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		<title>Updates to Tidal data page</title>
		<link>http://southerncentre.com/environment/coast/tidal-data/changes</link>
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			<item>
				<title>Tidal data</title>
				<link>http://southerncentre.com/environment/coast/2018-tidal-data</link>
				<description>
					
					
						&lt;div&gt;&lt;p&gt;&lt;del&gt;The 2018 tidal data is captured&lt;/del&gt; &lt;ins&gt;We do this to give us better information about flood risk&lt;/ins&gt; in &lt;del&gt;the report &lt;a title=&quot;Extreme Sea Levels at Christchurch Sites report&quot; href=&quot;http://southerncentre.com/assets/Documents/Environment/Water/Flooding-Land-Drainage/Extreme-Sea-Levels-at-Christchurch-Sites-report.PDF&quot;&gt;Extreme sea levels at Christchurch sites&lt;/a&gt; .&lt;/del&gt; &lt;ins&gt;these areas, to help us make informed planning and infrastructure decisions.&lt;/ins&gt;&lt;/p&gt;
&lt;ins&gt;
&lt;p&gt;A new study provides the Council with both new high tide statistics as well as an improved understanding of the dependency between rain events and high tide events. This is important to further improve our understanding of the flood risks in Christchurch.&lt;/p&gt;
&lt;p&gt;The 2021 study provides new high tide statistics, which updates the statistics in the 2018 report.&lt;/p&gt;
&lt;p&gt;The change in statistics from the 2018 report shows there’s a slightly higher water level predicted for most high tide events. The Pūharakekenui/Styx River flood statistics show slightly lower water levels for most less-frequent flood events.&lt;/p&gt;
&lt;p&gt;
&lt;div ccc=&quot;blockquote&quot; class=&quot;blockquote &quot; style=&quot;&amp;quot;width:100%;&amp;quot;&quot;&gt;
   &lt;a href=&quot;http://southerncentre.com/assets/Documents/Environment/Coast/BLM-Joint-Probability-Report.PDF&quot;&gt;2021 joint risks of pluvial and tidal flooding report (including the new statistics)&lt;/a&gt; 
  
&lt;/div&gt;
&lt;/p&gt;
&lt;/ins&gt;
&lt;p&gt;&lt;del&gt;&lt;div class=&quot;page-content accordion-section-wrapper&quot; ccc=&quot;section&quot;&gt;
    &lt;div class=&quot;accordion-section-expand-collapse&quot;&gt;
        &lt;button class=&quot;accordion-section-opencloseall-button&quot; style=&quot;display:none&quot;&gt;Open all&lt;/button&gt;
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        &lt;div class=&quot;accordion-section-item &quot;&gt;
        &lt;summary class=&quot;accordion-section-trigger&quot;&gt;
        &lt;span class=&quot;accordion-section-icon&quot; aria-hidden=&quot;true&quot;&gt;&lt;i class=&quot;fa-sharp fa-light fa-plus&quot; aria-hidden=&quot;true&quot;&gt;&lt;/i&gt;&lt;/span&gt;
        &lt;h2 class=&quot;accordion-section-title&quot;&gt;Monitoring and recording tide levels&lt;/h2&gt;
        
        
        &lt;/summary&gt;
        &lt;div class=&quot;accordion-section-content&quot;&gt;&lt;p&gt;Tide levels have been recorded Ferrymead Bridge since 1974 and at the Styx tide gates (Brooklands) since 1990, Sumner Head since 1994, and on the Avon at Bridge Street since 1997.&amp;nbsp; Tide levels are also recorded at Lyttelton.&lt;/p&gt;&lt;h3&gt;Historical trends in mean sea level rise&lt;/h3&gt;&lt;p&gt;The Ministry for the Environment in their document, Coastal Hazards and Climate Change - Guidance for Local Government, note that records from the four main port gauges indicate “there has been a doubling of mean sea level rise from an average of 1mm/year earlier last century to nearly 2mm/year from 1961”. &amp;nbsp;The Ministry also note satellite estimates of mean sea level rise of 4.4mm/year around New Zealand in the period 1993 to 2015.&lt;/p&gt;&lt;p&gt;NASA have assessed the rate of sea level rise on a global scale based on 25 years of American and European satellite data. They note the rate of sea level rise has increased from about 2.5mm/year in the 1990s to about 3.4mm/year today.&lt;/p&gt;&lt;div class=&quot;clearfix&quot;&gt;&lt;/div&gt;&lt;/div&gt;
    &lt;/div&gt;
    
        &lt;div class=&quot;accordion-section-item &quot;&gt;
        &lt;summary class=&quot;accordion-section-trigger&quot;&gt;
        &lt;span class=&quot;accordion-section-icon&quot; aria-hidden=&quot;true&quot;&gt;&lt;i class=&quot;fa-sharp fa-light fa-plus&quot; aria-hidden=&quot;true&quot;&gt;&lt;/i&gt;&lt;/span&gt;
        &lt;h2 class=&quot;accordion-section-title&quot;&gt;Using the high tide statistics&lt;/h2&gt;
        
        
        &lt;/summary&gt;
        &lt;div class=&quot;accordion-section-content&quot;&gt;&lt;p&gt;Record high tides in 2017 and 2018 in Christchurch (as also seen around the country) have prompted the 2018 review and update of tidal statistics for Christchurch coastal areas. The change in the statistics is partly a result of the longer period of data that is now available and partly due to climate change and sea level rise over the period of record.&lt;/p&gt;&lt;h3&gt;Using the statistics&lt;/h3&gt;&lt;p&gt;The 2018 High Tide Statistics give us better information about flood risk in coastal areas, to help us make informed planning and infrastructure decisions.&lt;/p&gt;&lt;p&gt;The Council uses high tide statistics as an input into flood modelling to determine minimum &lt;a title=&quot;Floor levels&quot; href=&quot;http://southerncentre.com/services/water-and-drainage/stormwater-and-drainage/flooding&quot;&gt;floor levels &lt;/a&gt;for building, design levels for infrastructure in tidally affected areas, flood management areas in the &lt;a title=&quot;Christchurch District Plan&quot; href=&quot;https://districtplan.ccc.govt.nz/pages/plan/book.aspx?exhibit=DistrictPlan&quot;&gt;Christchurch District Plan &lt;/a&gt;and other technical work such as coastal hazards.&lt;/p&gt;&lt;p&gt;Most properties in these tidally influenced areas will already have a standard comment about potential flooding and the risk of coastal inundation. Some LIMs will be updated to say the property is now considered to be at risk in a 1/50 year flood.&lt;/p&gt;&lt;h3&gt;Review of the statistics&lt;/h3&gt;&lt;p&gt;The 2018 analysis of the high tides was undertaken by Dr Derek Goring of Mulgor Consulting Ltd and has been peer reviewed by Charles Pearson of NIWA.&lt;/p&gt;&lt;p&gt;Environment Canterbury and NIWA have further reviewed the updated analysis of the high tides for Christchurch. Technical staff at Environment Canterbury concur with the methodology employed, agree with the updated information and support it being used to inform future planning considerations. NIWA also concluded that the analysis and review process were robust. NIWA noted the increase in the number of significant coastal flooding events around New Zealand, in the last five to ten years, and that they were updating the extreme sea levels (the high tides) for other districts.&lt;/p&gt;&lt;div class=&quot;clearfix&quot;&gt;&lt;/div&gt;&lt;/div&gt;
    &lt;/div&gt;
    
        &lt;div class=&quot;accordion-section-item &quot;&gt;
        &lt;summary class=&quot;accordion-section-trigger&quot;&gt;
        &lt;span class=&quot;accordion-section-icon&quot; aria-hidden=&quot;true&quot;&gt;&lt;i class=&quot;fa-sharp fa-light fa-plus&quot; aria-hidden=&quot;true&quot;&gt;&lt;/i&gt;&lt;/span&gt;
        &lt;h2 class=&quot;accordion-section-title&quot;&gt;Floor levels&lt;/h2&gt;
        
        
        &lt;/summary&gt;
        &lt;div class=&quot;accordion-section-content&quot;&gt;&lt;p&gt;The updated tide levels will be incorporated in the Avon, Heathcote and Styx River models to provide updated floor levels to protect new homes from flooding in tidally influenced areas.&lt;/p&gt;&lt;p&gt;The revised floor level information will be used for all new building consent applications in these areas. It will also be used in providing advice on resource consent applications in Flood Management Areas and High Flood Hazard Management Areas affected by tides.&lt;/p&gt;&lt;h2&gt;The impact on floor levels&lt;/h2&gt;&lt;p&gt;The impact on floor levels varies depending on the location within the city. For example, a floor level for a building consent near Bridge Street would be expected to rise around 150mm, and one near Brooklands Lagoon about 240mm when the new tidal data is taken into account.&amp;nbsp; The Council floor level viewer website will be updated using the new high tide statistics.&lt;/p&gt;&lt;p&gt;The table below shows planning level increases:&lt;/p&gt;&lt;table class=&quot;table-top-left&quot;&gt;
&lt;tbody&gt;
&lt;tr&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td&gt;&lt;span&gt;&lt;span&gt;High flood hazard management areas (1/500yr)&lt;/span&gt;&lt;br&gt;&lt;/span&gt;&lt;/td&gt;
&lt;td&gt;&lt;span&gt;Flood management areas (1/200yr)&lt;/span&gt;&lt;/td&gt;
&lt;td&gt;Building Act hazard notice (1/100yr)&lt;/td&gt;
&lt;td&gt;Building Act floor level (1/50yr)&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
&lt;td&gt;Ferrymead&lt;/td&gt;
&lt;td&gt;390mm&lt;/td&gt;
&lt;td&gt;290mm&lt;/td&gt;
&lt;td&gt;260mm&lt;/td&gt;
&lt;td&gt;230mm&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
&lt;td&gt;Bridge Street&lt;/td&gt;
&lt;td&gt;360mm&lt;/td&gt;
&lt;td&gt;260mm&lt;/td&gt;
&lt;td&gt;200mm&lt;/td&gt;
&lt;td&gt;150mm&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
&lt;td&gt;Brooklands&lt;/td&gt;
&lt;td&gt;460mm&lt;/td&gt;
&lt;td&gt;330mm&lt;/td&gt;
&lt;td&gt;280mm&lt;/td&gt;
&lt;td&gt;240mm&lt;/td&gt;
&lt;/tr&gt;
&lt;/tbody&gt;
&lt;/table&gt;&lt;div class=&quot;clearfix&quot;&gt;&lt;/div&gt;&lt;/div&gt;
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        &lt;div class=&quot;accordion-section-item &quot;&gt;
        &lt;summary class=&quot;accordion-section-trigger&quot;&gt;
        &lt;span class=&quot;accordion-section-icon&quot; aria-hidden=&quot;true&quot;&gt;&lt;i class=&quot;fa-sharp fa-light fa-plus&quot; aria-hidden=&quot;true&quot;&gt;&lt;/i&gt;&lt;/span&gt;
        &lt;h2 class=&quot;accordion-section-title&quot;&gt;Proposed District Plan changes&lt;/h2&gt;
        
        
        &lt;/summary&gt;
        &lt;div class=&quot;accordion-section-content&quot;&gt;&lt;p&gt;The Council recently approved asking the Minister to make proposed changes to the District Plan through the Section 71 process in relation to the Residential Unit Overlay. This includes changes to a policy and rule in the District Plan to clarify assessment of resource consent applications, and broadening the scope of an existing permitted activity rule for fairness and equity purposes. The Residential Unit Overlay applies to parts of Southshore, South New Brighton, New Brighton and Redcliffs. These areas will be affected by the updated high tide statistics.&lt;/p&gt;&lt;p&gt;The updated tide information does not change the appropriateness of the provisions sought in the section 71 process. The new information will be relevant to floor level heights for permitted activities, and the assessment of resource consent applications, for all relevant provisions in the District Plan including for the new ones in the section 71 process.&lt;/p&gt;&lt;p&gt;If the section 71 proposal is accepted, the new tide data will inform the assessment of individual resource consent applications, as it would without the District Plan changes.&amp;nbsp;&lt;/p&gt;&lt;h2&gt;Updating the District Plan&lt;/h2&gt;&lt;p&gt;When the Council is able to update its &lt;a title=&quot;District Plan&quot; href=&quot;https://districtplan.ccc.govt.nz/pages/plan/book.aspx?exhibit=DistrictPlan&quot;&gt;District Plan&lt;/a&gt;, Flood Management Areas, Fixed Minimum Floor Level Overlay and High Flood Hazard Management Areas will be updated to reflect the new tidal information.&lt;/p&gt;&lt;div class=&quot;clearfix&quot;&gt;&lt;/div&gt;&lt;/div&gt;
    &lt;/div&gt;
    
    &lt;div class=&quot;accordion-section-line&quot;&gt;&lt;/div&gt;
    &lt;div class=&quot;clearfix&quot;&gt;&lt;/div&gt;
&lt;/div&gt;&lt;/del&gt; &lt;ins&gt;&lt;div class=&quot;page-content accordion-section-wrapper&quot; ccc=&quot;section&quot;&gt;
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        &lt;div class=&quot;accordion-section-item &quot;&gt;
        &lt;summary class=&quot;accordion-section-trigger&quot;&gt;
        &lt;span class=&quot;accordion-section-icon&quot; aria-hidden=&quot;true&quot;&gt;&lt;i class=&quot;fa-sharp fa-light fa-plus&quot; aria-hidden=&quot;true&quot;&gt;&lt;/i&gt;&lt;/span&gt;
        &lt;h2 class=&quot;accordion-section-title&quot;&gt;2021 study main points&lt;/h2&gt;
        
        
        &lt;/summary&gt;
        &lt;div class=&quot;accordion-section-content&quot;&gt;&lt;p&gt;The 2021 report uses an advanced internationally recognised methodology for calculating the probability of high tide and rain events occurring – resulting in a high degree of accuracy for modelling flood risks.&lt;/p&gt;&lt;p&gt;The 2021 report also provides new high tide statistics. The methodology and results have been externally peer-reviewed by the external Multi Hazards Peer Review Panel.&lt;/p&gt;&lt;p&gt;Main points:&lt;/p&gt;&lt;ul&gt;
&lt;li&gt;2021 statistics predict a slightly higher water level for most high tide events. The Pūharakekenui/Styx River flood statistics show slightly lower water levels for most less-frequent flood events.&lt;/li&gt;
&lt;li&gt;The maximum increase in high tide levels is 84mm for a one-in-ten-year flood event at Ferrymead Bridge.&lt;/li&gt;
&lt;li&gt;The differences in high tide levels in the 2021 study compared to the 2018 study are within the margins used for determining floor levels (400mm) as well as for designing our (temporary) stopbanks and bunds (300mm).&lt;/li&gt;
&lt;li&gt;Changes are largely a result of two main factors:
&lt;ul&gt;
&lt;li&gt;The first is the use of a different methodology for determining extreme events compared to the methodology used in 2018. The new methodology allows for multiple events happening each year to be taken into account.&lt;/li&gt;
&lt;li&gt;The second factor relates to sea-level rise. Historic average sea levels are lower than those of the present day. As a result, the water levels related to historic events are also slightly lower than the level reached, if the same event would happen today. This change has been accounted for in the new high tide statistics.&lt;/li&gt;
&lt;/ul&gt;
&lt;/li&gt;
&lt;li&gt;As a result of this new study, we have a better understanding of the dependencies between rain events and high tide events. This allows us to more accurately predict water levels for specific extreme events.&lt;/li&gt;
&lt;li&gt;As a result of the new high tide data, whenever a LIM is requested for some properties they will be updated with the new information to say they&#039;re now considered to be at risk in a one-in-50 year flood. The number of properties likely to gain a new LIM comment is expected to be very small. That is because most of these properties will already have a comment about potential flooding and the risk of coastal inundation.&lt;/li&gt;
&lt;/ul&gt;&lt;p&gt;&lt;a class=&quot;external&quot; rel=&quot;external&quot; href=&quot;https://newsline.ccc.govt.nz/news/story/new-high-tide-levels-aid-christchurchs-flood-management&quot;&gt;Read more on Newsline&lt;span class=&quot;nonvisual-indicator&quot;&gt;(external link)&lt;/span&gt;&lt;/a&gt;.&lt;/p&gt;&lt;div class=&quot;clearfix&quot;&gt;&lt;/div&gt;&lt;/div&gt;
    &lt;/div&gt;
    
        &lt;div class=&quot;accordion-section-item &quot;&gt;
        &lt;summary class=&quot;accordion-section-trigger&quot;&gt;
        &lt;span class=&quot;accordion-section-icon&quot; aria-hidden=&quot;true&quot;&gt;&lt;i class=&quot;fa-sharp fa-light fa-plus&quot; aria-hidden=&quot;true&quot;&gt;&lt;/i&gt;&lt;/span&gt;
        &lt;h2 class=&quot;accordion-section-title&quot;&gt;Monitoring and recording tide levels&lt;/h2&gt;
        
        
        &lt;/summary&gt;
        &lt;div class=&quot;accordion-section-content&quot;&gt;&lt;p&gt;We continually monitor tide levels and use this information in our statistical analysis for high tides. We also look at weather patterns and sea-level rise.&lt;/p&gt;&lt;p&gt;We’ve been recording tide levels at Ferrymead Bridge since 1974 and at the Styx tide gates (Brooklands) since 1990, Sumner Head since 1994, and on the Avon at Bridge Street since 1997.&amp;nbsp;Tide levels are also recorded at Lyttelton.&lt;/p&gt;&lt;p&gt;Successive highest tides have been recorded over the years, culminating in the July 2017 and February 2018 high tides, which were about 300mm higher than the tides recorded in 1974.&lt;/p&gt;&lt;p&gt;Since 2018 we have not seen abnormally high tides in Christchurch.&lt;/p&gt;&lt;div class=&quot;clearfix&quot;&gt;&lt;/div&gt;&lt;/div&gt;
    &lt;/div&gt;
    
        &lt;div class=&quot;accordion-section-item &quot;&gt;
        &lt;summary class=&quot;accordion-section-trigger&quot;&gt;
        &lt;span class=&quot;accordion-section-icon&quot; aria-hidden=&quot;true&quot;&gt;&lt;i class=&quot;fa-sharp fa-light fa-plus&quot; aria-hidden=&quot;true&quot;&gt;&lt;/i&gt;&lt;/span&gt;
        &lt;h2 class=&quot;accordion-section-title&quot;&gt;Using the high tide statistics&lt;/h2&gt;
        
        
        &lt;/summary&gt;
        &lt;div class=&quot;accordion-section-content&quot;&gt;&lt;p&gt;The 2021 High Tide Statistics report updates the 2018 report.&lt;/p&gt;&lt;p&gt;We use high tide statistics data (including a statistical assessment of the correlation between high tide and rain events) as an input into flood modelling to determine minimum floor levels for building, design levels for infrastructure in tidally affected areas, flood management areas in the Christchurch District Plan and other technical work such as coastal hazards.&lt;/p&gt;&lt;p&gt;It will also be used in providing advice on resource consent applications in flood management areas and High Flood Hazard Management Areas affected by tides and/or joint high tides and rainfall events.&lt;/p&gt;&lt;p&gt;Read the 2021 joint risks of pluvial and tidal flooding report (including the new statistics).&lt;/p&gt;&lt;h3&gt;Using the statistics&lt;/h3&gt;&lt;p&gt;The 2021 high tide statistics give us better information about flood risk in coastal areas and areas influenced by tides, to help us make informed planning and infrastructure decisions.&lt;/p&gt;&lt;p&gt;The Council uses high tide statistics data (including a statistical assessment of the correlation between high tide and rain events) as an input into flood modelling to determine &lt;a href=&quot;http://southerncentre.com/services/water-and-drainage/stormwater-and-drainage/flooding/floor-level-requirements&quot;&gt;minimum floor levels&lt;/a&gt; for building, design levels for infrastructure in tidally affected areas, flood management areas in the &lt;a href=&quot;http://southerncentre.com/the-council/plans-strategies-policies-and-bylaws/plans/christchurch-district-plan&quot;&gt;Christchurch District Plan&lt;/a&gt; and other technical work such as coastal hazards.&lt;/p&gt;&lt;p&gt;As a result of the new high tide data, whenever a LIM is requested for some properties they will be updated with the new information to say they&#039;re now considered to be at risk in a one-in-50 year flood. Most properties in these tidally affected areas will already have a comment about potential flooding, and the risk of coastal inundation. It is expected that very few properties could gain a new LIM comment.&lt;/p&gt;&lt;h3&gt;Review of the statistics&lt;/h3&gt;&lt;p&gt;The 2021 high tides statistical assessment was carried out by GHD/HKV – a joint Christchurch-based consultancy and a Netherlands-based consultancy.&lt;/p&gt;&lt;p&gt;The work has been reviewed by the Council’s stormwater planning staff and has also been reviewed by the external Multi Hazards Peer Review Panel.&lt;/p&gt;&lt;div class=&quot;clearfix&quot;&gt;&lt;/div&gt;&lt;/div&gt;
    &lt;/div&gt;
    
        &lt;div class=&quot;accordion-section-item &quot;&gt;
        &lt;summary class=&quot;accordion-section-trigger&quot;&gt;
        &lt;span class=&quot;accordion-section-icon&quot; aria-hidden=&quot;true&quot;&gt;&lt;i class=&quot;fa-sharp fa-light fa-plus&quot; aria-hidden=&quot;true&quot;&gt;&lt;/i&gt;&lt;/span&gt;
        &lt;h2 class=&quot;accordion-section-title&quot;&gt;Floor levels&lt;/h2&gt;
        
        
        &lt;/summary&gt;
        &lt;div class=&quot;accordion-section-content&quot;&gt;&lt;p&gt;The updated high tide statistics data will be incorporated into the Pūharakekenui/Styx (Brooklands), Ōpāwaho/Heathcote and Ōtākaro/Avon River models to provide the design flood levels in tidally influenced areas. This is expected to take several months to complete.&lt;/p&gt;&lt;p&gt;The revised floor level information will be used for all new building consent applications. In flood management areas it will also be used in providing advice on resource consent applications in High Flood Hazard Management Areas and other areas affected by flooding.&lt;/p&gt;&lt;h3&gt;The impact on floor levels&lt;/h3&gt;&lt;p&gt;Our &lt;a class=&quot;external&quot; rel=&quot;external&quot; href=&quot;https://ccc.govt.nz/services/water-and-drainage/stormwater-and-drainage/flooding/floorlevelmap&quot;&gt;floor level viewer&lt;span class=&quot;nonvisual-indicator&quot;&gt;(external link)&lt;/span&gt;&lt;/a&gt;&amp;nbsp;will be updated with the new information. However, a large amount of information in the floor level viewer is based on model results and it will take several months to update the models and information.&lt;/p&gt;&lt;p&gt;The table below shows high tide statistics that are used for planning purposes:&lt;/p&gt;&lt;table class=&quot;table-top&quot;&gt;
&lt;tbody&gt;
&lt;tr&gt;
&lt;td style=&quot;width: 15%;&quot;&gt;Location&lt;/td&gt;
&lt;td&gt;High flood hazard management areas (1/500yr)&lt;/td&gt;
&lt;td&gt;Flood management areas (1/200yr)&lt;/td&gt;
&lt;td&gt;Building Act hazard notice (1/100yr)&lt;/td&gt;
&lt;td&gt;Building Act floor level (1/50yr)&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
&lt;td&gt;Bridge Street&lt;/td&gt;
&lt;td&gt;11.36m CDD&lt;/td&gt;
&lt;td&gt;11.27m CDD&lt;/td&gt;
&lt;td&gt;11.19m CDD&lt;/td&gt;
&lt;td&gt;11.12m CDD&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
&lt;td&gt;Ferrymead&lt;/td&gt;
&lt;td&gt;11.22m CDD&lt;/td&gt;
&lt;td&gt;11.14m CDD&lt;/td&gt;
&lt;td&gt;11.08m CDD&lt;/td&gt;
&lt;td&gt;11.03m CDD&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
&lt;td&gt;Sumner&lt;/td&gt;
&lt;td&gt;11.37m CDD&lt;/td&gt;
&lt;td&gt;11.29m CDD&lt;/td&gt;
&lt;td&gt;11.22m CDD&lt;/td&gt;
&lt;td&gt;11.16m CDD&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
&lt;td&gt;Styx&lt;/td&gt;
&lt;td&gt;11.37m CDD&lt;/td&gt;
&lt;td&gt;11.29m CDD&lt;/td&gt;
&lt;td&gt;11.24m CDD&lt;/td&gt;
&lt;td&gt;11.18m CDD&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
&lt;td&gt;Lyttelton&lt;/td&gt;
&lt;td&gt;11.11m CDD&lt;/td&gt;
&lt;td&gt;11.06m CDD&lt;/td&gt;
&lt;td&gt;11.02m CDD&lt;/td&gt;
&lt;td&gt;10.98m CDD&lt;/td&gt;
&lt;/tr&gt;
&lt;/tbody&gt;
&lt;/table&gt;&lt;div class=&quot;clearfix&quot;&gt;&lt;/div&gt;&lt;/div&gt;
    &lt;/div&gt;
    
        &lt;div class=&quot;accordion-section-item &quot;&gt;
        &lt;summary class=&quot;accordion-section-trigger&quot;&gt;
        &lt;span class=&quot;accordion-section-icon&quot; aria-hidden=&quot;true&quot;&gt;&lt;i class=&quot;fa-sharp fa-light fa-plus&quot; aria-hidden=&quot;true&quot;&gt;&lt;/i&gt;&lt;/span&gt;
        &lt;h2 class=&quot;accordion-section-title&quot;&gt;Climate change &lt;/h2&gt;
        
        
        &lt;/summary&gt;
        &lt;div class=&quot;accordion-section-content&quot;&gt;&lt;p&gt;Climate change is the biggest challenge of our time. It is already affecting our weather, health and wellbeing, natural environment, taonga species, mahinga kai, food production, biosecurity, infrastructure, and the economy.&lt;/p&gt;&lt;p&gt;Sea level rise is one of the challenges we face with ongoing climate change. Scientists predict a 30cm sea level rise by 2050, with a 50cm rise by 2075 and 1m by 2115, if global greenhouse gas emissions continue at the current rate.&lt;/p&gt;&lt;p&gt;This will have huge impacts on our district’s low-lying areas, cause significant drainage issues and place a major strain on our infrastructure and communities.&lt;/p&gt;&lt;p&gt;The updated high tide statistics have been derived from data where the effects of sea-level rise have been removed as best as possible. This means the statistics should more accurately show the actual natural variability in the tide and, therefore, provide more stable statistics for the future.&lt;/p&gt;&lt;h3&gt;We need to do more&lt;/h3&gt;&lt;p&gt;As a district, we need to reduce our carbon emissions and do what we can to mitigate the effects of climate change. We also need to prepare for the changes that are ahead of us and respond to the social, environmental and economic effects of our changing climate.&lt;/p&gt;&lt;p&gt;We’ve created our draft Ōtautahi Christchurch Climate Change Strategy&amp;nbsp;as a blueprint for collective action and part of a wider conversation about how we work together to reduce our greenhouse gas emissions to minimise future harm and plan for the ongoing effects of climate change.&lt;/p&gt;&lt;p&gt;&lt;a href=&quot;http://southerncentre.com/assets/Documents/Consultation/2021/03-March/STR3951-Draft-Otautahi-Christchurch-Climate-Change-Strategy-have-your-say-WEB.pdf&quot;&gt;Read the full draft Ōtautahi Christchurch Climate Change Strategy&lt;/a&gt;&lt;span class=&quot;fileExt&quot;&gt; [PDF, 604 KB]&lt;/span&gt;.&lt;/p&gt;&lt;div class=&quot;clearfix&quot;&gt;&lt;/div&gt;&lt;/div&gt;
    &lt;/div&gt;
    
    &lt;div class=&quot;accordion-section-line&quot;&gt;&lt;/div&gt;
    &lt;div class=&quot;clearfix&quot;&gt;&lt;/div&gt;
&lt;/div&gt;&lt;/ins&gt;&lt;/p&gt;&lt;/div&gt;
					
				</description>
				<pubDate>Wed, 23 Sep 2020 15:57:47 +1200</pubDate>
				<guid>http://southerncentre.com/environment/coast/2018-tidal-data</guid>
			</item>
		
			<item>
				<title>2018 tidal data</title>
				<link>http://southerncentre.com/environment/water/coastal/2018-tidal-data</link>
				<description>
					
						&lt;div&gt;&lt;em&gt;Title has changed:&lt;/em&gt; &lt;del&gt;2018 tidal&lt;/del&gt; &lt;ins&gt;Tidal&lt;/ins&gt; data&lt;/div&gt;
					
					
						&lt;div&gt;&lt;p&gt;The 2018 tidal data is captured &lt;del&gt;in&amp;nbsp;the report&amp;nbsp;&lt;/del&gt; &lt;ins&gt;in the report&lt;/ins&gt; &lt;a title=&quot;Extreme Sea Levels at Christchurch Sites report&quot; href=&quot;http://southerncentre.com/assets/Documents/Environment/Water/Flooding-Land-Drainage/Extreme-Sea-Levels-at-Christchurch-Sites-report.PDF&quot;&gt;Extreme sea levels at Christchurch sites&lt;/a&gt; .&lt;/p&gt;
&lt;p&gt;&lt;div class=&quot;page-content accordion-section-wrapper&quot; ccc=&quot;section&quot;&gt;
    &lt;div class=&quot;accordion-section-expand-collapse&quot;&gt;
        &lt;button class=&quot;accordion-section-opencloseall-button&quot; style=&quot;display:none&quot;&gt;Open all&lt;/button&gt;
    &lt;/div&gt;
    
        &lt;div class=&quot;accordion-section-item &quot;&gt;
        &lt;summary class=&quot;accordion-section-trigger&quot;&gt;
        &lt;span class=&quot;accordion-section-icon&quot; aria-hidden=&quot;true&quot;&gt;&lt;i class=&quot;fa-sharp fa-light fa-plus&quot; aria-hidden=&quot;true&quot;&gt;&lt;/i&gt;&lt;/span&gt;
        &lt;h2 class=&quot;accordion-section-title&quot;&gt;Monitoring and recording tide levels&lt;/h2&gt;
        
        
        &lt;/summary&gt;
        &lt;div class=&quot;accordion-section-content&quot;&gt;&lt;p&gt;Tide levels have been recorded Ferrymead Bridge since 1974 and at the Styx tide gates (Brooklands) since 1990, Sumner Head since 1994, and on the Avon at Bridge Street since 1997.&amp;nbsp; Tide levels are also recorded at Lyttelton.&lt;/p&gt;&lt;h3&gt;Historical trends in mean sea level rise&lt;/h3&gt;&lt;p&gt;The Ministry for the Environment in their document, Coastal Hazards and Climate Change - Guidance for Local Government, note that records from the four main port gauges indicate “there has been a doubling of mean sea level rise from an average of 1mm/year earlier last century to nearly 2mm/year from 1961”. &amp;nbsp;The Ministry also note satellite estimates of mean sea level rise of 4.4mm/year around New Zealand in the period 1993 to 2015.&lt;/p&gt;&lt;p&gt;NASA have assessed the rate of sea level rise on a global scale based on 25 years of American and European satellite data. They note the rate of sea level rise has increased from about 2.5mm/year in the 1990s to about 3.4mm/year today.&lt;/p&gt;&lt;div class=&quot;clearfix&quot;&gt;&lt;/div&gt;&lt;/div&gt;
    &lt;/div&gt;
    
        &lt;div class=&quot;accordion-section-item &quot;&gt;
        &lt;summary class=&quot;accordion-section-trigger&quot;&gt;
        &lt;span class=&quot;accordion-section-icon&quot; aria-hidden=&quot;true&quot;&gt;&lt;i class=&quot;fa-sharp fa-light fa-plus&quot; aria-hidden=&quot;true&quot;&gt;&lt;/i&gt;&lt;/span&gt;
        &lt;h2 class=&quot;accordion-section-title&quot;&gt;Using the high tide statistics&lt;/h2&gt;
        
        
        &lt;/summary&gt;
        &lt;div class=&quot;accordion-section-content&quot;&gt;&lt;p&gt;Record high tides in 2017 and 2018 in Christchurch (as also seen around the country) have prompted the 2018 review and update of tidal statistics for Christchurch coastal areas. The change in the statistics is partly a result of the longer period of data that is now available and partly due to climate change and sea level rise over the period of record.&lt;/p&gt;&lt;h3&gt;Using the statistics&lt;/h3&gt;&lt;p&gt;The 2018 High Tide Statistics give us better information about flood risk in coastal areas, to help us make informed planning and infrastructure decisions.&lt;/p&gt;&lt;p&gt;The Council uses high tide statistics as an input into flood modelling to determine minimum &lt;a title=&quot;Floor levels&quot; href=&quot;http://southerncentre.com/services/water-and-drainage/stormwater-and-drainage/flooding&quot;&gt;floor levels &lt;/a&gt;for building, design levels for infrastructure in tidally affected areas, flood management areas in the &lt;a title=&quot;Christchurch District Plan&quot; href=&quot;https://districtplan.ccc.govt.nz/pages/plan/book.aspx?exhibit=DistrictPlan&quot;&gt;Christchurch District Plan &lt;/a&gt;and other technical work such as coastal hazards.&lt;/p&gt;&lt;p&gt;Most properties in these tidally influenced areas will already have a standard comment about potential flooding and the risk of coastal inundation. Some LIMs will be updated to say the property is now considered to be at risk in a 1/50 year flood.&lt;/p&gt;&lt;h3&gt;Review of the statistics&lt;/h3&gt;&lt;p&gt;The 2018 analysis of the high tides was undertaken by Dr Derek Goring of Mulgor Consulting Ltd and has been peer reviewed by Charles Pearson of NIWA.&lt;/p&gt;&lt;p&gt;Environment Canterbury and NIWA have further reviewed the updated analysis of the high tides for Christchurch. Technical staff at Environment Canterbury concur with the methodology employed, agree with the updated information and support it being used to inform future planning considerations. NIWA also concluded that the analysis and review process were robust. NIWA noted the increase in the number of significant coastal flooding events around New Zealand, in the last five to ten years, and that they were updating the extreme sea levels (the high tides) for other districts.&lt;/p&gt;&lt;div class=&quot;clearfix&quot;&gt;&lt;/div&gt;&lt;/div&gt;
    &lt;/div&gt;
    
        &lt;div class=&quot;accordion-section-item &quot;&gt;
        &lt;summary class=&quot;accordion-section-trigger&quot;&gt;
        &lt;span class=&quot;accordion-section-icon&quot; aria-hidden=&quot;true&quot;&gt;&lt;i class=&quot;fa-sharp fa-light fa-plus&quot; aria-hidden=&quot;true&quot;&gt;&lt;/i&gt;&lt;/span&gt;
        &lt;h2 class=&quot;accordion-section-title&quot;&gt;Floor levels&lt;/h2&gt;
        
        
        &lt;/summary&gt;
        &lt;div class=&quot;accordion-section-content&quot;&gt;&lt;p&gt;The updated tide levels will be incorporated in the Avon, Heathcote and Styx River models to provide updated floor levels to protect new homes from flooding in tidally influenced areas.&lt;/p&gt;&lt;p&gt;The revised floor level information will be used for all new building consent applications in these areas. It will also be used in providing advice on resource consent applications in Flood Management Areas and High Flood Hazard Management Areas affected by tides.&lt;/p&gt;&lt;h2&gt;The impact on floor levels&lt;/h2&gt;&lt;p&gt;The impact on floor levels varies depending on the location within the city. For example, a floor level for a building consent near Bridge Street would be expected to rise around 150mm, and one near Brooklands Lagoon about 240mm when the new tidal data is taken into account.&amp;nbsp; The Council floor level viewer website will be updated using the new high tide statistics.&lt;/p&gt;&lt;p&gt;The table below shows planning level increases:&lt;/p&gt;&lt;table class=&quot;table-top-left&quot;&gt;
&lt;tbody&gt;
&lt;tr&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td&gt;&lt;span&gt;&lt;span&gt;High flood hazard management areas (1/500yr)&lt;/span&gt;&lt;br&gt;&lt;/span&gt;&lt;/td&gt;
&lt;td&gt;&lt;span&gt;Flood management areas (1/200yr)&lt;/span&gt;&lt;/td&gt;
&lt;td&gt;Building Act hazard notice (1/100yr)&lt;/td&gt;
&lt;td&gt;Building Act floor level (1/50yr)&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
&lt;td&gt;Ferrymead&lt;/td&gt;
&lt;td&gt;390mm&lt;/td&gt;
&lt;td&gt;290mm&lt;/td&gt;
&lt;td&gt;260mm&lt;/td&gt;
&lt;td&gt;230mm&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
&lt;td&gt;Bridge Street&lt;/td&gt;
&lt;td&gt;360mm&lt;/td&gt;
&lt;td&gt;260mm&lt;/td&gt;
&lt;td&gt;200mm&lt;/td&gt;
&lt;td&gt;150mm&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
&lt;td&gt;Brooklands&lt;/td&gt;
&lt;td&gt;460mm&lt;/td&gt;
&lt;td&gt;330mm&lt;/td&gt;
&lt;td&gt;280mm&lt;/td&gt;
&lt;td&gt;240mm&lt;/td&gt;
&lt;/tr&gt;
&lt;/tbody&gt;
&lt;/table&gt;&lt;div class=&quot;clearfix&quot;&gt;&lt;/div&gt;&lt;/div&gt;
    &lt;/div&gt;
    
        &lt;div class=&quot;accordion-section-item &quot;&gt;
        &lt;summary class=&quot;accordion-section-trigger&quot;&gt;
        &lt;span class=&quot;accordion-section-icon&quot; aria-hidden=&quot;true&quot;&gt;&lt;i class=&quot;fa-sharp fa-light fa-plus&quot; aria-hidden=&quot;true&quot;&gt;&lt;/i&gt;&lt;/span&gt;
        &lt;h2 class=&quot;accordion-section-title&quot;&gt;Proposed District Plan changes&lt;/h2&gt;
        
        
        &lt;/summary&gt;
        &lt;div class=&quot;accordion-section-content&quot;&gt;&lt;p&gt;The Council recently approved asking the Minister to make proposed changes to the District Plan through the Section 71 process in relation to the Residential Unit Overlay. This includes changes to a policy and rule in the District Plan to clarify assessment of resource consent applications, and broadening the scope of an existing permitted activity rule for fairness and equity purposes. The Residential Unit Overlay applies to parts of Southshore, South New Brighton, New Brighton and Redcliffs. These areas will be affected by the updated high tide statistics.&lt;/p&gt;&lt;p&gt;The updated tide information does not change the appropriateness of the provisions sought in the section 71 process. The new information will be relevant to floor level heights for permitted activities, and the assessment of resource consent applications, for all relevant provisions in the District Plan including for the new ones in the section 71 process.&lt;/p&gt;&lt;p&gt;If the section 71 proposal is accepted, the new tide data will inform the assessment of individual resource consent applications, as it would without the District Plan changes.&amp;nbsp;&lt;/p&gt;&lt;h2&gt;Updating the District Plan&lt;/h2&gt;&lt;p&gt;When the Council is able to update its &lt;a title=&quot;District Plan&quot; href=&quot;https://districtplan.ccc.govt.nz/pages/plan/book.aspx?exhibit=DistrictPlan&quot;&gt;District Plan&lt;/a&gt;, Flood Management Areas, Fixed Minimum Floor Level Overlay and High Flood Hazard Management Areas will be updated to reflect the new tidal information.&lt;/p&gt;&lt;div class=&quot;clearfix&quot;&gt;&lt;/div&gt;&lt;/div&gt;
    &lt;/div&gt;
    
    &lt;div class=&quot;accordion-section-line&quot;&gt;&lt;/div&gt;
    &lt;div class=&quot;clearfix&quot;&gt;&lt;/div&gt;
&lt;/div&gt;&lt;/p&gt;&lt;/div&gt;
					
				</description>
				<pubDate>Mon, 07 Jan 2019 09:31:52 +1300</pubDate>
				<guid>http://southerncentre.com/environment/water/coastal/2018-tidal-data</guid>
			</item>
		
			<item>
				<title>2018 tidal data</title>
				<link>http://southerncentre.com/environment/water/coastal/2018-tidal-data</link>
				<description>
					
					
						&lt;div&gt;&lt;p&gt;The 2018 tidal data is captured in&amp;nbsp;the report&amp;nbsp; &lt;a title=&quot;Extreme Sea Levels at Christchurch Sites report&quot; href=&quot;http://southerncentre.com/assets/Documents/Environment/Water/Flooding-Land-Drainage/Extreme-Sea-Levels-at-Christchurch-Sites-report.PDF&quot;&gt;Extreme &lt;del&gt;Sea Levels&lt;/del&gt; &lt;ins&gt;sea levels&lt;/ins&gt; at Christchurch &lt;del&gt;Sites&lt;/del&gt; &lt;ins&gt;sites&lt;/ins&gt;&lt;/a&gt; .&lt;/p&gt;
&lt;p&gt;&lt;div class=&quot;page-content accordion-section-wrapper&quot; ccc=&quot;section&quot;&gt;
    &lt;div class=&quot;accordion-section-expand-collapse&quot;&gt;
        &lt;button class=&quot;accordion-section-opencloseall-button&quot; style=&quot;display:none&quot;&gt;Open all&lt;/button&gt;
    &lt;/div&gt;
    
        &lt;div class=&quot;accordion-section-item &quot;&gt;
        &lt;summary class=&quot;accordion-section-trigger&quot;&gt;
        &lt;span class=&quot;accordion-section-icon&quot; aria-hidden=&quot;true&quot;&gt;&lt;i class=&quot;fa-sharp fa-light fa-plus&quot; aria-hidden=&quot;true&quot;&gt;&lt;/i&gt;&lt;/span&gt;
        &lt;h2 class=&quot;accordion-section-title&quot;&gt;Monitoring and recording tide levels&lt;/h2&gt;
        
        
        &lt;/summary&gt;
        &lt;div class=&quot;accordion-section-content&quot;&gt;&lt;p&gt;Tide levels have been recorded Ferrymead Bridge since 1974 and at the Styx tide gates (Brooklands) since 1990, Sumner Head since 1994, and on the Avon at Bridge Street since 1997.&amp;nbsp; Tide levels are also recorded at Lyttelton.&lt;/p&gt;&lt;h3&gt;Historical trends in mean sea level rise&lt;/h3&gt;&lt;p&gt;The Ministry for the Environment in their document, Coastal Hazards and Climate Change - Guidance for Local Government, note that records from the four main port gauges indicate “there has been a doubling of mean sea level rise from an average of 1mm/year earlier last century to nearly 2mm/year from 1961”. &amp;nbsp;The Ministry also note satellite estimates of mean sea level rise of 4.4mm/year around New Zealand in the period 1993 to 2015.&lt;/p&gt;&lt;p&gt;NASA have assessed the rate of sea level rise on a global scale based on 25 years of American and European satellite data. They note the rate of sea level rise has increased from about 2.5mm/year in the 1990s to about 3.4mm/year today.&lt;/p&gt;&lt;div class=&quot;clearfix&quot;&gt;&lt;/div&gt;&lt;/div&gt;
    &lt;/div&gt;
    
        &lt;div class=&quot;accordion-section-item &quot;&gt;
        &lt;summary class=&quot;accordion-section-trigger&quot;&gt;
        &lt;span class=&quot;accordion-section-icon&quot; aria-hidden=&quot;true&quot;&gt;&lt;i class=&quot;fa-sharp fa-light fa-plus&quot; aria-hidden=&quot;true&quot;&gt;&lt;/i&gt;&lt;/span&gt;
        &lt;h2 class=&quot;accordion-section-title&quot;&gt;Using the high tide statistics&lt;/h2&gt;
        
        
        &lt;/summary&gt;
        &lt;div class=&quot;accordion-section-content&quot;&gt;&lt;p&gt;Record high tides in 2017 and 2018 in Christchurch (as also seen around the country) have prompted the 2018 review and update of tidal statistics for Christchurch coastal areas. The change in the statistics is partly a result of the longer period of data that is now available and partly due to climate change and sea level rise over the period of record.&lt;/p&gt;&lt;h3&gt;Using the statistics&lt;/h3&gt;&lt;p&gt;The 2018 High Tide Statistics give us better information about flood risk in coastal areas, to help us make informed planning and infrastructure decisions.&lt;/p&gt;&lt;p&gt;The Council uses high tide statistics as an input into flood modelling to determine minimum &lt;a title=&quot;Floor levels&quot; href=&quot;http://southerncentre.com/services/water-and-drainage/stormwater-and-drainage/flooding&quot;&gt;floor levels &lt;/a&gt;for building, design levels for infrastructure in tidally affected areas, flood management areas in the &lt;a title=&quot;Christchurch District Plan&quot; href=&quot;https://districtplan.ccc.govt.nz/pages/plan/book.aspx?exhibit=DistrictPlan&quot;&gt;Christchurch District Plan &lt;/a&gt;and other technical work such as coastal hazards.&lt;/p&gt;&lt;p&gt;Most properties in these tidally influenced areas will already have a standard comment about potential flooding and the risk of coastal inundation. Some LIMs will be updated to say the property is now considered to be at risk in a 1/50 year flood.&lt;/p&gt;&lt;h3&gt;Review of the statistics&lt;/h3&gt;&lt;p&gt;The 2018 analysis of the high tides was undertaken by Dr Derek Goring of Mulgor Consulting Ltd and has been peer reviewed by Charles Pearson of NIWA.&lt;/p&gt;&lt;p&gt;Environment Canterbury and NIWA have further reviewed the updated analysis of the high tides for Christchurch. Technical staff at Environment Canterbury concur with the methodology employed, agree with the updated information and support it being used to inform future planning considerations. NIWA also concluded that the analysis and review process were robust. NIWA noted the increase in the number of significant coastal flooding events around New Zealand, in the last five to ten years, and that they were updating the extreme sea levels (the high tides) for other districts.&lt;/p&gt;&lt;div class=&quot;clearfix&quot;&gt;&lt;/div&gt;&lt;/div&gt;
    &lt;/div&gt;
    
        &lt;div class=&quot;accordion-section-item &quot;&gt;
        &lt;summary class=&quot;accordion-section-trigger&quot;&gt;
        &lt;span class=&quot;accordion-section-icon&quot; aria-hidden=&quot;true&quot;&gt;&lt;i class=&quot;fa-sharp fa-light fa-plus&quot; aria-hidden=&quot;true&quot;&gt;&lt;/i&gt;&lt;/span&gt;
        &lt;h2 class=&quot;accordion-section-title&quot;&gt;Floor levels&lt;/h2&gt;
        
        
        &lt;/summary&gt;
        &lt;div class=&quot;accordion-section-content&quot;&gt;&lt;p&gt;The updated tide levels will be incorporated in the Avon, Heathcote and Styx River models to provide updated floor levels to protect new homes from flooding in tidally influenced areas.&lt;/p&gt;&lt;p&gt;The revised floor level information will be used for all new building consent applications in these areas. It will also be used in providing advice on resource consent applications in Flood Management Areas and High Flood Hazard Management Areas affected by tides.&lt;/p&gt;&lt;h2&gt;The impact on floor levels&lt;/h2&gt;&lt;p&gt;The impact on floor levels varies depending on the location within the city. For example, a floor level for a building consent near Bridge Street would be expected to rise around 150mm, and one near Brooklands Lagoon about 240mm when the new tidal data is taken into account.&amp;nbsp; The Council floor level viewer website will be updated using the new high tide statistics.&lt;/p&gt;&lt;p&gt;The table below shows planning level increases:&lt;/p&gt;&lt;table class=&quot;table-top-left&quot;&gt;
&lt;tbody&gt;
&lt;tr&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td&gt;&lt;span&gt;&lt;span&gt;High flood hazard management areas (1/500yr)&lt;/span&gt;&lt;br&gt;&lt;/span&gt;&lt;/td&gt;
&lt;td&gt;&lt;span&gt;Flood management areas (1/200yr)&lt;/span&gt;&lt;/td&gt;
&lt;td&gt;Building Act hazard notice (1/100yr)&lt;/td&gt;
&lt;td&gt;Building Act floor level (1/50yr)&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
&lt;td&gt;Ferrymead&lt;/td&gt;
&lt;td&gt;390mm&lt;/td&gt;
&lt;td&gt;290mm&lt;/td&gt;
&lt;td&gt;260mm&lt;/td&gt;
&lt;td&gt;230mm&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
&lt;td&gt;Bridge Street&lt;/td&gt;
&lt;td&gt;360mm&lt;/td&gt;
&lt;td&gt;260mm&lt;/td&gt;
&lt;td&gt;200mm&lt;/td&gt;
&lt;td&gt;150mm&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
&lt;td&gt;Brooklands&lt;/td&gt;
&lt;td&gt;460mm&lt;/td&gt;
&lt;td&gt;330mm&lt;/td&gt;
&lt;td&gt;280mm&lt;/td&gt;
&lt;td&gt;240mm&lt;/td&gt;
&lt;/tr&gt;
&lt;/tbody&gt;
&lt;/table&gt;&lt;div class=&quot;clearfix&quot;&gt;&lt;/div&gt;&lt;/div&gt;
    &lt;/div&gt;
    
        &lt;div class=&quot;accordion-section-item &quot;&gt;
        &lt;summary class=&quot;accordion-section-trigger&quot;&gt;
        &lt;span class=&quot;accordion-section-icon&quot; aria-hidden=&quot;true&quot;&gt;&lt;i class=&quot;fa-sharp fa-light fa-plus&quot; aria-hidden=&quot;true&quot;&gt;&lt;/i&gt;&lt;/span&gt;
        &lt;h2 class=&quot;accordion-section-title&quot;&gt;Proposed District Plan changes&lt;/h2&gt;
        
        
        &lt;/summary&gt;
        &lt;div class=&quot;accordion-section-content&quot;&gt;&lt;p&gt;The Council recently approved asking the Minister to make proposed changes to the District Plan through the Section 71 process in relation to the Residential Unit Overlay. This includes changes to a policy and rule in the District Plan to clarify assessment of resource consent applications, and broadening the scope of an existing permitted activity rule for fairness and equity purposes. The Residential Unit Overlay applies to parts of Southshore, South New Brighton, New Brighton and Redcliffs. These areas will be affected by the updated high tide statistics.&lt;/p&gt;&lt;p&gt;The updated tide information does not change the appropriateness of the provisions sought in the section 71 process. The new information will be relevant to floor level heights for permitted activities, and the assessment of resource consent applications, for all relevant provisions in the District Plan including for the new ones in the section 71 process.&lt;/p&gt;&lt;p&gt;If the section 71 proposal is accepted, the new tide data will inform the assessment of individual resource consent applications, as it would without the District Plan changes.&amp;nbsp;&lt;/p&gt;&lt;h2&gt;Updating the District Plan&lt;/h2&gt;&lt;p&gt;When the Council is able to update its &lt;a title=&quot;District Plan&quot; href=&quot;https://districtplan.ccc.govt.nz/pages/plan/book.aspx?exhibit=DistrictPlan&quot;&gt;District Plan&lt;/a&gt;, Flood Management Areas, Fixed Minimum Floor Level Overlay and High Flood Hazard Management Areas will be updated to reflect the new tidal information.&lt;/p&gt;&lt;div class=&quot;clearfix&quot;&gt;&lt;/div&gt;&lt;/div&gt;
    &lt;/div&gt;
    
    &lt;div class=&quot;accordion-section-line&quot;&gt;&lt;/div&gt;
    &lt;div class=&quot;clearfix&quot;&gt;&lt;/div&gt;
&lt;/div&gt;&lt;/p&gt;&lt;/div&gt;
					
				</description>
				<pubDate>Fri, 07 Dec 2018 10:52:40 +1300</pubDate>
				<guid>http://southerncentre.com/environment/water/coastal/2018-tidal-data</guid>
			</item>
		
			<item>
				<title>2018 tidal data</title>
				<link>http://southerncentre.com/environment/water/coastal/2018-tidal-data</link>
				<description>
					
					
						&lt;div&gt;&lt;p&gt;The 2018 tidal data is captured in&amp;nbsp;the report&amp;nbsp; &lt;a title=&quot;Extreme Sea Levels at Christchurch Sites report&quot; href=&quot;http://southerncentre.com/assets/Documents/Environment/Water/Flooding-Land-Drainage/Extreme-Sea-Levels-at-Christchurch-Sites-report.PDF&quot;&gt;Extreme Sea Levels at Christchurch Sites&lt;/a&gt;.&lt;/p&gt;&lt;p&gt;&lt;div class=&quot;page-content accordion-section-wrapper&quot; ccc=&quot;section&quot;&gt;
    &lt;div class=&quot;accordion-section-expand-collapse&quot;&gt;
        &lt;button class=&quot;accordion-section-opencloseall-button&quot; style=&quot;display:none&quot;&gt;Open all&lt;/button&gt;
    &lt;/div&gt;
    
        &lt;div class=&quot;accordion-section-item &quot;&gt;
        &lt;summary class=&quot;accordion-section-trigger&quot;&gt;
        &lt;span class=&quot;accordion-section-icon&quot; aria-hidden=&quot;true&quot;&gt;&lt;i class=&quot;fa-sharp fa-light fa-plus&quot; aria-hidden=&quot;true&quot;&gt;&lt;/i&gt;&lt;/span&gt;
        &lt;h2 class=&quot;accordion-section-title&quot;&gt;Monitoring and recording tide levels&lt;/h2&gt;
        
        
        &lt;/summary&gt;
        &lt;div class=&quot;accordion-section-content&quot;&gt;&lt;p&gt;Tide levels have been recorded Ferrymead Bridge since 1974 and at the Styx tide gates (Brooklands) since 1990, Sumner Head since 1994, and on the Avon at Bridge Street since 1997.&amp;nbsp; Tide levels are also recorded at Lyttelton.&lt;/p&gt;&lt;h3&gt;Historical trends in mean sea level rise&lt;/h3&gt;&lt;p&gt;The Ministry for the Environment in their document, Coastal Hazards and Climate Change - Guidance for Local Government, note that records from the four main port gauges indicate “there has been a doubling of mean sea level rise from an average of 1mm/year earlier last century to nearly 2mm/year from 1961”. &amp;nbsp;The Ministry also note satellite estimates of mean sea level rise of 4.4mm/year around New Zealand in the period 1993 to 2015.&lt;/p&gt;&lt;p&gt;NASA have assessed the rate of sea level rise on a global scale based on 25 years of American and European satellite data. They note the rate of sea level rise has increased from about 2.5mm/year in the 1990s to about 3.4mm/year today.&lt;/p&gt;&lt;div class=&quot;clearfix&quot;&gt;&lt;/div&gt;&lt;/div&gt;
    &lt;/div&gt;
    
        &lt;div class=&quot;accordion-section-item &quot;&gt;
        &lt;summary class=&quot;accordion-section-trigger&quot;&gt;
        &lt;span class=&quot;accordion-section-icon&quot; aria-hidden=&quot;true&quot;&gt;&lt;i class=&quot;fa-sharp fa-light fa-plus&quot; aria-hidden=&quot;true&quot;&gt;&lt;/i&gt;&lt;/span&gt;
        &lt;h2 class=&quot;accordion-section-title&quot;&gt;Using the high tide statistics&lt;/h2&gt;
        
        
        &lt;/summary&gt;
        &lt;div class=&quot;accordion-section-content&quot;&gt;&lt;p&gt;Record high tides in 2017 and 2018 in Christchurch (as also seen around the country) have prompted the 2018 review and update of tidal statistics for Christchurch coastal areas. The change in the statistics is partly a result of the longer period of data that is now available and partly due to climate change and sea level rise over the period of record.&lt;/p&gt;&lt;h3&gt;Using the statistics&lt;/h3&gt;&lt;p&gt;The 2018 High Tide Statistics give us better information about flood risk in coastal areas, to help us make informed planning and infrastructure decisions.&lt;/p&gt;&lt;p&gt;The Council uses high tide statistics as an input into flood modelling to determine minimum &lt;a title=&quot;Floor levels&quot; href=&quot;http://southerncentre.com/services/water-and-drainage/stormwater-and-drainage/flooding&quot;&gt;floor levels &lt;/a&gt;for building, design levels for infrastructure in tidally affected areas, flood management areas in the &lt;a title=&quot;Christchurch District Plan&quot; href=&quot;https://districtplan.ccc.govt.nz/pages/plan/book.aspx?exhibit=DistrictPlan&quot;&gt;Christchurch District Plan &lt;/a&gt;and other technical work such as coastal hazards.&lt;/p&gt;&lt;p&gt;Most properties in these tidally influenced areas will already have a standard comment about potential flooding and the risk of coastal inundation. Some LIMs will be updated to say the property is now considered to be at risk in a 1/50 year flood.&lt;/p&gt;&lt;h3&gt;Review of the statistics&lt;/h3&gt;&lt;p&gt;The 2018 analysis of the high tides was undertaken by Dr Derek Goring of Mulgor Consulting Ltd and has been peer reviewed by Charles Pearson of NIWA.&lt;/p&gt;&lt;p&gt;Environment Canterbury and NIWA have further reviewed the updated analysis of the high tides for Christchurch. Technical staff at Environment Canterbury concur with the methodology employed, agree with the updated information and support it being used to inform future planning considerations. NIWA also concluded that the analysis and review process were robust. NIWA noted the increase in the number of significant coastal flooding events around New Zealand, in the last five to ten years, and that they were updating the extreme sea levels (the high tides) for other districts.&lt;/p&gt;&lt;div class=&quot;clearfix&quot;&gt;&lt;/div&gt;&lt;/div&gt;
    &lt;/div&gt;
    
        &lt;div class=&quot;accordion-section-item &quot;&gt;
        &lt;summary class=&quot;accordion-section-trigger&quot;&gt;
        &lt;span class=&quot;accordion-section-icon&quot; aria-hidden=&quot;true&quot;&gt;&lt;i class=&quot;fa-sharp fa-light fa-plus&quot; aria-hidden=&quot;true&quot;&gt;&lt;/i&gt;&lt;/span&gt;
        &lt;h2 class=&quot;accordion-section-title&quot;&gt;Floor levels&lt;/h2&gt;
        
        
        &lt;/summary&gt;
        &lt;div class=&quot;accordion-section-content&quot;&gt;&lt;p&gt;The updated tide levels will be incorporated in the Avon, Heathcote and Styx River models to provide updated floor levels to protect new homes from flooding in tidally influenced areas.&lt;/p&gt;&lt;p&gt;The revised floor level information will be used for all new building consent applications in these areas. It will also be used in providing advice on resource consent applications in Flood Management Areas and High Flood Hazard Management Areas affected by tides.&lt;/p&gt;&lt;h2&gt;The impact on floor levels&lt;/h2&gt;&lt;p&gt;The impact on floor levels varies depending on the location within the city. For example, a floor level for a building consent near Bridge Street would be expected to rise around 150mm, and one near Brooklands Lagoon about 240mm when the new tidal data is taken into account.&amp;nbsp; The Council floor level viewer website will be updated using the new high tide statistics.&lt;/p&gt;&lt;p&gt;The table below shows planning level increases:&lt;/p&gt;&lt;table class=&quot;table-top-left&quot;&gt;
&lt;tbody&gt;
&lt;tr&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td&gt;&lt;span&gt;&lt;span&gt;High flood hazard management areas (1/500yr)&lt;/span&gt;&lt;br&gt;&lt;/span&gt;&lt;/td&gt;
&lt;td&gt;&lt;span&gt;Flood management areas (1/200yr)&lt;/span&gt;&lt;/td&gt;
&lt;td&gt;Building Act hazard notice (1/100yr)&lt;/td&gt;
&lt;td&gt;Building Act floor level (1/50yr)&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
&lt;td&gt;Ferrymead&lt;/td&gt;
&lt;td&gt;390mm&lt;/td&gt;
&lt;td&gt;290mm&lt;/td&gt;
&lt;td&gt;260mm&lt;/td&gt;
&lt;td&gt;230mm&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
&lt;td&gt;Bridge Street&lt;/td&gt;
&lt;td&gt;360mm&lt;/td&gt;
&lt;td&gt;260mm&lt;/td&gt;
&lt;td&gt;200mm&lt;/td&gt;
&lt;td&gt;150mm&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
&lt;td&gt;Brooklands&lt;/td&gt;
&lt;td&gt;460mm&lt;/td&gt;
&lt;td&gt;330mm&lt;/td&gt;
&lt;td&gt;280mm&lt;/td&gt;
&lt;td&gt;240mm&lt;/td&gt;
&lt;/tr&gt;
&lt;/tbody&gt;
&lt;/table&gt;&lt;div class=&quot;clearfix&quot;&gt;&lt;/div&gt;&lt;/div&gt;
    &lt;/div&gt;
    
        &lt;div class=&quot;accordion-section-item &quot;&gt;
        &lt;summary class=&quot;accordion-section-trigger&quot;&gt;
        &lt;span class=&quot;accordion-section-icon&quot; aria-hidden=&quot;true&quot;&gt;&lt;i class=&quot;fa-sharp fa-light fa-plus&quot; aria-hidden=&quot;true&quot;&gt;&lt;/i&gt;&lt;/span&gt;
        &lt;h2 class=&quot;accordion-section-title&quot;&gt;Proposed District Plan changes&lt;/h2&gt;
        
        
        &lt;/summary&gt;
        &lt;div class=&quot;accordion-section-content&quot;&gt;&lt;p&gt;The Council recently approved asking the Minister to make proposed changes to the District Plan through the Section 71 process in relation to the Residential Unit Overlay. This includes changes to a policy and rule in the District Plan to clarify assessment of resource consent applications, and broadening the scope of an existing permitted activity rule for fairness and equity purposes. The Residential Unit Overlay applies to parts of Southshore, South New Brighton, New Brighton and Redcliffs. These areas will be affected by the updated high tide statistics.&lt;/p&gt;&lt;p&gt;The updated tide information does not change the appropriateness of the provisions sought in the section 71 process. The new information will be relevant to floor level heights for permitted activities, and the assessment of resource consent applications, for all relevant provisions in the District Plan including for the new ones in the section 71 process.&lt;/p&gt;&lt;p&gt;If the section 71 proposal is accepted, the new tide data will inform the assessment of individual resource consent applications, as it would without the District Plan changes.&amp;nbsp;&lt;/p&gt;&lt;h2&gt;Updating the District Plan&lt;/h2&gt;&lt;p&gt;When the Council is able to update its &lt;a title=&quot;District Plan&quot; href=&quot;https://districtplan.ccc.govt.nz/pages/plan/book.aspx?exhibit=DistrictPlan&quot;&gt;District Plan&lt;/a&gt;, Flood Management Areas, Fixed Minimum Floor Level Overlay and High Flood Hazard Management Areas will be updated to reflect the new tidal information.&lt;/p&gt;&lt;div class=&quot;clearfix&quot;&gt;&lt;/div&gt;&lt;/div&gt;
    &lt;/div&gt;
    
    &lt;div class=&quot;accordion-section-line&quot;&gt;&lt;/div&gt;
    &lt;div class=&quot;clearfix&quot;&gt;&lt;/div&gt;
&lt;/div&gt;&lt;/p&gt;&lt;/div&gt;
					
				</description>
				<pubDate>Fri, 07 Dec 2018 10:52:40 +1300</pubDate>
				<guid>http://southerncentre.com/environment/water/coastal/2018-tidal-data</guid>
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