available. These are also shown on the schematic in Figure 1.
Part 4 summarises the NIWA 2011 report on climate change projections for the
Bay of Plenty. It explains the scenarios and modelling approaches used in the
climate change assessment, and summarises the key climate change projections for
future temperature, rainfall, wind, drought, and pasture growth.
Part 5 summarises sea-level rise projections and climate change impacts on the
coastal margins in the Bay of Plenty from the NIWA 2006 report, IPCC estimates,
and MfE guidelines. It also shows how the sea-level rise estimates are applied in the
Regional Policy Statement.
Part 6 summarises the NIWA 2014 report on climate cycles in New Zealand and the
Bay of Plenty. It describes the main climate cycles affecting the Bay of Plenty region
and the impacts they have on rainfall, river flow and resulting flood risk. It also gives
recommendations as to how to consider climate cycles in infrastructure design.
Part 7 outlines how Council uses the available information on climate change as
part of its statutory role through regional policy, guidelines and projects.
Part 8 outlines the application of climate change in the RSS project and lists
recommendations for further work in this field in the future.
Part 9 concludes the consolidated report.
Part 10 contains references to the reports used in this consolidated report.
A Glossary is included in Appendix 1.
Appendix 2 shows rainfall projection maps for the Bay of Plenty for the four
seasons.
Climate Effects Consolidated Report – River Scheme Sustainability Project
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Part 3: Research summary
This section summarises the available research at an international, national and regional
level. It generally follows the top section of the schematic shown in Figure 1.
3.1
International
3.1.1
Intergovernmental Panel on Climate Change
The Intergovernmental Panel on Climate Change (IPCC) is an international scientific
body that assesses predictions of future climate based on published research. The
IPCC is an internationally accepted authority on climate change, that produces
reports that have the agreement of leading climate scientists and the consensus of
participating governments. The IPCC has published five comprehensive assessment
reports reviewing the latest climate science, the most recent being the Fifth
Assessment Report (Ar5) in 2014 (IPCC, 2014).
3.2
National
3.2.1
Ministry for the Environment
The Ministry for the Environment (MfE) prepared three comprehensive technical
reports, following the release of the Fourth Assessment Report on the science of
climate change by the IPCC (IPCC, 2007). These are: “Climate Change Effects
and Impacts Assessment” (MfE, 2008), “Coastal Hazards and Climate Change”
(MfE, 2008a) and “Tools for Estimating the Effects of Climate Change on Flood
flow” (MfE, 2010). Based on these technical reports, MfE has published guides for
Local Government to help to adapt to climate change (MfE, 2008b; MfE 2009; and
MfE, 2010a). These guides focus on increases in temperature, rainfall and sea level
throughout New Zealand. It is expected that these guides will be updated, based on
the IPCC Fifth Assessment Report by about 2016.
3.2.2
NIWA
The National Institute of Water and Atmospheric Research Ltd (NIWA) has
published “Coastal Adaptation to Climate Change – Pathways to Change” in
2011 as part of a study aiming to create the necessary information and tools, to
adapt to the impacts of climate change in the New Zealand coastal environment
(NIWA, 2011). It is a thorough collection of available information on climate change,
sea level rise and coastal hazards at the time, and outlines an adaptation pathway
with a step–by-step guide for local authorities and communities.
3.3
Regional
3.3.1
NIWA
A number of reports have been commissioned by BOPRC over time to assess
climate, climate trends and climate change projections in the Bay of Plenty. These
are briefly outlined below.
In 2003, NIWA reported on the climate variability and trends in the Bay of Plenty and
presented scenarios for future climate change in its report “The climate of the
Bay of Plenty: Past and Future” (NIWA, 2003).
Climate Effects Consolidated Report – River Scheme Sustainability Project
7
The climate change assessment part of the NIWA 2003 report was updated in 2011
in “An Updated Climate Change Assessment for the Bay of Plenty” (NIWA,
2011) and draws on a significant body of climate change modelling and knowledge,
developed both internationally and by NIWA. It collates modelling information,
projections for temperature, rainfall, and storminess and associated impacts on
droughts and pasture growth for the Bay of Plenty region. Findings of the report are
summarised in detail in Part 4.
In 2006, NIWA reviewed the effect of climate change on the Bay of Plenty coastline
in “Impacts of climate change on coastal margins of the Bay of Plenty” (NIWA,
2006). The report assesses the potential climate change impacts on the drivers of
coastal hazards that may affect the coastal margins of the Bay of Plenty coastline
over the next 50-100 years. A brief summary of the report’s findings are presented in
Part 5.
The National Institute of Water and Atmospheric Research Limited also provided an
“Assessment of Effects of Large-Scale Climate Oscillations on The Flood Risk
in the Bay of Plenty” in 2014 (NIWA, 2014). The report describes the main climate
cycles affecting New Zealand and the Bay of Plenty region, the impacts they have
on rainfall, river flow and resulting flood risk and their predictability. It also includes a
recommendation on whether and how infrastructure planning for river schemes
should consider climate cycles. The report is summarised in detail in Part 6.
Lastly, NIWA has recently prepared a report on the “Climate and Weather of the
Bay of Plenty”, which summarises climate data collected from 1981-2010 (NIWA,
2013). This report is not discussed further as it focuses on the past climate.
3.3.2
Earthwise
Earthwise Consulting has prepared a report on the “Biotic Effects of Climate
Change in the Bay of Plenty” (Earthwise Consulting, 2006). This report focuses on
the effects of climate change on biosecurity threats (pest animals and plants),
indigenous biodiversity, and economic land uses. This work draws on the findings of
the NIWA 2003 report and looks specifically at effects in the Tauranga Harbour
Catchment, on Rotorua Lakes, and on the Rangitaiki Plains.
For more detail please refer directly to these reports, listed in the references,
Part 10.
8
Climate Effects Consolidated Report – River Scheme Sustainability Project
Part 4: Climate Change for Bay of Plenty
An initial climate change assessment was undertaken by NIWA in 2003 (NIWA, 2003). It
presented scenarios for future climate change and commented on temperature, rainfall, and
wind changes for the Bay of Plenty for the next 50 to 100 years. Based on this report,
changes in climate that are likely to occur in the Bay of Plenty include:

Warmer winters, reduced frequency of frost inland and at higher elevations, and a
longer growing season.

Drier average conditions will lead to increased drought risk.

More frequent and intense rainfall events, with an increased risk of flooding and
erosion.

Possibly more tropical cyclones and periods of intensive storminess.
In 2011 the climate change assessment for the Bay of Plenty has been updated by NIWA.
This updated report draws on a significant body of climate change modelling and knowledge
undertaken internationally and by NIWA, over the intervening eight years. Below is a
summary of this report.
4.1
Climate change science
At BOPRC’s request, NIWA selected three “what-might?” scenarios to investigate in
its climate change assessment, based on emission scenarios described in the
Intergovernmental Panel on Climate Change Fourth Assessment Report
(IPCC AR4) (Figure 2):

If the middle-of-the-road greenhouse gas emission scenario (known as A1B)
occurred, what might the climate of the Bay of Plenty look like at
mid-century (2030-2049)?

If the middle-of-the-road greenhouse gas emission scenario (known as A1B)
occurred, what might the climate of the Bay of Plenty look like at
century-end (2080-2099)?

If the high greenhouse gas emission scenario (known as A2) occurred, what
might the climate of the Bay of Plenty look like at century-end
(2080-2099)?
Climate Effects Consolidated Report – River Scheme Sustainability Project
9
For convenience, these time periods are shortened to “2040” (equivalent to
2030-2049) and “2090” (2080-2099).
Figure 2:
Example of “what-might?” scenarios; IPCC projections of global
temperature increase. Solid coloured lines are multi-model global
averages of surface warming (relative to 1980-1999) for emission
scenarios B1, A1B and A2, shown as continuations of the
20th century simulations (black line). The coloured shading denotes
the ±1 standard deviation range of individual model annual averages.
The grey bars at right indicate the ‘likely range’ of temperature
increase at 2090-2099 relative to 1980-1999, along with the best
estimate (coloured horizontal line within each grey bar), for six
scenarios that span the full range of all IPCC emission scenarios.
(Adapted from Figure SPM-5, IPCC 2007).
Three spatial scales were used to inform these “what might” questions:
10

The Bay of Plenty average (i.e. the region as a whole), for seasonal and
annual mean rainfall and mean temperature.

The within-Bay-of-Plenty response; namely gridded data provided as GIS
layers, with data on a 5 x 5 km grid across the Bay of Plenty Regional Council
area of responsibility, for seasonal mean rainfall and seasonal mean
temperature (Figure 3).

Site-specific information (for example assessing air frosts at Rotorua), for a
range of extremes, such as air frosts, hot days, cold nights, drought and
pasture modelling, at sites selected by Council.
Climate Effects Consolidated Report – River Scheme Sustainability Project
Figure 3:
Example of gridded GID layer; The 10-model average projected
summer temperature change between 1980-1999 and 2080-2099,
under an A1B emission scenario (NIWA, 2011).
Lastly, two modelling approaches were used to inform the “what might” questions:

The average (mean) of 10 Global Climate Models (GCMs) empirically
downscaled to the Bay of Plenty region is the primary output given in this
report, for tabular data and all of the GIS layers containing gridded
5 x 5 km data. Comparisons between observational data and multiple climate
models (Lambert and Boer, 2001) show the group mean tends to have a lower
error than most, if not all, of the individual models. Therefore, the 10-model
average is the recommended “result” for Councils to use, if not using an
“envelope” approach. To cater for an “envelope” approach, the lowest and
highest response from the empirically downscaled GCM models, as well as
the single result from the Regional Climate Model (see below) are given, for a
selection of sites and variables.

The National Institute of Water and Atmospheric Research Limited’s Regional
Climate Model (RCM) was run, nested under one GCM, and the single RCM
result was incorporated into the report where relevant in Tables and Figures.
In particular, the RCM outputs were downscaled to the same 5 x 5 km grid as
the GCM data, and to selected station observations, and used to model
drought and pasture growth at selected sites, since there are more daily
climate variables available under the RCM projection than just temperature
and rainfall. Key differences between the GCM and RCM results were noted,
and these contributed to the overall synthesis of likely future climate in the
Bay of Plenty.
Climate Effects Consolidated Report – River Scheme Sustainability Project
11
Climate change science is complex, as is interpreting and using the results found.
Results can be viewed qualitatively for “big-picture” understanding of the likely
climate of a future, warmer Bay of Plenty - such as understanding, for example, that
drier winters are likely overall. Quantitative results are also available as GIS layers,
with data on a 5 x 5 km grid across the Bay of Plenty region. There are 32 GIS
layers available to BOPRC. Eight of these are climatological layers (i.e. reflect the
present climate), quantifying present seasonal mean rainfall and seasonal mean
temperatures, and 24 layers are future (seasonal) projections of likely change in
mean rainfall and temperature, based on the three “what-might?” situations outlined
previously. All the future layers are based on the (GCM) 10-model average.
4.2
Climate change projections for the Bay of Plenty
Climate change projections for the Bay of Plenty are:
4.2.1
Key temperature
Projections show an increase in temperature with time for the Bay of Plenty as
follows:
4.2.2

Warm by about 1.2°C by 2040 under the A1B scenario,

Warm by about 2.7°C by 2090 under A1B,

Warm by about 3.2°C by 2090 under the higher A2 emission scenario, and

Warm slightly more in winter than the annual mean.
Key rainfall
In contrast to projected temperature changes, the projected rainfall changes show
marked spatial variation across the Bay of Plenty. In summary, rainfall projections
for the Bay of Plenty include:
4.2.3

For the region as a whole, virtually no change in the 10-model average annual
precipitation by end-century, but a range across the models from a 10 percent
decrease to a 15-20 percent increase (A1B and A2 combined),

A weak tendency for decreased precipitation by 2090 along the coast
(about 5 percent),

A marked trend to winter rainfall decreases, especially for coastal locations,

A similar rainfall trend in spring to that in winter (i.e. a decrease),

A trend to increasing rainfall in the summer season, which is more marked for
inland locations than at the coast,

A similar rainfall trend in autumn to that in summer (i.e. an increase).
Key circulation, storminess and extreme wind results
A shift in the low pressure/storm track near New Zealand in a future warmer climate
is projected with drier winters but wetter summers. Daily extreme winds generated
by large-scale weather systems (such as fronts and lows) are projected to decrease
in summer but increase in winter, while small-scale convection will increase, which
is likely to affect small-scale extreme winds associated with thunderstorms and gust
fronts.
12
Climate Effects Consolidated Report – River Scheme Sustainability Project
4.2.4
Extreme temperature
The projected frequency of an air frost (air temperature below 0°C) becomes very
small by century-end at the selected Bay of Plenty sites, under GCM projections.
At present, the frequency of air frosts ranges from about five per year in Opotiki to
20 per year in Rotorua. By the end of the century, Rotorua is projected to
experience an air frost only one to two days a year under the A1B scenario, and is
projected to go some years without seeing a frost at all under A2. The frequency
of cold nights is also projected to become significantly smaller in all the future
scenarios.
Hot days (recording 25°C or more) are projected to become the norm during the
summer months by the end of the century. For example, Whakatane has an average
of 22 hot days occur per year, but by 2090 between 80 and 100 hot days per year
are projected. It should be noted that the RCM estimates a larger number of air
frosts and hot days, both under current climate and into the future.
4.2.5
Extreme rainfall projections
Since the water-holding capacity of the atmosphere increases with the temperature
(by about 7-8 percent more for every 1°C rise in temperature), it is widely accepted
that extreme rainfalls will also increase in a future warmer climate. A recent
New Zealand study suggests that increases in extreme precipitation events are
likely to be seen in nearly all regions of the country under a warmer climate, and
may well show increases larger than 7-8 percent for every 1°C rise in temperature.
Global Climate Models and RCM projections of extreme 24-hour rainfall at selected
sites within the Bay of Plenty, show a general increase in the magnitude of extreme
events in the future, although there are differences between the model projections.
4.2.6
Key drought results
On average, under current climate, droughts lasting more than a month are
infrequent in the Bay of Plenty. Low-intensity droughts lasting more than 14 days are
currently experienced in summer (on average) around 30 percent of the time at
Katikati and Te Puke, and about 20 percent of the time at Whakamarama and the
eastern sites Te Teko and Opotiki.
Projections under A1B and A2 by century-end show the largest changes are likely to
occur in droughts lasting longer than a month. At the five sites analysed, increases
of between 9 percent and 17 percent in time spent in low-intensity summer drought,
lasting one month or more, are likely at 2090 under A1B (compared to 20-26 percent
under A2, with the exception of Opotiki). Notably, under A2 at 2090, the time spent
in moderate and high-intensity droughts lasting a month or more is also generally
increased (by between 0-8 percent across all five sites), which is consistent with the
predictions in previous national drought analyses.
4.2.7
Key pasture growth modelling results
The relatively warm, dry summers and cool, wet winters in the Bay of Plenty yield an
annual pasture growth curve with a distinct, reliable, spring growth peak, variable
autumn growth peak and low winter growth (due to cool temperatures limiting growth
rates). Near the ranges, winter growth is lower and summer growth is higher than
along the coast, due to the lower temperatures and higher summer rainfall
observed.
Climate Effects Consolidated Report – River Scheme Sustainability Project
13
A coupled soil-water balance and pasture production model of stock-grazed
ryegrass pasture was used to model future pasture growth (with no adaptation).
Projections at 2090 show little change in annual pasture biomass but significant
changes in the seasonality of pasture growth in the Bay of Plenty. Projected higher
summer temperatures reduce summer pasture growth significantly at 2090 under
both A1B and A2. Milder winter temperatures result in large increases in winter
growth (double current levels along the coast, and treble inland by 2090). Total
spring growth and reliability of spring growth are unchanged.
In contrast, at mid-century under A1B, there is a projected reduction of low growth
years, giving a slightly higher median summer pasture growth, which reflects the
RCM and GCM 10-model average projection of increased summer rainfall under
A1B at 2040. This is most likely to be due to inter-decadal climate variability (i.e. wet
and/or dry decades), based on natural climate cycles.
4.2.8
Specific sites results
Whilst the previous section concentrated on results for the Bay of Plenty as a whole
and across the region based on gridded data, this section presents results at
selected sites within the Bay of Plenty.
14

Temperature: increased temperature, little spatial variation, i.e. Tauranga
warms about the same as Whakatāne.

Rainfall: rainfall projections show marked spatial variation across Bay of
Plenty. Maps of NIWA’s rainfall projections for the region are available as GIS
layers. Rainfall projections to end of century for the high end scenario (A2) are
shown in Appendix 2.

Air frosts: generally less air frosts (e.g. Rotorua now: 20 days per year; end
of century: 1-2 days per year.

Cold nights: fewer cold nights.

Hot days (>25℃) and very hot days (more than 30ºC): more hot days (e.g.
Whakatāne now: 22 per year, end of century: 80-100 per year). More very hot
days (e.g. Rotorua now: once every five years, end of century: twice a year).

Rainfall extremes: general increase in magnitude of extreme rain events.

Drought: a general increase in time spent in low-, moderate- and highintensity droughts lasting one month or more.

Pasture growth: little change in annual pasture biomass, but significant
changes in the seasonality of pasture growth in the Bay of Plenty.
Climate Effects Consolidated Report – River Scheme Sustainability Project
Part 5: Sea level rise for Bay of Plenty
5.1
Impacts on coastal margins
The NIWA report on impacts of climate change on the coastal margins of the
Bay of Plenty (NIWA, 2006) confirms that climatic variation can influence
storminess, wave conditions, sediment supply and coastal processes such as
erosion. Future changes in climate will alter these processes in the coastal
environment, but in many instances there needs to be more data to accurately
assess impacts. This also applies to sea level rise, which has been increasing at a
historical rate of around 1.8 mm/year. Accurate local impact assessment is not
possible until more information becomes available on rates of vertical land
movement throughout the Bay of Plenty and any acceleration that could occur with
global climate change. In the meantime, the current global estimate is considered
appropriate and it is recommended that, for planning purposes, an allowance of
0.5 m for 2100 is used.
5.2
Sea level rise
Global sea level rise estimates vary. The IPCC Fourth Assessment Report (IPCC,
2007) states that computer modelling has suggested a range of projected sea level
rise from 0.18-0.59 m by the end of the century, assuming contributions from ice
flow from Greenland and Antarctica remain at rates observed from 1993-2003. An
extra 0.1-0.2 m rise would be expected if these ice-sheet contributions were to grow,
in line with global temperature increases. Future sea level advice for
New Zealand is a base rise of 0.5 m and potential rise of at least 0.8 m (both are
relative to the 1980-1999 average) with an allowance of 10 mm per year beyond
2100, based on Ministry for the Environment Guidelines (MfE, 2008a).
The Intergovernmental Panel on Climate Change has released its Fifth Assessment
during 2014 (IPCC, 2014) and the Ministry for the Environment is expected to
update its guidelines during 2016 to reflect the IPCC5 findings. Current sea level
rise advice in Pathways to Change (NIWA, 2011) advises a minimum of 1.0 m rise
by 2115. Current climate change guidance from Ministry for the Environment (MfE,
2008a) projects forward to the year 2090. This is no longer a 100-year future
projection period. It is expected that the updated MfE Guidelines of 2016 will include
an updated 100-year projection period.
5.3
Council Policy – Operative Regional Policy Statement
The Operative Regional Policy Statement – Natural Hazard Policy NH11B: Providing
for climate change states:
Incorporate the effects of climate change in natural hazard risk assessment.
Authoritative up-to-date projections of changes in sea level, rainfall, temperature,
and storm frequency and severity will be used as updated scientific data become
available.
Use the following projections as minimum values when undertaking coastal hazard
assessments:
(a)
A 100-year time frame,
(b)
A projection of a base sea-level rise of at least 0.6 m (above the 1980–1999
average) for activities/developments which are relocatable,
Climate Effects Consolidated Report – River Scheme Sustainability Project
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(c)
A projection of a base sea-level rise of 0.9 m (above the 1980–1999 average)
for activities where future adaptation options are limited, such as regionally
significant infrastructure and developments which cannot be relocated, and
(d)
An additional sea-level rise of 10mm per annum for activities with life spans
beyond 2112.
Explanation
Climate change has implications for many natural hazards including coastal
hazards, landslip, sedimentation, wind, drought, fire and flooding.
Policy NH 11B seeks to ensure a consistent approach to identifying and assessing
coastal hazards, which aligns with the most recent and internationally accepted
scientific knowledge on climate change risk. This Policy and Policy IR 2B set out
minimum values for climate change projections, to be taken into account when
assessing natural hazards and identifying the types of natural hazards likely to be
exacerbated by climate change. Current sea-level rise projections have been
derived from: Coastal Hazards and Climate Change: A Guidance Manual for Local
Government in New Zealand, Ministry for the Environment, May 2008a.
Rationale for RPS policy NH 11B numbers differing from MfE guidance referenced
in the Explanation [Ministry for the Environment 2008. Coastal Hazards and Climate
Change. A Guidance Manual for Local Government in New Zealand. 2nd edition.
Revised by Ramsay, D, and Bell, R. (NIWA). Prepared for Ministry for the
Environment. viii+127 p. ISBN: 978-0-478-33118-9 (print), 978-0-478-33119-6
(electronic), ME number: 89]:
The values in Policy NH 11B were set in line with the New Zealand Coastal Policy
Statement, which requires a 100-year timeframe (minimum) and the guidance and
policy itself, which requires a rate of increase of 10 mm per year beyond 2100,
(to 2012, when Policy NH 11B was finalised) as follows:
For paragraph (b) of Policy NH 11B:
The current base sea-level rise of 0.5 m was set in 2007. Five years have elapsed.
10 mm per annum x 5 = 50 mm. So the 2012 base should be 0.5 + 0.05 = 0.55 m,
rounded to 0.6 m.
For (c):
The current base sea-level rise of 0.8 m was set in 2007. That guidance is for the
2090s (2090–2099). A minimum of 100 years, to 2112, requires an additional
13 years, 12 of which are “beyond 2100”.
10 mm per annum x 12 = 120 mm. So the 2012 base should be 0.8 + 0.12 = 0.92,
rounded to 0.9 m.
For (d):
Change “beyond 2100” to “beyond 2112”.
When taken to 2015, the (c) value, to two decimal places, would be 0.92 + (10 mm x
(2115-2112) = 0.92 + 0.03 = 0.95 m or 1.0 m to one decimal place.
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Climate Effects Consolidated Report – River Scheme Sustainability Project
Part 6: Climate cycles in the Bay of Plenty
The National Institute of Water and Atmospheric Research Limited’s 2014 Climate Cycles
report describes the main climate oscillations affecting New Zealand and the Bay of Plenty
region, and the impacts they have on rainfall, river flow and resulting flood risk. It also
describes the rainfall regime of New Zealand and recent trends in the Bay of Plenty rainfall
record. The report is summarised below.
6.1
Rainfall regime and trends
Precipitation in the region is highly variable spatially and temporally. Several trends
are identified:

Total rainfall generally decreased in the Bay of Plenty since the 1960s or
1970s, but this reduction was only statistically significant at the 95 percent
level at Tauranga. Year to year variability of total annual rainfall was found to
be large in the region.

Typically there are about 95 rain days per year in the Bay of Plenty at coastal
sites such as Tauranga and Ōpōtiki, but his has risen to up to 134 days per
year during extreme years.

There has been a significant, long-term trend towards fewer rain days at some
stations in the Bay of Plenty over the study period (1900-2002), with much of
this reduction occurring since the 1960s or 1970s. In very wet years, the
number of rain days was typically high, with the converse also true.

An extreme rain index was calculated measuring the fourth largest rainfall
amount per year. Extreme (large) daily rainfall has not changed significantly
over the 20th century in the Bay of Plenty. However, in the short-term, the
years from 1970-2002 have been atypical in that extreme daily rainfalls have
been generally lower than seen elsewhere in the historical climate record (at
least at coastal or lower evaluation stations). For this reason, planning or
policy decisions should not be made based on this part of the record alone.
Variability in extreme rainfall in the region remains very large and needs to be
considered.

The frequency of extreme daily rainfall has decreased across the
Bay of Plenty over the past 100 or so years, but the decrease is significant
only at Tauranga. Regardless, the climate from circa 1970-2002 was atypical,
in that extreme daily rainfalls were less frequent than recorded elsewhere in
the historical climate record.

The average magnitude of the top four (very extreme) daily rainfalls per year
has not significantly changed in the past 100 years across the Bay of Plenty
except at Tauranga, which shows a small decrease over the period
1910-2002. However, the 1980s and 1990s have been unusual at some
stations in the region in that extreme daily rainfalls have been generally
smaller in magnitude than seen at other times in the past. These stations
exhibit a large decrease in the extreme intensity index after the early 1970s,
and therefore recent climate is not generally representative for long-term
planning.

Over the 50-year period 1951-2000, seasonal rainfall has decreased over
most of the region in most seasons. Decreases have been larger in the west
(Tauranga westwards) than in the east (Whakatāne eastwards) and south.
Tauranga rainfall has decreased by about 10 percent in winter to 30 percent in
summer since 1951.
Climate Effects Consolidated Report – River Scheme Sustainability Project
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6.2
Impacts of climate oscillations
The report reviews four large-scale natural climate cycles and their corresponding
impacts on rainfall and flood flow in New Zealand and specifically the Bay of Plenty:
6.2.1

Interdecadal Pacific Oscillation (IPO).

El Nino Southern Oscillation (ENSO).

Southern Annular Mode (SAM).

Indian Ocean Dipole (IOD).
Interdecadal Pacific Oscillation
The Interdecadal Pacific Oscillation (IPO) is a natural fluctuation in climate over
parts of the Pacific Ocean. It shows characteristic circulation patterns for phases of
about 20-30 years. During the 20th Century, three major phases of the IPO were
identified – a positive drier phase (1922-1945) for the Bay of Plenty, a negative
wetter phase (1947-1977), and another positive phase (1978-1999). The start of the
21st Century has seen a return to negative, wetter, IPO conditions (Figure 4).
Figure 4
Phases of the IPO. Positive = dry; Negative = wet in the Bay of Plenty
(NIWA, 2014; Data courtesy of the Hadley Centre, UK Meteorological
Office).
These patterns are the “average” response and do not mean that every year of a
particular IPO phase will behave in the same way.
No scheme for predicting when a shift may occur is known.
6.2.2
El Nino Southern Oscillation
The El Nino Southern Oscillation (ENSO) is a natural fluctuation of the global
climate and refers to the variation in sea surface temperature across the equatorial
Pacific Ocean and in surface air pressure in the tropical western Pacific. El Nino and
La Nino refer to opposite extremes of the ENSO cycle and occur every three to
seven years. A common measure of the intensity and state of the ENSO events is
the Southern Oscillation Index (SOI) (Figure 5).
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Climate Effects Consolidated Report – River Scheme Sustainability Project
Figure 5
Southern Oscillation Index from 1930-2014. La Nina = positive =
wetter; El Nino = negative = drier for Bay of Plenty (NIWA, 2014).
In general, during an El Nino, New Zealand experiences a stronger than normal
south-westerly airflow leading to drier than normal conditions in the east of the
country (i.e. the Bay of Plenty). Conversely, during La Nina, more north-easterly
flows ensue, leading to wetter than normal conditions in the north and east of the
North Island. Individual events can differ substantially from this pattern. El Nino
Southern Oscillation can occur at any time of the year, but its peak usually occurs
during spring and summer. Once El Nino or La Nina events have commenced, their
evolution is partly predictable for the coming few months.
6.2.3
Southern Annular Mode
The Southern Annular Mode (SAM) is a ring of climatic variability circling the
South Pole. It influences the South Island more dominantly than the North Island.
The positive phase of the SAM during summer induced wetter conditions along the
east of the North Island. Likewise, the positive of the SAM in winter brings wetter
conditions to the Bay of Plenty.
6.2.4
Indian Ocean Dipole
The Indian Ocean Dipole (IOD) is a coupled ocean-atmosphere phenomenon in the
Indian Ocean, defined by the difference in sea surface temperature between a
western pole in the western Indian Ocean and an eastern pole in the eastern Indian
Ocean. A general effect of increased rainfall in the Bay of Plenty during a negative
phase is likely.
The SAM and IOD have less influence on rainfall and river flow in New Zealand, with
limited studies encompassing the Bay of Plenty region.
6.2.5
Analysis of river flows
Bay of Plenty river flows for the larger rivers have been well monitored. A study of
these records showed partial support for the concept of the IPO phases influencing
flood magnitude of some Bay of Plenty rivers (Rangitāiki, Tarawera and
Whakatāne). Analysis of extreme rainfall records for the region also offers some
supporting evidence of the IPO phases, although this effect is not evident in the
records of other rivers (Kaituna, Waioeka, Mōtū).
Climate Effects Consolidated Report – River Scheme Sustainability Project
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6.3
Climate change and other variables
Climate cycles will be superimposed on top of the impacts of climate change.
Therefore, adaptation to changes in rainfall and flood flow will need to incorporate
both the shorter-scale natural climatic variations as well as long-term trends.
The combination of climate change, interacting natural climate oscillations and other
variables such as land use change, make long-term impacts to flood risk difficult to
determine. There is some supporting evidence for the long-term climate cycles
(ENSO and IPO) likely to have an influence on the observed temporal clustering of
floods but the relationship is not always clear. Designers of permanent structures
such as bridges and stopbanks need to use all available records, particularly those
extending over two or more phases of the IPO.
6.4
Conclusion
At present, NIWA suggest there is insufficient evidence for delaying infrastructure
expenditure based on the timing and effects of climate cycles. They strongly
recommend to continue the collection of river flow, rainfall and other climate data
throughout the region, and re-examine relationships between flood flow and climate
cycles regularly. The continued monitoring will also be vital in any future assessment
of the potential impacts of climate change.
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Climate Effects Consolidated Report – River Scheme Sustainability Project
Part 7: Regional application of climate change and
sea level rise in policy and guidelines and projects
This section outlines how Council uses the available information on climate change as part of
its statutory role. It generally follows the bottom section of the schematic shown in Figure 1.
7.1
Local Government role
The statutory role of Local Government with respect to climate change, comes from
the Resource Management Act and sub-ordinate national policy statements. The
role can be liberally interpreted as assisting communities adapt to the foreseeable
effects of a changing climate. Central Government has the role for setting national
greenhouse gas emission targets and developing the market mechanisms to
achieve these (SOLGM, 2015).
7.2
Council policy and guidelines
The findings of the reports listed in Part 3, particularly projections on future
temperature, rainfall and sea level, are then used within BOPRC policy and
guidelines documents, such as the Regional Policy Statement Natural Hazards
(RPS Nat. Haz.), Position Statement on Climate Change in the Long Term Plan
2015-2025 (BOPRC, 2015), Regional Coastal Policy Statement (RCPS), Bay of
Plenty Regional Coastal Environment Plan, Hydrological and Hydraulic Guidelines,
Stormwater Guidelines, and the Asset Management Plan. More detail on sea level
rise predictions included in the Regional Policy Statement Natural Hazards (RPS
Nat. Haz.) is given in Part 5.
Bay of Plenty Regional Council aims to future-proof the region against climate
change by providing advice and developing policy to help the region adapt and
become more resilient to the effects of climate change. Some examples of what
Council is doing to manage/address climate change are outlined below. It should be
noted that the projects are integrated and draw off the learnings of each other.
7.2.1
Set policy and rules
The Bay of Plenty Regional Policy Statement (RPS) (BOPRC, 2014) requires the
effects of climate change to be recognised and provided for in integrated planning
and natural hazard risk assessment, noting that setting policy and rules for coastal
communities requires robust evidence. The Bay of Plenty RPS and the Regional
Coastal Environment Plan (BOPRC, 2014a) implements the Ministry for the
Environment (MfE) current guidance manual. Since it became operative in 2003, the
Regional Coastal Environment Plan has required sea-level rise to be taken into
account in identifying coastal hazards. This has in turn been included in relevant city
and district plans in the region.
7.2.2
Rivers and drainage schemes
Bay of Plenty Regional Council’s Infrastructure Strategy (2015 – 2045) (BOPRC,
2015a) and Rivers and Drainage Asset Management Plan (2014/2015) (BOPRC,
2015b) identified climate-change-related sea level rise and increased intensity and
frequency of storm events as significant issues. The Infrastructure Strategy
proposes to set aside $8.4M over the next 30 years, specifically for climate change
capital works for four rivers and drainage schemes that provide flood protection in
the region.
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Climate Effects Consolidated Report – River Scheme Sustainability Project
7.2.3
Regional flood risk management
Bay of Plenty Regional Council is working collaboratively with territorial authorities in
the region and other key stakeholders to establish a better way of mitigating flood
risk across the region. Current mechanisms tend to have a structural focus. A 100year catchment-wide focus, similar to the River Scheme Sustainability Project, will
be used to steer decision-making.
7.2.4
Provide guidance
Bay of Plenty Regional Council has prepared guidance documents that include
reference and design advice for the effects of climate change, referenced back to
MfE current guidance. These include the Hydraulic and Hydrological Guidelines
(BOPRC, 2012) and the Stormwater Guidelines (BOPRC, 2012a). Note: guideline
documents are non-statutory documents and are therefore non-enforceable.
7.2.5
Share local climate change projections with our communities
Bay of Plenty Regional Council commissioned NIWA (2011) to assess and model
the potential changes on temperature, rainfall, wind, drought, frost days and pasture
growth as a result of selected climate change scenarios as per IPCC4 projections.
This generated local-scale information (32 scenario combinations in GIS format) of
potential climate change impacts across the Bay of Plenty. This information was
shared with primary industries and research communities (e.g. Zespri, avocado
growers and HortResearch) and territorial authorities in our region for their use. The
information was also made into an easy-to-read and easy-to-relate-to pamphlet and
website material available for the wider community.
7.2.6
Provide technical advice - coastal calculator
Bay of Plenty Regional Council has commissioned NIWA to apply its latest coastal
science to the Bay of Plenty, to create a tool that calculates the height of the sea at
21 locations around the region. The tool calculates storm surge, wave set-up and
wave run-up, plus adds a linear sea-level rise elevation increase. The National
Institute of Water and Atmospheric Research Limited has completed similar analysis
for other New Zealand councils and translated results into coastal inundation maps
for some of them. The National Institute of Water and Atmospheric Research
Limited has completed inundation mapping of the Auckland Council using 1 and 2 m
SLR projections and this work is before the Environment Court, with NIWA being
expert witness for Auckland Council. We have been advised that the 1 m SLR
projected inundation levels, appear to have generated little public feedback but the
2 m SLR inundation zone is creating a vocal response.
7.2.7
Provide technical advice – floodplain mapping
Bay of Plenty Regional Council undertakes modelling to generate flood hazard maps
for areas associated with Council rivers and drainage schemes as part of floodplain
management strategies (EBOP, 2001; EBOP, 2008; EBOP, 2008a). The mapping
includes allowance for climate change derived rainfall and sea level rise. Flood
levels are used for flood scheme design and providing minimum floor-level advice.
Climate Effects Consolidated Report – River Scheme Sustainability Project
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7.2.8
Feedback to MfE for climate change guideline updates
Bay of Plenty Regional Council has participated in a workshop and provided
feedback to MfE, about what the industry requires from updated MfE Climate
Change Guidance documents. We have requested that more numbers, levels and
real applicable information be included in updated guidance, and that guidance is
updated in a timelier manner so it remains current and relevant. We have been
advised that MfE may not issue the update to the 2008 guidance to include IPCC5
for another year. The 2008 guidance provides projections to the year 2090 but the
100-year future window is now 2115, making the MfE guidance projections 25 years
too short, compared to 100-year statutory requirements in the RPS.
7.2.9
Advice to territorial authorities
Bay of Plenty Regional Council advises our territorial authorities on district plan
changes associated with flooding, climate change impacts and areas to be released
for development, so that we collaboratively create safer and more resilient
communities (one of our Community Outcomes).
7.3
Council projects
Current BOPRC projects that use the research findings are the River Scheme
Sustainability Project (RSS), the Water Programme and the Spatial Plan.
7.3.1
River Scheme Sustainability Project
Council’s River Scheme Sustainability Project incorporates climate change for future
decision-making in a 100-year framework for each flood scheme catchment. This
project aims to explore the best long-term sustainable solutions for the future of the
river schemes in the Bay of Plenty. Climate change factors increase the cost of hard
engineering solutions, so the Council project also considers “working with nature”,
soft engineering solutions and non-structural options where applicable.
7.3.2
Water Management Programme
The Water Management Programme is also including climate change within its
long-term planning.
7.3.3
Spatial planning
Bay of Plenty Regional Council is undertaking spatial planning analysis. The current
status is that layers of information are being developed and assessed, including
projected climate change impacts. Over the next six months the layers will be
integrated to develop a clear understanding and a document prepared detailing
findings.
7.3.4
Seek opportunities to build understanding
Bay of Plenty Regional Council is also taking part in case studies and sharing
information and knowledge with research institutions, to better understand how to
adapt to climate change. Current research partners include the International Global
Change Institute (IGCI, University of Waikato), LandCare Research, and NIWA.
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Climate Effects Consolidated Report – River Scheme Sustainability Project
Bay of Plenty Regional Council is participating in a case study in a Governmentfunded four-year targeted research project called “Climate Change, Impacts and
Implications for New Zealand”. This project aims to generate new knowledge about
likely climate change impacts, including those on ecosystems and primary
production.
One of the case studies is focused on wetlands in the lower Kaituna River
Catchment. The case study is looking into key pressures, critical time steps and
potential responses. The project is also exploring the increasing relevance of climate
change science and decision-making capacity to consider climate change risks
through collaborative learning process.
Climate Effects Consolidated Report – River Scheme Sustainability Project
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Part 8: Application of climate change
8.1
Effects of climate change on river schemes
The River Scheme Sustainability project’s goal is to set direction for sustainable
management of the five major river and drainage schemes (Kaituna Catchment
Control Scheme, Rangitāiki-Tarawera River Scheme, Whakatāne-Waimana River
Scheme, Waioeka-Otara River Scheme and Rangitāiki Drainage Scheme) for the
next 100 years. The goal is to reduce long-term risk of flood hazards while
encouraging environmentally and economically sustainable land-use practices, and
raising awareness and changing attitudes and behaviour in the communities.
As we expect the climate to change over the next 100 years, this will affect the
management of the river schemes. This report will help us better understand the
impact of weather cycles and climate change on the river schemes. Future climate
change impacts to consider are:
8.2

Sea level rise: affects all schemes similarly. Drainage, pumping, decreased
level of service of coastal flood protection.

Rainfall/storms: increased flood risk, decreased level of service of flood
protection and increased erosion, coastal storms effects and sediment
transport to estuaries and harbours. Increased drought risk may affect future
land use.
Recommendations for future work
To better manage river schemes sustainably in the long term, this report has
highlighted the following recommendations for further work in future:

Review NIWA’s Coastal Calculator: the coastal calculator is a tool developed
by NIWA to calculate design wave run-up levels for specific coastal areas
(review is currently under way).

IPCC 2014: The IPCC’s Fifth Assessment is published but waiting for
summary and guidance by MfE.

MfE 2016: an updated guidance document is due now, based on the IPCC
Fifth Assessment. It is expected to be available in 2016. Once the new
guidance document is available, regional applications documents should be
reviewed to ensure they are aligned with the new guide.

Climate change projected expenditure in the AMP and Infrastructure Strategy
should be updated once the new MfE guidance document is available. This
will quantify the climate change implications on the river schemes.

Review Climate Change projections: The climate change projections for the
Bay of Plenty (NIWA, 2011) should be reviewed and updated with any new
and significantly different climate change guidance from IPCC/MfE.

Maintain climate monitoring sites and regime to ensure trends in climate
change are captured.

Review climate cycles data in 10 years’ time.

Incorporate climate change information into planning/regulatory documents.
Climate Effects Consolidated Report – River Scheme Sustainability Project
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Part 9: Conclusion
Bay of Plenty Regional Council aims to future-proof the region against climate change by
providing advice and developing policy to help the region adapt and become more resilient to
the effects of climate change. The consolidated report outlines how the council uses the
research information in its policy, guidelines and projects.
International, national and regional guidance on climate change and its effects on the
Bay of Plenty are documented in this report, which looks at climate change and cycles for the
Bay of Plenty. Specific effects of climate change and climate effects in the Bay of Plenty are
presented in the context of their application to river schemes for consideration in the
long-term sustainability of these schemes.
The information summarised within this report presents a good starting point for further
investigating climate change considerations and incorporating climate change into our
planning and operation. In particular the River Scheme Sustainability project will utilise the
updated information when undertaking analysis of options for the future within a 100-year
framework for each scheme.
We expect additional climate change information from other agencies will become available
in the near future, including:

Ministry for the Environment - Coastal hazard and climate change guidance.

Parliamentary Commissioner for the Environment - Sea level rise.
Once available, this information should be incorporated into the development of a strategic
approach to climate change in the Bay of Plenty.
Climate Effects Consolidated Report – River Scheme Sustainability Project
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Part 10: References
BOPRC, 2012; Hydrological and Hydraulic Guidelines. Guideline 2012/02.
BOPRC, 2012a; Stormwater Management Guidelines for the Bay of Plenty region. Guideline
2012/01.
BOPRC, 2014; Operative Regional Policy Statement for the Bay of Plenty. Strategic Policy
Publication 2013/04.
BOPRC, 2014a; Proposed Regional Coastal Environment Plan. Strategic Policy Publication
2014/01.
BOPRC, 2015; Long Term Plan 2015-2025.
BOPRC, 2015a; Draft Infrastructure Strategy 2015-2045.
BOPRC, 2015b; 2014/2015 Draft Rivers and Drainage Asset Management Plan.
Earthwise Consulting, 2006. Biotic Effects of Climate Change in the Bay of Plenty. Prepared
for Environment Bay of Plenty, March 2006.
Environment Bay of Plenty and Ōpōtiki District Council, 2001. Waioeka-Otara Floodplain
Management Strategy.
Environment Bay of Plenty, 2008. Whakatāne-Waimana Floodplain Management Strategy.
Operations Publication 2008/09.
Environment Bay of Plenty, 2008a. Rangitāiki-Tarawera Floodplain Management Strategy.
Rivers and Drainage Publication 2008/01.
IPCC, 2007. Climate Change 2007: Fourth Assessment Report of the Intergovernmental
Panel on Climate Change.
IPCC, 2014. Climate Change 2014: Fifth Assessment Report of the Intergovernmental Panel
on Climate Change.
MfE, 2008. Climate Change Effects and Impact Assessment: A Guidance Manual for Local
Government in New Zealand; Ministry for the Environment, May 2008.
MfE, 2008a. Coastal hazards and climate change: A guidance manual for Local Government
in New Zealand; Ministry for the Environment, July 2008.
MfE, 2008b. Preparing for Climate Change: A guide for Local Government in New Zealand;
Ministry for the Environment, July 2008.
MfE, 2009. Preparing for Coastal Change: A guide for Local Government in New Zealand;
Ministry for the Environment, March 2009.
MfE, 2010. Tools for estimating the effects of climate change on flood flow: A guidance
manual for Local Government in New Zealand; Ministry for the Environment,
May 2010.
MfE, 2010a. Preparing for Future Flooding: A guide for Local Government in New Zealand;
Ministry for the Environment, May 2010.
Climate Effects Consolidated Report – River Scheme Sustainability Project
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NIWA, 2003. The Climate of the Bay of Plenty: Past and Future?; NIWA Client Report
AKL2003-044, prepared for Environment Bay of Plenty, June 2003.
NIWA, 2006. Impacts of climate change on coastal margins of the Bay of Plenty. NIWA
Client Report HAM2006-031, prepared for Environment Bay of Plenty, May 2006.
NIWA, 2011.Coastal Adaptation to Climate Change – Pathways to Change. November 2011.
NIWA, 2011a. An updated climate change assessment for the Bay of Plenty. NIWA Client
Report AKL2011-019, prepared for Bay of Plenty Regional Council, December 2011.
NIWA, 2013. The climate and weather of Bay of Plenty. NIWA Science and Technology
Series Number 62. 3rd edition, 2013.
NIWA, 2014. Assessment of the effects of large-scale climate oscillations on the flood risk in
the Bay of Plenty. NIWA Client Report AKL2014-035, prepared for Bay of Plenty
Regional Council, December 2014.
SOLGM, 2015. Climate Change and Local Government; DRAFT Report to the Society of
Local Government Managers, Sector Futures Working Party.
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Climate Effects Consolidated Report – River Scheme Sustainability Project
Appendices
Climate Effects Consolidated Report – River Scheme Sustainability Project
33
Appendix 1 – Glossary
AMP – Asset Management Plan.
BA – Building Act.
BOPRC – Bay of Plenty Regional Council.
CDEMA – Civil Defence and Emergency Management Act.
Climate – the weather conditions prevailing in an area in general or over a long period.
Climate Change – a change in global or regional climate patterns, in particular a change
apparent from the mid-20th Century onwards and attributed largely to the increased levels of
atmospheric carbon dioxide produced by the use of fossil fuels.
Climate Cycles – a recurring cyclical oscillation within global or regional climate, and a type
of climate pattern.
CPS – Coastal Policy Statement.
ECL – Earthwise Consulting Limited.
ENSO – El Nino Southern Oscillation.
FMS – Floodplain Management Strategy.
H&H Guidelines – Hydrological and Hydraulic Guidelines.
IOD – Indian Ocean Dipole.
IPO – Interdecadal Pacific Oscillation.
IPCC – Intergovernmental Panel on Climate Change.
LGA – Local Government Act.
LTP – Long-Term Plan.
MfE – Ministry for the Environment.
NIWA – National Institute of Water and Atmospheric Research Limited.
RF – Rainfall.
RFRMF – Regional Flood Risk Management Framework.
RMA – Resource Management Act.
RSS – River Scheme Sustainability Project.
SAM – Southern Annular Mode.
SLR – Sea Level Rise.
SOLGM – Society of Local Government Managers.
Climate Effects Consolidated Report – River Scheme Sustainability Project
35
SW guidelines – Stormwater Guidelines.
Temp – Temperature.
Weather – a state of the atmosphere at a particular place and time as regards heat,
cloudiness, dryness, sunshine, wind, rain etc.
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Climate Effects Consolidated Report – River Scheme Sustainability Project
Appendix 2 – Rainfall projection maps
Figure 6
Bay of Plenty projected spring (September-November) mean rainfall
change (%) to end century – high end scenario (A2)
Climate Effects Consolidated Report – River Scheme Sustainability Project
37
Figure 7
38
Bay of Plenty projected summer (December-February) mean rainfall
change (%) to end century – high end scenario (A2)
Climate Effects Consolidated Report – River Scheme Sustainability Project
Figure 8
Bay of Plenty projected autumn (March-May) mean rainfall change
(%) to end century – high end scenario (A2)
Climate Effects Consolidated Report – River Scheme Sustainability Project
39
Figure 9
40
Bay of Plenty projected winter (June-August) mean rainfall change
(%) to end century – high end scenario (A2)
Climate Effects Consolidated Report – River Scheme Sustainability Project