GETTING CLIMATE CHANGE INTO TRANSPORT CBAS Mberande River Crossing Case Study Craig Lawrence Advisor - Infrastructure Economics CPIU – MID 17 February 2014

Introduction Challenge consider global climate change models develop an economic appraisal using these draw conclusions about costs of climate change for a highly localised infrastructure environment Opportunity learn from a specific case study identify elements that can be included in practical climate change adaptation guidelines look for ways this can be operationalised by engineers

Some obvious questions Where is the Mberande catchment? What is the crossing like? Who uses the crossing? How can weather events be categorised? How was climate change incorporated? What were the outcomes of the analysis?

So where is Mberande crossing? In one of three catchments east of Honiara on the Guadalcanal Floodplain River runs from Kavo range to northern coast of Guadalcanal Flood events mainly from heavy rainfall on Kavo range Shaped the analysis

Catchment characteristics Challenging to model floods and riverine debris Heavily wooded regions upstream Significant rainfall occurs there Upstream source for most flood events at Mberande Steep topography generates significant velocities Flood conditions to bring large debris loads down

What is the crossing like? Continuous flow Variable watercourse High levels of rainfall Extreme flood events Heavy debris loads Low level bridge and earth approaches Viable alternative vehicle crossings not apparent

So who uses the crossing? Info on facilities/ services from Safeguards team Access to high schools Health clinics/services Palm oil operations Local markets General freight

We mapped transport need …

… for an avoided cost approach Impacts incremental to baseline – days access Engineering info around three archetype events 1-in-2, 1-in-10 and 1-in-20 year flood impacts Different service level availability/subsequent costs 1-in-20: assumes asset loss 1-in-10: significant flood events 1-in-2: lower impact, high frequency flooding Nuisance flooding (intraday impacts) ignored

Baseline had no climate change Event Flood event1-in-21-in-101-in-20 Repair cost/event$200,000$1.0 M- Replacement cost--$7.5 M Days to repair/ replace2 days7 days28 days Frequency over 25 years7 times1 time0 times Total days over 25 years14 days7 days0 days Cost over 25 years$1.4 M$1.0 M- Debris loadMinimalModerateSignificant

Challenges defining scenarios … Data limitations Downscaled Solomons climate model not available So detailed flood impact analysis not available Scenario modelling approach adopted Vary frequency of archetype flood events to match a series of climate change scenarios Climate modelling to 2030 and 2050 considered. Certain/likely scenarios derived from this

… meant it did get messy …

… but we resolved this … Cautious, conservative approach Scenarios for analysis period – baseline, historic weather patterns 1 – low impact (2030 certain scenario) 2 – medium-certain impact (2030 likely scenario) 3 – medium-likely impact, (2050 certain scenario) 4 – extreme impact (2050 likely scenario)

… with a scaled set of impacts …

… to create flood profiles … Frequencies allocated over 25 years No multiple event years Events backloaded in analysis period Dominant impact is asset loss 1-in-2 events become more significant

... that fed an economic model Excel used to apply climate change Costs of climate change estimated in individual worksheets for elements Net present cost calcs Flexible approach Scalable for impacts Could be used for other transport projects

Values estimates … Values calculated on the basis of costs incurred from transport service level interruption Cost of education services provided but not used – supported by a technical note Cost of health services provided but not used – supported by a technical note Value of palm oil affected by transport interruption Value of cash crops affected by lack of market access Value of general freight affected by lack of transport access

… had some limitations … Some climate change and flood data not available Economic development opportunities not considered National level estimates prepared – local estimates might produce different values Transport system/network effects not considered Changes in transport service prices not modelled Specific infrastructure solutions were not considered

... on our findings Benefits range from $0.9M  $16.4M, depending on scenario (CCI-0  CCI-4) and discount rate (12%  4%) Central result $4.9M is significant (CCI-3, 8% disc.) Engineering costs ~90% of total Important qualifications to achieving benefits Engineering design mitigates losses, cost less than loss Other asset degradation/loss does not affect Mberande

So what does this mean... Local impacts of climate change can be significant Baseline estimates are important to establish an appropriate level of climate change adaptation Not responding to these impacts increases costs of providing transport infrastructure Wider consequences from reduced access over time

... and what could we do? Increase resilience of transport infrastructure Demonstrate use of all current and available information Move from global science to applied practical responses Incorporate into engineering design Show significant risks identified and addressed Show value for money from increment adaptation spend Mitigate community impacts by improving transport access Avoid asset rebuilds that deprive infrastructure elsewhere Further discuss implementation in MID and wider Climate risk assessments, national transport priority, funding opportunities, stage of engineering work, disaster response

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